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The silicon anode is one of the primary contenders for lithium‐ion batteries of higher energy density owing to its outstanding theoretical capacity. However, the native SiO₂ layer (2–5 nm) on commercial silicon nanoparticles severely limits ion transport and induces polarization, especially under high current densities. This study systematically examines the influence of SiO₂ layer thickness on silicon anode performance, identifying significant polarization as the main barrier to stable cycling. To tackle this, a strategic electrolyte additive is suggested, bis(trimethylsilyl)trifluoroacetamide (BTA), which mitigates these effects by scavenging inactive SiO₂ and promoting the formation of conductive LixSiOy intermediates. Experimental and computational results show that BTA dramatically reduces electrochemical polarization and enhances Li⁺ transport, leading to superior cyclic stability. The Si anode with BTA‐modified electrolyte maintains 1436.5 mAh g−1 after 120 cycles at 500 mA g−1—substantially outperforming the base electrolyte (894.5 mAh g−1). This work highlights a critical strategy for overcoming kinetic barriers and advancing silicon anodes toward practical, high‐density energy applications. [ABSTRACT FROM AUTHOR]

For producing high‐capacity silicon (Si) anodes, a combined gas‐phase deposition and etching technique is developed to construct yolk‐shell structured silicon‐carbon composites. As a novel etching agent in battery field, NF3 is applied to selectively etch Si to tailor the architecture. Si particles as self‐sacrificed precursor have no need to build artificial or complex templates in advance, thereby greatly simplifying fabrication process and showcasing practicality. As a result, yolk‐shell structured silicon‐carbon composites are successfully fabricated in a single step. Sufficient buffer space between Si and carbon layer accommodates the significant expansion of Si during lithiation, preventing fracture of the carbon layer, which greatly improves service life of Si‐based anodes. Moreover, the refined particle size of Si and abundant pores in inner Si cores enhance the lithiation and de‐lithiation kinetic. Even with a high Si loading of 3.9 mg cm−2, the produced anode exhibits a superior areal capacity of 16.3 mAh cm−2 at 0.2 mA cm−2. Furthermore, at a high current density of 4 A g−1, it demonstrates an excellent capacity of 1114 mAh g−1 after 1000 cycles with a capacity retention of 96.3%. Additionally, with pre‐lithiation, it is successfully paired with an iron trifluoride cathode to construct high‐energy lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

The properties of lithium‐ion battery (LIB) anodes fabricated from nanoscale silicon Si and polyaniline (PANI) as a binder are reported. PANI is prepared by in situ polymerization of aniline in the presence of phytic acid, which serves both as dopant and as a gel‐forming agent. PANI pellets obtained by dry compression are used to investigate the morphology and to measure the resistivity of PANI and Si/PANI composites. The anodes are fabricated using the slurry technique. Their properties as a function of precursor ratio are studied in the half‐cell cells by charge–discharge characteristics, cyclic voltammetry, electrochemical impedance spectroscopy and cyclic lifetime. It is shown that stable cycling (>350 cycles at a current of 300 mA g−1) is inherent only to thin Si/PANI layers with composite loading <0.7 mg cm−2. The discharge capacity in this case is as high as 500–800 mAh g−1. [ABSTRACT FROM AUTHOR]

Silicon anodes, which exhibit high theoretical capacity and very low operating potential, are promising as anode candidates that can satisfy the conditions currently required for secondary batteries. However, the low conductivity of silicon and the alloying/dealloying phenomena that occur during charging and discharging cause sizeable volume expansion with side reactions; moreover, various electrochemical issues result in inferior cycling performance. Therefore, many strategies have been proposed to mitigate these problems, with the most commonly used method being the use of nanosized silicon. However, this approach leads to another electrochemical limitation—that is, an increase in side reactions due to the large surface area. These problems can effectively be resolved using coating strategies. Therefore, to address the issues faced by silicon anodes in lithium-ion batteries, this review comprehensively discusses various coating materials and the related synthesis methods. In this review, the electrochemical properties of silicon-based anodes are outlined according to the application of various coating materials such as carbon, inorganic (including metal-, metal oxide-, and nitride-based) materials, and polymer. Additionally, double shells introduced using two materials for double coatings exhibit more complementary electrochemical properties than those of their single-layer counterparts. The strategy involving the application of a coating is expected to have a positive effect on the commercialization of silicon-based anodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A fluorine-rich inorganic–organic hybrid coating (AlFHQ) is deposited onto Si anodes by MLD. • The interactions the between Li+ and organic groups help construct a mechanically-chemically robust LiF-rich hybrid SEI. • High-efficiency Li+ diffusion dynamics in the SEI is confirmed. • The optimized electrode enables commercial level areal capacity and stable cycling performance. Silicon anodes deliver batteries with energy densities much higher than those based on today's dominant graphite anodes. However, they commonly exhibit huge volume variations and unfavorable interface stability, causing a gradually diminishing capacity on extended cycling. Most Si-based batteries consisting Si/C composites in industry can only use a very limited amount of Si (<30 % by weight). Exploiting molecular layer deposition (MLD) technique, a fluorine-rich flexible inorganic–organic hybrid alucone (AlFHQ) shell is controllably deposited onto Si electrodes. Employing ex situ XPS and AFM, the AlFHQ film presents reversible electrochemical evolutions in terms of composition and morphology. The interactions the between Li+ and −O−2,3,5,6-fluorobenzene functional groups help to construct a mechanically-chemically robust LiF-rich hybrid solid electrolyte interphase (SEI) on Si anode, delivering enhanced interfacial stability and integrity of electrode. An optimized coating thickness (≈5 nm) for interfacial stabilization and Li+ transport kinetics is demonstrated, namely, Si@AlFHQ-20. The reported fluorine-rich hybrid modification technique endows (a), stable cycling of Si anode (≈3.8 mAh cm−2) with an ultrahigh initial Coulombic efficiency (ICE) of 92.3 %; (b), enhanced rate capability of 1468 mAh/g at 2.0 A g−1 and good cycling performance; and (c), overall cell (Si@AlFHQ-20//LiCoO 2 @Al 2 O 3) operational stability for more than 100 cycles under stringent cathode conditions (2.68 mAh cm−2, high cutoff voltage at 4.55 V). [ABSTRACT FROM AUTHOR]

Abstract Along with the constantly evolving functional microsystems toward more diversification, the more rigorous design deliberation of pursuing higher mass‐loading of electrode materials and low‐temperature fabrication compatibility have imposed unprecedented demand on integrable all‐solid‐state thin‐film microbatteries. While the classic thin‐film intercalation cathode prepared by vacuum‐based techniques inevitably encountered a post‐annealing process, tape‐casting technologies hold great merits both in terms of high‐mass loading and low‐temperature processing. In this work, a novel microbattery configuration is developed by the combination of traditional tape‐casting thick electrodes and sputtered inorganic thin‐film solid electrolytes (~3 μm lithium phosphorus oxynitride). Enabled by physically pressed or vapor‐deposited Li as an anode, solid‐state batteries with tape‐casted LiFePO4 electrodes exhibit outstanding cyclability and stability. To meet integration requirements, LiFePO4/LiPON/Si microbatteries were successfully fabricated at low temperatures and found to achieve a wide operating temperature range. This novel configuration has good prospects in promoting the thin‐film microbattery enabling a paradigm shift and satisfying diversified requirements.

Wearable electronics are surging for various applications ranging from critical functions like personal health monitoring to communication and entertainment. To power these electronic devices, advanced high‐performing textile‐based batteries are reckoned. In this work, a 1D textile yarn battery is designed using silicon (Si) nanoparticles wrapped in molybdenum disulfide (MoS2) as an anode and layered Ni‐rich material Li[Ni0.8Co0.1Mn0.1]O2 (NCM) as a cathode. The anode materials design is selected to ensure the use of Si due to its high specific capacity but suppressing its known issue of volume expansion by layered MoS2 nanosheets and, at the same time, MoS2 providing channels for lithium‐ion (Li‐ion) transport during electrochemical cycles. The NCM cathode, on the other hand, is adopted as it has higher energy density and improved cycle life. The full yarn battery (FYB) delivered an excellent electrochemical performance (areal capacity of 3.13 mAh cm−2, power density of 421 mW cm−3, and energy density of 78.9 mWh cm−3) with a capacity retention of 86% at 0.1 C and coulombic efficiency of 91.3%. This work pointed out a new way to design and fabricate textile‐based batteries with high‐performance materials using simple, cost‐effective, and scalable approaches targeting to be used as energy sources for future wearable electronics. [ABSTRACT FROM AUTHOR]

Silicon (Si) anodes hold great promise for enhancing the energy density of lithium‐ion batteries (LIBs). However, issues such as slow intrinsic kinetics and unstable interfaces caused by significant volume changes hinder the practical deployment of Si anodes. Fast charging is desired by Si‐related issues that worsen Li plating and dead Li, making it essential to overcome these for safe, reversible charging. Herein, a novel approach is proposed by combining structural design and solid electrolyte interface (SEI) modulation to enable efficient and safe fast charging of LIBs. 3D porous micro‐particles consisting of Si nanosheets coated with a pitch‐based carbon layer are successfully prepared. This design provides enhanced ion transport pathways while maintaining the material's intrinsic rate performance and tap density. Furthermore, the designed localized high‐concentration electrolyte (LHCE) exhibits a lower Li+ desolvation energy barrier and leads to the formation of a LiF‐rich SEI, mitigating the Li plating "tip effect" during fast charging, maintaining interface stability, and demonstrating high Coulombic efficiency. Overall, this study highlights the synergistic importance of structure design and SEI regulation in enhancing LIB anodes for fast charging, aiding in developing superior, safe energy storage. [ABSTRACT FROM AUTHOR]

In this paper, we design a binder GG-CA-GLY (abbreviation: GGC) for silicon negative electrode by guar gum as the backbone chain with self-healing function, combing and straightening the guar molecular chain of guar gum through the plasticizing effect of glycerol. The condensation reactions between the exposed hydroxyl sites of guar gum and the carboxyl groups of citric acid create a stronger hydrogen bond, so as to achieve the effect of self-healing and cope with the serious volume expansion effect of silicone-based materials. [Display omitted] • A easy polycondensation reaction is used to create a mechanically strong self-healing polymer (GGC). • GGC adhesives have excellent mechanical properties and facilitate rapid self-healing. • GGC@Si electrodes were prepared with excellent rate capability and higher cycling stability. • GGC adhesives have the ability to repair cracks and other damage on prepared silicon anodes, returning them to their original state. Silicon is a promising anode material for lithium-ion batteries with its superior capacity. However, the volume change of the silicon anode seriously affects the electrode integrity and cycle stability. The waterborne guar gum (GG) binder has been regarded as one of the most promising binders for Si anodes. Here, a unique steric molecular combing approach based on guar gum, glycerol, and citric acid is proposed to develop a self-healing binder GGC, which would boost the structural stability of electrode materials. The GGC binder is mainly designed to weaken van der Waals' forces between polymers through the plasticizing effect of glycerol, combing and straightening the guar molecular chain of GG, and exposing the guar hydroxyl sites of GG and the carboxyl groups of citric acid. The condensation reaction between the hydroxyl sites of GG and the carboxyl groups of citric acid forms stronger hydrogen bonds, which can help achieve self-healing effect to cope with the severe volume expansion effect of silicone-based materials. Silicon electrode lithium-ion batteries prepared with GGC binders exhibit outstanding electrochemical performance, with a discharge capacity of up to 1579 mAh/g for 1200 cycles at 1 A/g, providing a high capacity retention rate of 96%. This paper demostrates the great potential of GGC binders in realizing electrochemical performance enhancement of silicon anode. [ABSTRACT FROM AUTHOR]

An in-situ integrated electrode/self-healable polymer electrolyte for ultra-long cycling life in all-solid-state Si-based lithium batteries, driven by the incorporation of multiple dynamic bonds. [Display omitted] • Integration of Si anode/self-healing polymer electrolyte by in situ polymerization. • The Li+ environment was studied by experimental and theoretical calculation. • The electrolyte has high ionic conductivity and wide electrochemical window. • The Si-SHDSE|SHDSE|LCO-SHDSE pouch cells prototype with ultra-long cycling life. For all-solid-state lithium-ion batteries (ASSLIBs), silicon (Si) stands out as an appealing anodes material due to its high energy density and improved safety compared to lithium metal. However, the substantial volume changes during cycling result in poor solid-state physical contact and electrolyte–electrode interface issues, leading to unsatisfactory electrochemical performance. In this study, we employed in-situ polymerization to construct an integrated Si anodes/self-healing polymer electrolyte for ASSLIBs. The polymer chain reorganization stems from numerous dynamic bonds in the constructed self-healing dynamic supermolecular elastomer electrolyte (SHDSE) molecular structure. Notably, SHDSE also serves as a Si anodes binder with enhanced adhesive capability. As a result, the well-structured Li|SHDSE|Si-SHDSE cell generates subtle electrolyte–electrode interface contacts at the molecular level, which can offer a continuous and stable Li+ transport pathway, reduce Si particle displacement, and mitigate electrode volume expansion. This further enhances cyclic stability (>500 cycles with 68.1 % capacity retention and >99.8 % Coulombic efficiency). More practically, the 2.0 Ah wave-shaped Si||LiCoO 2 soft-pack battery with in-situ cured SHDSE exhibits strongly stabilized electrochemical performance (1.68 Ah after 700 cycles, 86.2 % capacity retention) in spite of a high operating temperatures up to 100 °C and in various bending tests. This represents a groundbreaking report in flexible solid-state soft-pack batteries containing Si anodes. [ABSTRACT FROM AUTHOR]

The use of a sacrificial cathode additive that contains a large amount of lithium is one potential solution to compensate for the irreversible capacity loss associated with next-generation anodes such as silicon. Antifluorite-type Li6CoO4 has attracted attention as a potential cathode additive owing to its remarkably high theoretical lithium extraction capacity. However, the complex mechanism of lithium extraction as well as the oxygen loss from Li6CoO4 is not well understood. A generalizable computational thermodynamics and experimental framework is presented to understand the lithium-extraction pathway of Li6CoO4. It is found that one lithium per formula unit can be topotactically extracted from Li6CoO4, followed by an irreversible and nontopotactic phase transformation to Li2CoO3 or LiCoO2 depending on the temperature. The results show that peroxide species may form to charge-compensate for Li extraction which is undesirable as this can lead to gas release during battery operation. It is suggested that charging Li6CoO4 at an elevated temperature that the electrolyte can withstand, redirects the reaction pathway and prevents the formation of intermediate peroxide species making it an effective and stable sacrificial cathode additive.

Silicon anodes, which exhibit high theoretical capacity and very low operating potential, are promising as anode candidates that can satisfy the conditions currently required for secondary batteries. However, the low conductivity of silicon and the alloying/dealloying phenomena that occur during charging and discharging cause sizeable volume expansion with side reactions; moreover, various electrochemical issues result in inferior cycling performance. Therefore, many strategies have been proposed to mitigate these problems, with the most commonly used method being the use of nanosized silicon. However, this approach leads to another electrochemical limitation—that is, an increase in side reactions due to the large surface area. These problems can effectively be resolved using coating strategies. Therefore, to address the issues faced by silicon anodes in lithium-ion batteries, this review comprehensively discusses various coating materials and the related synthesis methods. In this review, the electrochemical properties of silicon-based anodes are outlined according to the application of various coating materials such as carbon, inorganic (including metal-, metal oxide-, and nitride-based) materials, and polymer. Additionally, double shells introduced using two materials for double coatings exhibit more complementary electrochemical properties than those of their single-layer counterparts. The strategy involving the application of a coating is expected to have a positive effect on the commercialization of silicon-based anodes.

Silicon anodes with a high capacity of 4200 mAh g−1 and a low potential of 0.3 V (vs Li+/Li) enable lithium‐ion batteries with improved energy density. However, the thickened 3D solid‐electrolyte interphase (SEI) formation on Si particles in the liquid electrolytes consumes the electrolyte/active Si and blocks the Li+/e− transport, resulting in fast capacity fading. Herein, a high‐concentration polymer electrolyte (HCPE) is designed to build 2D SEI on the Si anode surface instead of the particles, which accommodates the volume change and maintains the continuous Li+/e− transport pathways as well. The retarding effect of NO3− lowers the polymerization rate of 1,3‐dioxolane (DOL), enabling 6 m LiFSI dissolution. The high concentration of LiFSI takes part in constructing the solvation structure and pulls the DOL away, reducing the decomposition of DOL and poly‐DOL (PDOL) and inducing the generation of a LiF‐ and Li3N‐rich SEI with high mechanical strength and fast Li+ transport capability. As a result, the cell using HCPE delivers a high capacity of 1765 mAh g−1 at 2C and maintains a high capacity of 2000 mAh g−1 after 100 cycles at 0.2C, which is superior to that of a liquid electrolyte (617 mAh g−1) and a low‐concentration polymer electrolyte (45 mAh g−1). [ABSTRACT FROM AUTHOR]

Silicon is a promising material for anodes in future generations of LIBs. However, its volume changes during the lithiation/delithiation process that degrades battery performance, making it an impractical alternative. To mitigate this issue, we have found a viable alternate solution, which is the preparation of adamantane-polyacrylic acid (AdEN-AA) and β-cyclodextrin-polyacrylic acid (βCD6A-AA) polymers as supramolecular binders. The advantage of these binders is that polymers leverage host-guest interactions. To carry out this research, we prepared the anode materials in water and in NMP, and then we studied their capacity to crosslink and gel. Additionally, we examined the extent of the supramolecular interaction vs. hydrogen bond. Thermogravimetric analysis showed that the thermal stability of the mixture of complementary polymer increased in the following order: AdEN-AA/βCD6A-AA in NMP

Highlights The Sn and Sb incorporation boosts the electronic conductivity and lithium diffusivity of Si anodes, thereby reducing the stress due to lithium concentration gradient. The lithiation of modified electrode mimics isotropic solid solution reaction, rather than the original anisotropic two-phase reaction of Si, effectively weakening the stress concentration. The silicon-rich particles exhibit a capacity of over 1.9 Ah g−1 after 100 cycles at 0.1 A g−1 and maintain the excellent cyclic stability at 3 A g−1.

Silicon is widely recognized as the most promising upgrade for graphite anodes due to its much higher capacity, natural abundance, and ability to be directly applied in the slurry-based, roll-to-roll production lines. However, in addition to the fast capacity decay, silicon anodes also suffer from inferior calendar life in practical applications due to the unstable solid-electrode interface (SEI). Until now, strategies to effectively improve the calendar life by tailored SEIs remain largely unclear, especially in high-Si content, zero-graphite anodes. Here, silicon anodes with superior calendar life are developed by adding small concentrations of multivalent salts into the baseline electrolyte. The Ca additive reacts with the F ions in the electrolyte, forming a layer of nanocrystalline CaF2 that is closely coated around the silicon particles. The CaF2-enabled new SEI is strong and dense, which effectively protects the silicon core from side reactions, leading to lower capacity decay after calendar aging at high voltage. More importantly, the Ca additive is effective universally for all available commercial silicon or SiO sources. This study provides a feasible and low-cost solution for developing silicon anodes with long calendar life, paving the way towards commercially viable silicon anodes.

Silicon-based, high-energy-density electrodes show severe microstructural degradation due to continuous expansion and contraction upon charging and discharging. This mechanical degradation behaviour affects the cell's lifetime by changing the microstructure morphology, altering transport parameters, and active volume losses. Since direct experimental observations of mechanical degradation are challenging, we develop a computer simulation approach that is based on real three-dimensional electrode microstructures. By assuming quasi-static cycling and taking into account the mechanical properties of the electrode's constituents we calculate the heterogeneous deformation and resulting morphological changes. Additionally, we implement an ageing model that allows us to compute a heterogeneously evolving damage field over multiple cycles. From the damage field, we infer the remaining electrode capacity. Using this technique, an anode blend of graphite particles and silicon carbon composite particles (SiC-C) as well as a cathode consisting of Lithium-Nickel-Manganese-Cobalt Oxide with molar ratio of 8:1:1 (NMC811) are studied. In a two-level homogenization approach, we compute, firstly, the effective mechanical properties of silicon composite particles and, secondly, the whole electrode microstructure. By introducing the damage strain ratio, the degradation evolution of the graphite SiC-C anode blend is studied for up to 95 charge-discharge cycles. With this work, we demonstrate an approach to how mechanical damage of battery electrodes can be treated efficiently. This is the basis for a full coupling to electrochemical simulations. [ABSTRACT FROM AUTHOR]

The silicon anode is promising for high‐energy density lithium‐ion batteries owing to its ultrahigh theoretical capacity. However, the practical deployment of Si anodes is significantly hindered by its large volume change and unstable electrode/electrolyte interphase associated with routine electrolytes. Herein, a cyclic ether‐based electrolyte is designed and shows high compatibility with Si anodes. By simply decreasing the prevalence of ethereal oxygen groups and increasing the degree of molecule unsaturation of 1,2‐dimethoxyethane simultaneously, the resulting cyclic tetrahydrofuran (THF) presents a weak solvation capability and strong polymerization. Experimental and computational evidence demonstrates this rational design leads to a remarkable improvement in electrochemical performance of Si anodes. By forming a thin, elastic, and LiF‐rich inorganic‐polymeric solid‐electrolyte interphase film, the Si electrode cycled in THF‐based electrolyte exhibits long‐term cycling stability with a high reversible capacity of 1995.7 mAh g−1 after 400 cycles. The full‐cells with Si/graphite anodes and LiFePO4 cathodes maintain over 80% capacity retention after 600 cycles. [ABSTRACT FROM AUTHOR]

A central challenge in practically using high‐capacity silicon (Si) as anode materials for lithium‐ion batteries is alleviating significant volume change of Si during cycling. One key to resolving the failure issues of Si is exploiting carefully designed polymer binders exhibiting mechanical robustness to retain the structural integrity of Si electrodes, while concurrently displaying elasticity and toughness to effectively dissipate external stresses exerted by the volume changes of Si. Herein, a highly elastic and tough polymer binder is proposed by interweaving polyacrylic acid (PAA) with poly(urea‐urethane) (PUU) elastomer for Si anodes. By systematically tuning molecular parameters, including molecular weights of hard/soft segments and structures of hard segment components, it is demonstrated that the mechanical properties of polymer binders, such as elasticity, toughness, and stress relaxation ability, strongly affect the cycling performance of Si electrodes. This study provides new insight into the rational design of polymer binders capable of accommodating the volume changes of Si, primarily by judicious modulation of the mechanical properties of polymer binders. [ABSTRACT FROM AUTHOR]

Silicon (Si) materials for use in Lithium ion batteries (LIBs) are of continued interest to battery manufacturers. With an increasing number of commercially available Si materials, evaluating their performance becomes a challenge. Here, we use an empirical fitting function presented earlier to aid in the analysis of galvanostatic charge‐discharge data of commercial Si half‐cells with relatively high loading. We find that the fitting procedure is capable of detecting dynamic changes in the cell, such as reversible capacity fade of the Si electrode. This fading is found to be due to the highly lithiated Li2Si↽⇀ ${ \mathbin{{\stackrel{\textstyle\rightharpoonup} { {\smash{\leftharpoondown}} } }} }$ Li3.5Si phase and that the behaviour is strongly dependent on the potential of this phase. EIS reveals that the Si electrode is responsible for the reversible behaviour due to progressive loss of Li+ leading to increasing resistance. SEM/EDX and XPS characterization are also employed to determine the origin of the irreversible resistance growth on the Si electrodes. [ABSTRACT FROM AUTHOR]

Silicon (Si) is anticipated to become one of the most promising anode materials for high‐energy‐density solid‐state battery (SSB) applications owing to its high theoretical specific capacity and low working potential. This work compares the electrochemical behavior of slurry‐cast electrodes in Si|Li6PS5Cl|In/InLi cells, with micron‐sized Si particles (≥99% active electrode material content) and polyacrylic acid (PAA) or polyvinylidene fluoride (PVDF) serving as active material and aqueous/nonaqueous model binder, respectively. The cycling stability of Si‐PVDF cells is found to decrease with increasing binder content (accelerated capacity fade), whereas the Si‐PAA cells show more or less the opposite trend. However, they exhibit a similar performance when using 0.5 wt% binder, with specific capacities of ≈850 mAh g−1 (for −0.51–0.11 V vs In/InLi) and high capacity retention depending on the cutoff potentials. This result suggests that PVDF can be substituted for by PAA in Si anodes for SSBs, thereby potentially decreasing cost and environmental impact. [ABSTRACT FROM AUTHOR]

Silicon has garnered significant attention as a promising anode material for high‐energy density Li‐ion batteries. However, Si can be easily pulverized during cycling, which results in the loss of electrical contact and ultimately shortens battery lifetime. Therefore, the Si anode binder is developed to dissipate the enormous mechanical stress of the Si anode with enhanced mechanical properties. However, the interfacial stability between the Si anode binder and Cu current collector should also be improved. Here, a multifunctional thiourea polymer network (TUPN) is proposed as the Si anode binder. The TUPN binder provides the structural integrity of the Si anode with excellent tensile strength and resilience due to the epoxy‐amine and silanol‐epoxy covalent cross‐linking, while exhibiting high extensibility from the random coil chains with the hydrogen bonds of thiourea, oligoether, and isocyanurate moieties. Furthermore, the robust TUPN binder enhances the interfacial stability between the Si anode and current collector by forming a physical interaction. Finally, the facilitated Li‐ion transport and improved electrolyte wettability are realized due to the polar oligoether, thiourea, and isocyanurate moieties, respectively. The concept of this work is to highlight providing directions for the design of polymer binders for next‐generation batteries. [ABSTRACT FROM AUTHOR]

Polymer binders are essential for Silicon (Si) anode‐based lithium‐ion batteries (LIBs). However, the synthetic guidance for aromatic polymer binder is relatively less explored compared to aliphatic polymer binders. In this study, polyimide‐based aromatic polymer binders are developed that have strong binding affinity with Si particles, a conductive agent and copper (Cu) current collector, and they show an improved initial discharge capacity of 2663 mAh g−1, which is 29% higher than that of Kapton‐based one (2071 mAh g−1). The copolymerization between "hard" and "soft" segments is crucial to achieve reversible volume expansion/contraction during the repeated charging/discharging process, resulting in the best cycle performance. The new binder ensures both excellent volume retention after full‐delithiation and allowed volume expansion at least to some extent upon full‐lithiation. This Study finds a power‐law relationship between the capacity of Si anode and the mechanical properties of the binder, i.e., the tensile stress (σ) and strain (ɛ). The initial discharge capacity is proportional to σn · ɛ (n = 2.3–2.7). Such an understanding of the relationships between polymer structure, mechanical properties of the polymer and binder performance clearly revealed the importance of the soft‐hard polymer structure for aromatic binders used in Si‐based high‐capacity lithium storage materials. [ABSTRACT FROM AUTHOR]

Highlights: The Sn and Sb incorporation boosts the electronic conductivity and lithium diffusivity of Si anodes, thereby reducing the stress due to lithium concentration gradient. The lithiation of modified electrode mimics isotropic solid solution reaction, rather than the original anisotropic two-phase reaction of Si, effectively weakening the stress concentration. The silicon-rich particles exhibit a capacity of over 1.9 Ah g−1 after 100 cycles at 0.1 A g−1 and maintain the excellent cyclic stability at 3 A g−1. Si is a promising anode material for Li ion batteries because of its high specific capacity, abundant reserve, and low cost. However, its rate performance and cycling stability are poor due to the severe particle pulverization during the lithiation/delithiation process. The high stress induced by the Li concentration gradient and anisotropic deformation is the main reason for the fracture of Si particles. Here we present a new stress mitigation strategy by uniformly distributing small amounts of Sn and Sb in Si micron-sized particles, which reduces the Li concentration gradient and realizes an isotropic lithiation/delithiation process. The Si8.5Sn0.5Sb microparticles (mean particle size: 8.22 μm) show over 6000-fold and tenfold improvements in electronic conductivity and Li diffusivity than Si particles, respectively. The discharge capacities of the Si8.5Sn0.5Sb microparticle anode after 100 cycles at 1.0 and 3.0 A g−1 are 1.62 and 1.19 Ah g−1, respectively, corresponding to a retention rate of 94.2% and 99.6%, respectively, relative to the capacity of the first cycle after activation. Multicomponent microparticle anodes containing Si, Sn, Sb, Ge and Ag prepared using the same method yields an ultra-low capacity decay rate of 0.02% per cycle for 1000 cycles at 1 A g−1, corroborating the proposed mechanism. The stress regulation mechanism enabled by the industry-compatible fabrication methods opens up enormous opportunities for low-cost and high-energy–density Li-ion batteries. [ABSTRACT FROM AUTHOR]

Although binders are a minor component in battery electrodes, they can improve the electrochemical performance considerably, particularly in conversion-type electrodes, such as the silicon (Si) anode, which has volume expansion problems. Although numerous binders are reported for Si anode, less attention has been paid to those prepared through controlled polymerization, which can allow the preparation of well-defined polymers. Herein, we report the facile synthesis of carboxylic acid-functionalized polynorbornene (CA-PNB) via ring-opening metathesis polymerization (ROMP) and apply this as the binder for Si anode. Owing to the ultrafast polymerization kinetics of ROMP, a high molecular weight polymer (∼279 kDa) with narrow dispersity (Đ=1.07) was readily prepared within 30 min. The resulting CA-PNB was used as the binder for a Si nanoparticle anode, which exhibits an initial coulombic efficiency of 81% and a specific capacity of 1,654 mAh g−1 after 100 cycles at 0.5 A g−1. These values outperform the Si anodes prepared using conventional polyvinylidene difluoride and carboxymethyl cellulose binders, probably due to the abundant carboxylic acid groups in the CA-PNB that offer stronger interactions with the Si surface. Since ROMP is a highly efficient polymerization tool to produce polymers with tailored architectures and controlled monomer sequences, this method will be valuable for the rational molecular design of high-performance binders for battery electrodes. [ABSTRACT FROM AUTHOR]

Silicon-based solid-state batteries (Si-SSBs) are now a leading trend in energy storage technology, offering greater energy density and enhanced safety than traditional lithium-ion batteries. This review addresses the complex challenges and recent progress in Si-SSBs, with a focus on Si anodes and battery manufacturing methods. It critically analyzes the lithiation process in Si anodes, emphasizing the significant volumetric expansion and evolving solid-electrolyte interphase (SEI), both of which are crucial for the electrochemical performance and durability of batteries. Innovations in anode design, such as morphological optimization and compositional alloying, have been explored to reduce mechanical stress and improve the electrochemical properties. Moreover, we elaborate in detail the essential steps in the layer-by-layer construction and encapsulation of Si-SSBs, which are vital for their stability and function. Finally, this review offers a thorough examination of present scientific and technological developments, providing insights and prospective pathways for researchers and industry professionals dedicated to advancing SSB technology.

Abstract A central challenge in practically using high‐capacity silicon (Si) as anode materials for lithium‐ion batteries is alleviating significant volume change of Si during cycling. One key to resolving the failure issues of Si is exploiting carefully designed polymer binders exhibiting mechanical robustness to retain the structural integrity of Si electrodes, while concurrently displaying elasticity and toughness to effectively dissipate external stresses exerted by the volume changes of Si. Herein, a highly elastic and tough polymer binder is proposed by interweaving polyacrylic acid (PAA) with poly(urea‐urethane) (PUU) elastomer for Si anodes. By systematically tuning molecular parameters, including molecular weights of hard/soft segments and structures of hard segment components, it is demonstrated that the mechanical properties of polymer binders, such as elasticity, toughness, and stress relaxation ability, strongly affect the cycling performance of Si electrodes. This study provides new insight into the rational design of polymer binders capable of accommodating the volume changes of Si, primarily by judicious modulation of the mechanical properties of polymer binders.

Abstract Silicon (Si) materials for use in Lithium ion batteries (LIBs) are of continued interest to battery manufacturers. With an increasing number of commercially available Si materials, evaluating their performance becomes a challenge. Here, we use an empirical fitting function presented earlier to aid in the analysis of galvanostatic charge‐discharge data of commercial Si half‐cells with relatively high loading. We find that the fitting procedure is capable of detecting dynamic changes in the cell, such as reversible capacity fade of the Si electrode. This fading is found to be due to the highly lithiated Li2Si ↽⇀ Li3.5Si phase and that the behaviour is strongly dependent on the potential of this phase. EIS reveals that the Si electrode is responsible for the reversible behaviour due to progressive loss of Li+ leading to increasing resistance. SEM/EDX and XPS characterization are also employed to determine the origin of the irreversible resistance growth on the Si electrodes.

Silicon (Si) is anticipated to become one of the most promising anode materials for high‐energy‐density solid‐state battery (SSB) applications owing to its high theoretical specific capacity and low working potential. This work compares the electrochemical behavior of slurry‐cast electrodes in Si|Li6PS5Cl|In/InLi cells, with micron‐sized Si particles (≥99% active electrode material content) and polyacrylic acid (PAA) or polyvinylidene fluoride (PVDF) serving as active material and aqueous/nonaqueous model binder, respectively. The cycling stability of Si‐PVDF cells is found to decrease with increasing binder content (accelerated capacity fade), whereas the Si‐PAA cells show more or less the opposite trend. However, they exhibit a similar performance when using 0.5 wt% binder, with specific capacities of ≈850 mAh g−1 (for −0.51–0.11 V vs In/InLi) and high capacity retention depending on the cutoff potentials. This result suggests that PVDF can be substituted for by PAA in Si anodes for SSBs, thereby potentially decreasing cost and environmental impact.

Abstract Silicon has garnered significant attention as a promising anode material for high‐energy density Li‐ion batteries. However, Si can be easily pulverized during cycling, which results in the loss of electrical contact and ultimately shortens battery lifetime. Therefore, the Si anode binder is developed to dissipate the enormous mechanical stress of the Si anode with enhanced mechanical properties. However, the interfacial stability between the Si anode binder and Cu current collector should also be improved. Here, a multifunctional thiourea polymer network (TUPN) is proposed as the Si anode binder. The TUPN binder provides the structural integrity of the Si anode with excellent tensile strength and resilience due to the epoxy‐amine and silanol‐epoxy covalent cross‐linking, while exhibiting high extensibility from the random coil chains with the hydrogen bonds of thiourea, oligoether, and isocyanurate moieties. Furthermore, the robust TUPN binder enhances the interfacial stability between the Si anode and current collector by forming a physical interaction. Finally, the facilitated Li‐ion transport and improved electrolyte wettability are realized due to the polar oligoether, thiourea, and isocyanurate moieties, respectively. The concept of this work is to highlight providing directions for the design of polymer binders for next‐generation batteries.

The demand for lithium‐ion batteries has significantly increased due to the increasing adoption of electric vehicles (EVs). However, these batteries have a limited lifespan, which needs to be improved for the long‐term use needs of EVs expected to be in service for 20 years or more. In addition, the capacity of lithium‐ion batteries is often insufficient for long‐range travel, posing challenges for EV drivers. One approach that has gained attention is using core–shell structured cathode and anode materials. That approach can provide several benefits, such as extending the battery lifespan and improving capacity performance. This paper reviews various challenges and solutions by the core–shell strategy adopted for both cathodes and anodes. The highlight is scalable synthesis techniques, including solid phase reactions like the mechanofusion process, ball‐milling, and spray‐drying process, which are essential for pilot plant production. Due to continuous operation with a high production rate, compatibility with inexpensive precursors, energy and cost savings, and an environmentally friendly approach that can be carried out at atmospheric pressure and ambient temperatures. Future developments in this field may focus on optimizing core–shell materials and synthesis techniques for improved Li‐ion battery performance and stability. [ABSTRACT FROM AUTHOR]

The use of a sacrificial cathode additive that contains a large amount of lithium is one potential solution to compensate for the irreversible capacity loss associated with next‐generation anodes such as silicon. Antifluorite‐type Li6CoO4 has attracted attention as a potential cathode additive owing to its remarkably high theoretical lithium extraction capacity. However, the complex mechanism of lithium extraction as well as the oxygen loss from Li6CoO4 is not well understood. A generalizable computational thermodynamics and experimental framework is presented to understand the lithium‐extraction pathway of Li6CoO4. It is found that one lithium per formula unit can be topotactically extracted from Li6CoO4, followed by an irreversible and nontopotactic phase transformation to Li2CoO3 or LiCoO2 depending on the temperature. The results show that peroxide species may form to charge‐compensate for Li extraction which is undesirable as this can lead to gas release during battery operation. It is suggested that charging Li6CoO4 at an elevated temperature that the electrolyte can withstand, redirects the reaction pathway and prevents the formation of intermediate peroxide species making it an effective and stable sacrificial cathode additive. [ABSTRACT FROM AUTHOR]

The use of a sacrificial cathode additive that contains a large amount of lithium is one potential solution to compensate for the irreversible capacity loss associated with next‐generation anodes such as silicon. Antifluorite‐type Li6CoO4 has attracted attention as a potential cathode additive owing to its remarkably high theoretical lithium extraction capacity. However, the complex mechanism of lithium extraction as well as the oxygen loss from Li6CoO4 is not well understood. A generalizable computational thermodynamics and experimental framework is presented to understand the lithium‐extraction pathway of Li6CoO4. It is found that one lithium per formula unit can be topotactically extracted from Li6CoO4, followed by an irreversible and nontopotactic phase transformation to Li2CoO3 or LiCoO2 depending on the temperature. The results show that peroxide species may form to charge‐compensate for Li extraction which is undesirable as this can lead to gas release during battery operation. It is suggested that charging Li6CoO4 at an elevated temperature that the electrolyte can withstand, redirects the reaction pathway and prevents the formation of intermediate peroxide species making it an effective and stable sacrificial cathode additive. [ABSTRACT FROM AUTHOR]

Silicon, as potential next‐generation anode material for high‐energy lithium‐ion batteries (LIBs), suffers from substantial volume changes during (dis)charging, resulting in continuous breakage and (re‐)formation of the solid electrolyte interphase (SEI), as well as from consumption of electrolyte and active lithium, which negatively impacts long‐term performance and prevents silicon‐rich anodes from practical application. In this work, fluorinated phosphazene compounds are investigated as electrolyte additives concerning their SEI‐forming ability for boosting the performance of silicon oxide (SiOx)‐based LIB cells. In detail, the electrochemical performance of NCM523 || SiOx/C pouch cells is studied, in combination with analyses regarding gas evolution properties, post‐mortem morphological changes of the anode electrode and the SEI, as well as possible electrolyte degradation. Introducing the dual‐additive approach in state‐of‐the‐art electrolytes leads to synergistic effects between fluoroethylene carbonate and hexafluorocyclotriphosphazene‐derivatives (HFPN), as well as enhanced electrochemical performance. The formation of a more effective SEI and increased electrolyte stabilization improves lifetime and results in an overall lower cell impedance. Furthermore, gas chromatography‐mass spectrometry measurements of the aged electrolyte with HFPN‐derivatives as an additive compound show suppressed ethylene carbonate and ethyl methyl carbonate decomposition, as well as reduced trans‐esterification and oligomerization products in the aged electrolyte. [ABSTRACT FROM AUTHOR]

Silicon‐based anodes are considered ideal candidate materials for next‐generation lithium‐ion batteries due to their high capacity. However, the low conductivity and large volume variations during cycling inevitably result in inferior cyclic stability. Herein, a dry method without binders is designed to fabricate Si‐based electrodes with single‐walled carbon nanotubes (SWCNTs) network and to explore the different mechanisms between SWCNT and multiwalled carbon nanotubes (MWCNTs) as a conductive network. As expected, higher initial discharge capacity (1785 mAh g−1), higher initial Coulombic efficiency (ICE, 81.52%) and outstanding cyclic stability are obtained from the SiOx@C|SWCNT anodes. Furthermore, its lithium‐ion diffusion coefficient (DLi+) is 3–4 orders of magnitude higher than that of SiOx@C|MWCNT. The underlying mechanism is clarified by in situ Raman spectroscopy and theoretical analysis. It is found that the SWCNTs can maintain good contact with SiOx@C even under tensile stresses up to 6.2 GPa, while the MWCNTs lose electrical contact due to alternating compressive stress up to 8.9 GPa and tensile stress up to 2.5 GPa during long‐term cycling. Under such very large stresses, the more flexible SWCNTs and their stronger van der Waals forces ensure that SiOx@C still has good contact with SWCNTs. [ABSTRACT FROM AUTHOR]

The development of high‐performance electrode materials is a long running theme in the field of energy storage. Silicon is undoubtedly among the most promising next‐generation anode material for lithium batteries. Of particular note, the use of nano‐Si, as the milestone advance, has opened the door of the commercialization of silicon, but is still hindered by issues related to cost, side reactions, and volumetric performance. Micro‐Si, competed unsuccessfully with nano‐Si long ago, but now has returned with its natural strengths in low cost, high tap density, and low interfacial reaction, and is regaining attention both from academia and industry. In this review, the promises of micro‐Si anodes are first clarified and then their pain points are presented followed by a summary of the potential remedies such as carbon encapsulation, binder design, and electrolyte modifications with improved mechanical and electrochemical stability. Finally, toward practical use of micro‐Si in future lithium batteries, major prospective directions are discussed. Carbon coatings with desired mechanical properties combined with a stable solid electrolyte are highlighted along with with their practical significance to exploit micro‐Si anodes. [ABSTRACT FROM AUTHOR]

The influence of the Cu current collector grade (cold‐rolled, annealed, or textured) and the ink solid fraction (SF) on the performance of Si‐based electrodes for Li‐ion batteries is investigated. Two binders are considered for this study: one of carboxymethyl cellulose and citric acid and the other which consists of the same organic components with added Zn(II) cations. These ones cross‐link the carboxylate moieties through coordination bonds. The fracture behavior and cyclability of the Zn‐free electrodes show a strong dependence on the Cu current collector grade. For this formulation, which has lower cohesion, the increase in electrode adhesion from the roughening of the surface of the current collector and/or the decrease of the current collector yield strength contribute to mitigate the electrode mechanical damage, therefore improving its cyclability. Such a dependence is not observed for the Zn cross‐linked electrodes which have a higher cohesion. Regarding the impact of the ink solid fraction, when a higher SF is used, the capacity retention and coulombic efficiency are enhanced for both formulations, though much more significantly for the Zn‐free formulation. The underlying mechanism causing this improvement may be partially related to the enhanced adsorption of binder on silicon particles with increasing SF. [ABSTRACT FROM AUTHOR]

Silicon is a promising alternative to the conventional graphite anode for lithium‐ion batteries (LIBs). However, pulverization of Si particles caused by volume expansion and formation of unstable solid electrolyte interphase can lead to several failure behaviors of LIBs. In contrast to LIBs employing liquid electrolytes, all‐solid‐state batteries (ASSBs) could exhibit totally different interfacial environments over Si anode materials, in terms of wetting properties of the Si surface by electrolyte. This characteristic interface of Si anode with solid‐state electrolyte (SSE) can change the electrochemical stability and long‐term life cycle performance of Si. In respect of commercialization, the incorporation of Si anode into ASSB could be the strongest approach to overcome the intrinsic limitations of anode materials. However, large contact losses between Si and SSE have to be handled in order to provide good electrochemical performance and stability. In this review, failure behaviors of Si anode within the SSE with proper characterization method is addressed and several design strategies for incorporation of Si anode into ASSB based on the following classifications are introduced: composite type and diffusion‐dependent type Si anodes. From this review, the possibility of Si anode for practical application to next‐generation ASSB by regulating its chemical and mechanical properties is suggested. [ABSTRACT FROM AUTHOR]

Silicon-containing polyester from tetramethoxysilane, ethylene glycol, and o-Phthalic anhydride were used as encapsulating materials for silicon nano powders (SiNP) via electrospinning, with Polyacrylonitrile (PAN) as spinning additives. In the correct quantities, SiNP could be well encapsulated in nano fibers (200–400 nm) using scanning electron microscopy (SEM). The encapsulating materials were then carbonized to a Si-O-C material at 755 °C (Si@C-SiNF-5 and Si@C-SiNF-10, with different SiNP content). Fiber structure and SiNP crystalline structure were reserved even after high-temperature treatment, as SEM and X-ray diffraction (XRD) verified. When used as lithium ion battery (LIB) anode materials, the cycling stability of SiNPs increased after encapsulation. The capacity of SiNPs decreased to ~10 mAh/g within 30 cycles, while those from Si@C-SiNF-5 and Si@C-SiNF-10 remained over 500 mAh/g at the 30th cycle. We also found that adequate SiNP content is necessary for good encapsulation and better cycling stability. In the anode from Si@C-SiNF-10 in which SiNPs were not well encapsulated, fibers were broken and pulverized as SEM confirmed; thus, its cycling stability is poorer than that from Si@C-SiNF-5. [ABSTRACT FROM AUTHOR]

The galvanostatic charge–discharge (GCD) behaviour of silicon (Si) is known to depend strongly on morphology, cycling conditions and electrochemical environment. One common method for analysing GCD curves is through differential capacity, but the data processing required necessarily degrades the results. Here we present a method of extracting empirical information from the delithiation step in GCD data for Si at C-rates above equilibrium conditions. We find that the function is able to quickly and accurately determine the best fit to historical half-cell data on amorphous Si nanowires and thin films, and analysis of the results reveals that the function is capable of distinguishing the capacity contributions from the Li 3.5 Si and Li 2 Si phases to the total capacity. The method can also pick up small differences in the phase behaviour of the different samples, making it a powerful technique for further analysis of Si data from the literature. The method was also used for predicting the size of the reservoir effect (the apparent amount of Li remaining in the electrode), making it a useful technique for quickly determining voltage slippage and related phenomena. This work is presented as a starting point for more in-depth empirical analysis of Si GCD data. [ABSTRACT FROM AUTHOR]

This work reports a new method to synthesize polyphenylmethanimine (polyPMI) as a linear or a hyperbranched, conjugated polymer using an aldehyde‐imine metathesis reaction. This work details the reaction mechanisms of this polymerization by characterizing a red‐shift in its absorption spectrum as polymer conjugation length increases and verifies that this optical shift results from extended π‐condensation using density functional theory. This new synthetic approach provides a polymer that can potentially be depolymerized for facile recyclability and is compatible with air‐ and water‐sensitive chemistries. As an example of the utility of this new approach, this work demonstrates that this polymer can be directly grown on silicon nanoparticles to create silicon anodes for lithium‐ion batteries with a high degree of electrochemical interfacial passivation. These silicon anodes exhibit Coulombic efficiencies above 99.9% and can accommodate silicon nanoparticle expansion and contraction during lithiation and delithiation as demonstrated by stable reversible capacities for 500 cycles. Finally, this work demonstrates that polyPMI facilitates the formation of a lithium fluoride rich solid electrolyte interphase that remains chemically and mechanically stable after long term cycling. [ABSTRACT FROM AUTHOR]

Fluoroethylene carbonate (FEC) has been proposed as an effective electrolyte additive that enhances the stability and elasticity of the solid electrolyte interphase (SEI) of emerging Si and Li metal anodes. However, uncertainties still remain on the exact mechanism through which FEC alters the electrolyte decomposition and SEI formation process. Herein, the influence of FEC on LiPF6/ethylene carbonate (EC) electrolytes for Si anodes is investigated through classical molecular dynamics, Fourier-transform infrared spectroscopy, and quantum chemical calculations. Albeit a minority species, FEC is found to significantly modify the solvation structure and reduction behavior of the electrolyte while being innocuous to transport properties. Even with limited 10% of FEC, the Li+ solvation structure exhibits a notably higher contact-ion pair ratio (14%) than the parent EC electrolyte (6%). Moreover, FEC itself, as a new fluorine-containing species, appears in 1/5 of the Li+ solvation shells. The Li+-coordinated FEC is found to reduce prior to EC and uncoordinated FEC which will passivate the anode surface at an early onset (ca. 0.3 V higher than EC) by forming LiF. The critical role of FEC in tailoring the Li+ solvation structure and as-formed protective SEI composition provides mechanistic insight that will aid in the rational design of novel electrolytes.

An ideal binder for high‐energy‐density lithium‐ion batteries (LIBs) should effectively inhibit volume effects, exhibit specific functional properties (e.g., self‐repair capabilities and high ionic conductivity), and require low‐cost, environmentally friendly mass production processes. This study adopts a synergistic strategy involving gradient (strong‐weak) hydrogen bonding to construct a hard/soft polymer composite binder with self‐healing abilities and high battery cell environments adaptability in LIBs. The meticulously designed 3D network structure comprising continuous electron transport pathways buffers the mechanical stresses caused by changes in silicon volume and improves the overall stability of the solid electrolyte interphase film. The Si‐based anode with a polymer composite binder poly(acrylic acid‐g‐ureido pyrimidinone5%)/polyethylene oxide (Si/PAA‐UPy5%/PEO) achieves a reversible capacity of 1245 mAh g−1 after 200 cycles at 0.5 C, which is 6.6 times higher than that of the Si/PAA anode. After 200 cycles at 0.2 A g−1, a half‐cell comprising Si/C anode with a polymer composite binder (Si/C/PAA‐UPy5%/PEO) has a remaining specific capacity of 420 mAh g−1 and a capacity retention rate of 79%. The corresponding full cell with a Li‐based cathode (LiFePO4/Si/C/PAA‐UPy5%/PEO) has an initial area capacity of 0.96 mAh cm−2 and retains an area capacity of 0.90 mAh cm−2 (capacity retention rate = 93%) after 100 cycles at 0.2 A g−1. [ABSTRACT FROM AUTHOR]

Lithium ion batteries (LIBs) using silicon as anode material are endowed with much higher energy density than state‐of‐the‐art graphite‐based LIBs. However, challenges of volume expansion and related dynamic surfaces lead to continuous (re‐)formation of the solid electrolyte interphase, active lithium losses, and rapid capacity fading. Cell failure can be further accelerated when Si is paired with high‐capacity, but also rather reactive Ni‐rich cathodes, such as LiNi0.8Co0.1Mn0.1O2 (NCM‐811). Here, the practical applicability of thermal evaporation of Li metal is evaluated as a prelithiation technique on micrometer‐sized Si (µ‐Si) electrodes in addressing such challenges. NCM‐811 || "prelithiated µ‐Si" full‐cells (25% degree of prelithiation) can attain a higher initial discharge capacity of ≈192 mAh gNCM‐811−1 than the cells without prelithiation with only ≈160 mAh gNCM‐811−1. This study deeply discusses significant consequences of electrode capacity balancing (N:P ratio) with regard to prelithiation on the performance of full‐cells. The trade‐off between cell lifetime and energy density is also highlighted. It is essential to point out that the phenomena discussed here can further guide the direction of research in using the thermal evaporation of Li metal as a prelithiation technique toward its practical application on Si‐based LIBs. [ABSTRACT FROM AUTHOR]

Surface coating approaches for silicon (Si) have demonstrated potential for use as anodes in lithium-ion batteries (LIBs) to address the large volume change and low conductivity of Si. However, the practical application of these approaches remains a challenge because they do not effectively accommodate the pulverization of Si during cycling or require complex processes. Herein, Si-embedded titanium oxynitride (Si-TiON) was proposed and successfully fabricated using a spray-drying process. TiON can be uniformly coated on the Si surface via self-assembly, which can enhance the Si utilization and electrode stability. This is because TiON exhibits high mechanical strength and electrical conductivity, allowing it to act as a rigid and electrically conductive matrix. As a result, the Si-TiON electrodes delivered an initial reversible capacity of 1663 mA h g−1 with remarkably enhanced capacity retention and rate performance. [ABSTRACT FROM AUTHOR]

This study proposes a novel method that uses intense pulsed light (IPL) technology for the simultaneous carbon reduction and binder modification of silicon anodes. By providing a rational design based on material properties and battery engineering, and employing an IPL, this approach offers new insights into selective heat treatment, paving the way for innovative advancements in battery electrode engineering. [Display omitted] • IPL enables selective heat treatment that is unattainable by conventional annealing. • HTB materials are introduced for uniform depth-directional heat treatment. • Conductive additives were further reduced by minimizing binder decomposition. • CQD-derived crosslinked binder to accommodate Si expansion was introduced via IPL. • Successful IPL application to SiNPs and SiMPs suggests broader applications. Silicon, which is gaining prominence as a potential anode material, exhibits long-term cycle stability issues owing to volume changes during cycling. This study presents a meticulously designed Si anode that employs intense pulsed light (IPL) technology to simultaneously reduce carbon additives and construct an effective carbon quantum dot (CQD)-derived binder system. IPL, as a light-material interaction technique, offers a novel approach for selective heat treatment with remarkably short processing durations on the order of milliseconds. By comprehensively considering the geometric structure, optical characteristics, and thermal properties of each electrode component, heat transfer bridge (HTB) materials are introduced to ensure a homogeneous depth-directional heat treatment and to minimize binder decomposition in the IPL process. By employing HTB materials, the binder can reach a controlled target temperature for the condensation reaction between poly (acrylic acid) and the CQDs. Simultaneously, higher heat generation in the conductive carbon than in the binder leads to selective additional carbon reduction. This unique approach provides selective heat treatment, which cannot be achieved using conventional methods, resulting in a Si anode with excellent cyclic stability and rate capability. The versatility of the IPL technology is further demonstrated by applying it to relatively inexpensive Si microparticles. [ABSTRACT FROM AUTHOR]

Silicon-based, high-energy-density electrodes show severe microstructural degradation due to continuous expansion and contraction upon charging and discharging. This mechanical degradation behaviour affects the cell’s lifetime by changing the microstructure morphology, altering transport parameters, and active volume losses. Since direct experimental observations of mechanical degradation are challenging, we develop a computer simulation approach that is based on real three-dimensional electrode microstructures. By assuming quasi-static cycling and taking into account the mechanical properties of the electrode’s constituents we calculate the heterogeneous deformation and resulting morphological changes. Additionally, we implement an ageing model that allows us to compute a heterogeneously evolving damage field over multiple cycles. From the damage field, we infer the remaining electrode capacity. Using this technique, an anode blend of graphite particles and silicon carbon composite particles (SiC-C) as well as a cathode consisting of Lithium-Nickel-Manganese-Cobalt Oxide with molar ratio of 8:1:1 (NMC811) are studied. In a two-level homogenization approach, we compute, firstly, the effective mechanical properties of silicon composite particles and, secondly, the whole electrode microstructure. By introducing the damage strain ratio, the degradation evolution of the graphite SiC-C anode blend is studied for up to 95 charge-discharge cycles. With this work, we demonstrate an approach to how mechanical damage of battery electrodes can be treated efficiently. This is the basis for a full coupling to electrochemical simulations.

Silicon (Si) has received special attention from both scientific research and corporate development for overcoming the current energy density bottleneck. However, the severe volume change and violent interfacial reaction diminish the full benefits of Si material and hamper its direct commercial utilization. Particle pulverization and the companied ionic/electronic isolation are regarded as the intrinsic reason for performance attenuation. Hence, a strategy that can maintain both electronic and ionic conductance on Si anode during the electrochemical process is of great significant for performance improvement and future commercial promotion. Accordingly, an ionic/electronic dual‐conductor coating layer fabrication route is done by in situ building Li4SiO4 fast ion conductor coating layer and implanting electron conduction network, labeled as Si@Li4SiO4/amorphous carbon (C)/carbon nanotubes (CNTs). Notably, the Si@Li4SiO4/C/CNT electrode delivers excellent long‐term cycling stability and prominent rate capability. These results demonstrate that the in situ‐formed fast ionic conductor coating layer facilitates the rapid Li+ diffusion, and the 3D network structure constructed by CNTs and amorphous carbon (polyvinylpyrrolidone‐derived carbon) effectively reinforce the structural stability and keep the electrical connection for the electrode. This study provides an ionic/electronic dual‐conductor coating design concept for Si‐based anode materials.

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The physical crosslinking of polymeric binders through coordination chemistry significantly improves the electrochemical performance of silicon‐based negative electrodes. Scanning electron microscopy coupled with energy dispersive X‐ray spectroscopy is used to probe the nanoscale morphology of such electrodes. This technique reveals the homogeneous coordination of carboxylated binder with Zn cations and its layering on the silicon surface. The solid electrolyte interphase (SEI) formed after the first cycle is denser with Zn‐coordinated binder and preferentially observed on binder‐depleted zones. The superiority of coordinated binders can be attributed to their capacity to better stabilize the electrode and the SEI layer due to improved mechanical properties. This results in a lower SEI impedance, a higher first cycle coulombic efficiency, and a 40% improvement of capacity retention after 50 cycles for highly loaded electrodes of over 6 mAh cm–2. [ABSTRACT FROM AUTHOR]