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To address the issues of dendrite growth and zinc corrosion in rechargeable zinc‐air batteries, multifunctional glycine/valine additives are introduced into the electrolyte. By regulating the solvation shell structure and enhancing interfacial stability, these additives aim to protect the reversibility and stability of the zinc anode. Glycine/valine molecules inhibit the formation of the [Zn(H2O)6]2+ and Zn5(OH)8(OAc)2·2H2O by‐products at the interface by replacing active water molecules in a strong alkaline environment. Additionally, they form a hydrophobic electric double layer on the zinc metal surface, during the charge/discharge process, and construct an in situ solid electrolyte interface layer. This further suppresses the hydrogen evolution reaction and dendrite growth. The superior long‐term cycling stability of Zn||Zn cells, Zn||Cu, and zinc‐air full cells demonstrates the effectiveness of glycine/valine additives. [ABSTRACT FROM AUTHOR]

In the face of growing environmental challenges and the need for alternative energy storage, lithium‐sulfur (Li‐S) batteries stand out for their high theoretical energy density and sulfur's eco‐friendliness. However, the practical application of Li‐S batteries faces significant obstacles, particularly at the cathode and anode. This study explores the transformative impact of 2D tellurene, focusing on how its dimensional variations influence Li‐S battery performance. At the cathode, tellurene not only improves the conductivity and sulfur utilization but also accelerates the conversion of lithium polysulfides (LiPSs). Its reduced size, compared to the bulk counterpart, offers numerous active sites for efficient Li‐ion migration and promotes LiPSs decomposition. At the anode, the protective polytellurosulfides are formed, thereby establishing a stable solid‐electrolyte interphase (SEI) and enhancing reversible lithium deposition. Diminishing the dimensions of tellurene improves its catalytic interface, leading to faster polysulfide conversion kinetics at the cathode and robust SEI formation at the anode. Li‐S batteries equipped with ultra‐thin tellurene‐modified separators demonstrate exceptional performance, exhibiting high areal capacity and significantly reduced capacity decay. Computational simulations further validate the advantages of optimizing tellurene dimensions, confirming its essential role in LiPSs decomposition and overall battery efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] Aqueous zinc batteries (AZBs) are promising for large-scale energy storage. However, severe side reactions and Zn dendrite growth are challenging. "Water-in-salt" and organic/aqueous hybrid electrolytes address these problems but compromise the high ionic conductivity, superior safety, low cost, and good sustainability. Herein, an asymmetric acceptor–donor small organic molecule (NMU) is proposed to boost Zn anodes without compromising the advantages of AZBs. It is found that NMU molecules alter the H-bonding network and reconstruct Zn2+ solvation sheath. Besides, NMU additives tend to be absorbed on the Zn surface to build a water-poor electrical double layer and can in-situ form a robust solid-electrolyte interphase layer that protects the Zn anode. The Zn (0 0 2) plane can be predominately guided by NMU. Consequently, the lifespan of the Zn||Zn cell using NMU can maintain over 3000 h and the average Coulombic efficiency of the Zn||Cu cell reaches 99.7 % throughout 1800 cycles. Additionally, our strategy can be applied in highly-stable and versatile full cells with MnO 2 , activated carbon and conversion-type I 2 (capacity retention: 92.5 % throughout 10,000 cycles) cathodes under practical electrode ratios. The Zn||I 2 pouch cell with NMU also presents good cycling stability over 1100 cycles. [ABSTRACT FROM AUTHOR]

Silicon (Si) is a promising anode material due to its high theoretical capacity and abundant presence as the second most common element in the earth's crust. However, the formation of an unstable solid-electrolyte interphase (SEI) and significant volume expansion during lithiation result in structural degradation, leading to a decrease in the cycle life for Si-based anodes. This paper reports on the electrochemical performance of the silicon/graphite (Si/Gr) electrodes coated with nanometer-thick ZnO layers prepared by atomic layer deposition (ALD). In our study, ZnO layers were deposited using 5–40 ALD cycles on Si/Gr electrodes of ∼20 μm thickness. Electrochemical measurements such as galvanostatic charging/discharging at different C-rates and electrochemical impedance spectroscopy were performed utilizing the pristine and 5–40 ALD cycles of ZnO on Si/Gr electrodes in a half-cell configuration. The Si/Gr electrodes (pristine and ZnO-coated) were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy (XPS) before and after electrochemical cell cycling. The ZnO-coated samples showed a better electrochemical rate performance than the uncoated pristine Si/Gr sample. The reversible conversion of the ZnO ALD films was demonstrated through dQ/dV plots and XPS analysis during (de)-lithiation. The ultrathin ZnO layers passivate the underlying Si/Gr electrodes, help in the formation of a stable SEI layer, and facilitate lithium-ion transport through the SEI layer. [ABSTRACT FROM AUTHOR]

At the nanoscale, the graphitic degree, surface area, and heteroatom doping are primary properties of any carbon material that influences anode performance for Li-ion battery (LIB) applications. The simultaneous control over nanostructured properties such as doping and surface area at the nanolevel remains challenging for achieving fast operating LIB. Here, we demonstrate a study on nitrogen-doped hierarchically nanoporous carbon (HNC) materials with specific dopant concentrations and tunable surface areas designed strategically via a dual-templating approach. The 3D nanoporous microflowers provide pathways to the lithium reservoir for fast charge–discharge. We explore the effect of different ammonia concentrations on nitrogen doping levels and the surface area of HNCs. Our findings reveal that consistently high surface area and excess nitrogen doping levels do not confer benefits. High-rate battery performance can be achieved at the expense of any of these properties. Using optimized HNC, we achieved a high-rate performance of 357 mAh g–1 at 2 A g–1 and approximately 87% stability retention after 600 cycles, showcasing its potential for LIB applications. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries (AZIBs) have been getting lots of attention in the field of large scale energy storage owing to their low cost, large capacity and excellent safety. However, Zn anodes have serious dendritic growth and corrosion hydrogen evolution issues, which hinder their further application. Herein, a simple drop-coating technique was used to build a thin sulfate poly(ether ketone) (SPEEK) solid-electrolyte interphase (SEI) on the surface of the Zn anode to address these issues. The sulfonated group (−SO3−） in SPEEK can provide rich coordination sites for Zn2+, controlling the uniform deposition of Zn2+. Therefore, the polymer SEI can block electrolytes and homogenize the Zn2+ flux, resulting that the modified Zn (SPEEK@Zn) anode could effectively limit the formation of dendrites and side reactions. At a current density of 0.5 mA cm−2, SPEEK@Zn electrodes can maintain an ultra-long plating/stripping cycle life of 1000 h. Full batteries based on SPEEK@Zn have more superior cycle stability than the bare ones. This approach offers a straightforward and scalable remedy for high-performance Zn anode batteries. [ABSTRACT FROM AUTHOR]

Rechargeable magnesium batteries (RMBs), as a low-cost, high-safety and high-energy storage technology, have attracted tremendous attention in large-scale energy storage applications. However, the key anode/electrolyte interfacial issues, including surface passivation, uneven Mg plating/stripping, and pulverization after cycling still result in a large overpotential, short cycling life, poor power density, and possible safety hazards of cells, severely impeding the commercial development of RMBs. In this review, a concise overview of recently advanced strategies to address these anode/electroyte interfacial issues is systematically classified and summarized. The design of magnesiophilic substrates, construction of artificial SEI layers, and modification of electrolyte are important and effective strategies to improve the uniformity/kinetics of Mg plating/stripping and achieve the stable anode/electrolyte interface. The key opportunities and challenges in this field are advisedly put forward, and the insights into future directions for stabilizing Mg metal anodes and the anode/electrolyte interface are highlighted. This review provides important references fordeveloping the high-performance and high-safety RMBs.

• The key Mg/electrolyte interfacial issues in RMBs are proposed. • Advanced strategies for optimizing Mg/electrolyte interphase are summarized. • The perspectives for designing an idea Mg/electrolyte interface are provided. Rechargeable magnesium batteries (RMBs), as a low-cost, high-safety and high-energy storage technology, have attracted tremendous attention in large-scale energy storage applications. However, the key anode/electrolyte interfacial issues, including surface passivation, uneven Mg plating/stripping, and pulverization after cycling still result in a large overpotential, short cycling life, poor power density, and possible safety hazards of cells, severely impeding the commercial development of RMBs. In this review, a concise overview of recently advanced strategies to address these anode/electroyte interfacial issues is systematically classified and summarized. The design of magnesiophilic substrates, construction of artificial SEI layers, and modification of electrolyte are important and effective strategies to improve the uniformity/kinetics of Mg plating/stripping and achieve the stable anode/electrolyte interface. The key opportunities and challenges in this field are advisedly put forward, and the insights into future directions for stabilizing Mg metal anodes and the anode/electrolyte interface are highlighted. This review provides important references fordeveloping the high-performance and high-safety RMBs. [ABSTRACT FROM AUTHOR]

Regulation of the surface film characteristics of Li‐metal is a pivotal strategy for augmenting the electrochemical performance of Li‐metal batteries. This investigation elucidates a straightforward approach to surface film modification, namely, pre‐treatment via a CO2 gas reaction, and its subsequent impact on the electrochemical attributes of Li‐metal electrodes. Analysis of the topography and composition of the Li metal surfaces revealed the transformation of the surface film into a more uniform layer enriched with inorganic compounds, including Li2CO3 and Li2O, by pre‐treatment. This pre‐treatment process significantly enhances the electrochemical properties, such as cyclability and overpotential, in Li/Li symmetric cells, primarily because of the formation of an improved solid‐electrolyte interphase (SEI) derived from the altered surface film on Li metal electrodes. The reformed SEI significantly increases the mobility of Li ions through the interphase, thereby attenuating the impedance associated with Li‐ion migration within the SEI. This resistance attenuation is instrumental in alleviating the overpotentials, thereby significantly refining the electrochemical plating and stripping dynamics of Li metal electrodes. [ABSTRACT FROM AUTHOR]

The in situ‐formed polymer electrolytes provide a vital solution for improving both safety and performance in the high‐voltage lithium metal batteries. This study reports new poly(ester‐alt‐acetal) (PEA) electrolytes, synthesized through in situ alternating copolymerization of glutaric anhydride and 1,3‐dioxane. In the presence of 25 wt.% lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), three lithium salts, lithium difluoro(oxalate)borate (LiDFOB), lithium hexafluorophosphate (LiPF6), and lithium tetrafluoroborate (LiBF4) are employed as the catalysts for the copolymerization. These lithium salts can modulate the compositions of the solid‐electrolyte interphase (SEI) layer. PEA‐LiPF6 exhibits outstanding SEI chemistry, with observing the highest LiF content, thereby achieving a remarkable critical current density of up to 2.5 mA cm−2, a Li+ transference number of 0.81, and an expansive electrochemical stability window of 6.0 V. Furthermore, PEA‐LiPF6 demonstrates noteworthy capacity retention rates of 96.6% (0.5 C, 200th/first cycle in LiFePO4||Li), 95.6% (0.5 C, 100th/first cycle in LiMn0.6Fe0.4PO4||Li), 95.1% (1 C, 100th/first cycle in LiCoO2||Li), and 87.0% (1 C, 100th/first cycle in LiNi0.6Co0.2Mn0.2O2||Li full‐cells). This work demonstrates a facile in situ route to fabricate polymer electrolytes for high‐voltage lithium‐metal batteries with balanced and comprehensive performance. [ABSTRACT FROM AUTHOR]

Anion‐derived solid‐electrolyte interphase (SEI) has received growing attention owing to its appealing properties like fast ion transport and excellent passivation effect. However, a sophisticated understanding of anion‐derived SEI is lacking. To common wisdom, anion‐derived SEI features an inorganic‐rich composition. Herein, it is reveal that the freshly formed anion‐derived SEI consists of a polymer‐rich outer layer and an inorganic inner layer. Then, the organic components dissolve during the discharge process, while the inorganic species with low solubility are retained in the empty SEI husk. The accumulation of empty SEI husks during cycling forms a reacted lithium (Li) layer, which features a much higher content of anion‐derived inorganic species than the newly formed SEI. Therefore, the acknowledged "anion‐derived inorganic‐rich SEI" actually refers to the reacted Li layer instead of the freshly formed SEI. This work provides fruitful insights on the compositional features of anion‐derived SEI. [ABSTRACT FROM AUTHOR]

Ether‐based electrolyte is beneficial to obtaining good low‐temperature performance and high ionic conductivity in potassium ion batteries. However, the dilute ether‐based electrolytes usually result in ion‐solvent co‐intercalation of graphite, poor cycling stability, and hard to withstand high voltage cathodes above 4.0 V. To address the aforementioned issues, an electron‐withdrawing group (chloro‐substitution) was introduced to regulate the solid‐electrolyte interphase (SEI) and enhance the oxidative stability of ether‐based electrolytes. The dilute (~0.91 M) chloro‐functionalized ether‐based electrolyte not only facilitates the formation of homogeneous dual halides‐based SEI, but also effectively suppress aluminum corrosion at high voltage. Using this functionalized electrolyte, the K||graphite cell exhibits a stability of 700 cycles, the K||Prussian blue (PB) cell (4.3 V) delivers a stability of 500 cycles, and the PB||graphite full‐cell reveals a long stability of 6000 cycles with a high average Coulombic efficiency of 99.98 %. Additionally, the PB||graphite full‐cell can operate under a wide temperature range from −5 °C to 45 °C. This work highlights the positive impact of electrolyte functionalization on the electrochemical performance, providing a bright future of ether‐based electrolytes application for long‐lasting, wide‐temperature, and high Coulombic efficiency PIBs and beyond. [ABSTRACT FROM AUTHOR]

For the lithium (Li) metal anode, constructing a strong and durable protective layer with lithium‐ion permeability is crucial, especially in high donor number (DN) solvent system. High DN solvent‐based electrolytes can support both higher capacity and lower charge overpotential in the rechargeable lithium–oxygen batteries (LOBs). However, Li anodes in high DN solvent system suffer from severe corrosion and uncontrolled dendrite growth due to the unstable solid‐electrolyte interphase (SEI). Typically, this interface is formed in situ through electrochemical processes with complicated component and spatial distribution. Here, a functional molecule is introduced to construct an ion‐wall (IW) on Li surface by prechemical sequential reactions (p‐CSRs), through which the crystalline nanoparticles as bricks and amorphous hybrid compounds as the mortar can be produced to build such a "wall." Different from the conventional SEI, this wall is not only compact and uniform, but also possess high strength, excellent passivation properties and high ionic conductivity. With these properties, the IW could suppress Li dendrites and inhabit the side reaction, supporting highly reversible Li plating/stripping behavior in high DN solvent system. As a result, the cycle stability of LOBs based on the IW protected Li anode is significantly improved. [ABSTRACT FROM AUTHOR]

Previously, lithium-acetylide (Li2C2) had been identified as electrolyte degradation product on lithium-metal based electrodes using Raman spectroscopy. This raised the question, if Li2C2 is also be formed on graphitic electrodes in lithium-ion batteries without lithium metal present. In order to shed light on this research question, we performed a series of in situ Raman experiments with graphitic electrodes in half- and full-cell configuration. The recorded cell potential dependent spectra clearly prove the presence of Li2C2 in the lithiated state of the electrodes, but the according peak vanishes when delithiating. This observation indicates a somewhat reversible process involving Li2C2. Several chemical/electrochemical reactions are in question to contribute to this effect. With respect to its properties and potential role in the solid-electrolyte interphase (SEI) DFT calculations of Li2C2-nanoclusters were performed, which revealed an exceptionally low energy band gap, hence a remarkable electric conductivity. In conjunction with a relatively high ionic conductivity, Li2C2 appears to play a key role in the degradation of lithium-ion batteries, which had not yet been revealed nor taken into account in simulations of the interphase.

Highlights Cetyltrimethylammonium cations can shield the repelling force on anions to attract more anions into electric double layer region during lithium plating process, facilitating the formation of inorganic-rich solid-state electrolyte interphase (SEI). An inorganic-rich (N/F-containing species) structure of SEI can be evidenced by the in-depth analysis. The cycling lifetime of Li||Li symmetric cell in the designed electrolyte can be extended from 500 to 1300 h. Moreover, full cells with a high cathode mass loading of >10 mg cm-2 can be stably cycled over 180 cycles.

Zinc metal batteries (ZMBs) hold great promise for large‐scale energy storage in renewable solar and wind farms. However, their widespread application is hindered by poor stability and unsatisfactory low‐temperature performance, attributed to issues such as dendrite formation, strong Zn2+‐H2O coordination, and electrolyte freezing. Herein, a deep eutectic sol electrolyte (DESE) is proposed by mixing SiO2 nanoparticles with a solution composed of 1,3‐dioxolane (DOL) and Zn(ClO4)2·6H2O for stable low‐temperature ZMBs. By substituting the strong Zn2+‐ H2O coordination with favorable Zn2+‐DOL coordination, the DESE exhibits exceptional antifreezing capability at temperatures beyond −40 °C. The formation of Si‐O‐Zn2+ bond near SiO2 nanoparticles further improves the low‐temperature performance of the DESE by decreasing Zn2+ desolvation energy. Moreover, the SiO2 nanoparticles co‐plating/co‐stripping with Zn metal, forming a reversible and homogeneous SiO2‐enriched interphase to protect the Zn anode from dendrite growth and interfacial side reactions. Remarkably, the DESE‐based ZMB full cells exhibit significantly prolonged cycle life of 8000 cycles at 1 A g−1 at 25 °C and 700 cycles at 0.2 A g−1 at ‐40 °C. This work provides a promising strategy to design advanced electrolytes for practical low‐temperature ZMBs. [ABSTRACT FROM AUTHOR]

Highlights: Cetyltrimethylammonium cations can shield the repelling force on anions to attract more anions into electric double layer region during lithium plating process, facilitating the formation of inorganic-rich solid-state electrolyte interphase (SEI). An inorganic-rich (N/F-containing species) structure of SEI can be evidenced by the in-depth analysis. The cycling lifetime of Li||Li symmetric cell in the designed electrolyte can be extended from 500 to 1300 h. Moreover, full cells with a high cathode mass loading of >10 mg cm-2 can be stably cycled over 180 cycles. An anion-rich electric double layer (EDL) region is favorable for fabricating an inorganic-rich solid–electrolyte interphase (SEI) towards stable lithium metal anode in ester electrolyte. Herein, cetyltrimethylammonium bromide (CTAB), a cationic surfactant, is adopted to draw more anions into EDL by ionic interactions that shield the repelling force on anions during lithium plating. In situ electrochemical surface-enhanced Raman spectroscopy results combined with molecular dynamics simulations validate the enrichment of NO3−/FSI− anions in the EDL region due to the positively charged CTA+. In-depth analysis of SEI structure by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry results confirmed the formation of the inorganic-rich SEI, which helps improve the kinetics of Li+ transfer, lower the charge transfer activation energy, and homogenize Li deposition. As a result, the Li||Li symmetric cell in the designed electrolyte displays a prolongated cycling time from 500 to 1300 h compared to that in the blank electrolyte at 0.5 mA cm−2 with a capacity of 1 mAh cm−2. Moreover, Li||LiFePO4 and Li||LiCoO2 with a high cathode mass loading of > 10 mg cm−2 can be stably cycled over 180 cycles. [ABSTRACT FROM AUTHOR]

Quasi‐solid‐state electrolytes (QSSEs) based on ionic liquids are recognized as one of the frontrunners of electrolytes for ensuring the safety and high energy density of next‐generation lithium batteries. However, the incapacity of such systems to meet the performance demands of batteries is significantly subject to the properties of the electrolyte and the intricacies of related interfacial processes. Recently, we have designed a high‐performing pyrrolidinium bis(trifluoromethylsulfonyl)imide (Py14TFSI) based QSSE (Py‐Gel), with introducing LiBF4 and LiCl, which served as a system for probing the dynamic Li deposition mechanism. Herein, we focus on understanding the mechanisms of Py‐Gel formation and examining the chemistry and structure as well as the properties of the solid‐electrolyte interphases (SEIs) formed in the Py‐Gel and their influences on Li deposition. Spectroscopic characterizations suggest the existence of a cross‐linked structure in Py‐Gel, for which multiple intermolecular/intramolecular hydrogen bondings and ionic coulumbic interactions among Py cations, TFSI− anions, and Li salts are responsible. The Py‐Gel electrolyte exhibits exceptional electrical properties at room temperature. Different SEIs are prepared in the Py‐Gel via electrochemical protocols to elucidate that the synergy between a well‐featured electrolyte and an outstanding SEI is vital for stable cycling of Li metal anodes in such a QSSE. [ABSTRACT FROM AUTHOR]

Silicon is a promising anode material for next‐generation lithium‐ion batteries. However, the volume change and the voltage hysteresis during lithiation and delithiation are two substantial drawbacks to their lifetime and performance. The reason for the voltage hysteresis in amorphous silicon nanoparticles covered by a solid‐electrolyte interphase (SEI) is investigated. Concentration gradients inside the nanoscale silicon cannot produce the massive stresses necessary to cause the reported voltage hysteresis. The chemo‐mechanical model shows that plastic deformation of the stiff, inorganic SEI during lithiation and delithiation reproduces the observed silicon open‐circuit voltage hysteresis. Additionally, the viscous behavior of the SEI explains the difference between the voltage hysteresis observed at low currents and after relaxation. It is concluded that the visco‐elastoplastic behavior of the SEI is the origin of the voltage hysteresis in silicon nanoparticle anodes. Thus, consideration of the SEI mechanics is crucial for further improvements. [ABSTRACT FROM AUTHOR]

The increasing need for electrochemical energy storage drives the development of post‐lithium battery systems. Among the most promising new battery types are sodium‐based battery systems. However, like its lithium predecessor, sodium batteries suffer from various issues like parasitic side reactions, which lead to a loss of active sodium inventory, thus reducing the capacity over time. Some problems in sodium batteries arise from an unstable solid electrolyte interphase (SEI) reducing its protective power e. g., due to increased solubility of SEI components in sodium battery systems. While it is known that the electrolyte affects the SEI structure, the exact formation mechanism of the SEI is not yet fully understood. In this study, we follow the initial SEI formation on a piece of sodium metal submerged in propylene carbonate with and without the electrolyte salt sodium perchlorate. We combine X‐ray photoelectron spectroscopy, gas chromatography, and density functional theory to unravel the sudden emergence of propylene oxide after adding sodium perchlorate to the electrolyte solvent. We identify the formation of a sodium chloride layer as a crucial step in forming propylene oxide by enabling precursors formed from propylene carbonate on the sodium metal surface to undergo a ring‐closing reaction. Based on our combined theoretical and experimental approach, we identify changes in the electrolyte decomposition process, propose a reaction mechanism to form propylene oxide and discuss alternatives based on known synthesis routes. [ABSTRACT FROM AUTHOR]

The implementation of silicon (Si)‐containing negative electrodes is widely discussed as an approach to increase the specific capacity of lithium‐ion batteries. However, challenges caused by severe volume changes and continuous (re‐)formation of the solid‐electrolyte interphase (SEI) on Si need to be overcome. The volume changes lead to electrolyte consumption and active lithium loss, decaying the cell performance and cycle life. Herein, the additive 2‐sulfobenzoic acid anhydride (2‐SBA) is utilized as an SEI‐forming electrolyte additive for SiOx‐containing anodes. The addition of 2‐SBA to a state‐of‐the‐art carbonate‐based electrolyte in high‐voltage LiNi0.8Mn0.1Co0.1O2, NMC811||artificial graphite +20% SiOx pouch cells leads to improved electrochemical performance, resulting in a doubled cell cycle life. The origin of the enhanced cell performance is mechanistically investigated by developing an advanced experimental technique based on operando attenuated total reflection Fourier‐transform infrared (ATR‐FTIR) spectroscopy. The operando ATR‐FTIR spectroscopy results elucidate the degradation mechanism via anhydride ring‐opening reactions after electrochemical reduction on the anode surface. Additionally, ion chromatography conductivity detection mass spectrometry, scanning electron microscopy, energy dispersive X‐ray analysis, and quantum chemistry calculations are employed to further elucidate the working mechanisms of the additive and its degradation products. [ABSTRACT FROM AUTHOR]

Abstract Regulation of the surface film characteristics of Li‐metal is a pivotal strategy for augmenting the electrochemical performance of Li‐metal batteries. This investigation elucidates a straightforward approach to surface film modification, namely, pre‐treatment via a CO2 gas reaction, and its subsequent impact on the electrochemical attributes of Li‐metal electrodes. Analysis of the topography and composition of the Li metal surfaces revealed the transformation of the surface film into a more uniform layer enriched with inorganic compounds, including Li2CO3 and Li2O, by pre‐treatment. This pre‐treatment process significantly enhances the electrochemical properties, such as cyclability and overpotential, in Li/Li symmetric cells, primarily because of the formation of an improved solid‐electrolyte interphase (SEI) derived from the altered surface film on Li metal electrodes. The reformed SEI significantly increases the mobility of Li ions through the interphase, thereby attenuating the impedance associated with Li‐ion migration within the SEI. This resistance attenuation is instrumental in alleviating the overpotentials, thereby significantly refining the electrochemical plating and stripping dynamics of Li metal electrodes.

Rechargeable zinc (Zn) metal batteries have long been plagued by dendrite growth and parasitic reactions due to the absence of a stable Zn-ion conductive solid-electrolyte interphase (SEI). Although the current strategies assist in suppressing dendritic Zn growth, it is still a challenge to obtain the operation-stability of Zn anode with high Coulombic efficiency (CE) required to implement a sustainable and long-cycling life of Zn metal batteries. In this perspective, we summarize the advantages of the functional gradient interphase (FGI) and try to fundamentally understand the transport behaviors of Zn ions, based on recently an article understanding Zn chemistry. The correlation between the function-orientated design of gradient interphase and key challenges of Zn metal anodes in accelerating Zn2+ transport kinetics, improving electrode reversibility, and inhibiting Zn dendrite growth and side reactions was particularly emphasized. Finally, the rational design and innovative directions are provided for the development and application of functional gradient interphase in rechargeable Zn metal battery systems.

Ether solvents are suitable for formulating solid-electrolyte interphase (SEI)-less ion-solvent cointercalation electrolytes in graphite for Na-ion and K-ion batteries. However, ether-based electrolytes have been historically perceived to cause exfoliation of graphite and cell failure in Li-ion batteries. In this study, we develop strategies to achieve reversible Li-solvent cointercalation in graphite through combining appropriate Li salts and ether solvents. Specifically, we design 1M LiBF4 1,2-dimethoxyethane (G1), which enables natural graphite to deliver ~91% initial Coulombic efficiency and >88% capacity retention after 400 cycles. We captured the spatial distribution of LiF at various length scales and quantified its heterogeneity. The electrolyte shows self-terminated reactivity on graphite edge planes and results in a grainy, fluorinated pseudo-SEI. The molecular origin of the pseudo-SEI is elucidated by ab initio molecular dynamics (AIMD) simulations. The operando synchrotron analyses further demonstrate the reversible and monotonous phase transformation of cointercalated graphite. Our findings demonstrate the feasibility of Li cointercalation chemistry in graphite for extreme-condition batteries. The work also paves the foundation for understanding and modulating the interphase generated by ether electrolytes in a broad range of electrodes and batteries. [ABSTRACT FROM AUTHOR]

Solid electrolyte interphase (SEI) makes the electrochemical window of aqueous electrolytes beyond the thermodynamics limitation of water. However, achieving the energetic and robust SEI is more challenging in aqueous electrolytes because the low SEI formation efficiency (SFE) only contributed from anion‐reduced products, and the low SEI formation quality (SFQ) negatively impacted by the hydrogen evolution, resulting in a high Li loss to compensate for SEI formation. Herein, we propose a highly efficient strategy to construct Spatially‐Temporally Synchronized (STS) robust SEI by the involvement of synergistic chemical precipitation‐electrochemical reduction. In this case, a robust Li3PO4‐rich SEI enables intelligent inherent growth at the active site of the hydrogen by the chemical capture of the OH− stemmed from the HER to trigger the ionization balance of dihydrogen phosphate (H2PO4−) shift to insoluble solid Li3PO4. It is worth highlighting that the Li3PO4 formation does not extra‐consume lithium derived from the cathode but makes good use of the product of HER (OH−), prompting the SEI to achieve 100 % SFE and pushing the HER potential into −1.8 V vs. Ag/AgCl. This energetic and robust SEI offers a new way to achieve anion/concentration‐independent interfacial chemistry for the aqueous batteries. [ABSTRACT FROM AUTHOR]

Silicon suboxides (SiOx) materials are highly desirable as anode for high energy Li‐ion batteries due to their much higher specific capacity than conventional graphite anode. However, the low initial Coulombic efficiency (ICE) and inadequate capacity retention of SiOx anode arising from its immense volume variation during repeated lithiation/delithiation process greatly hinder its practical applications. To address these drawbacks of SiOx, by a simple calcination method, a robust and fast‐ion conducting interphase enriched of LiF, Li2C2O4, LiBO2, and Li2B4O7 is rationally pre‐constructed With the assistance of this pre‐constructed artificial protective layer, the formed solid‐electrolyte interphase (SEI) layer possesses high Young's modulus and fast Li+ conducting, and thus can accommodate the plastic deformation of SiOx anode, alleviate the parasitic reactions, and maintain the electrode integrity upon cycling. Thus, the modified SiOx (M‐SiOx) anode exhibits higher ICE, better capacity retention and superior rate capability. More encouragingly, full cells pairing the M‐SiOx anode with LiNi0.8Mn0.1Co0.1O2 cathode show a high capacity retention of 80.6% for 200 cycles. This paper reveals the importance of pre‐constructing an artificial SEI layer and regulating interfacial chemistry in improving the performance of SiOx‐based anodes, which is a milestone work for boosting the large scale application of SiOx‐based anodes. [ABSTRACT FROM AUTHOR]

Si anodes are of great interest for next‐generation Li‐ion batteries due to their exceptional energy density. One of the problems hindering the adoption of this material is the presence of electrolyte decomposition reactions that result in capacity fade and Coulombic inefficiency. This work studies the influence of the decomposition layer in Si on its electrochemical performance using thermogalvanic profiling, a non‐destructive in operando technique. This is accomplished by comparing thermogalvanic profiles of uncoated thin‐film Si to those of lithium phosphorus oxynitride (LiPON)‐coated Si, in which decomposition reactions are inhibited. Through a combination with physico‐chemical methods including scanning electron microscopy and time‐of‐flight secondary ion mass spectrometry, the thermogalvanic profiles are found to contain signatures that reflect the nature of the decomposition layer. More specifically, this decomposition layer appears to gradually develop a passivating function during the first electrochemical cycles. Thermogalvanic profiles collected at later cycles indicate that this passivating behavior is eventually lost, causing the observed capacity degradation. The identification of a passivating regime in Si is highly relevant for the development of high‐capacity Li‐ion batteries. In addition, the use of thermogalvanic profiles to track the properties of decomposition layers could be of interest for monitoring the formation or degradation of battery cells. [ABSTRACT FROM AUTHOR]

The pulverization of alloying anodes significantly restricts their use in lithium‐ion batteries (LIBs). This study presents a dual‐phase solid electrolyte interphase (SEI) design that incorporates finely dispersed Al nanoparticles within the LiPON matrix. This distinctive dual‐phase structure imparts high stiffness and toughness to the integrated SEI film. In comparison to single‐phase LiPON film, the optimized Al/LiPON dual‐phase SEI film demonstrates a remarkable increase in fracture toughness by 317.8 %, while maintaining stiffness, achieved through the substantial dissipation of strain energy. Application of the dual‐phase SEI film on an Al anode leads to a 450 % enhancement in cycling stability for lithium storage in dual‐ion batteries. A similar enhancement in cycling stability for silicon anodes, which face severe volume expansion issues, is also observed, demonstrating the broad applicability of the dual‐phase SEI design. Specifically, homogeneous Li−Al alloying has been observed in conventional LIBs, even when paired with a high mass loading LiNi0.5Co0.3Mn0.2O2 cathode (7 mg cm−2). The dual‐phase SEI film design can also accelerate the diffusion kinetics of Li‐ions through interface electronic structure regulation. This dual‐phase design can integrate stiffness and toughness into a single SEI film, providing a pathway to enhance both the structural stability and rate capability of alloying anodes. [ABSTRACT FROM AUTHOR]

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The lithium‐mediated nitrogen reduction reaction (Li‐NRR) is a promising method for decentralized ammonia synthesis using renewable energy. An organic electrolyte is utilized to combat the competing hydrogen evolution reaction, and lithium is plated to activate the inert N2 molecule. Ethanol is commonly used as a proton shuttle to provide hydrogen to the activated nitrogen. In this study, we investigate the role of ethanol as a proton shuttle in an electrolyte containing tetrahydrofuran and 0.2 M lithium perchlorate. Particularly designed electrochemical experiments show that ethanol is necessary for a good solid‐electrolyte interphase but not for the synthesis of ammonia. In addition, electrochemical quartz crystal microbalance (EQCM) demonstrates that the SEI formation at the onset of lithium plating is of specific importance. Chemical batch synthesis of ammonia combined with real‐time mass spectrometry confirms that protons can be shuttled from the anode to the cathode by other species even without ethanol. Moreover, it raises questions regarding the electrochemical nature of Li‐NRR. Finally, we discuss electrolyte stability and electrochemical electrode potentials, highlighting the role of ethanol on electrolyte degradation. [ABSTRACT FROM AUTHOR]

Zn electrodeposition mechanism is a cornerstone of dendritic issue exploration in Zn‐ion battery. Investigation of the inherent early‐stage Zn plating kinetics and its dependence on the reactivity of anode‐electrolyte interphase is crucial. Herein, the kinetic evolution of Zn plating on three characteristic substrates is quantified: fresh Zn, commercial Zn foil, and Zn foil with spontaneously generated solid‐electrolyte interphase (SEI). Using scanning electrochemical microscopy analysis, the original interphase regulation of Zn deposit orientation and the competitive reaction between Zn deposition and SEI passivation are studied in situ. Furthermore, the SEI layer can suppress the dendrite growth at initial state by guiding the horizontal alignment of Zn flakes and promote Zn plating process. This approach provided a feasible consideration into interphase engineering of various metal anodes. [ABSTRACT FROM AUTHOR]

Abstract Quasi‐solid‐state electrolytes (QSSEs) based on ionic liquids are recognized as one of the frontrunners of electrolytes for ensuring the safety and high energy density of next‐generation lithium batteries. However, the incapacity of such systems to meet the performance demands of batteries is significantly subject to the properties of the electrolyte and the intricacies of related interfacial processes. Recently, we have designed a high‐performing pyrrolidinium bis(trifluoromethylsulfonyl)imide (Py14TFSI) based QSSE (Py‐Gel), with introducing LiBF4 and LiCl, which served as a system for probing the dynamic Li deposition mechanism. Herein, we focus on understanding the mechanisms of Py‐Gel formation and examining the chemistry and structure as well as the properties of the solid‐electrolyte interphases (SEIs) formed in the Py‐Gel and their influences on Li deposition. Spectroscopic characterizations suggest the existence of a cross‐linked structure in Py‐Gel, for which multiple intermolecular/intramolecular hydrogen bondings and ionic coulumbic interactions among Py cations, TFSI− anions, and Li salts are responsible. The Py‐Gel electrolyte exhibits exceptional electrical properties at room temperature. Different SEIs are prepared in the Py‐Gel via electrochemical protocols to elucidate that the synergy between a well‐featured electrolyte and an outstanding SEI is vital for stable cycling of Li metal anodes in such a QSSE.

Lithium metal anode holds great promises for next-generation battery technologies but is notoriously difficult to work with. The key to solving this challenge is believed to lie in the ability of forming stable solid-electrolyte interphase (SEI) layers. To further address potential safety issues, it is critical to achieve this goal in nonflammable electrolytes. Building upon previous successes in forming stable SEI in conventional carbonate-based electrolytes, here we report that reversible Li stripping/plating could be realized in triethyl phosphate (TEP), a known flame retardant. The critical enabling factor of our approach was the introduction of oxygen, which upon electrochemical reduction induces the initial decomposition of TEP and produces Li3 PO4 and poly-phosphates. Importantly, the reaction was self-limiting, and the resulting material regulated Li plating by limiting dendrite formation. In effect, we obtained a functional SEI on Li metal in a nonflammable electrolyte. When tested in a symmetric Li∥Li cell, more than 300 cycles of stripping/plating were measured at a current density of 0.5 mA cm-2 . Prototypical Li-O2 and Li-ion batteries were also fabricated and tested to further support the effectiveness of this strategy. The mechanism by which the SEI forms was studied by density functional theory (DFT), and the predictions were corroborated by the successful detection of the intermediates and products.

A novel poly(ether block amide) (PEBA) based solid-state polymer electrolyte (SPE) was prepared using a casting method, in which 20wt% lithium (Li) bis-(trifluoromethanesulfonyl)imide (LiTFSI) and aluminum oxide (Al2O3) nanoparticles were used as the Li salt and solid plasticizer, respectively. In the case of addition of 3wt% Al2O3 nanoparticles, ion conductivity of the obtained PEBA 2533–20wt% LiTFSI-3wt% Al2O3 SPE was 3.57 × 10−5 S cm−1 at 25 °C. Furthermore, the Li symmetrical battery assembled with it showed excellent cycling stability (1000 h) at 0.1 mA cm−2. While, the assembled all-solid-state Li/PEBA 2533–20% LiTFSI-3wt% Al2O3/LiFePO4 (areal capacity: 0.15 mAh cm−2) battery maintained 94.9% of the maximal capacity (133.9 mAh g−1@0.1 mA cm−2) at 60 °C even after 650 cycles with a superior average coulombic efficiency (CE) of 99.84%. By using X-ray photoelectron spectroscope (XPS), self-aggregation layer (SAL) of polyamide 12 (PA12) of PEBA 2533 was discovered, which should contribute to promoting the robustness of lithium fluoride (LiF) enriched solid-electrolyte interphase (SEI) layer. In addition, it is considered that the state of interface between SPE and cathode should be the cause of voltage polarization of the full cell.

Alongside the pursuit of high energy density and long service life, the urgent demand for low-temperature performance remains a long-standing challenge for a wide range of Li-ion battery applications, such as electric vehicles, portable electronics, large-scale grid systems, and special space/seabed/military purposes. Current Li-ion batteries suffer a major loss of capacity and power and fail to operate normally when the temperature decreases to −20 ​°C. This deterioration is mainly attributed to poor Li-ion transport in a bulk carbonated ester electrolyte and its derived solid–electrolyte interphase (SEI). In this mini-review discussing the limiting factors in the Li-ion diffusion process, we propose three basic requirements when formulating electrolytes for low-temperature Li-ion batteries: low melting point, poor Li+ affinity, and a favorable SEI. Then, we briefly review emerging progress, including liquefied gas electrolytes, weakly solvating electrolytes, and localized high-concentration electrolytes. The proposed novel electrolytes effectively improve the reaction kinetics via accelerating Li-ion diffusion in the bulk electrolyte and interphase. The final part of the paper addresses future challenges and offers perspectives on electrolyte designs for low-temperature Li-ion batteries.

Janus-type Ni 3 Sn 2 S 2 -CNT heterostructure can efficiently tolerate the large volume expansions of electrode materials, prevent their detrimental aggregation, barricade the oxidation and shuttling of intermediate polysulfides, and guarantee reversible redox reactions for durable cycles. [Display omitted] Ternary transition-metal tin chalcogenides, with their diverse compositions, abundant constituents, high theoretical capacities, acceptable working potentials, excellent conductivities, and synergistic active/inactive multi-components, hold promise as anode materials for metal-ion batteries. However, abnormal aggregation of Sn nanocrystals and the shuttling of intermediate polysulfides during electrochemical tests detrimentally affect the reversibility of redox reactions and lead to rapid capacity fading within a limited number of cycles. In this study, we present the development of a robust Janus-type metallic Ni 3 Sn 2 S 2 -carbon nanotube (NSSC) heterostructured anode for Li-ion batteries (LIBs). The synergistic effects of Ni 3 Sn 2 S 2 nanoparticles and a carbon network successfully generate abundant heterointerfaces with steady chemical bridges, thereby enhancing ion and electron transport, preventing the aggregation of Ni and Sn nanoparticles, mitigating the oxidation and shuttling of polysulfides, facilitating the reforming of Ni 3 Sn 2 S 2 nanocrystals during delithiation, creating a uniform solid-electrolyte interphase (SEI) layer, protecting the mechanical integrity of electrode materials, and ultimately enabling highly reversible lithium storage. Consequently, the NSSC hybrid exhibits an excellent initial Coulombic efficiency (ICE > 83 %) and superb cyclic performance (1218 mAh/g after 500 cycles at 0.2 A/g and 752 mAh/g after 1050 cycles at 1 A/g). This research provides practical solutions for the intrinsic challenges associated with multi-component alloying and conversion-type electrode materials in next-generation metal-ion batteries. [ABSTRACT FROM AUTHOR]

LiF‐rich solid‐electrolyte‐interphase (SEI) can suppress the formation of lithium dendrites and promote the reversible operation of lithium metal batteries. Regulating the composition of naturally formed SEI is an effective strategy, while understanding the impact and role of fluorine (F)‐based Li‐salts on the SEI characteristics is unavailable. Herein, LiFSI, LiTFSI, and LiPFSI are selected to prepare solid polymer electrolytes (SPEs) with poly(ethylene oxide) and polyimide, investigating the effects of molecular size, F contents and chemical structures (F‐connecting bonds) of Li‐salts and revealing the formation of LiF in the SEI. It is shown that the F‐connecting bond is more significant than the molecular size and F element contents, and thus the performances of cells using LiPFSI are slightly better than LiTFSI and much better than LiFSI. The SPE containing LiPFSI can generate a high amount of LiF, and SPEs containing LiPFSI and LiTFSI can generate Li3N, while there is no Li3N production in the SEI for the SPE containing LiFSI. The preferential breakage bonds in LiPFSI are related to its position to Li anode, where Li‐metal as the anode is important in forming LiF, and consequently the LiPFSI reduction mechanism is proposed. This study will boost other energy storage systems beyond Li‐ion chemistries. [ABSTRACT FROM AUTHOR]

Operation of lithium‐based batteries at low temperatures (<0 °C) is challenging due to transport limitations as well as sluggish Li+ kinetics at the electrode interface. The complicated relationships among desolvation, charge transfer, and transport through the solid electrolyte interphase (SEI) at low temperatures are not well understood, hindering electrolyte development. Here, an ether/hydrofluoroether and fluoroethylene carbonate (FEC)‐based ternary solvent electrolyte is developed to improve Li cycling at low temperatures (Coulombic efficiency of 93.3% at ‐40 °C), and the influence of the local solvation structure on interfacial Li+ kinetics and SEI chemistry is further revealed. The hydrofluoroether cosolvent allows for modulation of the solvation structure, thereby enabling facile Li+ desolvation while forming an inorganic‐rich SEI, which are both beneficial for lowering Li+ kinetic barriers at the interface. This cosolvent also increases the oxidative stability of the electrolyte to over 4.0 V versus Li/Li+, thereby enabling cycling of NMC‐based full cells at −40 °C. This study advances the understanding of the influence of Li+ solvation structure, SEI chemistry, and interfacial Li+ kinetics on Li electrochemistry at low temperatures, providing new design considerations for creating effective low‐temperature electrolyte systems. [ABSTRACT FROM AUTHOR]

Interfacial instability, viz., pore formation in the lithium metal anode (LMA) during discharge leading to high impedance, current focusing induced solid–electrolyte (SE) fracture during charging, and formation/behaviour of the solid–electrolyte interphase (SEI), at the anode, is one of the major hurdles in the development of solid‐state batteries (SSBs). Also, understanding cell polarization behaviour at high current density is critical to achieving the goal of fast‐charging battery and electric vehicle. Herein, via in situ electrochemical scanning electron microscopy (SEM) measurements, performed with freshly deposited lithium microelectrodes on transgranularly fractured fresh Li6PS5Cl (LPSCl), the LiǀLPSCl interface kinetics are investigated beyond the linear regime. Even at relatively small overvoltages of a few mV, the LiǀLPSCl interface shows non‐linear kinetics. The interface kinetics possibly involve multiple rate‐limiting processes, i.e., ion transport across the SEI and SE|SEI interfaces, as well as charge transfer across the LiǀSEI interface. The total polarization resistance RP of the microelectrode interface is determined to be ≈ 0.8 Ω cm2. It is further shown that the nanocrystalline lithium microstructure can lead to a stable LiǀSE interface via Coble creep along with uniform stripping. Also, spatially resolved lithium deposition, i.e., at grain surface flaws, grain boundaries, and flaw‐free surfaces, indicates exceptionally high mechanical endurance of flaw‐free surfaces toward cathodic load (>150 mA cm−2). This highlights the prominent role of surface defects in dendrite growth. [ABSTRACT FROM AUTHOR]

The transition from lithium‐based energy storage to post lithium systems plays a crucial part in achieving an environmentally sustainable energy infrastructure. Prime candidates for the replacement of lithium are sodium and potassium batteries. Despite being critical to battery performance, the solid electrolyte interphase (SEI) formation process for Na and K batteries remains insufficiently understood, especially compared to the well‐established lithium systems. Using ab initio molecular dynamics (AIMD) simulations based on density functional theory (DFT) calculations, we study the first steps of SEI formation upon the decomposition of typical solvent molecules on lithium, sodium and potassium metal anodes. We find that two dominant products form during the early SEI formation of cyclical carbonates on alkali metal anodes, carbon monoxide and alkali‐carbonate. The carbonate‐producing reaction is thermodynamically favorable for all tested metals, however, Na and K exhibit a much stronger selectivity than Li towards carbonate formation. Furthermore, we propose a previously unknown reaction mechanism for the CO polymerization on metallic lithium. [ABSTRACT FROM AUTHOR]

Lithium-ion battery formation affects battery cost, energy density, and lifetime. An improved understanding of the first cycle of solid-electrolyte interphase (SEI) growth on carbonaceous negative electrodes could aid in the design of optimized formation protocols. In this work, we systematically study SEI growth during the formation of carbon black negative electrodes in a standard carbonate electrolyte. We show that the initial ethylene carbonate (EC) reduction reaction occurs at ∼0.5-1.2 V during the first lithiation, except under fast lithiation rates (≥10C). The products of this EC reduction reaction do not passivate the electrode; only the SEI formed at lower potentials affects the second-cycle Coulombic efficiency. Thus, cycling quickly through the voltage regime of this reaction can decrease both formation time and first-cycle capacity loss, without an increase in subsequent-cycle capacity loss. We also show that the capacity consumed by this reaction is minimized at low temperatures and low salt concentrations. Finally, we discuss the mechanism behind our experimental results. This work reveals the fundamental processes underlying initial SEI growth on carbonaceous negative electrodes and provides insights for both optimizing the battery formation process and enabling novel electrolytes.

Abstract Interfacial instability, viz., pore formation in the lithium metal anode (LMA) during discharge leading to high impedance, current focusing induced solid–electrolyte (SE) fracture during charging, and formation/behaviour of the solid–electrolyte interphase (SEI), at the anode, is one of the major hurdles in the development of solid‐state batteries (SSBs). Also, understanding cell polarization behaviour at high current density is critical to achieving the goal of fast‐charging battery and electric vehicle. Herein, via in situ electrochemical scanning electron microscopy (SEM) measurements, performed with freshly deposited lithium microelectrodes on transgranularly fractured fresh Li6PS5Cl (LPSCl), the LiǀLPSCl interface kinetics are investigated beyond the linear regime. Even at relatively small overvoltages of a few mV, the LiǀLPSCl interface shows non‐linear kinetics. The interface kinetics possibly involve multiple rate‐limiting processes, i.e., ion transport across the SEI and SE|SEI interfaces, as well as charge transfer across the LiǀSEI interface. The total polarization resistance RP of the microelectrode interface is determined to be ≈ 0.8 Ω cm2. It is further shown that the nanocrystalline lithium microstructure can lead to a stable LiǀSE interface via Coble creep along with uniform stripping. Also, spatially resolved lithium deposition, i.e., at grain surface flaws, grain boundaries, and flaw‐free surfaces, indicates exceptionally high mechanical endurance of flaw‐free surfaces toward cathodic load (>150 mA cm−2). This highlights the prominent role of surface defects in dendrite growth.

Due to the high abundance of their components, low cost, and high safety, zinc‐based batteries open up new vistas for large‐scale energy storage. However, their stability, lifetime, and reversibility are impaired by passivation and dendrite growth of the Zn anode. Here, this challenge is circumvented by an iodine post‐functionalized zeolitic imidazolate framework‐90 (ZIF‐90‐I) additive, in which the polycation absorbed on Zn anode can regulate solid–electrolyte interphase (SEI) formation in the 1 m Zn(TFSI)2 electrolyte and induce Zn2+ uniform deposition. Moreover, the I3−/I− redox can rejuvenate dead Zn and inhibit dendrites. With the ZIF‐90‐I additive, Zn plating/stripping at 99.5% Coulombic efficiency for 120 cycles is obtained in Zn||Ti cells at 20 mA cm−2/1 mAh cm−2. In addition, Zn||Zn cells show steady cycling for 1200 h at 5 mA cm−2/1 mAh cm−2 with stable overpotentials. The utilization rate of Zn reaches up to 68.6%. In situ optical microscopy reveals smooth, uniform Zn plating, and the Zn‐rejuvenated function from the I3−/I− redox couple. The refreshed SEI with the increase of Zn‐rich complexes, and nitrides from adsorbed polycations, are uniform and ZnF2‐rich in the Zn(TFSI)2 + ZIF‐90‐I electrolyte. The full Zn||air cells in Zn(TFSI)2 + ZIF‐90‐I electrolyte exhibit excellent cycling stability with stable polarization voltage at 0.1 mA/0.05 mAh cm−2. [ABSTRACT FROM AUTHOR]

Rechargeable batteries with iodine‐based cathodes have recently been the subject of significant interest due to the moderately high theoretical specific energy (≈600 Wh kg−1) and high‐rate capability (>5 C) of the iodine cathode. Progress however has been impeded by the relatively low iodine contents of reported iodine‐based cathodes. This is likely due to high rates of poly‐iodide shuttling and cell instability that takes place at higher cell loadings. To reinforce the lithium metal anode, oxygen gas is introduced in the cells, which leads to a more robust solid‐electrolyte interphase (SEI) layer, improving cell stability. This oxygen‐assisted lithium‐iodine (OALI) battery overcomes many of the shortcomings of other reported lithium‐iodine batteries by utilizing a simple to fabricate lithium iodide (LiI) on activated carbon cathode with cell operating under an oxygen containing atmosphere to realize high‐rate capability (>50 mA cm−2) and high areal capacity (>12 mAh cm−2). [ABSTRACT FROM AUTHOR]

A novel poly(ether block amide) (PEBA) based solid-state polymer electrolyte (SPE) was prepared using a casting method, in which 20wt% lithium (Li) bis-(trifluoromethanesulfonyl)imide (LiTFSI) and aluminum oxide (Al 2 O 3) nanoparticles were used as the Li salt and solid plasticizer, respectively. In the case of addition of 3wt% Al 2 O 3 nanoparticles, ion conductivity of the obtained PEBA 2533-20wt% LiTFSI-3wt% Al 2 O 3 SPE was 3.57 × 10 - 5 S cm - 1 at 25 °C. Furthermore, the Li symmetrical battery assembled with it showed excellent cycling stability (1000 h) at 0.1 mA cm - 2. While, the assembled all-solid-state Li/PEBA 2533-20% LiTFSI-3wt% Al 2 O 3/LiFePO 4 (areal capacity: 0.15 mAh cm - 2) battery maintained 94.9% of the maximal capacity (133.9 mAh g - 1@0.1 mA cm - 2) at 60 °C even after 650 cycles with a superior average coulombic efficiency (CE) of 99.84%. By using X-ray photoelectron spectroscope (XPS), self-aggregation layer (SAL) of polyamide 12 (PA12) of PEBA 2533 was discovered, which should contribute to promoting the robustness of lithium fluoride (LiF) enriched solidelectrolyte interphase (SEI) layer. In addition, it is considered that the state of interface between SPE and cathode should be the cause of voltage polarization of the full cell. [ABSTRACT FROM AUTHOR]

The universal cathode crossover such as chemical and oxygen has been significantly overlooked in lithium metal batteries using high‐energy cathodes which leads to severe capacity degradation and raises serious safety concerns. Herein, a versatile and thin (≈25 μm) interlayer composed of multifunctional active sites was developed to simultaneously regulate the Li deposition process and suppress the cathode crossover. The as‐induced dual‐gradient solid‐electrolyte interphase combined with abundant lithiophilic sites enable stable Li stripping/plating process even under high current density of 10 mA cm−2. Moreover, X‐ray photoelectron spectroscopy and synchrotron X‐ray experiments revealed that N‐rich framework and CoZn dual active sites can effectively mitigate the undesired cathode crossover, hence significantly minimizing Li corrosion. Therefore, assembled lithium metal cells using various high‐energy cathode materials including LiNi0.7Mn0.2Co0.1O2, Li1.2Co0.1Mn0.55Ni0.15O2, and sulfur demonstrate significantly improved cycling stability with high cathode loading. [ABSTRACT FROM AUTHOR]

Na metal is an attractive anode material for rechargeable Na ion batteries, however, the dendritic growth of Na can cause serious safety issues. Along with modifications of solid-electrolyte interphase (SEI), engineering the electrode has been reported to be effective in suppressing Na dendritic growth, likely by reducing localized current density accumulation. However, fundamental understanding of Na growth at the nanoscale is still limited. Here, we report an in-situ study of Na electrodeposition in electrochemical liquid cells with the electrodes in different surface roughness, e.g., flat or sharp curvature. Real time observation using transmission electron microscopy (TEM) reveals the Na electrodeposition with remarkable details. Relatively large Na grains (in the micrometer scale) are achieved on the flat electrode surface. The local SEI thickness variations impact the growth rate, thus the morphology of individual grains. In contrast, small Na grains (in tens of nanometers) grow explosively on the electrode at the point with sharp curvature. The newly formed Na grains preferentially deposit at the base of existing grains close to the electrode. Further studies using continuum-based computational modeling suggest that the growth mode of an alkali metal (e.g. Na) is strongly influenced by the transport properties of SEI. Our direct observation of Na deposition in combination with the theoretical modeling provides insights for comprehensive understanding of electrode roughness and SEI effects on Na electrochemical deposition.

Na metal is an attractive anode material for rechargeable Na ion batteries, however, the dendritic growth of Na can cause serious safety issues. Along with modifications of solid-electrolyte interphase (SEI), engineering the electrode has been reported to be effective in suppressing Na dendritic growth, likely by reducing localized current density accumulation. However, fundamental understanding of Na growth at the nanoscale is still limited. Here, we report an in-situ study of Na electrodeposition in electrochemical liquid cells with the electrodes in different surface roughness, e.g., flat or sharp curvature. Real time observation using transmission electron microscopy (TEM) reveals the Na electrodeposition with remarkable details. Relatively large Na grains (in the micrometer scale) are achieved on the flat electrode surface. The local SEI thickness variations impact the growth rate, thus the morphology of individual grains. In contrast, small Na grains (in tens of nanometers) grow explosively on the electrode at the point with sharp curvature. The newly formed Na grains preferentially deposit at the base of existing grains close to the electrode. Further studies using continuum-based computational modeling suggest that the growth mode of an alkali metal (e.g. Na) is strongly influenced by the transport properties of SEI. Our direct observation of Na deposition in combination with the theoretical modeling provides insights for comprehensive understanding of electrode roughness and SEI effects on Na electrochemical deposition.

Li‐metal battery (LMB) suffers from the unexpected Li dendrite growth and unstable solid‐electrolyte interphase (SEI), especially in the extreme conditions, such as high rates and low temperatures (LT). Herein, a high‐rate and stable LT LMB is realized by regulating electrolyte chemistry. A weak Li+‐solvating solvent 2‐methyltetrahydrofuran is used as electrolyte solvent to mitigate the kinetic barrier for Li+ de‐solvation. Moreover, a co‐solvent tetrahydrofuran with a high donor number is incorporated to improve the LT solubility of Li salts, achieving an improved ionic conductivity while maintaining the weak Li+‐solvation effect. Furthermore, abundant FSI‐ anions in contact‐ion pairs are presented, facilitating the formation of a stable LiF‐enriched SEI. Consequently, the Li||Li battery can be operated at 10 mA cm‐2 with a small polarization of 154 mV at −40 °C. Meanwhile, an outstanding cumulative cycling capacity of 4000 mAh cm‐2 at 8.0 mA cm‐2 is achieved, reaching a record high level in LT alkali metal symmetric batteries. Also, rechargeable high‐rate and stable full batteries are achieved at −40 °C. This work demonstrates the superiority of electrolyte chemistry for synergistic regulation of both ion transfer kinetics and SEI toward ultrafast and stable rechargeable LMBs at LT. [ABSTRACT FROM AUTHOR]

Solid‐electrolyte interphase (SEI) seriously affects battery's cycling life, especially for high‐capacity anode due to excessive electrolyte decomposition from particle fracture. Herein, we report an ultrathin SEI (3–4 nm) induced by Cu+‐tailored double electrical layer (EDL) to suppress electrolyte consumption and enhance cycling stability of CuS anode in sodium‐ion batteries. Unique EDL with SO3CF3‐Cu complex absorbing on CuS in NaSO3CF3/diglyme electrolyte is demonstrated by in situ surface‐enhanced Raman, Cyro‐TEM and theoretical calculation, in which SO3CF3‐Cu could be reduced to CuF2‐rich SEI. Dispersed CuF2 and F‐containing compound can provide good interfacial contact for formation of ultrathin and stable SEI film to minimize electrolyte consumption and reduce activation energy of Na+ transport. As a result, the modified CuS delivers high capacity of 402.8 mAh g−1 after 7000 cycles without capacity decay. The insights of SEI construction pave a way for high‐stability electrode. [ABSTRACT FROM AUTHOR]