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Electrochemical CO2reduction reaction (eCO2RR) is a meaningful way for CO2depletion and value addition. And electrocatalysts play great roles in the CO2reduction product selectivity. SnOx-based catalysts have been widely used in formate production. However, the activity and selectivity are still unsatisfying, especially at the industrial level current density (>0.2 A cm–2) for pure HCOOH production. In this work, we proposed a triple-metal composite electrocatalyst with high oxygen vacancy contents and an abundant grain-boundary strategy for the eCO2RR. In particular, oxygen vacancies in the designed catalyst reached 13.9%. When catalysts were employed as catalysts for eCO2RR, both high HCOOH FE and long-term electrolysis stability under acid electrolytes were obtained. The FE of HCOOH was around 87.9% at 0.3 A cm–2and was stable even after 15,000 s of electrolysis. This work provides a new path for electrocatalyst design and highly efficient HCOOH production.

Because of the high specific capacity and low cost, Ni-rich layered oxide (NRLO) cathodes are one of the most promising cathode candidates for the next high-energy-density lithium-ion batteries. However, they face structure and interface instability challenges, especially the battery safety risk caused by using an intrinsic flammable organic liquid electrolyte. In this regard, a solid electrolyte with high safety is of great significance to promote the development of energy storage. Among them, sulfide electrolytes are considered to be the most potential substitutes for liquid electrolytes because of their high ionic conductivity and good processing properties. Nevertheless, the interfacial incompatibility between the sulfide electrolyte and NRLO cathode is the critical challenge for high-performance sulfide all-solid-state lithium batteries (ASSLBs). In this review, we summarize the problems of the Ni-rich cathode/sulfide solid electrolyte interface and the strategies to improve the interface stability. On the basis of these insights, we highlight the scientific problems and technological challenges that need to be resolved urgently and propose several potential directions to further improve the interface stability. The objective of this study is to provide a comprehensive understanding and insightful recommendations for the enhancement of the sulfide ASSLBs with NRLO cathode.

The ether-based electrolytes show excellent performance on anodes in sodium-ion batteries (SIBs), but they still show poor compatibility with the cathodes. Here, ether electrolytes with NaBF4as the main salt or additive were applied in NFM//HC full cells and showed enhanced performance than the electrolyte with NaPF6. Then, BF4–was found to have a stronger interaction with Na+, which could reduce the solvation of Na+with the solvent, thus inducing the formation of the cathode electrolyte interface (CEI) and solid electrolyte interface (SEI) layers rich in inorganic species. Moreover, the morphology, structure, composition, and solubility of CEI and SEI were explored, concluding that NaBF4could induce more stable CEI and SEI layers rich in B-containing species and inorganics. This work proposes using NaBF4as the main salt or additive to improve the performance of ether electrolytes in NFM//HC full cells, which provides a strategy to improve the compatibility of ether-based electrolytes and cathodes.

•Multi-scale boron penetration from atomic to particle levels is proposed toward stabilizing Ni-rich cathode.•Trace boron doping in TM sites of surface layer strengthens structural stability.•Conductive LBO as binder facilitates Li+diffusion and ameliorates intergranular cracks formation.•LBO coated on primary/secondary particle surface alleviates gas evolution during electrochemical process.

The electrochemical CO2reduction reaction (CO2RR) is a promising approach to upgrading CO2into methane (CH4) and other high-value-added chemicals, critical for lowering carbon emissions and mitigating the greenhouse effect. However, the selectivity of CO2RR to methane remains low at the current densities required for commercialization. Herein, we report a simple one-step synthesis of monodisperse copper-based catalysts for efficient electromethanation of CO2. Through rational regulation of active sites, the selectivity for methane production can reach as high as 57.02% under the current density of 300 mA cm–2as a result of suppressed C–C coupling for improved *CO hydrogenation. This work offers an effective strategy to regulate Cu-based catalysts to manage the hydrogenation of *CO for CO2RR toward CH4formation.

The lithiophilic interconnected CuxO nanofibers, which provide abundant pathways for electron transmission that boosts the kinetics of electrochemical reactions, are beneficial for the uniform deposition of lithium metal.

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The increasing demand for energy density pushes LiCoO2(LCO) to work at higher voltage (≥4.5 V), which brings a series of problems including detrimental phase transition and structural instability. Various elemental doping has been proven an effective strategy to improve its structure stability. However, the understanding of elemental doping homogeneity effect is not enough, whether in terms of the controllability of doping homogeneity or its complex consequences. In this work, LCO powders with different Al doping homogeneity were synthesized and tested under high voltage (≥4.5 V) in both half and full cell at room and high temperature, respectively. The results show that the Al homogeneously doped LCO showed better cycling stability and rate performance compared to the inhomogeneous LCO sample. Particularly, the discharge capacity of Al homogeneously doped LCO after 500 cycles under 4.5 V in full cells could reach 160.1 mAh/g at 1.0 C with 94.1 % capacity retention. Postmortem characterization demonstrates that a better doping homogeneity favors the stability of both the bulk and interface as well as the kinetic conditions. This study provided new insights about LCO performance fading, which sheds new light on the development of high-voltage LCO products

Metal-loaded nitrogen-doped carbon (M@N–C) catalysts have shown promise as electrocatalysts for replacing noble metal catalysts in industrial processes. To study the influence on structural and performance caused by different bimetal doping, a family of bimetals CoM@N–C (M = Cu/Ni/Fe) composites with porous surface and abundant C defects were well-designed. After bimetallic doping, more defects are introduced into the carbon frameworks, and the metal-N species are fixed. As such, efficient utilization of active sites and rapid mass transfer make the reaction kinetics process more favorable and stable. Density functional theory calculations indicate that Cu/Ni doping optimizes the electronic environment of the Co–N, resulting in the balanced adsorption and dissociation of oxygen intermediates. While the synergy of FeCo activates the O=O, which promotes the sharp decrease in free energy of ∗OOH to ∗O, shifting the rate-determining step for oxygen reduction reaction. This indicates the adsorption site transfer of CoFe0.05@N–C in oxygen reduction and evolution reactions. The CoFe0.05@N–C catalyst exhibits superior bifunctional catalytic activity (with a potential gap of 0.80 V) than that of Pt catalysts. This work presents a simple strategy to fabricate well-defined bimetals doping in bifunctional oxygen electrocatalysts and it is expected to inspire future work on the role of electronic structure modulation and interface engineering.

Ultra-high nickel material is considered to be a promising cathode material. However, with the increase of nickel content, the interfacial side reactions between the cathode and electrolyte become increasingly serious. Herein, an atomically controllable ionic conductor Li3PO4(LPO) coating is deposited on the LiNi0.90Co0.06Mn0.04O2(NCM9064) based electrode by the atomic layer deposition method. The results shows that the LPO coating is uniformly and densely covered on the surface of secondary particles of NCM9064, helping to prevent the direct contact between the electrolyte and cathode during the charging-discharging process. In addition, the coating layer is electrochemically stable. As a result, the interfacial side reactions during the long cycle are effectively suppressed, and the solid electrolyte interphase layer at the interface is stabilized. The electrode with 20 layers of LPO deposition (ALD-LPO-20) exhibits an excellent capacity retention of 81% after 200 cycles in 2.8-4.3 V at 25 °C, which is 18% higher than the unmodified material (ALD-LPO-0). Besides, the moderate LPO coating improves the rate capability and high temperature cycling performance of NCM9064. This study provides a method for the modification of ultra-high nickel cathode materials and corresponding electrodes.

LiNO3is introduced as collaborate lithium salts for controlling particle size of single crystal LiNi0.9Co0.055Mn0.045O2cathode. The as-prepared materials at the size of 1 μm shows the best kinetics of Li+diffusion and electrochemical performance.

Polytungstates uniformly embedding into highly-conductive CNFs present joint contribution of chemical absorbing and physical blocking to suppressing the shuttling of polysulfides.

Overcharge safety is of great importance for extending the application of lithium ion batteries. The evolution of morphology, structural and thermal stability of lithium ion batteries during overcharge are systematically investigated in this work.

Multifunctional LiAlSiO4embedded PEO polymer, characterized as excellent Li+conduction properties, good electrochemical stability and enhanced mechanical strength, constructs high-performance solid-state lithium batteries with large specific capacity, good rate capability, and superior cycling stability.

Lithium ion capacitors (LICs) have been widely used as energy storage devices due to their high energy density and high power density. For LICs, pre-lithiation of negative electrode is necessary. In this work, we employ a bifunctional Li6CoO4(LCO) as cathodic pre-lithiation reagent to improve the electrochemical performance of LICs. The synthesized LCO exhibited high first charge specific capacity of 721 mAh g−1and extremely low initial coulombic efficiency of 3.19%, providing sufficient Li+for the pre-lithiation of negative electrode in the first charge. Simultaneously, Li6–xCoOyis generated from LCO during the first charge process, which exhibits pseudocapacitive property and contributes to capacity in form of surface capacitance during subsequent cycles, increasing the capacity of capacitive positive electrode. With the appropriate amounts of addition to the positive side in LICs, this bifunctional prelithiation reagent LCO shows significantly improved the electrochemical performance with the energy density of 78.5 Wh kg−1after 300 cycles between 2.0 and 4.2 V at 250 mA g−1.

Polycations are used extensively in applications ranging from enhanced oil recovery to biomaterials. Poly[N,N-(dimethylamino)ethyl acrylate] (PDMAEA) has attracted interest for biomaterial applications because of its rapid hydrolysis; however, the mechanism of hydrolysis and the conditions that affect degradation often appear amiss in the field. In this report, a detailed 1H NMR spectroscopy study of the hydrolysis of PDMAEA was carried out between pH 0 and 14. In contrast to a widely held view, the rates of hydrolysis of this polymer were found to be highly pH-dependent with half-lives varying from years to minutes as a function of pH. The extent of hydrolysis was also found to be pH-dependent, with a distinct plateau at about 50–60% hydrolysis at pH 7 due to the electrostatic repulsion of anionic carboxylate groups and hydroxide. This was contrasted with the acid-catalyzed mechanism where hydrolysis of PDMAEA at pH 0.3 did not show a plateau in the extent of hydrolysis, reaching 88% hydrolysis after 8 days at 70 °C. In addition, the effects of neighboring functional groups on DMAEA hydrolysis in copolymers were explored, with anionic, neutral/hydrophilic, and cationic comonomers found to affect the rates of hydrolysis up to 20-fold at pH 7. Finally, two novel analogues of DMAEA with an additional dimethylamino group in different positions of the side chain were synthesized and polymerized to probe the effect of this added tertiary amine on the hydrolysis of the ester linkages. Poly[1,3-bis (dimethylamino)-2-propyl acrylate] (PBDMAPA) hydrolyzed more than 500 times faster at pH 7 than its linear isomer poly[2-((2-(dimethylamino)ethyl)(methyl)amino)ethyl acrylate] (PDEMEA). These results further highlight the importance of the intramolecular interactions of the dimethylamino substituent of PDMAEA and the effect of proximity and steric hindrance of the amino group as well as neighboring functional groups of comonomers.

Si anode is considered to be one of the most promising candidates for the next-generation lithium-ion batteries (LIBs). However, the severe volume variation of Si (>300%) during the lithiation/delithiation process results in unstable interface and thus contributes to poor cycling stability. Moreover, the relatively low conductivity derived from the semiconductor nature of Si leads to inferior rate performance. Herein, Li2SiO3layer with fast lithium-ions transport capability and high mechanical property was formed on Si surface in an in-situ electrochemical method. The relationships between the valence of SiOxand LixSiOyconstituents were readily studied. Fortunately, the as-prepared Si@ES-LSO showed great potential to mitigate the expansion and high lithium-ions diffusion coefficient. When employed as anode materials for LIBs, the modified Si anode delivered a specific capacity of 2074.8 mAh g-1at 1000 mA g-1with a retention ratio of 98.9% after 100 cycles, demonstrating superior electrochemical performance. This work provides a facial and efficient strategy for the roadmap of Si anode application.

LiNiO2(LNO) is one of the most promising cathode materials for lithium-ion batteries. Tungsten element in enhancing the stability of LNO has been researched extensively. However, the understanding of the specific doping process and existing form of W is still not perfect. This study proposes a lithium-induced grain boundary phase W doping mechanism. The results demonstrate that the introduced W atoms first react with the lithium source to generate a Li-W-O phase at the grain boundary of primary particles. With the increase of lithium ratio, W atoms gradually diffuse from the grain boundary phase to the interior layered structure to achieve W doping. The feasibility of grain boundary phase doping is verified by first principles calculation. Furthermore, it is found that the Li2WO4grain boundary phase is an excellent lithium ion conductor, which can protect the cathode surface and improve the rate performance. The doped W can alleviate the harmful H2↔H3 phase transition, thereby inhibiting the generation of microcracks, and improving the electrochemical performance. Consequently, the 0.3wt% W-doped sample provides a significant improved capacity retention of 88.5% compared with the pristine LNO (80.7%) after 100 cycles at 2.8-4.3 V under 1 C.

Nickel-rich cathode materials have received widespread attention due to their high energy density. However, the poor rate capability and inferior cycle stability seriously hinder their large-scale application. The traditional co-precipitation method for preparing them has a long process and easily arises agglomeration leading to inhomogeneous element distribution. Here, a novel precursor containing Li element was prepared by ultrafast spray pyrolysis (SP) in 3-5 s. Then the precursor was used to synthesize pristine LiNi0.9Co0.05Mn0.05O2(NCM90) and 1% Mg modified LiNi0.9Co0.05Mn0.05O2(NCM90-Mg1). This method gets rid of mixing Li/Mg source and the precursor prepared by common co-precipitation, thus could achieve homogeneous lithiation and Mg2+doping. The cell parameter cis expanded, and the cation disorder is reduced after Mg2+doping. Furthermore, the harmful H2-H3 phase transition in NCM90-Mg1 is also well suppressed. As a result, the obtained NCM90-Mg1 shows better electrochemical performance than NCM90. Within 2.8-4.3 V (25 °C), the specific discharge capacity of NCM90-Mg1 at 5 C is as high as 169.1 mAh/g, and an outstanding capacity retention of 70.0% (10.0% higher than NCM90) can be obtained after 400 cycles at 0.5 C. At 45 °C, a capacity retention of 81.9% after 100 cycles at 1 C is recorded for NCM90-Mg1. Moreover, the NCM90-Mg1 also exhibits superior cycle stability when cycled at high cut-off voltage (4.5 V, 25 °C), possessing the capacity retention of 79.2% after 200 cycles at 1 C. Therefore, SP can be proposed as a powerful method for the preparation of multi-element materials for next-generation high energy density LIBs.

The matching of poly(ethylene oxide) (PEO)-based electrolytes with ultrahigh-nickel cathode materials is crucial for designing new-generation high-energy-density solid-state lithium metal batteries (SLMBs), but it is limited by serious interfacial side reactions between PEO and ultrahigh-nickel materials. Here, a high-concentration electrolyte (HCE) interface with a customized Li+solvation sheath is constructed between the cathode and the electrolyte. It induces the formation of an anion-regulated robust cathode/electrolyte interface (CEI), reduces the unstable free-state solvent, and finally achieves the compatibility of PEO-based electrolytes with ultrahigh-nickel cathode materials. Meanwhile, the corrosion of the Al current collector caused by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) ions is prevented by lithium difluoro(oxalato)borate (LiDFOB) ions. The synergistic effect of the double lithium salt is achieved by a well-tailored ratio of TFSI–and DFOB–in the first solvation sheath of Li+. Compared with reported PEO-based SLMBs matched with ultrahigh-nickel (Ni ≥ 90%) cathodes, the SLMB in this work delivers a high discharge specific capacity of 216.4 mAh g–1(0.1C) even at room temperature. This work points out a direction to optimize the cathode/electrolyte interface.

A thermodynamically directed Ta/Ti dual-modification has been proposed to successfully engineer a multifunctional Ni-rich LiNi0.834Co0.11Mn0.056O2cathode incorporating a LiTaO3grain boundary coating alongside simultaneous Ti-doping, which is determined by the variation tendency of the structure/interface formation energy when introducing foreign elements. Notably, the dual-modification strategy significantly improves the structural/interfacial stability and Li+diffusion kinetics of Ni-rich cathode.

In this paper, electrochemical performance of coated titanium anodes in the manganese electrowinning process are investigated. The turbid anolyte can be avoid by using coated titanium anodes compared to conventional Pb anodes, and the generation of manganese dioxide (MnO2) on anode can be also reduced. The deposited manganese dioxide layer on coated titanium anodes are uniform and compact after electrolysis by using Scanning electron microscopy (SEM), which is totally different from that on Pb anodes. The possible mechanism involving permanganate ion is proposed and confirmed by Square wave voltammetry (SWV) and in-situ ultraviolet-visible spectrophotometry (UV-VIS). Moreover, the cell voltage for coated titanium anodes is about 270 mV lower than that of traditional Pb anodes, exhibiting well energy saving effect. Linear sweep voltammetry and Tafel curves show that coated titanium anodes have lower Tafel slope and possess a better catalytic property for oxygen evolution reaction. Finally X-ray photoelectron spectroscopy (XPS) analysis manifests the Ru element can be oxidized to a higher valence state and has a blocking effect for active oxygen. Our results here offer some basic electrochemical data for the anode in electrolytic manganese system, and provide a promising path for replacing Pb anodes in electrolytic manganese industry.

The rapid rise of electrode impedance and capacity decay of Ni‐rich layered cathode materials during high‐voltage cycling are rooted in their severe structural degradation. Here we present a feasible strategy, anchoring ∼1 % K+into the Li+sites of LiNi0.8Co0.15Al0.05O2as an excellent structural stabilizer, to overcome aforementioned issues, and the similarities and differences in terms of modification mechanism is compared with Na+. Showing difference with Na+that tends to migrate into electrolyte during high‐voltage cycling, K+occupies in Li+site firmly because of its larger ionic radius and lower migrating ability, which sustainably prevent the irreversible phase transition between two hexagonal phases (H2 and H3) and impede the cation migration in highly delithiated state, thus suppressing the structural degradation. Benefiting from these merits, Li0.99K0.01Ni0.8Co0.15Al0.05O2delivers a large initial discharge capacity of 217 mAh g−1at 0.1 C and maintains stable cycling at 1 C in a high voltage of 4.6 V (remaining 87.4 % of its initial capacity after 150 cycles). The mechanism proposed in this work, accounting for enhanced structural stability under high‐voltage cycling by K+anchoring in Ni‐rich cathode materials, provides a vital hint for rational designing advanced cathode materials to pursue high energy density Li‐ion batteries. K+anchoring in Li+sites of LiNi0.8Co0.15Al0.05O2prevent the collapse of host structure and inhibit cation migration in highly delithiated state. Benefit from these, Li0.99K0.01Ni0.8Co0.15Al0.05O2exhibits superior high‐voltage electrochemical performances.

This study focuses on suppressing the voltage decay and improving the electrochemical performance of Li‐rich and manganese‐based (LRM) material by Nb2O5coating, which is realized by an effective soft‐chemical route using a mixture of ethanol and water as co‐solvent. After Nb2O5coating, the resulted material demonstrates superior electrochemical performance as cathode material for LIBs. Particularly, it shows an excellent capacity retention of 98 % after 200 cycles at 1 C (1 C=250 mA g−1). Voltage decay within cycling is also obviously suppressed by Nb2O5coating. Moreover, it exhibits superior rate capacities, delivering 189 and 152 mAh g−1at high current densities of 2 and 5 C, respectively. The improved electrochemical performance of Nb2O5coated sample can be attributed to that Nb2O5can suppress the phase transformation and voltage decay by acting as not only a fast ion conductor to accelerate the lithium ion diffusion at the cathode/electrolyte interface, but also an inert protective layer to reduce the direct contact between the cathode and electrolyte. A study on the suppressing the voltage decay and improving the electrochemical performance of Li‐rich and manganese‐based (LRM) material by Nb2O5coating, the protective effects of Nb2O5have been investigated systematically.

Accurate modeling and simulation of lithium-ion batteries are beneficial to predict the battery performance. However, the acquisition and verification of parameters are still the main factors that determine the accuracy of the model simulation results. In this paper, direct current internal resistance (DCR) is systematically decomposed differ from the timescale response characteristics and thus DCR decomposition model is constructed. The numerical expressions and the key parameters of different resistances components are reasonably evaluated. Based on the estimated original results, a series of parameters are successfully collected and the strong correlation to DCR is further defined. When applied the proposed DCR model to a commercial high voltage 4.45 V LiCoO2pouch battery, the simulated results can well match with the experiments, implying the workable of this strategy. This paper shed light on guiding electrochemical parameters design, especially for high energy-density commercial batteries.

Hard carbon draws great interests as anode material in lithium ion batteries (LIBs) due to its high theoretical capacity, high rate capability and abundance of its precursors. Herein we firstly synthesize the lignin-melamine resins by grafting melamine onto lignin. Afterwards, nitrogen doped hard carbon is prepared by the pyrolysis of lignin-melamine resins with the aid of catalyst (Ni(NO3)2·6H2O) at 1000 °C. Compared with the samples without nitrogen-doping and catalysis, as-prepared nitrogen doped hard carbon exhibits higher reversible capacity (345 mAh g–1at 0.1 A g−1), higher rate capability (145 mAh g−1at 5 A g–1) and excellent cycling stability. The superior electrochemical performance is ascribed to the synergistic effect of nitrogen doping, graphitic structure and amorphous structure. Among them, nitrogen doping could create the vacancies around the nitrogen sites, which enhance the reactivity and the electronic conductivity of materials. Additionally, graphitic structure also enhances the electronic conductivity of materials, thus improving the electrochemical performance of hard carbon. It is worthwhile that lignin, renewable and abundant biopolymer, is converted to hard carbon with good electrochemical performance, which realizes the high value utilization of lignin.

An Ostwald ripening-based route is proposed to prepare Ni-rich layered cathodes with Co-rich surface for lithium-ion batteries (LIBs). Commercially available Ni0.8Co0.1Mn0.1(OH)2and spray pyrolysis derived porous Co3O4are used as mixed precursors. During the lithiation reaction process under high-temperature, the porous Co3O4microspheres scatter primary particles and spontaneously redeposit on the surface of Ni-rich spheres according to Ostwald ripening mechanism, forming the Ni-rich materials with Co-rich outer layers. When evaluated as cathode for LIBs, the resultant material shows ability to inhibit the cation disorder, relieves the phase transition from H2 to H3 and diminishes side reactions between the electrolyte and Ni-rich cathode material. As a result, the obtained material with Co-rich outer layers exhibits much more improved cycle and rate performance than the material without Co-rich outer layers. Particularly, NCM-Co-1 (molar ratio of Ni0.8Co0.1Mn0.1(OH)2/Co3O4is 60:1) delivers a reversible capacity of 159.2 mA h g−1with 90.5% capacity retention after 200 cycles at 1 C. This strategy provides a general and efficient way to produce gradient substances and to address the surface problems of Ni-rich cathode materials. 本文提出了一种基于奥斯特瓦尔德熟化制备具有富钴表面的高镍正极材料的方法. 采用了商业化的Ni0.8Co0.1Mn0.1(OH)2和喷雾热解制备了多孔Co3O4作为前驱体. 在高温固相反应锂化过程中, 多孔的Co3O4会分解成颗粒. 根据奥斯特瓦尔德熟化过程, 这些颗粒与锂盐反应并自发地沉积于高镍材料的表面, 形成具有富钴表层的高镍正极材料. 作为锂离子电池正极材料时, 改性后的材料中阳离子的混排得到抑制, H2到H3的相变程度降低, 并减少了电解液和高镍正极材料之间的副反应. 因此, 具有富钴表层的高镍正极材料相比于原始材料循环和倍率性能得到很大提升. NCM-Co-1 (Ni0.8Co0.1Mn0.1(OH)2/Co3O4的摩尔比为 60:1)在1 C下循环200次放电容量仍有159.2 mA h g−1, 容量保持率为90.5%. 这一策略为制备梯度正极材料以及解决高镍正极材料的表面问题提供了一种通用而有效的方法.

In this study we report a series of nickel-rich layered cathodes LiNi1−2xCoxMnxO2(x = 0.075, 0.05, 0.025) prepared from chlorides solution via ultrasonic spray pyrolysis. SEM images illustrate that the samples are submicron-sized particles and the particle sizes increase with the increase of Ni content. LiNi0.85Co0.075Mn0.075O2delivers a discharge capacity of 174.9 mAh g−1with holding 93% reversible capacity at 1 C after 80 cycles, and can maintain a discharge capacity of 175.3 mAh g−1at 5 C rate. With increasing Ni content, the initial specific capacity increases while the cycling and rate performance degrades in some extent. These satisfying results demonstrate that spray pyrolysis is a powerful and efficient synthesis technology for producing Ni-rich layered cathode (Ni content > 80%).

It is of great significance to discover new negative electrode materials featuring a low operating voltage, high capacity and improved initial coulombic efficiency for lithium ion batteries. This is the first report on the use of orthorhombic Li3V(MoO4)3as a promising anode material that exhibits natural advantages over reported traditional metal oxides. High-crystalline Li3V(MoO4)3nanoparticles decorated with carbon are synthesized by a facile mechanochemical route followed by low-temperature (480°C) calcination. The lithium storage ability of the prepared Li3V(MoO4)3anode is fully tapped at 3.0–0.01V vs. Li+/Li, displaying a lower voltage plateau than the conversion-type metal oxides. It delivers a high reversible specific capacity of 999 mAh g−1at 50mAg−1and a high coulombic efficiency of 82.6%. Moreover, it maintains a capacity retention of 92% after 75 cycles at 500mAg−1. The GITT-determined Li+diffusion coefficient ranges from 10−10to 10–13cm2s−1along with the voltage. The lithium storage mechanism indicates that Li3V(MoO4)3can be considered a pre-lithiated material. In-situ XRD testing during the first cycle reflects the conversion reaction of Li3V(MoO4)3. These insights will benefit the discovery of novel anode materials for lithium-ion batteries.

The further development of lithium–sulfur (Li–S) batteries is limited by the fact that the soluble polysulfide leads to the shuttle effect, thereby reducing the cycle stability and cycle life of the batteries. To address this issue, here a thin and lightweight (8 μm and 0.24 mg cm–2) reduced graphene oxide@MoS2(rGO@MoS2) interlayer between the cathode and the commercial separator is developed as a polysulfide barrier. The rGO plays the roles of both a polysulfide physical barrier and an additional current collector, while MoS2has a high chemical adsorption for polysulfides. The experiments demonstrate that the Li–S cell constructed with an rGO@MoS2-coated separator shows a high reversible capacity of 1122 mAh g–1at 0.2 C, a low capacity fading rate of 0.116% for 500 cycles at 1 C, and an outstanding rate performance (615 mAh g–1at 2 C). Such an interlayer is expected to be ideal for lithium–sulfur battery applications because of its excellent electrochemical performance and simple synthesis process.

Nickel-rich cathode materials preparation requires a timewise lengthy and complicated chemical reaction, which results in challenges in determining a suitable sintering schedule to obtain a high-quality product. In this article, a multiparticle cellular automaton modeling method is proposed to capture and track the complex grain dynamics evolution process. According to the chemical reaction mechanism, the sintering process is divided into three main reactions, with each reaction's starting and ending temperature points determined based on thermal hysteresis. Then multiparticle state transition rules based on the Arrhenius formula and experiments data are constructed to obtain a multiparticle cellular automaton with kinetic properties. To realize dynamic simulation under multiple heating rates, a kinetic parameter transfer method is designed, in which particle swarm optimization and least squares estimation algorithms are adopted. Based on the above model, the final Li/Ni cation mixing parameter of the preparation is predicted by combining X-ray diffraction experiments analysis with the Li/Ni cation mixing law in reactions. The simulation results show that the proposed modeling method can accurately simulate the grain dynamics evolution of the cathode materials, which can provide a valuable reference for optimizing the sintering schedule in the sintering process of the cathode materials.

Sodium-ion batteries are one of the ideal devices for large-scale energy storage systems, and hard carbon is a promising negative electrode material for sodium-ion batteries. In this paper, we carefully study three commercial hard carbon (HC) materials with different structures and find that the interlayer spacing, defects, particle size, and pore size of the materials have significant impacts on the performance. The materials are used to analyze the sodium storage behaviors in the slope and plateau regions through charge/discharge, CV, and GITT tests. To eliminate the adverse impact of overpotential on the metal sodium electrode in the half-cell system, we use a three-electrode system to measure the capacity of different HCs in the slope and plateau regions. It is found that the sodium storage of the slope region is accompanied by both adsorption and intercalation behaviors. The K-HC with the largest interlayer spacing (0.393 nm) and the largest number of defects (AD/AGvalue is 1.30) has the highest sodium storage specific capacity (288.29 mAh·g–1) and slope area capacity contribution (107.04 mAh·g–1). In addition, the kinetics of different HC materials are studied. The GITT and EIS results indicate that Na+diffusion is the easiest in A-HC materials, so they exhibit better rate performance. Due to a large number of defects (AD/AG= 1.30) and large layer spacing (0.393 nm), the K-HC material has the highest capacitance contribution (0.2 mV·s–1, 47.6%) and sodium storage specific capacity (288.29 mAh·g–1).

The Ni-rich layered cathode material LiNi0.8Co0.1Mn0.1O2(NCM811) with high specific capacity and acceptable rate performance is one of the key cathode materials for high-energy-density lithium-ion batteries. Coprecipitation, the widely utilized method in the precursor synthesis of NCM811 materials, however, suffers long synthetic processes and challenges in uniform element distribution. The spray pyrolysis method is able to prepare oxide precursors in seconds where all transition-metal elements are well distributed, but the difficulty of lithium distribution will also arise when the lithium salts are added in the subsequent sintering process. Herein, a fresh one-step spray pyrolysis approach is proposed for preparing high-performance NCM811 cathode materials by synthesizing lithium-contained precursors in which all elements are well distributed at a molecular level. The precursors with folded morphology and exceptional uniformity are successfully obtained at a low pyrolysis temperature of 300 °C by an acetate system. Furthermore, the final products commendably inherit the folded morphology of the precursors and exhibit excellent cyclic retentions of 94.6% and 88.8% after 100 and 200 cycles at 1 C (1 C = 200 mA g–1), respectively.

This work proposes a capacity perturbation strategy to better reveal the potential of apparent critical current density of Li/solid electrolyte interface by decreasing the impact of the dynamic interfacial state variation on the measurement results.

Overcharge is one of the most common causes that triggers thermal runaway of lithium-ion batteries, which leads to personal injury and property loss. Therefore, it is momentous to penetrate into the mechanism of overcharge and enhance the overcharge safety from the essence of battery materials. Herein, the combined Al doping and Al2O3coating strategies are applied to the LiCoO2cathode materials, which are employed to enhance the overcharge performance of 950 mAh LiCoO2-based pouch-type full cells. The results show that only the pouch-type full cells using LiCoO2with both Al doping and Al2O3coating as cathode pass the 1C/10 V overcharge test successfully. In-situ X-ray diffraction (XRD) and differential electrochemical mass spectrometry (DEMS) results illustrate that the critical factors leading to thermal runaway lie in the structural instability of LiCoO2and the violent interfacial reaction rooted in electrolyte decomposition. Further post analysis of pouch-type full cells demonstrate that the enhanced overcharge safety depends on the synergetic effect of Al doping and Al2O3coating of LiCoO2. That is the Al doping can enhance the structural robustness of LiCoO2significantly, while the coated Al2O3works as a passive film to cut off the further reaction between the cathode and the electrolyte during overcharge.