Ultrathin Zincophilic Interphase Regulated Electric Double Layer Enabling Highly Stable Aqueous Zinc‑Ion Batteries

The practical application of aqueous zinc-ion batteries for large-grid scale systems is still hindered by uncontrolled zinc dendrite and side reactions.Regulating the elec-trical double layer via the electrode/electrolyte interface layer is an effective strategy to improve the stability of Zn anodes.Herein,we report an ultrathin zincophilic ZnS layer as a model regu-lator.At a given cycling current,the cell with Zn@ZnS electrode displays a lower potential drop over the Helmholtz layer(stern layer)and a suppressed diffuse layer,indicating the regulated charge distribution and decreased electric double layer repulsion force.Boosted zinc adsorption sites are also expected as proved by the enhanced electric double-layer capacitance.Consequently,the symmetric cell with the ZnS protection layer can stably cycle for around 3,000 h at 1 mA cm^(-2) with a lower overpotential of 25 mV.When coupled with an I2/AC cathode,the cell demonstrates a high rate performance of 160 mAh g^(-1) at 0.1 A g^(-1) and long cycling stability of over 10,000 cycles at 10 A g^(-1).The Zn||MnO_(2) also sustains both high capacity and long cycling stability of 130 mAh g^(-1) after 1,200 cycles at 0.5 A g^(-1).

锂金属阳极表面SEI膜的制备与研究

采用将锂金属阳极浸润在氟化铜混合溶液的方法对锂阳极表面进行SEI层的人工修饰。系统观察不同浓度氟化溶液和浸润时间对阳极表面生成SEI膜的影响,选择1.0%质量分数CuF_(2)溶液浸润10 s为最佳实验条件。结合电化学测试与形貌表征研究锂金属电池循环时间、阳极界面上锂的沉积情况和SEI层的力学性能,结果表明,人工SEI层在不同电流密度下将锂电池循环时间提高了160%~446%,促进锂在界面层均匀沉积且显著抑制锂枝晶的生长。研究结果对锂金属电池通过表面修饰实现长循环、高倍率充放电研究具有一定的指导意义。

Lithiophilic Li-Si alloy-solid electrolyte interface enabled by high-concentration dual salt-reinforced quasi-solid-state electrolyte

Solid polymer electrolytes(SPEs)are urgently required to achieve practical solid-state lithium metal batteries(LMBs)and lithium-ion batteries(LIBs),Herein,we proposed a mechanism for modulating interfacial conduction and anode interfaces in high-concentration SPEs by LiDFBOP.Optimized electrolyte exhibits superior ionic conductivity and remarkable interface compatibility with salt-rich clusters:(1)polymer-plastic crystal electrolyte(P-PCE,TPU-SN matrix)dissociates ion pairs to facilitate Li+transport in the electrolyte and regulates Li^(+)diffusion in the SEI.The crosslinking structure of the matrix compensates for the loss of mechanical strength at high-salt concentrations;(2)dual-anion TFSI^(-)_(n)-DFBOP^(-)_(m)in the Li^(+)solvation sheath facilitates facile Li^(+)desolvation and formation of salt-rich clusters and is conducive to the formation of Li conductive segments of TPU-SN matrix;(3)theoretical calculations indicate that the decomposition products of LiDFBOP form SEI with lower binding energy with LiF in the SN system,thereby enhancing the interfacial electrochemical redox kinetics of SPE and creating a solid interface SEI layer rich in LiF.As a result,the optimized electrolyte exhibits an excellent ionic conductivity of9.31×10^(-4)S cm^(-1)at 30℃and a broadened electrochemical stability up to 4.73 V.The designed electrolyte effectively prevents the formation of Li dendrites in Li symmetric cells for over 6500 h at0.1 mA cm^(-2).The specific Li-Si alloy-solid state half-cell capacity shows 711.6 mAh g^(-1)after 60 cycles at 0.3 A g^(-1).Excellent rate performance and cycling stability are achieved for these solid-state batteries with Li-Si alloy anodes and NCM 811 cathodes.NCM 811‖Prelithiated silicon-based anode solid-state cell delivers a discharge capacity of 195.55 mAh g^(-1)and a capacity retention of 97.8%after 120 cycles.NCM 811‖Li solid-state cell also delivers capacity retention of 84.2%after 450 cycles.

Facilitating prelithiation of silicon carbon anode by localized high-concentration electrolyte for high-rate and long-cycle lithium storage

The commercialization of silicon-based anodes is affected by their low initial Coulombic efficiency(ICE)and capacity decay,which are attributed to the formation of an unstable solid electrolyte interface(SEI)layer.Herein,a feasible and cost-effective prelithiation method under a localized highconcentration electrolyte system(LHCE)for the silicon-silica/graphite(Si-SiO_(2)/C@G)anode is designed for stabilizing the SEI layer and enhancing the ICE.The thin SiO_(2)/C layers with-NH_(2) groups covered on nano-Si surfaces are demonstrated to be beneficial to the prelithiation process by density functional theory calculations and electrochemical performance.The SEI formed under LHCE is proven to be rich in ionic conductivity,inorganic substances,and flexible organic products.Thus,faster Li+transportation across the SEI further enhances the prelithiation effect and the rate performance of Si-SiO_(2)/C@G anodes.LHCE also leads to uniform decomposition and high stability of the SEI with abundant organic components.As a result,the prepared anode shows a high reversible specific capacity of 937.5 mAh g^(-1)after 400 cycles at a current density of 1 C.NCM 811‖Li-SSGLHCE full cell achieves a high-capacity retention of 126.15 mAh g^(-1)at 1 C over 750 cycles with 84.82%ICE,indicating the great value of this strategy for Si-based anodes in large-scale applications.

Stable operation of highly loaded pure Si-Fe anode under ambient pressure via carboxy silane-directed robust solid electrolyte interphase

Incorporation of higher content Si anode material beyond 5 wt% to Li-ion batteries(LIBs)is challenging,owing to large volume change,swelling,and solid electrolyte interphase(SEI)instability issues.Herein,a strategy of diacetoxydimethylsilane(DAMS)additive-directed SEI stabilization is proposed for a stable operation of Si-0.33FeSi_(2)(named as Si-Fe)anode without graphite,which provides siloxane inorganics and organics enrichment that compensate insufficient passivation of fluoroethylene carbonate(FEC)additive and reduce a dependence on FEC.Unprecedented stable cycling performance of highly loaded(3.5 mA h cm^(-2))pure Si-Fe anode is achieved with 2 wt%DAMS combined with 9 wt%FEC additives under ambient pressure,yielding high capacity 1270 mA h g^(-1)at 0.5 C and significantly improved capacity retention of 81% after 100 cycles,whereas short circuit and rapid capacity fade occur with FEC only additive.DAMS-directed robust SEI layer dramatically suppresses swelling and particles crossover through separator,and therefore prevents short circuit,demonstrating a possible operation of pure Si or Sidominant anodes in the next-generation high-energy-density and safe LIBs.

Regulating the inner Helmholtz plane structure at the electrolyte-electrode interface for highly reversible aqueous Zn batteries

The development of aqueous Zn batteries is limited by parasitic water reactions,corrosion,and dendrite growth.To address these challenges,an inner Helmholtz plane(IHP)regulation method is proposed by employing low-cost,non-toxic maltitol as the electrolyte additive.The preferential adsorption behavior of maltitol can expel the water from the inner Helmholtz plane,and thus hinder the immediate contact between Zn metal and H_(2)O.Meanwhile,strong interaction between maltitol and H_(2)O molecules can restrain the activity of H_(2)O.Besides,the"IHP adsorption effect"along with the low LUMO energy level of maltitol-CF_(3)SO_(3)^(-)can promote the in-situ formation of an organic-inorganic complex solid electrolyte interface(SEI)layer.As a result,the hydrogen/oxygen evolution side reaction,corrosion,and dendrites issues are effectively suppressed,thereby leading to highly reversible and dendrite-free Zn plating/stripping.The Zn‖I_(2)battery with hybrid electrolytes also demonstrates high electrochemical performance and ultralong cycling stability,showing a capacity retention of 75%over 20000 charge-discharge cycles at a large current density of 5 A g^(-1).In addition,the capacity of the device has almost no obvious decay over20000 cycles even at-30℃.This work offers a successful electrolyte regulation strategy via the IHP adsorption effect to design electrolytes for high-performance rechargeable Zn-ion batteries.

蒙脱土基材料在锂金属电池中的应用研究进展

锂金属电池作为下一代高能量密度电池的代表,近年来受到了广泛的关注和研究。然而,锂金属电池的商业化应用依然面临着重大的挑战,如锂枝晶的不可控生长和电解质界面稳定性差导致电池的循环性能较差,甚至引发严重的安全问题。蒙脱土因其独特的结构,大的比表面积以及良好的热稳定性,有望用于锂金属电池中来提高其电化学性能。因此,在锂金属电池中引入蒙脱土基材料被认为是解决上述问题最有效的方法之一。综述了用于高性能锂金属电池的蒙脱土基材料、改性策略等相关研究进展,并对其未来发展进行了展望。

Artificial solid electrolyte interface layer based on sodium titanate hollow microspheres assembled by nanotubes to stabilize zinc metal electrodes

Recently,aqueous zinc-ion batteries with intrinsic safety,low cost,and environmental benignity have attracted tremendous research interest.However,zinc dendrites,harmful side reactions,and zinc metal corrosion stand in the way.Herein,we use lepidocrocite-type sodium titanate hollow microspheres assembled by nanotubes to constitute an artificial solid electrolyte interface layer on the zinc metal electrode.Thanks to the hierarchical structure with abundant open voids,negative-charged layered framework,low hydrophilicity,electrically insulting nature,and large ionic conductivity,the sodium titanate coating layer can effectively homogenize the electric field,promote the Zn^(2+)ion transfer,guide the Zn^(2+)ion flux,reduce the desolvation barrier,improve the exchange current density,and accommodate the plated zinc metal.Consequently,this coating layer can effectively suppress zinc dendrites and other unfavorable effects.With this coating layer,the Zn//Zn symmetric cell is able to provide an impressive cumulative zinc plating capacity of 1375 m Ah cm^(-2) at a current density of 5 m A cm^(-2).This coating layer also contributes to significantly improved electrochemical performances of Zn//MnO_(2) battery and zincion hybrid capacitor.This work offers new insights into the modifications of zinc metal electrodes.

Implanting a preferential solid electrolyte interphase layer over anode electrode of lithium ion batteries for highly enhanced Li^+ diffusion properties

The lithium-ion batteries are recognized as the most promising energy storage system,but it still does not meet the power requirements of electric vehicle batteries owing to low volumetric energy density with the traditional graphite electrode system.In this study,we report the development of a novel electrode system fabricated by implantation of a solid electrolyte interphase(SEI)layer on the graphite surface.The SEI-implanted graphite electrode is made using a lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)-based electrolyte and cycled with a lithium tetrafluoroborate LiBF4-based electrolyte.This new electrode system shows significantly enhanced electrochemical properties owing to the rapid and efficient diffusion of Li ions through the SEI layer between the electrolyte and electrode.This graphite electrode with its pre-formed SEI layer achieves a reversible capacity of 357 mAh g^-1 at 0.5 C after 50 cycles,which is significantly higher than that of commercial lithium-ion battery systems constructed with LiPF6(312mAh g^-1).The resulting unique electrode system could present a new avenue in SEI research for highperformance lithium-ion batteries.

冷冻电镜观察固态锂电池界面

固态锂电池(SSLBs)有望兼顾高能量密度和高安全性,是未来电池领域的重要发展方向。固态电解质(SSE)与电极材料之间存在界面阻抗大、相容性差等问题,严重地制约着它的发展。然而,由于辐照敏感特性,难以直接采用常规透射电子显微镜(TEM)观察界面结构。冷冻电镜(Cryo⁃EM)可以有效地缓解辐照损伤,提供更准确、真实的结构信息,有助于深入理解界面微观结构与SSLBs电化学性能之间的构效关系。本文综述了Cryo⁃EM用于观测SSLBs界面的晶体结构和化学组成,揭示了界面形成和演化机制以及SSLBs的失效机制。最后展望了Cryo⁃EM在表征SSLBs界面所面临的挑战和未来的研究方向。Cryo⁃EM在SSLBs界面研究中发挥越来越重要的作用,逐渐成为推动高性能SSLBs发展的必备技术。

Porous LiF layer fabricated by a facile chemical method toward dendrite-free lithium metal anode

Lithium metal is supposed to be critical material for constructing next-generation batteries due to extremely high capacity and ultralow redox potential. However, the perplexing issue of lithium dendrite growth impedes the commercial application. The initial nucleation and low Li ions diffusion rate in the electrolyte/electrode interface dominate the deposition behavior. Therefore, a uniform and flexible interface is urgently needed. Here, a facile method is proposed to prepare a thin and porous LiF-rich layer (TPL) by the in-situ reaction of small amount of ammonium hydrogen difluoride (NH4HF2) and Li metal. The deposition morphology on Li metal anode with LiF layer is significantly flat and homogeneous owning to low lateral diffusion barrier on LiF crystals and the porous structure of TPL film. Additionally, the symmetrical cells made with such TPL Li anodes show significantly stable cycling over 100 cycles at high current density of 6 mA/cm^2. The TPL Li|LiFePO4 full cells keep over 99% capacity retention after 100 cycles at 2.0 C. This approach serves as a facile and controllable way of adjusting the protective layer on Li metal.

硅负极表面构建人造SEI膜及软包电池应用研究

硅基材料在脱嵌锂过程产生较大的体积变化,造成SEI膜的破损和不断重构,限制了其大规模应用。本文将聚丙烯酸和聚环氧乙烷通过层层组装技术,包覆在硅负极表面,形成人造SEI膜,通过红外、SEM等分析了构建人造SEI膜后硅负极材料结构及表面变化情况。并将该硅负极材料组装成软包全电池,评估了25℃和45℃循环测试、EIS等性能。结果表明通过构建人造SEI膜可以明显提升硅负极电池循环容量保持率和减低电芯厚度,25℃循环600T,容量保持率由87.9%提高到92.6%,电芯的膨胀率为10.7%下降到9.4%。45℃循环500T,容量保持率由83.5%提高到85.9%,电芯的膨胀率为12.6%下降到10.9%。循环后通过截面SEM表征显示,构建PAA/PEO人造SEI膜后的硅颗粒循环后总SEI膜厚度由0.35μm降低到0.2μm,具有很好的应用前景。

Lithium plating-free 1 Ah-level high-voltage lithium-ion pouch battery via ambi-functional pentaerythritol disulfate

Elevating the charge cut-off voltage beyond traditional 4.2 V is a commonly accepted technology to increase the energy density of Li-ion batteries(LIBs) but the risk of Li-dendrites and fire hazard increases as well. The use of ambi-functional additive, which forms stable solid electrolyte interphase(SEI) simultaneously at both cathode and anode, is a key to enabling a dendrites-free and well-working high-voltage LIB. Herein, a novel ambi-functional additive, pentaerythritol disulfate(PEDS), at 1 wt% without any other additive is demonstrated. We show the feasibility and high impacts of PEDS in forming lithium sulfateincorporated robust SEI layers at NCM523 cathode and graphite anode in 1 Ah-level pouch cell under4.4 V, 25 °C and 0.1 C rate, which mitigates the high-voltage instability, metal-dissolution and cracks on NCM523 particles, and prevents Li-dendrites at graphite anode. Improved capacity retention of 83%after 300 cycles is thereby achieved, with respect to 69% with base electrolyte, offering a promising path toward the design of practical high-energy LIBs.

基于刚度比的基础隔震结构减震系数

水平向减震系数是隔震设计的重要指标.将上部结构与隔震层刚度之比作为基本变量,通过双自由度等效模型对减震系数的影响因素进行了理论研究.通过振型分析计算了上部结构的等效转换系数,推导了刚度比形式的内力和减震系数表达式,分析了减震系数的影响因素,计算了隔震结构满足减震系数要求所需的刚度比限值.发现减震系数曲线存在不变量即基准曲线,提出基准点概念.结果表明,刚度比和隔震层阻尼比是减震系数的决定因素,减震系数随刚度比或隔震层阻尼比增大而减小;当刚度比大于4.5或8时,减震系数分别低于0.5或0.4;与5个工程实例对比,减震系数表达式准确性较好.成果整理成表格可供查阅.

Modification of solid electrolyte interface layer between PVDF-based electrolyte and lithium anode

Poly(vinylidene fluoride)(PVDF)-based polymer electrolytes(PEs)with good electrochemical performance and processability as well as low-cost advantage,have great potential applications in solid-state lithium(Li)metal batteries(SSLMBs).PVDF-based PEs are generally produced by employing a solution-casting approach with N,N-dimethylformamide(DMF)as the solvent,accompanied by the formation of[DMF-Li^(+)]complex,which facilitates the Li-ion transport.However,the residual DMF can react continuously with lithium(Li)metal,thereby deteriorating the interface layer in the middle of the PVDF-based PEs and Li anodes.Herein,we introduce propylene carbonate(PC)into the PVDF-based PEs to regulate the solvation structure and stabilize the interface layer between the PEs and Li anodes.PC accelerates the dissociation of lithium oxalyldifluoroborate(LiODFB).Consequently,“lithium propylene dicarbonate(LPDC)‒B-O”oligomer forms as the interfacial layer with high tenacity,homogeneity,and densification,which improves the interfacial contact and suppresses the continuous reaction between the residual DMF and Li anode.We further demonstrate that the PVDF-based PE prepared with DMF-PC mix-solvents shows improved room-temperature ionic conductivity(1.18×10^(-3) S/cm),enhanced stability against electrodes,and superior cycling performance in LiCoO_(2)-based SSLMBs(maintaining 84% of the initial discharge capacity after 300 cycles).

High-modulus solid electrolyte interphase layer with gradient composition enables long-cycle all-solid-state lithium-sulfur batteries

All-solid-state lithium-sulfur batteries(ASSLSBs) have become one of the most potential candidates for the next-generation high-energy systems due to their intrinsic safety and high theoretical energy density.However, PEO-based ASSLSBs face the dilemma of insufficient Coulombic efficiency and long-term stability caused by the coupling problems of dendrite growth of anode and polysulfide shuttle of cathode. In this work, 1,3,5-trioxane(TOX) is used as a functional additive to design a PEO-based composite solidstate electrolyte(denoted as TOX-CSE), which realizes the stable long-term cycle of an ASSLSB. The results show that TOX can in-situ decompose on the anode to form a composite solid electrolyte interphase(SEI) layer with rich-organic component. It yields a high average modulus of 5.0 GPa, greatly improving the mechanical stability of the SEI layer and thus inhibiting the growth of dendrites. Also,the robust SEI layer can act as a barrier to block the side reaction between polysulfides and lithium metal.As a result, a Li-Li symmetric cell assembled with a TOX-CSE exhibits prolonged cycling stability over 2000 h at 0.2 m A cm^(-2). The ASSLSB also shows a stable cycling performance of 500 cycles at 0.5 C.This work reveals the structure–activity relationship between the mechanical property of interface layer and the battery's cycling stability.

岩溶强发育区场地类别划分探讨及对超高层结构设计的影响

广州某项目处于岩溶强发育区,在拟建场地大面积为Ⅱ类的情况下,勘察单位根据从天然地面起算的覆盖层厚度将溶沟部分区域的场地类别划分为Ⅲ类。设计单位宏观地从场地概念、微观的以地下室底板底起算覆盖层厚度进行充分论证探讨,认为整个项目场地类别可按Ⅱ类进行设计,并顺利通过超限审查和施工图审查。此外对比了采用《高层建筑混凝土结构技术规程:JGJ 3—2010》[1]及《高层建筑混凝土结构技术规程:广东省标准DBJ/T 15-92—2021》[2]因场地类别不同对超高层结构设计影响的差异,同时对T1栋超高层采用文献[2]分别按Ⅱ类、Ⅲ类场地计算,结果表明:对于长周期结构,地震影响系数对场地类别的敏感性文献[1]低于文献[2];T1栋调整前的基底剪力Ⅲ类场地比Ⅱ类场地大35%,调整后的基底剪力Ⅲ类场地比Ⅱ类场地大10%;T1栋最终按Ⅱ类场地进行设计,节约造价约5%~8%。

硅负极材料的储锂机理与电化学改性进展

硅作为锂离子电池负极材料具有极高的比容量,被认为是最有应用潜力的下一代锂离子电池负极候选材料。本文系统总结了硅负极材料的电化学储锂特性和储锂机理,分析了硅负极材料存在的主要问题及原因。针对存在的问题,从嵌脱锂过程硅材料粉化调控、稳定固体电解质界面膜(SEI膜)的构建和硅材料导电性调变3方面对硅负极材料的电化学改性进展进行了评述,并指出了硅负极储锂材料今后的研究方向。

P(VDF-HFP)-poly(sulfur-1,3-diisopropenylbenzene) functional polymer electrolyte for lithium–sulfur batteries

Lithium–sulfur(Li–S)battery as a high-energy density electrochemical energy storage system has attracted many researchers’attention.However,the shuttle effect of Li–S batteries and the challenges associated with lithium metal anode caused poor cycle performance.In this work,the organosulfide poly(sulfur-1,3-diisopropenylbenzene)(PSD)was prepared as cathode material and additive of P(VDFHFP)polymer electrolyte(P(VDF-HFP)).It was verified that P(VDF-HFP)polymer electrolyte with 10%PSD(P(VDF-HFP)-10%PSD)showed a higher ionic conductivities than that of liquid electrolyte up to2.27×10-3 S cm-1 at room temperature.The quasi-solid-state Li-S batteries fabricated with organosulfide cathode material PSD and P(VDF-HFP)based functional polymer electrolyte delivered good cycling stability(780 m Ah g-1 after 200 th cycle at 0.1 C)and rate performance(613 m Ah g-1 at 1 C).The good cycling performance could be attributed to the synergistic effect of components,including the interaction between polysulfides and polymer main chain in the organosulfide cathode,the sustained organic/inorganic hybrid stable SEI layer formed by polymer electrolyte additive PSD,the improved cathode/electrolyte interface and the good affinity between P(VDF-HFP)based functional polymer electrolyte and Li metal surface.This strategy herein may provide a new route to fabricate high-performance Li–S batteries through the organosulfide cathode and functional polymer electrolyte.

“Polymer-in-ceramic” based poly(ε-caprolactone)/ceramic composite electrolyte for all-solid-state batteries

Inspired by the concept of "polymer-in-ceramic",a composite poly(ε-caprolactone)(PCL)/ceramic containing LiTFSI is prepared and investigated as a solid electrolyte for all-solid-state batteries.The composite with the optimum concentration of 45 wt% LiTFSI and 75 wt% Li1.5Al0.5Ge1.5(PO4)3(LAGP,NASICON-type structure) exhibits a high ionic conductivity(σi=0.17 mS cm-1) at 30℃,a transference number of 0.30,and is stable up to 5.0 V.The composite electrolyte is a flexible and self-standing membrane.Solid-state LiFePO4//Li batteries with this composite electrolyte demonstrate excellent cycling stability with high discharge capacity of 157 mA h g-1,high capacity retention of 96% and coulombic efficiency of 98.5% after 130 cycles at 30℃ and 0.1 C rate.These electrochemical properties are better than other PCL-based allsolid-lithium batteries,and validate the concept of "polymer-in-ceramic" by avoiding the drawback of lower conductivity in prior "polymer-in-ceramic" electrolyte at high concentration of the ceramic.