Anchoring polysulfide with artificial solid electrolyte interphase for dendrite-free and low N/P ratio Li-S batteries

Lithium sulfur batteries are regarded as a promising candidate for high-energy-density energy storage devices.However,the lithium metal anode in lithium-sulfur batteries encounters the problem of lithium dendrites and lithium metal consumption caused by polysulfide corrosion.Herein we design a dualfunction PMMA/PPC/LiNO3composite as an artificial solid electrolyte interphase(PMCN-SEI)to protect Li metal anode.This SEI offers multiple sites of C=O for polysulfide anchoring to constrain corrosion of Li metal anode.The lithiated polymer group and Li3N in PMCN-SEI can homogenize lithium-ion deposition behavior to achieve a dendrite-free anode.As a result,the PMCN-SEI protected Li metal anode enables the Li||Li symmetric batteries to maintain over 300 cycles(1300 h)at a capacity of 5 m Ah cm^(-2),corresponding to a cumulative capacity of 3.25 Ah cm^(-2).Moreover,Li-S batteries assembled with 20μm of Li metal anode(N/P=1.67)still deliver an initial capacity of 1166 m A h g-1at 0.5C.Hence,introducing polycarbonate polymer/inorganic composite SEI on Li provides a new solution for achieving the high energy density of Li-S batteries.

The influence of formation temperature on the solid electrolyte interphase of graphite in lithium ion batteries

Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase(SEI)covered on the graphite anode determines the service life of a battery.The formation method and the formation temperature at initial cycle of a battery determine the feature of the SEI.Herein,we investigate the gap of formation behavior in both a half cell(graphite matches with lithium anode)and a full cell(graphite matches with NCM,short for LiNixCoyMn1-x-yO2)at different temperatures.We conclude that high temperature causes severe side reactions and low temperature will result in low ionic conductive SEI layer,the interface formed at room temperature owns the best ionic conductivity and stability.

Solid Electrolyte Interface in Zn-Based Battery Systems

Due to its high theoretical capacity(820 mAh g^(−1)),low standard electrode potential(−0.76 V vs.SHE),excellent stability in aqueous solutions,low cost,environmental friendliness and intrinsically high safety,zinc(Zn)-based batteries have attracted much attention in developing new energy storage devices.In Zn battery system,the battery performance is significantly affected by the solid electrolyte interface(SEI),which is controlled by electrode and electrolyte,and attracts dendrite growth,electrochemical stability window range,metallic Zn anode corrosion and passivation,and electrolyte mutations.Therefore,the design of SEI is decisive for the overall performance of Zn battery systems.This paper summarizes the formation mechanism,the types and characteristics,and the characterization techniques associated with SEI.Meanwhile,we analyze the influence of SEI on battery performance,and put forward the design strategies of SEI.Finally,the future research of SEI in Zn battery system is prospected to seize the nature of SEI,improve the battery performance and promote the large-scale application.

Long‐life lithium batteries enabled by a pseudo‐oversaturated electrolyte

The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging for the liquid electrolyte.Herein,a novel pseudo‐oversaturated electrolyte(POSE)is prepared by introducing 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether(TTE)to adjust the coordination structure between diglyme(G2)and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI).Surprisingly,although TTE shows little solubility to LiTFSI,the molar ratio between LiTFSI and G2 in the POSE can be increased to 1:1,which is much higher than that of the saturation state,1:2.8.Simulation and experimental results prove that TTE promotes closer contact of the G2 molecular with Li^(+)in the POSE.Moreover,it also participates in the formation of electrolyte/electrode interphases.The electrolyte shows outstanding compatibility with both the Li metal anode and typical high‐voltage cathodes.Li||Li symmetric cells show a long life of more than 2000 h at 1 mA cm^(−2),1 mAh cm^(−2).In the meantime,Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cell with the POSE shows a high reversible capacity of 134.8 mAh g^(−1 )after 900 cycles at 4.5 V,1 C rate.The concept of POSE can provide new insight into the Li^(+)solvation structure and in the design of advanced electrolytes for LMBs.

Synergy effect of regulated Li-plating and functional solid electrolyte interphase on graphite anodes

The growth of Li dendrites poses potential safety hazard to lithium-ion batteries(LIBs),and eliminating Li dendrites thoroughly stills face tough difficulties ahead.Thus,regulating Li-plating is a critical optimization-direction to address the issue.Herein,a“graphite-Li hybrid”anode with high reversibility is realized under the constant-capacity lithiation(CCL).Within CCL,the uniform distribution of Li-plating on the graphite surface is successfully achieved.The evolution in different states of solid electrolyte interphase(SEI)is investigated in detail to study the interaction between the potentials and impedance during the process of Liintercalation and Li-deintercalation.Under the potential below 0 V and the state of charge(SOC)of 110%relative to the theoretical capacity,the F-rich SEI with high stability is constructed to hinder the emergency of Li dendrites and maintain the intact structure of graphite anode under long cycling.The cell presents more than 100%Coulombic efficiency(CE)with the 900 cycles,demonstrating the reversible Li-plating and the utilization of defects.And the CCL half-cell provides a good cycling performance and specific capacity of 900 cycles at 0.5 C,it is attributed to the synergy effect of stable inorganic-rich SEI and regulated active Li-plating.

A Review of Solid Electrolyte Interphase(SEI)and Dendrite Formation in Lithium Batteries

Lithium-metal batteries with high energy/power densities have significant applications in electronics,electric vehicles,and stationary power plants.However,the unstable lithium-metal-anode/electrolyte interface has induced insufficient cycle life and safety issues.To improve the cycle life and safety,understanding the formation of the solid electrolyte interphase(SEI)and growth of lithium dendrites near the anode/electrolyte interface,regulating the electrodeposition/electrostripping processes of Li^(+),and developing multiple approaches for protecting the lithium-metal surface and SEI layer are crucial and necessary.This paper comprehensively reviews the research progress in SEI and lithium dendrite growth in terms of their classical electrochemical lithium plating/stripping processes,interface interaction/nucleation processes,anode geometric evolution,fundamental electrolyte reduction mechanisms,and effects on battery performance.Some important aspects,such as charge transfer,the local current distribution,solvation,desolvation,ion diffusion through the interface,inhibition of dendrites by the SEI,additives,models for dendrite formation,heterogeneous nucleation,asymmetric processes during stripping/plating,the host matrix,and in situ nucleation characterization,are also analyzed based on experimental observations and theoretical calculations.Several technical challenges in improving SEI properties and reducing lithium dendrite growth are analyzed.Furthermore,possible future research directions for overcoming the challenges are also proposed to facilitate further research and development toward practical applications.

SEI膜形貌与结构对锂离子电池性能的影响

固态电解质界面膜(SEI)是电解液与电极在固/液相界面上发生电化学反应后,覆盖在电极表面的钝化层,其通常形成于电池的化成阶段,具有传导离子、隔绝电子的特征。优良的SEI膜对于提高锂离子电池(LIBs)的循环寿命、安全性等具有重要意义。不同电解液体系形成的SEI膜形貌和结构各不相同,对LIBs性能具有不同程度的影响。因此,深入分析SEI膜形貌和结构与电池性能之间的构效关系很重要。本文首先综述了影响SEI膜结构和性质的因素;然后阐述了原位/非原位表征SEI膜形貌和结构的主要方法,并介绍了一种新型的电化学阻抗表征技术;最后总结了SEI膜结构对LIBs离子传输、锂沉积和界面脱溶剂化等方面的影响。通过总结SEI膜的结构与LIBs性能之间的关系,以期靶向调控SEI膜结构提升锂离子电池性能。

Enhanced interfacial compatibility of FeS@N,S-C anode with ester-based electrolyte enables stable sodium-ion full cells

The development of sodium-ion full cells is seriously suppressed by the incompatibility between electrodes and electrolytes. Most representatively, high-voltage ester-based electrolytes required by the cathodes present poor interfacial compatibility with the anodes due to unstable solid electrode interphase(SEI). Herein, Fe S@N,S-C(spindle-like Fe S nanoparticles individually encapsulated in N,S-doped carbon) with excellent structural stability is synthesized as a potential sodium anode material. It exhibits exceptional interfacial stability in ester-based electrolyte(1 M NaClO_(4) in ethylene carbonate/propylene carbonate with 5% fluoroethylene carbonate) with long-cycling lifespan(294 days) in Na|Fe S@N,S-C coin cell and remarkable cyclability in pouch cell(capacity retention of 82.2% after 170 cycles at 0.2 A g^(-1)).DFT calculation reveals that N,S-doping on electrode surface could drive strong repulsion to solvated Na_(2) and preferential adsorption to ClO_(4)^(-) anion, guiding the anion-rich inner Helmholtz plane.Consequently, a robust SEI with rich inorganic species(NaCl and Na_(2)O) through the whole depth stabilizes the electrode–electrolyte interface and protects its integrity. This work brings new insight into the role of electrode’s surface properties in interfacial compatibility that can guide the design of more versatile electrodes for advanced rechargeable metal-ion batteries.

钠离子电池电解液溶剂化结构对SEI的影响

在钠离子电池中电解液是关键组成部分,其内部的溶剂化结构对固体电解质界面(SEI)的形成和组成具有重要影响,并直接影响钠离子电池的电化学性能。文章探讨钠离子电池电解液中溶剂化结构对SEI性质和电池性能的影响机制,总结高浓度电解液溶剂化结构研究的相关成果,探讨溶剂浓度、种类及溶剂化结构对SEI的影响,阐述了电解液中阴阳离子、溶剂分子间作用与钠离子电池性能之间的构效关系。

In-situ constructed polymer/alloy composite with high ionic conductivity as an artificial solid electrolyte interphase to stabilize lithium metal anode

Lithium(Li)metal is regarded as the best anode material for lithium metal batteries(LMBs)due to its high theoretical specific capacity and low redox potential.However,the notorious dendrites growth and extreme instability of the solid electrolyte interphase(SEI)layers have severely retarded the commercialization process of LMBs.Herein,a double-layered polymer/alloy composite artificial SEI composed of a robust poly(1,3-dioxolane)(PDOL)protective layer,Sn and LiCl nanoparticles,denoted as PDOL@Sn-LiCl,is fabricated by the combination of in-situ substitution and polymerization processes on the surface of Li metal anode.The lithiophilic Sn-LiCl multiphase can supply plenty of Li-ion transport channels,contributing to the homogeneous nucleation and dense accumulation of Li metal.The mechanically tough PDOL layer can maintain the stability and compact structure of the inorganic layer in the long-term cycling,and suppress the volume fluctuation and dendrites formation of the Li metal anode.As a result,the symmetrical cell under the double-layered artificial SEI protection shows excellent cycling stability of 300 h at 5.0 mA·cm^(−2)for 1 mAh·cm^(−2).Notably,the Li||LiFePO_(4)full cell also exhibits enhanced capacity retention of 150.1 mAh·g^(−1)after 600 cycles at 1.0 C.Additionally,the protected Li foil can effectively resist the air and water corrosion,signifying the safe operation of Li metal in practical applications.This present finding proposed a different tactic to achieve safe and dendrite-free Li metal anodes with excellent cycling stability.

Solid electrolyte interphase on anodes in rechargeable lithium batteries

Highly safe and efficient rechargeable lithium batteries have become an indispensable component of the intelligent society powering smart electronics and electric vehicles.This review summarizes the formation principle,chemical compositions,and theoretical models of the solid electrolyte interphase(SEI)on the anode in the lithium battery,involving the functions and influences of the electroactive materials.The discrepancies of the SEI on different kinds of anode materials,as well as the choice and design of the electrolytes are detailedly clarified.Furthermore,the design strategies to obtain a stable and efficient SEI are outlined and discussed.Last but not least,the challenges and perspectives of artificial SEI technology are briefly proposed for the development of high-efficiency batteries in practice.

Perspective on the critical role of interface for advanced batteries

As an efficient and environmental friendly energy storage system, lithium battery has been integrated into daily mobile life [1].Lithium batteries are becoming indispensable to all types of electronic products such as laptop computers, mobile phones, digital cameras [2]. A typical lithium battery consists of positive electrode(cathode), negative electrode(anode), electrolyte and other inactive materials(binder, conductive agent, separator) [3].

电解液组成对锂离子电池碳负极SEI膜性能的影响

综述了液态锂离子二次电池中,电解液组成包括电解质盐、溶剂特别是电解液添加剂对碳负极SEI膜性能的影响,还叙述了改进电极/溶液界面反应的电极表面预成膜方法等。对影响SEI膜的机理作了分析。

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。

Constructing a fluorinated interface layer enriched with Ge nanoparticles and Li-Ge alloy for stable lithium metal anodes

Lithium metal batteries(LMBs)based on metallic Li exhibit high energy density to be competent for advanced energy storage applications.However,the unstable solid electrolyte interphase(SEI)layer due to continuous decomposition of electrolytes,and the attendant problem of Li dendrite growth frustrate their commercialization process.Herein,a hybrid SEI comprising abundant LiF,lithiophilic Li-Ge alloy,and Ge nanoparticles is constructed via a simple brush coating method.This fluorinated interface layer with embedded Ge-containing components isolates the Li anode from the corrosive electrolyte and facilitates homogenous Li nucleation as well as uniform growth.Consequently,the modified Li anode exhibits remarkable stability without notorious Li dendrites,delivering stable cycling lives of more than 1000 h for symmetric Li||Li cells and over 600 cycles for Li||Cu cells at 1 mA·cm^(−2).Moreover,the reinforced Li anodes endow multiple full-cell architectures with dramatically improved cyclability under different test conditions.This work provides rational guidance to design an artificial hybrid SEI layer and would stimulate more ideas to solve the dendrite issue and promote the further development of advanced LMBs.

氧化锂基复合正极补锂材料的制备及对电池电化学性能的影响

锂离子电池在首次充放电过程中,其负极表面形成的固态电解质界面(SEI)膜会消耗部分正极材料的活性锂,导致不可逆的容量损失,降低锂离子电池能量密度。为解决此问题,选用氧化锂作为牺牲锂盐以补偿锂离子电池的首次不可逆容量损失,提高电池容量和循环性能。通过将催化剂LiMnO_(2)、Li_(2)O和导电炭黑(SP)按一定质量比研磨混合,制备了Li_(2)O基正极补锂材料LiMnO_(2)/Li_(2)O/SP。为研究其补锂性能,选用磷酸铁锂作为正极,石墨作为负极,TCGG-Si作为电解液,组装了2032扣式全电池,通过充放电测试,研究了该正极补锂材料对电池电化学性能的影响。结果表明,当LiMnO_(2)/Li_(2)O/SP的质量分数分别为50%、45%和5%时,在10 mA·g^(-1)的电流密度下充电至4.3 V,LiMnO_(2)/Li_(2)O/SP复合材料的首次充电比容量可达526.5 mAh·g^(-1),首次库伦效率为14.63%,其在首次充电过程中分解释放活性锂的过程是不可逆的,并在第4次后完全丧失容量,说明Li_(2)O/LiMnO_(2)/SP复合材料可以作为补锂材料添加到正极材料中。将质量分数为3.6%的Li_(2)O/LiMnO_(2)/SP复合材料加入到磷酸铁锂半电池中,半电池的首次充电比容量为186.5 mAh·g^(-1),相较LiFePO_(4)比容量(166.8 mAh·g^(-1))提高了19.7 mAh·g^(-1),说明补锂剂已发挥作用,该部分多余的容量可用于形成石墨SEI膜。将Li_(2)O/LiMnO_(2)/SP添加到磷酸铁锂-石墨全电池体系中作为正极补锂剂,不仅可补偿石墨负极的首次不可逆容量损失,还可提高全电池的循环性能。全电池的首次可逆容量为158.2 mAh·g^(-1),循环100次的可逆比容量为108.0 mAh·g^(-1);相较于未添加情况,全电池首次充电比容量增加了12.9 mAh·g^(-1),可逆比容量提高了11.6 mAh·g^(-1),经100次循环后容量保持率提升了13.90%。

Smart materials for safe lithium-ion batteries against thermal runaway

In recent years,the new energy storage system,such as lithium ion batteries(LIBs),has attracted much attention.In order to meet the demand of industrial progress for longer cycle life,higher energy density and cost efficiency,a quantity of research has been conducted on the commercial application of LIBs.However,it is difficult to achieve satisfying safety and cycling performance simultaneously.There may be thermal runaway(TR),external impact,overcharge and overdischarge in the process of battery abuse,which makes the safety problem of LIBs more prominent.In this review,we summarize recent progress in the smart safety materials design towards the goal of preventing TR of LIBs reversibly from different abuse conditions.Benefiting from smart responsive materials and novel structural design,the safety of LIBs can be improved a lot.We expect to provide a comprehensive reference for the development of smart and safe lithium-based battery materials.

锂离子电池SEI成膜添加剂的研究

开发高效优质的固体电解质界面(SEI)成膜添加剂是提高锂离子电池性能的一种经济而有效的途径.本文从SEI成膜添加剂成膜机理的角度,分析和评价了已有的还原型添加剂、反应型添加剂及修饰型添加剂的作用效果;综述了理论计算在锂离子电池SEI成膜添加剂研究中的应用,并提出了"理论设计、材料合成、性能评估"三个研究环节无缝连接锂离子电池中SEI成膜添加剂创新研发的新思路.

Empowering the Future: Exploring the Construction and Characteristics of Lithium-Ion Batteries

Lithium element has attracted remarkable attraction for energy storage devices, over the past 30 years. Lithium is a light element and exhibits the low atomic number 3, just after hydrogen and helium in the periodic table. The lithium atom has a strong tendency to release one electron and constitute a positive charge, as Li . Initially, lithium metal was employed as a negative electrode, which released electrons. However, it was observed that its structure changed after the repetition of charge-discharge cycles. To remedy this, the cathode mainly consisted of layer metal oxide and olive, e.g., cobalt oxide, LiFePO4, etc., along with some contents of lithium, while the anode was assembled by graphite and silicon, etc. Moreover, the electrolyte was prepared using the lithium salt in a suitable solvent to attain a greater concentration of lithium ions. Owing to the lithium ions’ role, the battery’s name was mentioned as a lithium-ion battery. Herein, the presented work describes the working and operational mechanism of the lithium-ion battery. Further, the lithium-ion batteries’ general view and future prospects have also been elaborated.

锂离子电池SEI膜形成机理及化成工艺影响

固体电解质相界面(SEI)膜是锂离子电池在化成工艺过程中形成的重要物质,它的形成以及性能优劣对锂离子电池的最终性能有着重要影响,同时,锂离子电池生产中的化成工艺直接影响SEI膜的性质优劣。综述了电池负极上SEI膜的形成概况、化成工艺的参数控制对SEI膜形成过程和性质的作用,以及其对锂离子电池性能的影响。Si基负极材料是未来负极材料的重点发展方向,分析了针对Si基负极材料的SEI膜形成所面临的困难与挑战,以及Si基负极的化成工艺参数控制是改进电池生产的必要手段与基础。