Status and challenges facing representative anode materials for rechargeable lithium batteries

Rechargeable lithium batteries have been widely regarded as a revolutionary technology to store renewable energy sources and extensively researched in the recent several decades.As an indispensable part of lithium batteries,the evolution of anode materials has significantly promoted the development of lithium batteries.However,since conventional lithium batteries with graphite anodes cannot meet the ever-increasing demands in different application scenarios(such as electric vehicles and large-scale power supplies)which require high energy/power density and long cycle life,various improvement strategies and alternative anode materials have been exploited for better electrochemical performance.In this review,we detailedly introduced the characteristics and challenges of four representative anode materials for rechargeable lithium batteries,including graphite,Li_(4)Ti_(5)O_(12),silicon,and lithium metal.And some of the latest advances are summarized,which mainly contain the modification strategies of anode materials and partially involve the optimization of electrode/electrolyte interface.Finally,we make the conclusive comments and perspectives,and draw a development timeline on the four anode materials.This review aims to offer a good primer for newcomers in the lithium battery field and benefit the structure and material design of anodes for advanced rechargeable lithium batteries in the future.

Research Progress for the Development of Li-Air Batteries: Addressing Parasitic Reactions Arising from Air Composition

Li-air batteries are an extremely attractive technology for electrical energy storage,especially in long-range electric vehicles,owing to their high theoretical specific energy.However,many issues still exist before their practical realization.Herein,the sole complexity of electrode reaction in Li-air batteries is presented.And the critical components that influence the electrochemical performance of aprotic Li-air batteries operating in ambient air are discussed.These include the mechanisms and pathways of CO_(2)/Li_(2)CO_(3) and H_(2)O/LiOH,catalysts of CO_(2) reduction/evolution reactions,and reactions between the Li anode and air constituents.If these challenges can be solved,Li-air batteries will soon be realized for practical application.Some hot topics in field of Li-air batteries should be focused,such as the fundamental mechanism research referring to interfacial reactions of atmosphere components on porous electrode and Li metal anode,high-efficiency solid catalyst design,and discovery of suitable soluble redox mediators.

In-situ/operando characterization techniques in lithium-ion batteries and beyond

Nowadays,in-situ/operando characterization becomes one of the most powerful as well as available means to monitor intricate reactions and investigate energy-storage mechanisms within advanced batteries.The new applications and novel devices constructed in recent years are necessary to be reviewed for inspiring subsequent studies.Hence,we summarize the progress of in-situ/operando techniques employed in rechargeable batteries.The members of this large family are divided into three sections for introduction,including bulk material,electrolyte/electrode interface and gas evolution.In each part,various energy-storage systems are mentioned and the related experimental details as well as data analysis are discussed.The simultaneous strategies of various in-situ methods are highlighted as well.Finally,current challenges and potential solutions are concluded towards the rising influence and enlarged appliance of in-situ/operando techniques in the battery research.

Progress on multiphase layered transition metal oxide cathodes of sodium ion batteries

As one of the most promising secondary batteries in large-scale energy storage,sodium ion batteries(SIBs) have attracted wide attention due to the abundant raw materials and low cost.Layered transition metal oxides are one kind of popular cathode material candidates because of its easy synthesis and large theoretical specific capacity.Yet,the most common P2 and O3 phases show distinct structural characteristics respectively.O3 phase can serve as a sodium reservoir,but it usually suffers from serious phase transition and sluggish kinetics.For the P2 phase,it allows the fast sodium ion migration in the bulk and the structure can maintain stable,but it is lack of sodium,showing a great negative effect on Coulombic efficiency in full cell.Thus,single phase structure almost cannot achieve satisfied comprehensive sodium storage performances.Under these circumstances,exploiting novel multiphase cathodes showing synergetic effect may give solution to these problems.In this review,we summarize the recent development of multiphase layered transition metal oxide cathodes of SIBs,analyze the mechanism and prospect the future potential research directions.

Electrolyte design principles for low-temperature lithium-ion batteries

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℃.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 Liion batteries:low melting point,poor Liþaffinity,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.

基于高效电解液的稳定电极界面实现锂金属负极大倍率循环

为了推动可快充锂金属电池的发展,迫切需要研发出能够大倍率充放、稳定循环的锂金属负极.在大电流密度条件下工作时,锂电池内部电解液会形成很大的浓度梯度,从而加剧锂金属的不均匀沉积,阻碍其表面稳定钝化层的形成,降低锂金属负极库仑效率.本文通过引入一种高浓度双盐电解液4 molL^(-1)LiFSI-Li NO_(3)/DOL,以提升锂金属负极的倍率性能.研究表明,该电解液体系中充足的锂盐能够快速钝化新鲜的锂沉积物;DOL则可以在锂金属表面形成具有良好柔韧性的有机层,显著提升固体电解质中间相在锂金属负极快速沉积溶解过程中的机械稳定性.锂金属负极的倍率性能由此显著提高,在电流密度高达8.0 m A cm^(-2)的条件下,该电极可以稳定循环240圈以上,且平均库仑效率达到99.14%.

Oxygen vacancy promising highly reversible phase transition in layered cathodes for sodium-ion batteries

Phase transition is common during (de)-intercalating layered sodium oxides, which directly affects the structural stability and electrochemical performance. However, the artificial control of phase transition to achieve advanced sodium-ion batteries is lacking, since the remarkably little is known about the influencing factor relative to the sliding process of transition-metal slabs upon sodium release and uptake of layered oxides. Herein, we for the first time demonstrate the manipulation of oxygen vacancy concentrations in multinary metallic oxides has a significant impact on the reversibility of phase transition, thereby determining the sodium storage performance of cathode materials. Results show that abundant oxygen vacancies intrigue the return of the already slide transition-metal slabs between O_(3) and P_(3) phase transition, in contrast to the few oxygen vacancies and resulted irreversibility. Additionally, the abundant oxygen vacancies enhance the electronic and ionic conductivity of the Na0.9Ni0.3Co0.15Mn0.05Ti0.5O2 electrode, delivering the high initial Coulombic efficiency of 97.1%, large reversible capacity of 112.7 mAh·g−1, superior rate capability upon 100 C and splendid cycling performance over 1,000 cycles. Our findings open up new horizons for artificially manipulating the structural evolution and electrochemical process of layered cathodes, and pave a way in designing advanced sodium-ion batteries.

结构设计稳定T2型富锂层状正极氧化物电极材料中的阴阳离子氧化还原活性

得益于阴离子氧化还原反应的引入,富锂材料具有较高的输出容量而被认为是下一代高能量密度电池正极材料的选择之一.然而氧相关的阴离子氧化还原反应的利用常常伴随着不可逆的晶格氧析出和严重的结构畸变.此外,由于复杂的阴阳离子氧化还原反应,使得富锂材料的电荷补偿机理也需要进一步澄清.本文报道了一种T2型Li_(0.72)[Li_(0.12)Ni_(0.36)Mn_(0.52)]O_(2)正极材料.研究发现,与其他典型的富锂层状正极不同,其具有不同于传统富锂材料的四面体碱金属配位环境与ABB′A′氧堆垛顺序.得益于其良好的结构稳定性和可逆的锂离子脱嵌过程,层状T2型正极材料具有良好的电化学稳定性,在较长的循环中具有较少的容量衰减和电压下降.研究人员通过详细的光谱表征,不仅标定了复杂的阴离子氧化还原行为,而且预估了相应的阳离子/阴离子氧化还原反应对应的电化学容量,这进一步阐明具有复杂氧化还原行为材料的电荷补偿机理.

一种基于析氮反应的新型高比能硅-硫化聚(丙烯腈)电池

高比能锂-硫电池的实际应用面临两大致命障碍:一是源于硫正极的“穿梭效应”,二是锂金属负极带来的低库仑效率和安全问题,为了彻底解决这些问题,本文提出了一种新型的硅-硫化聚(丙烯腈)全电池。在这种不含锂金属的系统中,锂源被预加载在正极中,采用析氮反应将锂离子注入硅基负极.基于固-固转化机制的硫化聚(丙烯腈)正极可以从根本上规避“穿梭效应”.同时,与锂金属负极相比,硅基负极可以实现更有效的利用和更高的安全性.采用该技术的全电池可提供1169.3mAhg^(-1)的容量并稳定循环100次,显示出优异的电化学稳定性.此外,即使在4.2 mgcm^(-2)高硫载量的实用软包电池也可以实现513.2 Whkg^(-1)的高比能量.本文还通过原位方法研究和分析了正极中析氮反应的机制.值得注意的是,这种电池设计完全匹配当前的电池生产工艺,制造成本低,为采用析氨反应开发无金属锂电池开辟道路.

金属空气电池:进展与展望

“双碳”背景下,金属空气电池拥有很高的理论比能量,有望实现高比能电化学储能体系,但限于材料体系创新和反应机理认识,走向实用还有许多科学和技术问题亟需解决.本文总结了近年来金属空气电池领域研究工作,并分别介绍了(开放/封闭式)锂氧电池、固态锂氧电池、锂-二氧化碳电池、钠氧电池、锌空电池的最新进展.这些金属空气电池虽有差异,但有一些共性问题,比如都是基于转化反应机制、涉及气体在电极孔道中传质瓶颈、电解质稳定性问题、正极离子-电子通道不畅、电极反应机理模糊、固-固界面反应缺少电催化剂等难题.本文基于这些问题,对未来的工作方向提出了一些设想,最后总结了目前面临的机遇和挑战并展望了该领域今后的重点发展方向.

Correction to:Solid‑State Electrolytes for Lithium‑Ion Batteries:Fundamentals,Challenges and Perspectives

Correction to:Electrochem Energy Rev https://doi.org/10.1007/s41918-019-00048-0 In the version of this article initially published,the superscript number representing the affiliations of the first author Wenjia Zhao was incorrect and 1 was omitted.It should be 1 and 4.