摘要
锂离子电池作为一种高能量密度可充放电电池,其应用的广度和深度导致其需求量持续递增,特别是在新能源汽车中的规模化应用,使人们对其性能和安全性提出了更高的要求。作为锂离子电池的重要组成部分,正极材料的优劣极大地影响了电池的整体性能。LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)三元氧化物正极材料因高容量及优异的倍率性能而被深入研究,展现出巨大商业应用前景。然而,阳离子混排、结构稳定性差以及与电解液发生反应而导致的容量衰减和循环性能变差成为制约其应用的不利因素。对正极材料进行表面包覆改性是改善上述问题的简便有效方法之一。可用来包覆的材料种类繁多,碳包覆是其中一种简单、低成本改性策略。本文综述了近年来碳包覆LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)正极材料方面的相关研究进展,在简要介绍LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)正极材料结构及性能特点、主要失效机制的基础上,重点阐述了碳包覆策略的原理、包覆方法与工艺、包覆的碳源种类等,未来碳包覆LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)正极材料的发展方向将主要集中在多层复杂包覆以及碳材料与正极材料之间的相互作用机制研究。
As a kind of high energy density charge-discharge battery,lithium ion battery is widely used in many fields,especially in the large-scale application of new energy vehicles.With the increasing demand for lithium ion battery,higher requirements for its performance and safety have been put forward.The cathode material,as an important part of lithium ion battery,greatly affects the overall performance of the battery.LiNi_(x)Co_(y)Mn_(1-x-y)O_(2) ternary oxide cathode material has been studied deeply because of its high capacity and excellent rate performance.However,the negative factors of cation mixing,poor structure stability and also the capacity fading and cycling performance degradation caused by the side reaction with the electrolyte are restricting its further development and application.Surface coating modification is one of the simple and effective methods to improve the above-mentioned problems.There is a wide variety of materials that can be used as coating layers,in which the carbon coating is a simple and low-cost modification strategies.The research progress about the carbon coating strategies of LiNi_(x)Co_(y)Mn_(1-x-y)O_(2) ternary oxide cathode materials in recent years was reviewed.On the basis of introducing the structure,properties and main failure mechanism of LiNi_(x)Co_(y)Mn_(1-x-y)O_(2) cathode materials,the principle of the carbon coating strategy,coating methods and processes,and the types of carbon sources were elaborated.Compared with other types of coating modification,the carbon coating had its unique advantages:(1)Carbon has excellent electron and ion conductivity,which plays a key role in improving battery multiplier performance.(2)Carbon has stability in the electrolyte,and the carbon distributed on the surface of particles and in pores is conducive to the transfer of electrons between particles,improving the diffusion coefficient of lithium ions and reducing the generation of polarization.(3)The low density of carbon materials is helpful for improving the specific capacity of batteries,and the cost is relatively low,which is conducive to promoting the carbon coating to large-scale use.At present,many surface coating methods such as chemical vapor deposition(CVD),coprecipitation method,hydrothermal/solvothermal method,sol-gel method,solid phase method and spray drying method had been applied in the studies when carbon was used for surface coating modification of cathode material,and the option of coating method could affect the properties of cathode materials.In addition,the choice of carbon source also had an impact on the properties of cathode materials.Carbon sources could be divided into organic carbon sources and inorganic carbon sources,where carbohydrates,polymer,graphene and carbon nanotubes were usually used.Organic carbon source precursors generally needed to undergo a high temperature carbonization process,while for inorganic carbon sources,the process was relatively simple.Research showed that the effect of single carbon coating layer often had its own limitations,so the future development direction of the carbon coating would be multi-layer coating or"hybrid"coating,so as to utilize the synergistic effect of different cladding materials or heterogeneous materials.At the same time,the interaction mechanism between carbon material and cathode material was still unclear,especially the interface interaction between cathode material and carbon coating layer in the cycle process was poorly understood,and the understanding about how the carbon material interacts with other components of the cathode material to improve the efficiency of electron and ion transport was still lacking.Therefore,the relevant mechanism study would also be the focus of the future research for the carbon coating of LiNi_(x)Co_(y)Mn_(1-x-y)O_(2) cathode material.
作者
张可翔
王泽
唐淑璟
彭洪亮
闫二虎
孙立贤
Zhang Kexiang;Wang Ze;Tang Shujing;Peng Hongliang;Yan Erhu;Sun Lixian(School of Materials Science and Engineering,Guilin University of Electronic Technology,Guilin 541004,China;Guangxi Key Laboratory of Information Materials,Guilin 541004,China)
出处
《稀有金属》
北大核心
2025年第4期565-579,共15页
Chinese Journal of Rare Metals
基金
广西高校中青年教师科研基础能力提升项目(2019KY0251)
国家自然科学基金项目(52061010)
自治区级桂林电子科技大学大学生创新创业训练计划项目(202010595076)
广西八桂学者专项经费资助。
