摘要
石墨是重要的锂离子电池负极材料,但天然石墨的初始库伦效率低、循环稳定性和倍率性能较差等缺点限制其应用。为了提高石墨结构稳定性及其电化学性能,以Al(NO_(3))_(3)·9H_(2)O为铝源,利用氨水调节pH,采用沉淀法在石墨表面均匀包覆一层Al(OH)_(3),并进一步热处理制备Al_(2)O_(3)包覆石墨负极材料。此方法与原子层沉积法相比,具有过程简单和成本低廉的优点,比溶胶-凝胶法反应进程更好控制且能耗更低。当Al_(2)O_(3)包覆质量分数为1.03%时,获得表面光滑的改性石墨,Al_(2)O_(3)包覆层可起到预成型固态电解质界面(SEI)的作用,降低SEI膜的再生及锂离子的损耗。电化学性能试验表明,该材料在充放电过程中表现出优异的倍率性能及循环稳定性,将原料石墨和1.03%(质量分数)Al_(2)O_(3)包覆改性的石墨负极材料分别与锂片组装成锂离子电池,在0.1C(1.0C=372 mA∙h/g)的电流密度下,充放电循环100次后,其比容量分别为212.59 mA∙h/g和354.37 mA∙h/g,容量保持率分别为67.99%和98.59%。
Graphite is an important anode material for lithium⁃ion batteries,but the low initial coulombic efficiency,short cycle life,and poor rate performance of natural graphite limit its application.In order to improve the stability of its graphite structure and electrochemical performance,Al(NO_(3))_(3)·9H_(2)O was used as the aluminum source with adjusting the pH with ammonia water and uniformly coating a layer of Al(OH)_(3)on the surface of graphite by precipitation method,and Al_(2)O_(3)coated graphite anode material was further prepared by heat treatment.Compared with the atomic layer deposition method,this method had the advantages of simple process and low cost,better control of the reaction process and lower energy con⁃sumption than the sol gel method.When the Al_(2)O_(3)coating mass was 1.03%,the modified graphite surface was smooth.The Al_(2)O_(3)coating layer could serve as a preformed solid electrolyte interface(SEI),reducing the regeneration of SEI and the consumption of lithium ions during subsequent cycling processes.Electrochemical performance tests showed that the materi⁃als exhibited excellent rate performance and cycling stability during charge and discharge processes.Graphite and Al_(2)O_(3)coated graphite anode materials with a modification amount of 1.03%were assembled with lithium sheets to form lithium⁃ion batteries.After 100 cycles of charge and discharge at a current density of 0.1C(1.0C=372 mA∙h/g),the specific capaci⁃ties were 212.59 mA∙h/g and 354.37 mA∙h/g,with capacity retention rates of 67.99%and 98.59%,respectively.
作者
凌政
孙陆
田朋
叶俊伟
LING Zheng;SUN Lu;TIAN Peng;YE Junwei(School of Chemical Engineering,Dalian 116024,China;Liaoning Province Magnesium Special Functional Material Preparation and Application Technology Engineering Laboratory,Dalian University of Technology,Dalian 116024,China)
出处
《无机盐工业》
北大核心
2025年第12期18-25,共8页
Inorganic Chemicals Industry
基金
国家自然科学基金项目(22378053)
企业委托项目(HX20230646)。
关键词
锂离子电池
氧化铝
表面改性
负极材料
lithium⁃ion batteries
alumina
surface modification
anode material
