氯掺杂富锂正极材料Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.5)4O_(2)调控晶格氧反应活性及电化学性能  

Cl-Doping Lithium-Rich Cathode Material Li1.2Ni0.13Co0.13Mn0.54O2 for Regulating Lattice Oxygen Reactivity and Electrochemical Performance

作　　者：周国俊 瞿翊帆 李阿飞 唐伟建 陈章贤 杨则恒 张卫新 ZHOU Guojun;Qu Yifan;LI Afei;TANG Weijian;CHEN Zhangxian;YANG Zeheng;ZHANG Weixin(School of Chemistry and Chemical Engineering,Hefei University of Technology,Anhui Key Laboratory of Controllable Chemical Reaction&Material Chemical Engineering,Hefei 230009,China)

机构地区：[1]合肥工业大学化学与化工学院,可控化学与材料化工安徽省重点实验室,合肥230009

出　　处：《硅酸盐学报》2022年第10期2579-2590,共12页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金项目(91834301,91534102);安徽省科技重大专项(201903a05020021)。

摘　　要：富锂正极材料因具有能量密度高、电压窗口大等优点受到关注,然而首次Coulombic效率低、循环性能差等缺点阻碍了其商业化应用。采用共沉淀法并通过不同摩尔比的氯离子(Cl^(-))掺杂制备了Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2-x)Cl_(x)(x=0,0.025,0.050,0.100)富锂正极材料。通过X射线光电子能谱、原位X射线衍射和恒电流间歇滴定等技术系统研究了Cl^(-)掺杂对其电化学性能提升的调控机制。结果表明:Cl^(-)掺杂量为0.05时,该正极材料在0.2 C倍率下首次Coulombic效率由72.8%提升至81.5%,在1 C倍率下经200圈循环,容量保持率由57.9%提升至79.1%。材料优异的电化学性能归因于Cl^(-)掺杂能调控材料中O^(2-)的电化学行为,使其更多氧化为O^(n-)(n<2),抑制O_(2)的产生和逸出,减小结构的破坏。同时,由于Cl^(-)具有较大的离子半径,能扩大富锂材料的层间距,降低极化过电位,加快锂离子扩散速率,因此有效提升富锂正极材料的首次Coulombic效率和循环性能。Lithium-rich cathode materials have attracted great interests due to their advantages,such as high energy density and wide voltage window.However,their shortcomings like low initial coulombic efficiency and poor cycle performance have hindered their commercial application.Lithium-rich cathode materials Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2-x)Cl_(x)(x=0,0.025,0.050,0.100)with different molar ratios of chloride ion(Cl^(-))doping were prepared by a co-precipitation method.The regulation mechanism of Cl^(-)doping on the improvement of the electrochemical performance was investigated by X-ray photoelectron spectroscopy,in-situ X-ray diffraction and galvanostatic intermittent titration analysis.Compared with the pristine material,the initial coulombic efficiency of the cathode material with Cl^(-) doping in a molar ratio of 0.05 increases from 72.8%to 81.5%at 0.2 C,and the capacity retention increases from 57.9%to 79.1%after 200 cycles at 1 C.It is indicated that Cl^(-)doping can regulate the electrochemical behavior of O^(2-) by oxidizing the more into O^(n-)(n<2)and less production of oxygen gas,thus reducing the structural deterioration.Meanwhile,the larger ion radius of Cl^(-) can expand the layer spacing,reduce the polarization and accelerate the lithium ions diffusion in the lithium-rich and manganese-based cathode material,thereby enhancing the initial coulombic efficiency and the cycle performance.

关 键 词：锂离子电池 富锂正极材料 阴离子掺杂 循环性能 

分 类 号：TM912.9[电气工程—电力电子与电力传动]