氟掺杂富锂层状氧化物的电化学性能  

Electrochemical performance of F-doped lithium-rich layered oxide

作　　者：缪胤宝 刘嘉[1] 曾杰 彭望 王帅[1] 陈显彪[1] 刘伟昊 陈哲[1] 张文华 MIAO Yinbao;LIU Jia;ZENG Jie;PENG Wang;WANG Shuai;CHEN Xianbiao;LIU Weihao;CHEN Zhe;ZHANG Wenhua(School of Electrical Engineering,Nanchang Institute of Technology,Nanchang,Jiangxi 330000,China)

机构地区：[1]南昌工程学院电气工程学院,江西南昌330000

出　　处：《电池》2024年第5期628-633,共6页Battery Bimonthly

基　　金：国家自然科学基金(22269014),江西省教育厅项目(GJJ211913,GJJ211915)。

摘　　要：富锂锰基正极材料的应用前景广阔,但循环稳定性较差。为增强材料的电化学稳定性,设置F掺杂浓度梯度实验。采用聚合-热解法,通过优化丙烯酸聚合过程中的原料比例,制备Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54) O_(2-x)F_(x)材料,探究F掺杂比例对正极材料微观形貌和电化学稳定性的影响,定量分析首次充放电过程中,不同阶段氧化还原反应的容量释放情况。采用XRD、SEM分析样品的物相组成和微观形貌;采用恒流充放电和电化学阻抗测试分析样品的电化学性能。F掺杂可提升富锂锰基正极材料的电化学稳定性,x=0.03时,样品LMNC-F0.03的层状结构明显,阳离子混排程度低,电化学稳定性最优。以0.5 C在2.0~4.8 V循环100次,放电比容量为186.97 mAh/g,容量保持率为85.76%,放电中值电压保持率为84.93%;2.0 C倍率下的平均放电比容量为147.68 mAh/g。The lithium-rich manganese-based cathode materials have broad application prospects,but the cycle stability is poor.To enhance the electrochemical stability of materials,an F-doping concentration gradient experiment is set up.By optimizing the raw material preparation ratio during the acrylic acid polymerization process,Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54) O_(2-x)F_(x) material is prepared using the polymer-pyrolysis method.The effect of F-doping ratios on the microstructure and electrochemical stability of cathode materials is investigated,and the capacity release of different oxidation-reduction reactions during the initial cycle of charge and discharge is quantitatively analyzed.The phase compositions and morphology of the samples are observed by XRD and SEM.The electrochemical performance of the samples is analyzed by galvanostatic charge-discharge and electrochemical impedance tests.The electrochemical stability of lithium-rich manganese-based cathode materials can be improved by F-doping.When x=0.03,the sample LMNC-F 0.03 exhibits a distinct layered structure with a low degree of cation mixing and optimal electrochemical stability.After 100 cycles at 0.5 C rate in 2.0-4.8 V,the specific discharge capacity is 186.97 mAh/g,with a capacity retention rate of 85.76%,a median voltage retention rate of 84.93%;the average specific discharge capacity at 2.0 C rate is 147.68 mAh/g.

关 键 词：F掺杂 富锂锰基层状氧化物 聚合-热解法 锂离子电池 电化学性能 

分 类 号：TM912.9[电气工程—电力电子与电力传动]