摘要
针对富锂锰基层状材料xLi_2MnO_3·(1-x)LiMO_2(M为Mn、Co、Ni)存在着充放电循环性能差的缺点,采用溶胶-凝胶法制备氟掺杂Li_(1.2)Mn_(0.56)Ni_(0.16)Co_(0.08)O_(2-x)F_x正极材料,以提高这种材料的长循环充放电性能。研究结果表明,氟掺杂材料的晶体结构与未掺杂材料相似,但氟掺杂明显改善了充放电长循环性能的稳定性。在125 mA/g电流密度下电池循环500次,掺杂5%F的Li_(1.2)Mn_(0.56)Ni_(0.16)Co_(0.08)O_(1.95)F_(0.05)材料比容量保持率为79.2%,并且极大地抑制了放电平台电位的衰减,而未掺杂的Li_(1.2)Mn_(0.56)Ni_(0.16)Co_(0.08)O_2材料的比容量保持率仅为16%,其放电电位平台已经消失。这些结果表明氟掺杂能有效地抑制富锂锰基层状结构正极材料充放电过程中比容量和放电平台的衰减。
To overcome poor stability of the lithium-rich and manganese-based layered material x Li 2MnO3·(1-x)LiMO2(M=Mn,Co,Ni)during charge-discharge long-cycles,we prepared the fluorine-doped Li1.2-Mn0.56Ni0.16Co0.08O2-xFx by sol-gel method in this paper.Our results show that the crystal structure of the fluorine doped materials is similar to that of the undoped material,but the fluorine doping significantly improves the long-cycling stability of the materials during charge-discharge process.After cycling 500 times at a current density of125 mA/g,the Li1.2Mn0.56Ni0.16Co0.08O1.95F0.05 doped with 5%exhibits 79.2%of its initial specific capacity,and the loss of the discharge voltage plateau was greatly decreased.However,the undoped Li1.2Mn0.56-Ni0.16Co0.08O2Material exhibits only16%of its initial capacity,and its discharge voltage plateau has completely disappeared.These results indicate that fluorine doping can effectively decrease the loss of specific capacity and discharge platform of lithium-rich manganese-based layered cathode materials during charge and discharge process.
作者
张世龙
李东林
李童心
周俊祥
曹婷
孔祥泽
樊小勇
苟蕾
ZHANG Shilong;LI Donglin;LI Tongxin;ZHOU Junxiang;CAO Ting;KONG Xiangze;FAN Xiaoyong;GOU Lei(Energy Materials and Devices Laboratory,School of Materials Scienceand Engineering,Chang'an University,Xi'an 710064,China)
出处
《功能材料》
EI
CAS
CSCD
北大核心
2019年第4期4164-4169,共6页
Journal of Functional Materials
基金
国家科学自然基金资助项目(21473014)
陕西省自然科学基金资助项目(2016JM5082)
关键词
富锂锰基层状材料
循环性能
氟掺杂
放电电位平台
lithium-rich manganese-based layered material
cycle performance
fluo-rine doping
discharge voltage plateau
