Enhanced cyclic stability of partially disordered spinel cathodes through direct fluorination with gaseous fluorine  

作　　者：Yong-Nian Ma Ling-Chen Kong Shao-Shan Chen Yong Wang Li-Dong Sun Cong Peng Meng-Meng Qin Yu Li Wei Feng 

机构地区：[1]Tianjin Key Laboratory of Composite and Functional Materials,School of Materials Science and Engineering,Tianjin University,Tianjin,300072,China [2]Institute of Advanced Technology and Equipment,Beijing University of Chemical Technology,Beijing,100029,China

出　　处：《Rare Metals》2024年第4期1635-1646,共12页稀有金属（英文版）

基　　金：financially supported by the National Key R and D Program of China(No.2022YFB3805702);State Key Program of the National Natural Science Foundation of China(No.52130303);National Natural Science Foundation of China(Nos.51973152,51973119,52103093;52173078)。

摘　　要：Spinel-type cathodes are considered an optimal substitute for conventional layered oxide cathodes owing to their use of inexpensive and earth-abundant manganese as the redox-active element.Moreover,the introduction of cation disorder can effectively suppress the detrimental two-phase reaction to realize high capacities in a wide voltage range.However,the continuous capacity decay during cycles has hindered the widespread application of these cathode materials.Inorganic fluorides exhibit excellent electrochemical stability at high voltage;therefore,in this study,the direct F2 gas reaction with a partially disordered spinel cathode(Li_(1.6)Mn_(1.6)O_(3.7)F_(0.3,)LMOF1.6)was initially applied to investigate the impacts of fluorination on the surface structure and electrochemical performances.The inorganic fluorinated layer,mainly containing LiF,was distributed uniformly on the surface of LMOF1.6nanoparticles after fluorination for an appropriate time without the turbulence caused by the valency of manganese cation,which improved the capacity retention and rate capability by the suppression of structural damage,parasitic reaction,and cation dissolution.The LMOF1.6cathode fluorinated for 0.5 h exhibited a capacity of283.6 mAh·g^(-1)at 50 mA·g^(-1)and an enhanced capacity retention of 29.6%after 50 cycles in the voltage range of1.5-4.8 V,as compared to the pristine LMOF1.6 with only27.9%capacity retention.

关 键 词：Spinel-type cathodes Direct fluorination Capacity retention ability High rate capability 

分 类 号：TB34[一般工业技术—材料科学与工程] TM912[电气工程—电力电子与电力传动]