Abstract
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 excel-lent electrochemical stability at high voltage;therefore,in this study,the direct F2 gas reaction with a partially dis-ordered spinel cathode(Li1.6Mn1.6O3.7F0.3,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 LMOF1.6 nanoparticles 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 LMOF1.6 cathode fluorinated for 0.5 h exhibited a capacity of 283.6 mAh·g-1 at 50 mA·g-1 and an enhanced capacity retention of 29.6％after 50 cycles in the voltage range of 1.5-4.8 V,as compared to the pristine LMOF1.6 with only 27.9％capacity retention.
基金项目
National Key R and D Program of China(2022YFB3805702)
State Key Program of the National Natural Science Foundation of China(52130303)
National Natural Science Foundation of China(51973152)
National Natural Science Foundation of China(51973119)
National Natural Science Foundation of China(52103093)
National Natural Science Foundation of China(52173078)
NETL
NSTL
万方数据