The effect of vanadium doping on the cycling performance of LiNi0.5Mn1.5O4 spinel cathode for high voltage lithium-ion batteries

Abstract

High voltage LiNi 0.5 Mn 1.5 O 4 (LMNO) spinel cathode has been attracting high interest due to its high energy density and cobalt-free chemistry. However, high temperature (50 °C) cycling behavior is not very good because of the electrolyte decomposition, metal dissolutions, and the formation of gas products. To improve the high-temperature cycling behavior of the LMNO spinel cathode, vanadium doping was employed. For this purpose, pristine LMNO, LiNi 0.45 Ti 0.1 Mn 1.45 O 4 , and LiNi 0.4 V 0.1 Mn 1.5 O 4 cathode materials were synthesized and their elevated temperature cycling behavior was compared. After 200 cycles, the 10% V-doped LMNO still has an excellent cycling performance of 99.5 mAh g −1 (capacity fade is 6.55%) at 50 °C and 1C-rate compared to 28.8 mAh g −1 pristine LMNO (capacity fade is 70.4%), and 84 mAh g −1 LiNi 0.45 Ti 0.1 Mn 1.45 O 4 capacity retention (capacity fade is 25.6%), respectively. These results showed that the V-doped LMNO design is the proper solution for high-temperature durability. • Increasing wt% doping percentage of vanadium causes nickel divanadate impurity. • Mn dissolution is not main capacity fade reason for LMNO. • Active lithium loss causes rapid capacity fade for V-doped LMNO//SiC full-cell.