Improving High-Temperature Cycle Stability and Rate Performance of LiNi0.82Co0.11Mn0.07O2 Cathode Materials Using Hydrogen Peroxide Solution Washing System

Abstract

In this study, for the removal of residual lithium (Li2CO3,LiOH) from a nickel-rich cathode material surface, LiNi0.82Co0.11Mn0.07O2 cathode materials were washed with an aqueous solution of hydrogen peroxide (H2O2).H2O2 ( pH6.04), a weak acid, can easily decompose Li2CO3 and LiOH as an oxidizing agent. On titration of residual lithium, the amounts of LiOH and Li2CO3 are 390 and 605ppm,25 - and 47 -times lower, after H2O2 washing compared to 10,296 and 28,440ppm, respectively, in case of cathode materials before washing. On DSC thermal analysis, the peak temperature and calorific value of the cathode material washed with H2O2 were 245.5∘C and 602.0 J/g, respectively, whereas the bare case was 208.6∘C and 1,071 J/g, respectively. Therefore, H2O2-washed LiNi0.82Co0.11Mn0.07O2 cathode materials had higher capacity heat retention after 100 cycles at 55∘C(85.6% at 0.5C) than the bare LiNi0.82Co0.11Mn0.07O2 cathode materials (78.6% at 0.5C).