Effect of Residual Lithium Rearrangement on Ni-rich Layered Oxide Cathodes for Lithium-Ion Batteries

Abstract

A water washing process can effectively reduce the presence of residual lithium with minimal effect on lithium-ion battery cell performance. We investigated the effects of varying the amount of water used for washing and the temperature used to evaporate the water on Li1.00Ni0.80Co0.15Mn0.05O2 . The residual lithium decreased and the cell performance deteriorated as the amount of water used for washing was increased from 0.7 to 5 times the amount of active material. The temperature at which the active material was dried after washing had a considerable effect on the reformation of the residual lithium layer after heat treatment. A ratio of water/active material of 1:1 and a drying temperature of 120 degrees C were selected as the optimal washing conditions, achieving a residual lithium content of less than 1000 ppm with minimum deterioration in cell performance: as a result of the treatment. the total volume of gas evolution was reduced by 25%.