Synthesis of LiNi0.6Co0.2Mn0.2O2 Using Supercritical Carbon Dioxide as a Cathode Material for Lithium-Ion Batteries

Abstract

A supercritical carbonation method for the preparation of lithium-ion battery precursor (Ni0.6Co0.2Mn0.2CO3) is proposed. With appropriate selection of reaction temperature, pressure and pH, a desirable stoichiometry of transition metal ratio (6 : 2 : 2) can be achieved. The precursor synthesis time plays a significant role in the battery performance as the transition metal ion distributions become more uniform with increasing reaction time. This results in a more stable layered structure, lower cation mixing level, higher electrochemical reversibility, and lower impedance. The battery made of the precursor prepared under the best synthesis conditions can achieve a discharge capacity of 174.2 mAh g−1 in the first cycle and a capacity retention of 93.0 % after 50 cycles using a current density of 60 mA g−1. This study proves the feasibility of using supercritical carbon dioxide as the reagent for the coprecipitation of lithium-ion battery precursor Ni0.6Co0.2Mn0.2CO3. Furthermore, this method can possibly be applied to the synthesis of other carbonate-based materials.