Effect of cooling method on the electrochemical performance of 0.5Li₂MnO₃·0.5LiNi_0.5Mn_0.5O₂ cathodes

Abstract

0.5Li₂MnO₃·0.5LiNi_0.5Mn_0.5O₂ powders were synthesized by coprecipitation, and high temperature sintered with different cooled methods, such as cooled with furnace material, water material, and in liquid nitrogen (N-material). The effect of cooling methods on physical and electrochemical properties are discussed through the characterizations of X-ray diffraction (XRD), scanning electron microscopy, electrochemical impedance spectroscopy (EIS), and discharge, cyclic, and rate tests. XRD results show that all samples exhibit layered characteristics. The electrochemical performance results indicate that the N-material has the best electrochemical performance. The discharge capacity at 0.1 and 5 C are 279 and 99 mAhg⁻¹, respectively. The coulomb efficiency is highest, 78.4 %. The capacity retention after 50 cycles at 0.2 C is 97.1 %. EIS results show that the charge transfer resistance of N-materials is lowest, which is responsible for higher rate capacity.