The intercalation/deintercalation kinetic studies on the structure-integrated cathode material 0.5Li2MnO3 0.5LiNi0.5Mn0.5O2

Abstract

A cathode material, 0.5Li2MnO3 0.5LiNi0.5Mn0.5O2, was prepared by citric acid-assisted sol–gel method and its electrochemical performance was investigated. It delivered a charge capacity of 270 mAh g−1 and a discharge capacity of 189 mAh g−1 in the first cycle. With the increase of current density from 14 to 28 mA g−1, the discharge capacity dropped severely to 130 mA g−1. Obviously, the rate capability of the material was inferior to most of the oxide cathode materials. The diffusion coefficient of this material was calculated to be 6.04 × 10−12 cm2 s−1 from the results of cyclic voltammetry measurements. Moreover, diffusion coefficients between 3.13 × 10−12 and 1.22 × 10−10 cm2 s−1 in the voltage range of 3.8–4.7 V were obtained by capacity intermittent titration technique. This, together with the localized Li2MnO3 domains in the crystal structure, may validate the poor rate capability.