A Single-Pot Co-Precipitation Synthesis Route for Ni-Rich Layered Oxide Materials with High Cycling Stability

Abstract

In this work we report variations of LiNi0.88Mn0.06Co0.06O2 synthesised through a single-pot oxalic acid co-precipitation route, in which all cation precursors were added in the same step. The effects of Al-doping, heat-treatment temperature and Li precursor excess were investigated with physicochemical and electrochemical characterisation. Phase pure and well-ordered polycrystalline materials were successfully synthesised for all Al-doped and undoped compositions. Undoped LiNi0.88Mn0.06Co0.06O2 prepared at 750 °C with 4 at% excess Li precursor showed excellent cycling stability in NMC||LTO cells with an initial capacity of 201 mAh/g at 0.1 C at 20 °C, and a capacity retention of 81 % after 415 cycles. The Al-doped variations LiNi0.88Mn0.04Co0.06Al0.02O2 and LiNi0.88Mn0.06Co0.04Al0.02O2 were synthesised, and they showed similar initial electrochemical performance to undoped LiNi0.88Mn0.06Co0.06O2, but Al-doping via the oxalic acid co-precipitation route resulted in shorter cycle life. The study outlines the importance of the processing parameters to achieve Ni-rich layered oxides with a long cycle life without further surface modifications.