Facile Molten Vanadate-Assisted Surface Treatment Strategy for Li₂MnO₃ Activation of Li-Rich Cathode Materials

Li-rich transition metal oxides (Li1+XM1–XO2) are known as the next generation of cathode materials for lithium-ion batteries by reason of their high specific capacity. However, oxygen release and structural conversion in Li-rich layered oxides during the initial charge result in low initial Coulomb efficiency (ICE) and uninterrupted capacity attenuation. In this paper, we show a molten vanadate-assisted strategy at low temperature combined with washing treatment to regulate the amount of labile oxygen removed from the surface of Li-rich oxide (Li1.25Ni0.126Co0.126Mn0.530O2, LRMO). The pre-activation strategy leads to a considerable suppression of O2 and CO2 generation in the course of the first charge and noteworthily enables the structural stability of the LRMO during the charging/discharging process. Consequently, the molten vanadate-assisted strategy-treated LRMO material exhibits a high discharge capacity of 276 mA h g–1 and an enhanced ICE of 95.1% during the first cycling at 0.1C. This research establishes a fruitful approach to ameliorate the ICE and address the potential decline of the Li-rich cathode material.