Enhancing the reversibility of the chemical evolution of the Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode via a simple pre-oxidation process

Abstract

For developing commercially viable LiNi_1−x−yMn_xCo_yO₂ (NCM), it is necessary to alleviate the irreversible chemical process upon Li-ion insertion/extraction, which primarily accounts for prevailing capacity loss, impedance buildup as well as low columbic efficiency. To resolve this issue, we herein propose a simple but novel method to alter the chemical composition by a facile treatment of H₂O₂, which remarkably reduces the cation mixing of Li⁺/Ni²⁺ and residual lithium on the cathode. The tailored composition contributes great resistance to the structural reconstruction and enhancement in structural reversibility, as shown by in situ Raman and high-resolution transmission electron microscope (HRTEM) results. Thus, the modified sample outperforms the pristine one; it exhibits cyclability with 95.7% capacity retention over 300 cycles, high columbic efficiency and enhanced rate capability.