Ce and F Dual-Doping Strategy for High Cycle Performance of Lithium-Rich Layered Oxide Materials

Abstract

Li-rich layered oxides (LrLOs) attracted much attention due to their high specific capacity. However, LrLOs have disadvantages such as fast voltage decay and poor cycle stability. In this work, we propose a dual-doping strategy based on Ce and F ions to respond to the defects of LrLOs. This work shows that Ce and F have a strong synergistic effect in LrLOs cathode materials. Dual-doping makes the structure of the cathode materials more stable, which is mainly manifested by inhibiting the extraction of lattice oxygen, reducing the migration of cations during the cycle, and reducing the corrosion of the electrolyte to the cathode materials. Thereby, the work improves the cycle performance of the cathode materials. The capacity retention rate is 84.3% for 200 cycles at 1[Formula: see text]C (versus 59.6%). The median discharge voltage is 3.2155[Formula: see text]V after 200 cycles at 1[Formula: see text]C (versus 2.9485[Formula: see text]V). The voltage decay is 0.4706[Formula: see text]V for 200 cycles at 1[Formula: see text]C (versus 0.6923[Formula: see text]V). Interestingly, our research found that Ni[Formula: see text] of the Li layer also plays an important role in the process of improving cycle performance. This work provides new ideas for solving the cycle stability of LrLOs cathode materials and suppressing voltage decay.