Lattice-oxygen modulation for redox stabilization and multi-electron transfer in lithium-rich cathodes

Abstract

Lithium-rich layered oxides (LRLOs) are promising cathode materials due to their high specific capacity, energy density, and operating voltage. However, their performance is hindered by the limited redox activity of transition metals, leading to oxygen redox instability, oxygen release, and capacity degradation. To address these issues, we propose an innovative lattice-oxygen modulation (LOM) strategy that incorporates Mn³⁺ and Ti⁴⁺ into the Li_1.2Cr_0.3Mn_0.4Ti_0.1O₂ system, effectively mitigating Cr migration, stabilizing oxygen redox reactions, and reinforcing structural integrity. This results in improved electrochemical performance, as demonstrated by a 56.5 mAh g⁻¹ increase in initial discharge capacity to 364.2 mAh g⁻¹, with 71.3 % capacity retention after 30 cycles, reflecting a 20.2 % improvement in cycling stability. Density functional theory (DFT) calculations confirm enhanced Cr redox reversibility and reduced oxygen evolution, further strengthening structural stability. These synergistic effects highlight the pivotal role of the LOM strategy in optimizing both electrochemical performance and structural integrity, offering a scalable pathway to improve capacity and cycling stability in lithium-rich cathodes.