Enabling stable cobalt-free Li-rich cathodes through a one-step dual-modified strategy

Abstract

Cobalt-free Lithium-rich layered oxides (LRLOs) are promising cathodes for low-cost and high-energy-density Li-ion batteries. However, their remarkable capacity comes with challenges including structural degradation, irreversible oxygen release and sluggish kinetics. Herein, we conduct a one-step dual-modified strategy by yttrium doping and Li₃PO₄ surface modification. Combining density-functional theory calculations with in-situ X-ray diffraction and in-situ differential electrochemical mass spectrometry, the Y³⁺ doping and Li₃PO₄ nano coating modified LRLOs is demonstrated has an excellent structural stability with enhanced Li⁺ diffusion kinetics and stabilized oxygen lattice. Excellent rate performance and thermal stability are achieved: high discharge specific capacity of 221 mAh·g⁻¹ at room temperature (96.5 % at 1 C after 100 cycles) and incredible discharge specific capacity of 210 mAh·g⁻¹ at 55 °C (91.8 % at 2 C after 100 cycles). This work resolves the safety and stability issues and provides a feasible strategy for Co-free LRLOs.