Modulating Coupled Polyhedral Distortion in Li-Rich Cathodes for Synergistically Inhibiting Capacity and Voltage Decay

Abstract

Achieving significant enhancements in both capacity and voltage stability remains a formidable challenge for Li-rich layered cathodes. The severe performance degradation is attributed to large lattice strain, irreversible oxygen release and transition metal migration, but the most critical factor responsible for structural destabilization is still elusive. Here, based on density functional theory calculations, machine learning and experimental validation, a multi-hierarchy screening of complex multi-element doping systems is developed from electrochemical activity, lattice strain, oxygen stability and transition metal migration barrier. It is further identified that the coupled polyhedral distortion parameter D+σ² of the substitution element is the most significant feature that affects the structural stability during cycling. The Li-rich layered cathode developed based on the predicted results exhibits remarkable long-term capacity stability (95.8% capacity retention over 300 cycles) and negligible voltage loss (0.02% voltage decay per cycle). This study provides a general approach by modulating coupled polyhedral distortion for the rational design of cathode materials and can be expanded to the discovery of other advanced electrodes.