Conformal Li₃PO₄-coating synergized epitaxial Mn-doping consolidating chemical and structural stability of Ni-rich LiNi_0.9Co_0.1O₂ cathode

Poor safety and cycle-life of Ni-rich layered oxides caused by the interfacial side reactions and bulk structural degradation seriously encumber their commercialization. Herein, a one-pot hetero-precursor transformation approach has been developed to simultaneously achieve surface-coating and subsurface-doping of Ni-rich layered oxides, and a highly stable heterogeneous interface architecture, integrating an outer Li₃PO₄ coating layer and a surficial Mn-doping layer, is well designed to enhance chemical and structural stability and eliminate surface impurity. The cathode architectural design exploits advantages of both surface-coating and elemental-doping, where the superficial Mn-doping induces a nanoscale anchoring layer, suppressing transition-metal-ion migration and ameliorating phase transition reversibility, and conformal surface Li₃PO₄ coating with three-dimensional channels promotes Li-ion transport and suppresses electrolyte decomposition. Due to the improvement in chemical and structural stability and electrical properties, the modified LiNi_0.9Co_0.1O₂ cathode enables much enhanced electrochemical performance, especially high-voltage tolerance and long-cycle stability. The optimal cathode demonstrates a high capacity retention of 90.5% after 100 cycles at 0.2 C in half-cell within 2.80−4.35 V, while its pouch full-cell coupled with graphite enables excellent capacity retention of 86.8% after 900 cycles at 1 C. This work provides a straightforward and economical surface modification strategy for boosting chemical and structural stability of Ni-rich cathode materials.