Conductive binary Li borate glass coating for improved Ni-rich positive electrode in sulfide-based all-solid-state Li batteries

Coating Ni-rich layered oxide positive electrodes is essential to improve their electrochemical performance in sulfide-based all-solid-state Li batteries, but achieving cost-effective, high-performance positive electrodes remains challenging. In this work, we apply a thin (~3 nm) conductive binary Li borate glass coating (0.5Li2O·0.5B2O3) onto single-crystal LiNi0.8Co0.1Mn0.1O2 using a simple dry process and heating. This coated positive electrode delivers 209 mAh g−1 specific capacity at a specific current of 20 mA g−1 with 79.7% initial Coulombic efficiency, retains 87.8% capacity after 1000 cycles at a specific current of 200 mA g−1, and achieves 14.6 mAh cm−2 areal capacity. Pouch cells with this positive electrode reach 383 Wh kg−1 specific energy, and sustain 300 cycles at a specific current of 66.67 mA g−1. Various characterizations reveal that this coating can enhance Li-ion transport, stabilize the positive electrode lattice, and strengthen the interface between positive electrode and sulfide electrolyte. Here we show that conductive glass coatings enable high-voltage positive electrodes with high stability and specific energy in all-solid-state batteries.