Al 2 O 3 ‐Coated, Single Crystal Zr/Y co‐Doped High‐Ni NCM Cathode Materials for High‐Performance Lithium‐Ion Batteries

Abstract High Ni‐layered oxides are promising cathode candidates for lithium‐ion batteries (LIBs) owing to their high‐specific capacity, high energy density, and low cost. However, their thermal and cycling performances often suffer from the inevitable interfacial reactions, oxygen loss, transition metal dissolution, and irreversible H2‐H3 lattice distortion. Herein, small doses of Zr/Y co‐doped and Al 2 O 3 coated single‐crystal high‐Ni NCM (LiNi 0.83 Co 0.12 Mn 0.05 O 2 ) materials (ZrY‐NCM@Al) are synthesized via a facile high‐temperature solid‐state reaction. The Al 2 O 3 surface coating works as a protective layer to inhibit the side reaction on the interface between electrodes and electrolytes. The Zr/Y co‐doping improves the structural stability of the NCM and suppresses the irreversible structure transition from H2 to H3. When ZrY‐NCM@Al is used as a cathode, the square‐aluminum‐shell full battery with artificial graphite anode exhibits a high capacity of 50 Ah and a high energy density of 230 Wh kg −1 . After 1000 cycles at 45 °C and 1 C constant current and constant voltage (CCCV), the battery retained 89.2% of its capacity and an energy density of 204 Wh kg −1 , demonstrating excellent thermal and cycling performances. This study paves a novel route to the fabrication of high‐Ni cathode materials for LIBs with excellent cycling and thermal stability.