Ultra‐High Temperature Operated Ni‐Rich Cathode Stabilized by Thermal Barrier for High‐Energy Lithium‐Ion Batteries

Abstract The pursuit of high energy density batteries has expedited the fast development of Ni‐rich cathodes. However, the chemo‐mechanical degradation induced by local thermal accumulation and anisotropic lattice strain is posing great obstacles for its wide applications. Herein, a highly‐antioxidative BaZrO 3 thermal barrier engineered LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode through an in situ construction strategy is first reported to circumvent the above issues. It is found that the Zr ions are incorporated to Ni‐rich material lattice and influence on the topotactic lithiation as well as enhance the oxygen electronegativity through the rigid Zr─O bonds, which effectively alleviates the lattice strain propagation and decreases the excessive oxidization of lattice oxygen for charge compensation. More importantly, the BaZrO 3 thermal barrier with an ultra‐low thermal conductivity validly impedes the fast heat exchange between electrode and electrolyte to mitigate the severe surface side reactions. This helps an ultra‐high mass loading Li‐ion pouch cell deliver a specific energy density of 690 Wh kg −1 at active material level and an excellent capacity retention of 92.5% after 1400 cycles under 1 C at 25 °C. Tested at a high temperature of 55 °C, the pouch type full‐cell also exhibits 88.7% in capacity retention after 1200 cycles.