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 BaZrO₃ thermal barrier engineered LiNi_0.8Co_0.1Mn_0.1O₂ 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 BaZrO₃ 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.