No abstract

Operating Li-ion batteries in a harsh environment will greatly degrade the cyclic performance and safety of Ni-rich layered cathodes, which challenges the current modification approaches to form a more stable interface with the electrolyte and a robust crystal structure. Herein, we demonstrate the surface engineering enabling V-doped and ZrV 2 O 7 -coated Ni-rich layered cathodes (V-NCM@ZVO), where stoichiometric ZVO generates on the surface of oxides and tailorable V subsequently diffuses into the bulk phase during high-temperature lithiation. The introduction of high-energy V−O bonds vastly refrains the lattice oxygen escape, and meantime, ionic conductive and electrochemically inert ZVO ensures a robust interphase on the Ni-rich cathode, greatly enhancing the thermal stability. At 55 °C, the modified cathode displays a high reversible capacity of 220.3 mAh g −1 at 0.2 C and 183.0 mAh g −1 at 10 C. More impressively, the assembled V-NCM@ZVO//graphite pouch-type cell exhibits a capacity retention of 90.2% at 1 C after 400 cycles at 55 °C. This work exhibits a feasible modification strategy to strengthen the surface and crystal stability in parallel of Ni-rich cathodes to meet high-temperature Li-ion batteries.