Restraining the escape of lattice oxygen enables superior cyclic performance towards high-voltage Ni-rich cathodes

Layered Ni-rich cathodes, operating at high voltage with superior cyclic performance, are required to develop future high-energy Li-ion batteries. However, the worst lattice oxygen escape at the high-voltage region easily causes structural instability, rapid capacity fading and safety issues upon cycling. Here, we report a dual-track strategy to fully restrain the escape of lattice oxygen from Ni-rich cathodes within 2.7-4.5 V by one-step Ta doping and CeO₂ coating according to their different diffusion energy barriers. The doped Ta can alleviate the charge compensation of oxygen anions as a positive charge centre to reduce the lattice oxygen escape and induce the formation of elongated primary particles, significantly inhibiting microcrack generation and propagation. Additionally, the layer of CeO₂ coating effectively captures the remaining escaped oxygen and then the captured oxygen feeds back into the lattice during subsequent discharge. The resultant Ni-rich cathode enables a capacity of 231.3 mAh g^-1 with a high initial coulombic efficiency of 93.5%. A pouch-type full cell comprising this cathode and a graphite anode exhibits >1000 times life cycles at 1C in the 2.7-4.5 V range, with 90.9% capacity retention.