Suppress moisture sensitivity of Ni-rich cathode materials by bioinspired self-assembly hydrophobic layer

Ni-rich layered oxides have shown great potential as lithium-ion batteries in the field of powered vehicles. However, the chemical instability at the cathode–air interface leads to high sensitivity in humid air and easily produces residual lithium, posing challenges for interfacial stability. In this work, we used alkyl phosphoric (AP) material as a bioinspired coating on the surface of LiNi0.83Mn0.11Co0.06O2 (N83) for molecular self-assembly to form a strongly robust cathode–air interface with improved chemical environmental stability. Results showed that the bioinspired self-assembled hydrophobic coating (BSHC) inhibits the formation of residual lithium due to Li+/H+ ion exchange on the high nickel surface and improves the stability of the cathode–air interface. Moreover, the lithium phosphate generated by surface conversion remarkably enhances the migration rate of Li+, alleviates irreversible gas release, and effectively inhibits electrolyte erosion. Given the synergistic effect, the Ni-rich material coated with 16 carbon chains of alkyl phosphoric (N83@16C) provide higher capacity (151.3 mAh/g) and capacity retention (91.38%) after 300 cycles, exhibiting excellent chemical and cycling stability after exposure. This work helps improve the environmental chemical stability of Ni-rich materials and provides guidance for the development of other cathode materials with sensitive cathode–air interfaces.