Boosting high-voltage cyclic stability of nickel-rich layered cathodes in full-cell by metallurgy-inspired coating strategy

Abstract

Increasing the cutoff voltage is an effective way to boost the energy density of lithium ion full-cells which use the layered nickel-rich oxides. However, the practical application of nickel-rich cathode is severely hindered by the structural degradation and grave capacity loss. Herein, we find that the deterioration of full-cell capacity retention is correlated with the lithium loss in the anode solid electrolyte interphase (SEI) especially at high voltage. The Ni and Mn ions dissolved from the cathode deposit in the anode SEI triggers lithium trapping, and consequently expedites the consumption of cyclical lithium ions. Be based on this finding, an innovative metallurgy-inspired approach of creating a uniform hydroxide layer on the cathode surface and inhibiting separate nucleation of hydroxide that employ carbon dioxide as acidic inducing precipitant, is introduced. Finally, the ultra-thin Al2O3-encapsulated cathodes are obtained after annealing process. Benefiting from the prominent physical-chemical protection function of nanoscale oxide layer, the developed cathode exhibits outstanding cycle durability in full-cell with a capacity retention of ~80% after 800 cycles at 25 °C. Notably, the modified full-cell possesses well thermal stability go through nail penetration test. This work offers an industrial-scale coating paradigm toward high performance nickel-rich cathode for application in full-cells.