Synthesis of high-voltage (4.7 V) LiCoO2 cathode materials with Al doping and conformal Al2O3 coating by atomic layer deposition

Abstract

The electrochemical properties of high-voltage (4.7 V) LiCoO₂ cathode materials with Al doping and a conformal Al₂O₃ coating by atomic layer deposition were studied in this paper. It was found that at ≤4.5 V, the Al₂O₃ ALD coating is sufficient to sustain the stability of LiCoO₂, with capacities of 190 mA h g⁻¹ at 0.1C and 175 mA h g⁻¹ at 1C. However, at 4.7 V, Al doping is more effective at maintaining the cycling life than the Al₂O₃ coating. LiCoO₂ with an Al₂O₃ ALD coating loses 34% of its initial capacity, but LiCoO₂ with Al doping preserves 81% of its initial capacity after 110 cycles, indicating a more pronounced effect on retaining the structural stability of LiCoO₂.