A “three-in-one” strategy via La2O3-ZrO2 coating to effectively enhance the electrochemical performance of LiCoO2

Abstract

The rapid capacity decay of LiCoO2 (LCO) at high operating voltage is primarily attributed to severe interface/structure degradation. Surface coating has been recognized as an effective strategy for enhancing the interface/structure stability of LCO. To achieve a balance between effective protection and fast Li+ transport, the selection of suitable coating materials is crucial. In this study, a composite coating layer comprising La2O3 and ZrO2 was prepared using a simple solid-phase method. The resulting LCO coated with this La2O3-ZrO2 layer (LCO@LaZr) showed significantly improved electrochemical performance. After 200 cycles at 1 C, LCO@LaZr demonstrated a higher capacity retention of 90.3% compared to uncoated LCO (46.5%). Furthermore, LCO@LaZr exhibited superior rate capability, achieving a high capacity of 165.6 mAh g−1 at 10 C, while uncoated LCO delivered a lower capacity of 113.7 mAh g−1. The La2O3-ZrO2 coating enhanced the performance of LCO through a “three-in-one” strategy. La2O3 reduced the Li+ diffusion barrier, thereby promoting Li+ transport, while ZrO2 improved the surface/interface stability of the cathode. Moreover, the continuous and uniform La2O3-ZrO2 layer effectively prevented direct contact between the cathode and the electrolyte, thereby suppressing undesirable side reactions. This study presents an efficient strategy for the surface coating of high-energy density cathodes.