Towards Superior Electrochemical Property of Nickel-High Cathode Materials with a Multi-Functional Modification Strategy

Abstract

The layer nickel-high materials are attractive high-energy cathodes for lithium-ion batteries (LIBs), but still suffer from structure degradation that heavily retards their practical applications. In this study, a multi-functional modification approach with monosodium phosphate to enhance electrochemical properties of the LiNi0.8Co0.1Mn0.1O2 cathode materials via a synchronous lithium oxidation route is reported. The dihydrogen phosphate ions convert the residual lithium compounds into Li3PO4 attaching on the material surface, effectively decreasing the unwanted residual lithium compounds and enhancing the surface stability. Further, it is worth noting that the generated Li3PO4 also dedicates to stabilizing the surface by capturing detrimental by-products. Additionally, the structure stability and reversibility are notably improved as well, which benefits from the doping of sodium in the bulk phase. The sodium ions occupy the lithium sites forming NaO6 octahedron, availably expanding the c-axis spacing and inhibiting the cation mixing. As a result, the modified materials exhibit a discharge capacity of 181.2 mAh g−1 over 3.0–4.4 V at 1 C, as well as a corresponding capacity retention of 97.26% after 100 cycles. Based on our work, this modification strategy delivers a reasonable approach for the development of advanced cathode materials.