Phase component-controllable synthesis of layered-spinel composite materials as high-performance cathode for lithium-ion battery

Abstract

A layered-spinel composite cathode material, LixMn0.75Ni0.25O(1.75+x/2), with controllable phase composition was synthesized by a hydrothermal method followed by calcination. Composite cathode materials that contained different amounts of spinel were synthesized by adjusting the reaction duration in the hydrothermal process. The spinel phase decreases with increasing reaction time, whereas the layered phase increases. For a hydrothermal time of 10h, a composite material with 22.42wt% spinel component and 63.98wt% layered component showed the best cycle performance of approximately 200mAhg-1 at 0.5C rates. When the hydrothermal time was 2h, a composite material with 34.00wt% spinel component and 53.53wt% layered component was obtained. The as-synthesized composite exhibits the highest first discharge capacity (245.3mAhg-1) and the best rate capability (105.3mAhg-1 at 5C), which can be ascribed to an appropriate content of layered and spinel phase; the layered component provides composite structural integrity and the spinel phase enables excellent rate performance.