A PrussianBlue Analog-Derived NiS2/CoS2/CuS2 Ternary Composite as Secondary Battery AnodeDisplaying High Capacity and Excellent Full-Cell Performance

Abstract Developing high-capacity and fast reaction kinetic sodium-ion (Na-ion) battery anodes still remains a big challenge. Here, a ternary heterostructure composite of NiS2/CoS2/CuS2 with hollow cubic structure configuration is developed by sulfurizing a NiCoCu-based prussian blue analog precursor. The ternary sulfides synergistically enhance electron/ion transport, while the hollow cubic morphology improves structural stability during cycling which is confirmed through in situ studies such as in situ Raman and X-ray diffraction. The NiS2/CoS2/CuS2 anode delivers a high capacity of 671 mAh g–1 after cycling 250 times under 0.5 A g–1, and it maintains 417 mAh g–1 after 900 cycles at 1 A g–1. The NiS2/CoS2/CuS2 anode-based full cell when paired with a NVP cathode achieves 310 mAh g–1 after 1000 cycles under 0.5 A g–1, displaying a good applicability potential. It is expected these findings are of great significance to develop long-life, high-capacity Na-ion batteries.