Preparation of Cu7.2S4@N, S co-doped carbon honeycomb-like composite structure for high-rate and high-stability sodium-ion storage.

Sodium ion batteries (SIBs) attract most of the attention as alterative secondary battery systems for future large-scale energy storage and power batteries due to abundance resource and low cost. However, the lack of anode materials with high-rate performance and high cycling-stability has limited the commercial application of SIBs. In this paper, Cu7.2S4@N, S co-doped carbon (Cu7.2S4@NSC) honeycomb-like composite structure was designed and prepared by a one-step high-temperature chemical blowing process. As an anode material for SIBs, Cu7.2S4@NSC electrode exhibited an ultra-high initial Coulomb efficiency (94.9%) and an excellent electrochemical property including a high reversible capacity of 441.3 mAh g-1 after 100 cycles at 0.2 A g-1, an excellent rate performance of 380.4 mAh g-1 even at 5 A g-1, and a superior long-cycle stability with a capacity retention rate of approximately 100% after 700 cycles at 1A g-1.