Achieving High-Rate and Stable Sodium-Ion Storage by Constructing Okra-Like NiS<sub>2</sub>/FeS<sub>2</sub>@Multichannel Carbon Nanofibers
Gaoya Ren, Tiantian Tang, Shanshan Song, Yaxuan Li, Jingyi Gao, Yuting Wang, Zhujun Yao, Shenghui Shen, Liqiang Zhang, Yunna Guo, Yefeng Yang
Abstract
Transition metal sulfides (TMSs) are considered as promising anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacities. However, the relatively low electrical conductivity, large volume variation, and easy aggregation/pulverization of active materials seriously hinder their practical application. Herein, okra-like NiS 2 /FeS 2 particles encapsulated in multichannel N-doped carbon nanofibers (NiS 2 /FeS 2 @MCNFs) are fabricated by a coprecipitation, electrospinning, and carbonization/sulfurization strategy. The combined advantages arising from the hollow multichannel structure in carbon skeleton and heterogeneous NiS 2 /FeS 2 particles with rich interfaces can provide facile ion/electron transfer paths, ensure boosted reaction kinetics, and help maintain the structural integrity, thereby resulting in a high reversible capacity (457 mA h g –1 at 1 A g –1 ), excellent rate performance (350 mA h g –1 at 5 A g –1 ), and outstanding long-term cycling stability (93.5% retention after 1100 cycles). This work provides a facile and efficient synthetic strategy to develop TMS-based heterostructured anode materials with high-rate and stable sodium storage properties.