Controllable deposition of FeV2S4 in carbon fibers for sodium-ion storage with high capacity and long lifetime

Abstract

Metal sulfides with high specific capacities have drawn considerable attention in the field of sodium-ion batteries (SIBs). As a typical metal sulfide, FeV2S4 always suffers rapid decay of capacities because of its low stability arising from large volume change. FeV2S4 nanoparticles with controllable sizes and distribution are encapsulated in carbon nanofibers (CNFs) with the help of graphene oxide (GO) to fabricate FeV2S4@GO@CNF. As a result, FeV2S4@GO@CNF anodes show enhanced electrochemical performances for Na+ storage when compared with FeV2S4@CNF with more particles on the surface. Typically, the capacity of FeV2S4@GO@CNF can be maintained at 411 mA h g−1 after 200 cycles (0.1 A g−1) and 227 mA h g−1 over 500 cycles (1 A g−1) in SIBs. Moreover, they can deliver a capacity of 170.2 mA h g−1 after 150 cycles (0.1 A g−1) at 0°C. In addition, full cells based on FeV2S4@ GO@CNF anodes and Na3V2(PO4)3/C cathodes achieve a remarkable capacity of 164 mA h g−1 after 100 cycles at 0.5 A g−1. The high specific capacities and stability of FeV2S4@GO@CNF can be attributed to GO, which controls the size of FeV2S4 nanoparticles and their distribution in CNFs, resulting in the enhanced stability of FeV2S4@GO@CNF. This study may provide a new strategy for the synthesis of nanoparticle-CNF composites in catalysts and batteries.[Figure not available: see fulltext.]