Novel Design and Fabrication of Bi2S3@NC Nanofibers As Promising Anodes for Advanced Potassium Energy Storage

Bi2S3 has been considered as an extremely attractive anode for potassium energy storage due to its low cost, good safety, easy synthesis and high theoretical capacity. Nevertheless, it possesses a poor potassium storage performance in practical application because of its sluggish kinetics and severe volume change. To address these challenges, the designed nitrogen-doped carbon-modified Bi2S3 (Bi2S3@NC) nanofibers have been successfully prepared by an electrospinning route and carbonization process. In this designed nanocomposite, the nanosized Bi2S3 particles are uniformly distributed within the one-dimensional mesoporous nanofibers. The constructed mesopores can greatly buffer the volume change of Bi2S3 nanocrystals during the K+ insertion and extraction. Meanwhile, the one-dimensional conductive networks formed by nitrogen-doped carbon fibers are helpful to promote the electronic conductivity of Bi2S3 nanoparticles. This obtained Bi2S3@NC anode exhibits excellent rate capability (467 mAh/g at 1 A/g) and good cyclic performance (79% capacity retention ratio at 5 A/g for 1000 cycles). This study offers a good approach for constructing advanced electrode materials with fast electrochemical reactions.