Boosting reaction kinetics of polycrystalline phase Fe 7 S 8 /FeS 2 heterostructures encapsulated in hollow carbon nanofibers for superior fast sodium storage

An Fe 7 S 8 /FeS 2 heterojunction grown in hollow fibers was designed. This heterojunction can regulate the valence state of iron sulfide, further change its crystal phase, increase the diffusion coefficient, and contribute to high-rate in SIBs.