Metal-organic-framework derived carbon-coated FeSe2 nanoparticles facilitate efficient sodium ion storage

Transition metal selenides are considered as potential anode materials for sodium -ion batteries (SIBs) due to their high theoretical capacity. However, the slow kinetic reaction, poor conductivity and severe volume change during sodium ion intercalation/deintercalation process limit its large-scale application. In this study, FeSe2/C was prepared through hydrothermal and subsequent annealing process. The conductive carbon layer of FeSe2/C can not only promote sodium ion diffusion and electron transfer but also improve the conductivity and release structure damage. As a result, when used as an anode in SIBs, the obtained FeSe2/C exhibits an excellent rate capability of 420 mAh g-1 at 20 A g-1 and high cycle stability of 412 mAh g-1 at 10 A g-1 after 1000 cycles. The excellent electrochemical properties suggest that FeSe2/C is a promising anode material for SIBs.