“…The initial discharge/charge capacities of the FeSe x @C/MB, FeSe x /MB, FeSe 2 –Fe 2 O 3 , and MB electrodes were 579/350, 574/356, 441/304, and 376/109 mAh g −1 , and their Coulombic efficiencies (CEs) were 60%, 62%, 69%, and 29%, respectively. Compared with FeSe x /MB, the lower initial CE of FeSe x @C/MB could be attributed to the presence of disordered carbon material with a high initial irreversible capacity [ 60 , 61 ]. Meanwhile, the lowest initial CE of MB was attributed to its high specific surface area, which provided more sites for the formation of an irreversible SEI layer.…”