FeSO4 as a Novel Li-Ion Battery Cathode

FeSO 4 has the characteristics of low cost and theoretical high energy density (799 W⋅h⋅kg −1 with a two-electron reaction), which can meet the demand for next-generation lithium-ion batteries. Herein, FeSO 4 as a novel high-performance conversion-reaction type cathode is investigated. We use dopamine as a carbon coating source to increase its electronic conductivity. FeSO 4 @C demonstrates a high reversible specific capacity (512 mA⋅h⋅g −1 ) and a superior cycling performance (482 mA⋅h⋅g −1 after 250 cycles). In addition, we further study its reaction mechanism. The FeSO 4 is converted to Fe and Li 2 SO 4 during lithium ion insertion and the Fe|Li 2 SO 4 grain boundaries further store additional lithium ions. Our findings are valuable in exploring other new conversion-type lithium ion battery cathodes.