FeSO4 as a Novel Li-Ion Battery Cathode

FeSOhas the characteristics of low cost and theoretical high energy density(799 W·h·kgwith a two-electron reaction), which can meet the demand for next-generation lithium-ion batteries. Herein, FeSOas a novel highperformance conversion-reaction type cathode is investigated. We use dopamine as a carbon coating source to increase its electronic conductivity. FeSO@C demonstrates a high reversible specific capacity(512 mA·h·g)and a superior cycling performance(482 mA·h·gafter 250 cycles). In addition, we further study its reaction mechanism. The FeSOis converted to Fe and LiSOduring lithium ion insertion and the Fe—LiSOgrain boundaries further store additional lithium ions. Our findings are valuable in exploring other new conversion-type lithium ion battery cathodes.