Inverse spinel transition metal oxides for lithium-ion storage with different discharge/charge conversion mechanisms

- Inverse spinel structure relieves the irreversible phase transition of electrodes.
- Anodes with the same structure show different discharge/charge conversion mechanisms.
- High reversible capacity confirms the potential feasibility of composites.

Inverse spinel transition metal oxides (Fe3O4, MnFe2O4, Fe3O4/reduced graphene oxide and MnFe2O4/reduced graphene oxide) are prepared by a facile ethylene-glycol-assisted hydrothermal method. The stability of inverse spinel structure and the high specific surface area of nanoscale provide transition metal oxides with high specific capacity. And the surface modification with reduced graphene oxide improves the poor conductivity of pristine transition metal oxides. Pristine Fe3O4 and MnFe2O4 deliver the high initial discharge capacity of 1137.1 and 1088.9 mAh g−1, respectively. Fe3O4/reduced graphene oxide and MnFe2O4/reduced graphene oxide get the reversible capacity of 645.8 and 720 mAh g−1, respectively, even after 55 cycles. The different discharge/charge conversion mechanisms make them different capacity stability. The great electrochemical performances of composites offer electrodes with suitable characteristics for high-performance energy storage application.