A new series of spinels, ZnNixMnxCo2-2xO4, are reported as a high-voltage and high-capacity cathode material for non-aqueous Zn-ion batteries. Mn, Ni co-substitution for Co in ZnCo2O4 is demonstrated to be an efficient method to facilitate Zn-deintercalation and enhance discharge capacity, which provides guidelines for designing more attractive multivalent cathodes materials.
Significance and Impact
Our research shows the successful substitution of Ni and Mn for Co in ZnNixMnxCo2-2xO4 spinels. Full cells constructed using new spinels as cathodes paired with a metal anode showed capacities over 200 cycles of 174 mAh/g and an open circuit potential of 2.05 V. This achievement opens the door to further multivalent cathodes.
- XRD, XPS, ICP-AES and SEM-EDX analyses show the successful substitution of Ni and Mn for Co in ZnCo2O4 spinels and Ni, Co, and Mn exhibit +2, +3, and +4 valence states, respectively.
- Structural dynamics involving Ni-migration conjoined to multiple redox pair conversions likely facilitate Zn2+ de-/intercalation and sustain good cycling performance.