Aqueous Magnesium Zinc Hybrid Battery: An Advanced High-Voltage and High-Energy MgMn2O4 Cathode

Driven by energy demand and commercial necessities, rechargeable aqueous metal ion batteries (RAMBs) have gained increasing attention over the last few decades as high-power and high-energy hubs for large-scale and ecofriendly energy storage devices (ESDs). However, recently explored RAMBs still do not provide the performance needed in order to be realized in grid scale storage operations due to their poor electrochemical stability, low capacity, low working voltage, and apparently low specific energies. Herein, we have fabricated a new RAMB using MgMn2O4 as the cathode and zinc as the anode for the first time. The stable electrochemical performance of this RAMB at high current rates (similar to 80% capacity retention at 500 mA g(-1) after 500 cycles) and a very high specific energy of 370 Wh kg(-1) at a specific power of 70 W kg(-1) make this newcomer to the family of RAMBs a serious contender for the exploration of safe and green ESDs in the near future.