A Short Review: Comparison of Zinc-Manganese Dioxide Batteries with Different pH Aqueous Electrolytes

As the world moves towards sustainable and renewable energy sources, there is a need for reliable energy storage systems. A good candidate for such an application could be to improve secondary aqueous zinc-manganese dioxide (Zn-MnO2) batteries. For this reason, different aqueous Zn-MnO2 battery technologies are discussed in this short review, focusing on how electrolytes with different pH affect the battery. Improvements and achievements in alkaline aqueous Zn-MnO2 batteries the recent years have been briefly reviewed. Additionally, mild to acidic aqueous electrolyte employment in Zn-MnO2 batteries has been described, acknowledging their potential success, as such a battery design can increase the potential by up to 2 V. However, we have also recognized a novel battery electrolyte type that could increase even more scientific interest in aqueous Zn-MnO2 batteries. Consisting of an alkaline electrolyte in the anode compartment and an acidic electrolyte in the cathode compartment, this dual (amphoteric) electrolyte system permits the extension of the battery cell potential above 2 V without water decomposition. In addition, papers describing pH immobilization in aqueous zinc-manganese compound batteries and the achieved results are reported and discussed.