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

Abstract

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.

Mn deposition/dissolution chemistry and its contemporary application in R&D of aqueous batteries

“…After the original invention of Pb-acid batteries, many rechargeable battery technologies emerged, such as the Ni||Cd, Metal||Hydride, and Ni||Zn batteries. While the discovery of MnO 2 ||Zn primary battery by Georges-Lionel Leclanché has been translated into commercial portable electronic devices (Lim et al, 2021;Durena and Zukuls, 2023;Feng et al, 2023).…”

Rechargeable Zn−MnO2 Batteries: Progress, Challenges, Rational Design, and Perspectives

“…In the meantime, a higher voltage window up to ~2 V could be achieved. [11] However, it should be noted that parasitic reactions become severe at the Zn anode site in acidic medium, such as corrosion of Zn metal resulted in production of H 2 gas. Nonetheless, in the case of the 2 M ZnSO 4 + 0.1 M MnSO 4 (pH = 4.8), MnO 2 exhibits improved cyclic stability, and hydrogen evolution can also be effectively suppressed.…”

“…By increasing the H + concentration in the electrolyte, the dissolution reaction of MnO 2 during discharging can be enhanced (equation (6) and (7)). In the meantime, a higher voltage window up to ~2 V could be achieved [11] . However, it should be noted that parasitic reactions become severe at the Zn anode site in acidic medium, such as corrosion of Zn metal resulted in production of H 2 gas.…”

Aqueous Rechargeable Zinc–Metal Batteries: A Critical Analysis

“…Cathode doping, separator engineering, and the development of porous anodes in an additive-contained electrolyte can improve the cycling life, but the DOD needs to be increased without reducing the cycle life to prevent energy losses due to lower cathode and anode utilization. , Thus, to avoid crystal fracture of the cathode, Mn 3+ dissolution, and passivation and dendrite formation at the Zn anode, a battery cycling protocol consisting of a 20% DOD for the first-electron MnO 2 capacity is presently recommended, which allows long-term cycling, although this protocol limits the energy density, rendering it uncompetitive for long-term grid-based SESSs. The use of the two-electron reaction to increase the energy density with low cost per kWh may be difficult to achieve for many RAM battery manufacturers.…”