Balancing pH Mismatch in Electrolytic Zn‐MnO ₂ Batteries via a Synergetic Anion–Proton Interactive Electrolyte

ABSTRACT

Electrolytic Zn‐MnO ₂ batteries (EZMBs) are considered a promising technology for grid‐scale energy storage due to their low cost, high specific capacity, high operating voltage and safety. However, the tradeoff between the mildly acidic environment for high‐efficiency zinc deposition on anode and the high concentration of protons required to trigger the MnO ₂ /Mn ²⁺ conversion reaction on cathode leads to the pH mismatch issue, finally causing the instability and short lifespan of current EZMBs. In this study, a synergetic anion–proton interactive (SAPI) electrolyte regulation strategy is reported to balance the pH mismatch, which can not only regulate the electrode‐electrolyte interfacial microenvironment to promote the deposition of highly (002)‐oriented Zn plane with high resistance to the hydrogen evolution reaction and corrosion on anode, but also accelerate the redox reaction of MnO ₂ /Mn ²⁺ conversion on cathode, simultaneously. As a result, the SAPI electrolyte enables a 40‐fold lifespan enhancement of over 5000 cycles at a current density of 10 mA cm ⁻² in Zn‐Zn symmetric cells as compared to the pristine electrolyte. Furthermore, the EZMBs in SAPI electrolyte achieve an elevated average discharge voltage of 0.4 V and about 10‐fold stable cycling lifespan than the pristine one. This strategy provides novel insights into designing long‐life EZMBs and orientational deposition of zinc anode.