Toward Stable Mn Metal Anodes and Electrolyte Design for Mn‐Based Batteries

Why It Matters

Stable Mn metal anodes could boost energy density and reduce cost for large‑scale storage, accelerating adoption of high‑performance rechargeable batteries.

Key Takeaways

• Mn offers higher capacity, lower redox potential than Zn
• Hydrogen evolution and dendrites hinder Mn anode durability
• Concentrated aqueous electrolytes widen stability window
• Halogen‑mediated non‑aqueous solvents suppress water side reactions
• Protective interphases and alloying improve Mn plating efficiency

Pulse Analysis

Manganese’s attractive electrochemical profile—its –1.19 V versus SHE redox potential and a theoretical capacity exceeding that of zinc—has sparked interest among researchers seeking higher‑energy rechargeable systems. The metal’s abundance and low cost make it a compelling alternative for grid‑scale storage and electric‑vehicle applications, where every millivolt of voltage gain translates into longer range or reduced material expenses. Yet, the same reactivity that offers these benefits also triggers rapid corrosion and hydrogen evolution when Mn contacts conventional aqueous electrolytes, undermining cycle life and safety.

To tame these parasitic reactions, scientists are engineering electrolytes that fundamentally reshape the Mn‑water interface. Water‑in‑salt formulations, featuring ultra‑high salt concentrations, suppress free‑water activity and broaden the electrochemical stability window, allowing Mn to plate and strip with markedly reduced hydrogen evolution. Parallel efforts explore halogen‑mediated non‑aqueous solvents, where fluorinated anions create a protective solvation sheath that limits water‑induced side reactions. Additives such as organic film‑formers further engineer a solid‑electrolyte interphase (SEI) that physically blocks dendrite nucleation while maintaining ionic conductivity, delivering reversible Mn deposition over hundreds of cycles.

Beyond electrolyte chemistry, alloying Mn with metals like nickel or copper and applying artificial interphases have emerged as powerful strategies to modulate electronic structure and mechanical properties. These modifications lower the overpotential for Mn nucleation, distribute current density more evenly, and inhibit dendritic protrusion. Collectively, these advances outline a clear pathway toward practical Mn‑metal batteries, promising higher energy density, lower material costs, and improved safety. Continued integration of electrolyte design, interphase engineering, and alloy development will be critical for translating laboratory breakthroughs into commercial products that reshape the rechargeable‑battery landscape.