Revitalizing nanoscale solid-solid conversion enables ultrastable aqueous batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-manganese (Zn-Mn) batteries are promising for grid storage.
• Limited battery lifetime is caused by irreversible solid product formation during deposition-dissolution reactions.
• Controlling the size of solid products is a critical challenge.

Purpose of the Study:

• To develop a strategy to control solid product size in Zn-Mn batteries.
• To improve the stability and lifespan of aqueous Zn-Mn batteries.
• To enable reversible Mn(II, l)-Mn(IV, s) conversion pathways.

Main Methods:

• Constructing a size-revitalizing layer (SRL) on MnO2 using Bi2O3 as an optimal modifier.
• Regulating the interfacial microenvironment through sustained Mn release and interaction with solid products.
• Investigating the effect of SRL on solid product size, ion diffusion, and electrochemical pathways.

Main Results:

• The SRL effectively stabilized nanoscale solid products, reducing their size from >10 μm to the nanoscale.
• This size control enabled a reversible Mn(II, l)-Mn(IV, s) pathway, suppressing irreversible Mn(II, l)-Mn(III, s) routes.
• Coin cells with high-mass-loading cathodes achieved over 1000 cycles at 2 C.
• Scaled iron-plate cells demonstrated stable operation for 110 days.

Conclusions:

• The size-controlled solid-solid conversion strategy using SRL significantly enhances battery stability and resolves irreversible capacity degradation.
• This approach offers a promising solution for long-duration, large-scale energy storage systems.
• The strategy has broad applicability for diverse electrode materials in advanced energy storage.