A solid-to-solid metallic conversion electrochemistry toward 91% zinc utilization for sustainable aqueous batteries

Area of Science:

• Electrochemistry
• Materials Science
• Nanotechnology

Background:

• Diffusion-limited aggregation (DLA) of metal ions during plating/stripping causes dendrite growth, limiting metallic anode performance.
• Conventional solid-to-liquid (StoL) and liquid-to-solid (LtoS) processes are prone to dendrite formation, impacting battery safety and lifespan.

Purpose of the Study:

• To develop a new solid-to-solid (StoS) conversion electrochemistry to inhibit dendrite growth.
• To improve the utilization ratio of metals in electrochemical energy storage devices.

Main Methods:

• Investigated reversible conversion reactions between sparingly soluble metal carbonates (Zn, Cu) and their corresponding metals at the electrode/electrolyte interface.
• Employed molecular dynamics simulations to analyze anion transport and compare StoS with conventional LtoS/StoL processes.
• Fabricated and tested zinc-based anodes using 2ZnCO3·3Zn(OH)2 in asymmetric and full cells, and assembled a 1-Ah pouch cell.

Main Results:

• The StoS process effectively eliminates DLA and dendrites, outperforming conventional LtoS/StoL methods.
• 2ZnCO3·3Zn(OH)2 demonstrated high zinc utilization (ca. 95.7% in asymmetric cells, 91.3% in full cells).
• The 1-Ah pouch cell achieved stable operation over 500 cycles with 80% capacity retention over 2000 cycles in full cells, and a total energy density of 135 Wh kg−1.

Conclusions:

• The novel StoS conversion electrochemistry offers a promising strategy for dendrite-free metallic anodes.
• This approach significantly enhances metal utilization and battery cycle life.
• The developed technology holds potential for high-energy-density and long-lasting battery applications.