Homogenizing Zn Deposition in Hierarchical Nanoporous Cu for a High-Current, High Areal-Capacity Zn Flow Battery

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Zinc anodes offer a cost-effective solution for flow batteries but suffer from dendrite formation due to non-uniform deposition in porous frameworks.
• Achieving stable, long-duration energy storage requires thick zinc deposits, exacerbating stability issues.

Purpose of the Study:

• To develop a hierarchical nanoporous electrode that homogenizes zinc deposition for improved zinc anode stability in flow batteries.
• To investigate the potential of a modified copper foam electrode for long-duration, high-performance zinc-based flow batteries.

Main Methods:

• Copper foam was alloyed with zinc to form Cu5Zn8, followed by a dealloying process to create a nanoporous structure with controlled pore sizes.
• Density functional theory simulations were used to understand zinc nucleation behavior.
• In situ microscopy monitored the morphological evolution and zinc deposition process.
• The electrode's performance was evaluated in a zinc-iodine flow battery under demanding cycling conditions.

Main Results:

• The hierarchical nanoporous electrode facilitated uniform zinc nucleation and deposition, suppressing dendrite formation.
• The electrode maintained high hydraulic permeability (≈10-11 m2) while creating nanoscale pores and pits.
• Stable cycling for 200 hours was achieved at a high current density (60 mA cm-2) and capacity (60 mAh cm-2) in a zinc-iodine flow battery.

Conclusions:

• The developed hierarchical nanoporous copper electrode effectively homogenizes zinc deposition, significantly enhancing the stability and cycle life of zinc-based flow batteries.
• This approach offers a promising strategy for realizing inexpensive, long-duration electricity storage solutions.
• The results meet practical demands for stable and reliable electrochemical energy storage systems.