Breaking Mass Transport Limit for Hydrogen Evolution-Inhibited and Dendrite-Free Aqueous Zn Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Conventional batteries face limitations in current rate and capacity due to mass-transport limits.
• Zinc metal electrodes typically perform optimally below these critical current densities.

Purpose of the Study:

• To investigate the enhancement of zinc metal electrode performance beyond the mass-transport limit.
• To explore the efficacy of pulsed-current protocols for high-performance zinc batteries.

Main Methods:

• Utilizing pulsed-current protocols for zinc plating/stripping.
• Analyzing thermodynamics and kinetics of competing reactions (Zn growth, hydrogen evolution).
• Evaluating battery performance with high mass loading and areal capacity.

Main Results:

• Achieved cumulative capacities of 11.0 Ah cm^-2 at 80 mA cm^-2 and 3.8 Ah cm^-2 at 160 mA cm^-2.
• Demonstrated promoted (002)-textured Zn growth and suppressed hydrogen evolution.
• Enabled long-life Zn batteries with high mass loading (29 mg_cathode cm^-2) and high areal capacity (7.9 mAh cm^-2).

Conclusions:

• Pulsed-current protocols significantly enhance Zn metal electrode performance beyond mass-transport limits.
• Understanding reaction thermodynamics and kinetics is key to optimizing pulsed-current strategies.
• This approach offers a viable strategy for developing dendrite-free metal batteries with high capacity and high current rates.