Surface Electric Field Shielding for Passivation-Free Zinc Anode Dissolution in Alkaline Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Zinc anodes in alkaline electrolytes suffer from spontaneous passivation, limiting battery capacity and performance.
• Existing methods like zinc powder or sponge structures increase surface area but worsen hydrogen evolution.

Purpose of the Study:

• To introduce a new strategy for mitigating zinc anode passivation using miniature Faraday cages.
• To enhance zinc anode performance and stability in primary and rechargeable batteries.

Main Methods:

• Fabrication of interwoven bismuth dendrite layers on zinc plate anodes (Bi@Zn).
• Utilizing multi-scale characterizations and simulations to analyze passivation mechanisms.
• Testing Bi@Zn anodes in primary zinc-air and nickel-zinc rechargeable batteries.

Main Results:

• Bi@Zn anodes achieved near-complete zinc dissolution and over 100 mAh cm⁻² discharge capacity, outperforming bare zinc in lean electrolytes.
• Bismuth (Bi) Faraday cages were shown to delay passivation by dissipating electric fields, suppressing detrimental ion accumulation and precipitation.
• Primary zinc-air batteries with Bi@Zn showed full discharge, while bare zinc failed early.
• Nickel-zinc batteries demonstrated a fivefold improvement in cycling stability with Bi@Zn anodes.

Conclusions:

• Surface electric field shielding using bismuth Faraday cages is an effective strategy to prevent zinc anode passivation.
• This approach significantly enhances zinc anode utilization, discharge capacity, and cycling stability.
• The effectiveness of copper shielding layers validates the general applicability of electric field shielding for zinc anodes.