Gradient Electrolyte Strategy Achieving Long-Life Zinc Anodes.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries suffer from short cycle life due to localized dendrite formation.
• High-concentration electrolytes promote dense zinc deposition but are incompatible with glass-fiber separators.
• Low-concentration electrolytes offer good wettability but lead to rapid dendrite growth.

Purpose of the Study:

• To develop a novel electrolyte gradient strategy for stable aqueous zinc-ion batteries.
• To overcome the limitations of conventional electrolytes in zinc anode performance.
• To enhance the lifespan and efficiency of zinc-ion battery systems.

Main Methods:

• Establishing a zinc-ion concentration gradient from the anode to the separator.
• Utilizing a common zinc sulfate electrolyte.
• Testing Zn||Zn symmetric cells and Zn||NVO full cells under various current densities.

Main Results:

• Zn||Zn symmetric cells achieved 14,000 ultralong cycles at 5 mA cm⁻² and 1 mAh cm⁻².
• Symmetric cells maintained over 10,000 cycles at a higher current density of 20 mA cm⁻².
• Zn||NVO full cells with high-load cathodes demonstrated stable performance, retaining 58% capacity after 1200 cycles at 16 mA cm⁻².

Conclusions:

• The electrolyte gradient strategy effectively ensures separator wettability and dendrite-free zinc deposition.
• This approach offers a simple, low-cost, and promising method for developing practical, long-life aqueous zinc anodes.
• The strategy significantly enhances the cycle life and performance of zinc-ion batteries.