A Nanocluster Colloidal Electrolyte Enables Highly Stable and Reversible Zinc Anodes

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) are promising for stationary energy storage due to safety and cost.
• However, AZIBs face challenges with zinc (Zn) anode instability, including dendrite growth and side reactions, limiting battery lifespan.
• Uncontrolled Zn deposition and dissolution lead to capacity fading and safety concerns.

Purpose of the Study:

• To develop a novel strategy for stabilizing zinc anodes in aqueous zinc-ion batteries.
• To investigate the efficacy of a nanocluster colloidal electrolyte in suppressing dendrite formation and side reactions.
• To enhance the cycling stability and lifespan of zinc anodes and full AZIB cells.

Main Methods:

• A nanocluster colloidal electrolyte strategy was employed, utilizing copper nanoclusters (CuNCs).
• CuNCs were used to create a zincophilic and protective interlayer on the zinc anode surface.
• Electrochemical performance, including Coulombic efficiency and cycling lifespan, was evaluated for modified zinc anodes and full cells.

Main Results:

• The CuNC-modified electrolyte effectively suppressed zinc dendrite formation and parasitic side reactions.
• Zinc anodes demonstrated high Coulombic efficiency (99.8% over 2100 cycles) and extended lifespans (2200 h at 0.5 mA cm⁻² and 1300 h at 5 mA cm⁻²).
• A full cell utilizing the modified electrolyte achieved over 15,000 cycles of improved cycling durability.

Conclusions:

• The nanocluster colloidal electrolyte strategy is highly effective in stabilizing zinc anodes for AZIBs.
• CuNCs provide an interfacial modification that promotes uniform Zn stripping/plating and mitigates degradation.
• This approach offers a promising pathway for designing advanced electrolytes for stable and long-lasting zinc-based energy storage systems.