Stabilizing Zinc Anode through Ion Selection Sieving for Aqueous Zn-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc ion batteries (AZIBs) face challenges from dendrite growth and corrosion caused by water and sulfate ions.
• These issues limit the practical application and long-term stability of AZIBs.

Purpose of the Study:

• To develop artificial solid electrolyte interfaces (SEIs) for stabilizing zinc anodes in AZIBs.
• To enhance the electrochemical performance and cycle life of AZIBs through protective SEI layers.

Main Methods:

• Constructed artificial SEIs using sodium and calcium bentonite with layered structures anchored to zinc anodes (NB@Zn and CB@Zn).
• Investigated the protective properties of the bentonite SEI layer, including isolation of water molecules and transport channels for Zn²⁺.
• Utilized theoretical calculations to assess the binding energy of Zn²⁺ with bentonite electrodes and analyzed ion-sieving capabilities.

Main Results:

• The bentonite protective layer effectively isolated reactive water molecules and provided efficient Zn²⁺ transport channels.
• Theoretical results indicated higher binding energy for Zn²⁺ on bentonite electrodes, enhancing Zn-ion deposition kinetics.
• Full batteries (NB@Zn//MnO₂ and CB@Zn//MnO₂) demonstrated improved capacities (96.7 and 70.4 mAh g^-1 at 2.0 A g^-1 after 1000 cycles, respectively).

Conclusions:

• Artificial SEIs based on bentonite effectively stabilize zinc anodes by preventing dendrite growth and corrosion.
• The ion-selective sieving mechanism of the bentonite layer enhances Zn²⁺ deposition and overall battery performance.
• This approach offers a promising strategy for developing high-performance and stable aqueous zinc ion batteries.