Win-Win Strategies Enable Efficient Anode-Less Zinc-Ion Hybrid Supercapacitors

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Electrochemical energy storage (EES) devices require higher energy and power densities for practical applications.
• Anode-free concepts are emerging as a strategy to enhance EES device performance.
• Developing efficient anodes is crucial for advancing zinc-ion hybrid supercapacitors.

Purpose of the Study:

• To develop a zincophilic layer for an alternative anode in anode-less zinc-ion hybrid supercapacitors (ALZHSCs).
• To investigate the electrochemical properties and performance of the novel anode material.
• To evaluate the energy density, power ability, and cycling stability of the assembled ALZHSC device.

Main Methods:

• Coating a 20 μm zincophilic layer of ZIF-8 and sodium alginate (SA) on Cu foil (Z8-SA@Cu).
• Electrochemical measurements including plating/stripping tests and rate capability analysis.
• Post-mortem analyses to understand the anode's behavior during cycling.

Main Results:

• The Z8-SA@Cu anode exhibited a reduced nucleation barrier and overpotential.
• Limited zincate formation and improved Zn²⁺ flux were observed.
• The ALZHSC device demonstrated impressive rate capability (40 mAh/g at 1 mA/cm²) and excellent cycling stability (88% retention after 12,000 cycles).

Conclusions:

• The Z8-SA@Cu anode is a promising material for ALZHSCs.
• The developed anode enhances Zn plating/stripping efficiency and ion transport.
• The ALZHSC device shows superior gravimetric energy density and high-power ability compared to traditional ZHSCs.