Flower-like Highly Open-Structured Binder-Free Zn-Co-Oxide Nanosheet for High-Performance Supercapacitor Electrodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Supercapacitors (SCs) are crucial energy-storing devices, but practical applications are limited by low energy density and poor rate capability.
• The use of binding agents in electrode fabrication often hinders the performance of SCs.

Purpose of the Study:

• To develop highly efficient and cost-effective binder-free electrodes for supercapacitors.
• To enhance the rate capability and energy density of supercapacitors through novel material design.

Main Methods:

• Fabrication of flower-like, highly open-structured binder-free ZnCo2O4 micro-flowers composed of nanosheets.
• Support of the ZnCo2O4 micro-flowers on nickel foam (ZnCoO@NF) to create advanced electrodes.

Main Results:

• The ZnCoO@NF electrode demonstrated a superior specific capacitance of 1132 F·g⁻¹ at 2 A·g⁻¹.
• An improved rate capability of up to 91.8% was achieved as the current varied from 2 to 20 A·g⁻¹.
• The electrode exhibited excellent cycling stability, retaining 99% capacitance after 7000 cycles at 20 A·g⁻¹.

Conclusions:

• The binder-free ZnCoO@NF electrode offers enhanced performance due to its stable micro/nano-multiscale architecture.
• This architecture facilitates simultaneous high electron conduction and fast ion transportation, crucial for supercapacitor efficiency.