Knitting Controllable Oxygen-Functionalized Carbon Fiber for Ultrahigh Capacitance Wire-Shaped Supercapacitors

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Wire-shaped supercapacitors (WSCs) are crucial for wearable electronics but suffer from low energy density.
• High-performance nanostructured materials for WSCs are limited by low mass loading in wire-shaped electrodes due to slow ion transport.
• Existing WSCs struggle to meet the energy demands of practical applications.

Purpose of the Study:

• To overcome the mass loading limitations in wire-shaped electrodes for WSCs.
• To enhance the energy density and overall performance of WSCs.
• To develop a viable method for fabricating high-performance, high-mass wire-shaped electrodes.

Main Methods:

• Surface engineering of microstructured carbon fibers (CFs) to introduce controllable oxygen functional groups.
• Utilizing these functionalized CFs as active materials for wire-shaped electrodes (WSEs).
• Employing a knitting method to achieve high mass loading in the WSEs.

Main Results:

• Achieved ultrahigh capacitance in WSEs with high mass loading (∼6.1 mg cm^-1): 435.1 mF cm^-1, 1539.7 mF cm^-2, and 68.4 mF cm^-3.
• Demonstrated a WSC with superior performance (195.3 mF cm^-1 and 33 μW h cm^-1) compared to existing carbon, polymer, and metal oxide devices.
• Successfully fabricated WSEs with significantly increased mass loading compared to previous studies.

Conclusions:

• The surface engineering strategy effectively enhances electron/ion transport and redox activity in carbon fibers.
• This approach enables the fabrication of high-mass WSEs, significantly boosting WSC energy density.
• The developed WSCs show great potential for practical applications in wearable electronics and beyond.