Long Life with Ultrahigh Capacitance Flexible Electrode At Practical Mass Loading For Battery Supercapacitor Hybrid.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Designing cost-effective, biodegradable flexible electrodes for high-performance energy storage remains challenging.
• Industry standards require high mass loading (>10 mg cm⁻²) for stable and durable devices.

Purpose of the Study:

• To design and fabricate flexible, biodegradable electrodes for eco-friendly battery supercapacitor hybrids (BSHs).
• To achieve high mass loading and superior electrochemical performance using readily available materials.

Main Methods:

• Electroless deposition of a NiB layer onto laboratory filter paper (FP) to create conductive Ni/NiB-FP.
• Electrodeposition of nickel iron phosphide (NiFeP) active material onto Ni/NiB-FP to achieve high mass loadings (4.5–17 mg cm⁻²).
• Electrochemical activation and surface reconstruction of the NiFeP@Ni/NiB-FP electrode.

Main Results:

• The NiFeP@Ni/NiB-FP electrode (17 mg cm⁻²) exhibited an ultrahigh areal capacitance of 37.5 F cm⁻² at 5 mA cm⁻².
• Exceptional rate capability (90.6% retention at 30 mA cm⁻²) and ultrastable cycling performance (retaining 37.4 F cm⁻² after 1329 hours).
• A tandem device of four BSH cells achieved a stable operational voltage up to 6 V, powering multiple electronic devices.

Conclusions:

• The developed flexible paper-based electrodes are promising for next-generation, sustainable energy storage solutions.
• The fabrication method offers a scalable and cost-effective approach for producing high-performance flexible electrodes.
• The demonstrated applications highlight the versatility and practical potential of these biodegradable energy storage devices.