Hybrid Supercapacitor Increases Capacity 2.4x
Capacitors and their much smaller-than-battery capacitance have always presented energy storage and cost challenges. More recently, supercapacitors with greater capacity and performance have been developed using such nanocarbon materials as carbon nanotubes (CNTs) that provide greater capacitance but are still at a high price tag. By lowering the price tag and bumping up capacity, there should be substantial interest from various applications, including the IoT device segment.
Researchers at Tohoku University have tackled both challenges. Using a molecular coating approach, they successfully increased a capacitor’s capacity, lifetime durability, and cost-effectiveness and published their research in the journal ACS Applied Materials Interfaces.
The team increased capacity by 2.4x (to 907 F/gAC) compared to a carbon-alone approach by sprinkling iron azaphthalocyanine (FeAzPc-4N), a type of blue pigment, onto activated carbon. They were also able to increase a capacitor electrode’s durability, proven by testing with 20,000 cycles of charging and discharging—the capacitor cell had sufficient output power to illuminate LEDs.
The research showed that high-capacity hybrid supercapacitors to be realized by using iron azaphthalocyanine (FeAzPc-4N) adsorbed activated carbons (ACs) by combining an electric double layer of activated carbon surfaces and redox reactions of FeAzPc-4N molecules. Increasing the mixing ratio of FeAzPc-4N with ACs achieves a maximum capacity of 907 F/g AC, as is rapid charging and discharging at 20 A/g.
The approach allows the molecule to adsorb at the molecular level using its redox capabilities. The capacitor electrode developed by the researchers can increase capacity to the level of supercapacitors using CNTs using commonly available and inexpensive activated carbon. This opens the door for next-generation energy devices. The team, however, isn’t finished yet. Their next step is to make the supercapacitor even more super-powered.
Full release: Research News – Achieving a Supercapacitor Through the ‘Molecular Coating’ Approach | Tohoku University Global Site
