Molecular coating technique boosts supercapacitors

Researchers from Tohoku University have increased the capacity, lifetime durability and cost-effectiveness of a capacitor. A capacitor is a device used as part of a circuit that can store and release energy, like a battery. What makes a capacitor different from a battery is that it takes less time to charge. However, capacitors have a smaller capacity than batteries, so they cannot store large amounts of energy at once. In recent years, supercapacitors (capacitors with increased capacity and performance) have been developed using nanocarbon materials, such as carbon nanotubes (CNTs), which increase the surface area and overall capacity. However, due to the expensive nature of nanocarbon materials, large-scale production using this technique is not cost-effective.

The researchers have reportedly increased the capacity of capacitors by 2.4 times (to 907 F/g_AC) compared to carbon alone by sprinkling iron azaphthalocyanine (FeAzPc-4N), a type of blue pigment, onto activated carbon. This allows the molecule to absorb at the molecular level, utilising its redox capabilities. The study also found that 20,000 charge-discharge cycles are possible, even in high-load regions of 20 A/g_AC, making it feasible to power LEDs.

Professor Hiroshi Yabu said the increased lifespan compared to batteries could help reduce waste, as the same capacitor can be reused many times. “The components of capacitors are also significantly less toxic than batteries,” Yabu said.

The capacitor electrode developed by the researchers can increase capacity to the level of supercapacitors using CNTs while using commonly available and inexpensive activated carbon, making it a possible option for next-generation energy devices.

The research findings have been published in the journal ACS Materials & Interfaces.

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