A capacitor acts like a quick-charging battery, capable of rapidly storing and releasing energy. So, what happens when it becomes ‘super’? Researchers are exploring ways to enhance energy efficiency.
Scientists from Tohoku University have triumphantly boosted the capacity, lifespan, and affordability of capacitors in their quest for an energy-efficient future. Capacitors are devices incorporated in circuits that can store and release energy similar to batteries. However, unlike batteries, they can be charged much faster. For instance, while your phone’s battery can power your device instantly, recharging it to full capacity is a slow process.
Even though capacitors may seem superior, they face significant hurdles. Their energy storage capacity is much lower than that of batteries, meaning they can’t hold substantial amounts of energy at once. Additionally, they tend to be quite costly. Recent advancements have led to the creation of supercapacitors—these have enhanced capacity and performance thanks to the use of nanocarbon materials like carbon nanotubes (CNTs), which boost surface area and overall storage. Nevertheless, the high cost of nanocarbon materials makes large-scale production of this technology economically unfeasible.
To address these limitations and enhance capacitor performance, a research team was created, including Professor Hiroshi Yabu from Tohoku University, AZUL Energy Co., Ltd. (a spin-off from the university), and the AZUL Energy x Tohoku University Bio-Inspired GX Co-Creation Center. Their research was published in ACS Applied Materials & Interfaces on June 20, 2024.
The team achieved a 2.4 times increase in capacitor capacity (up to 907 F/gAC) compared to just using carbon by applying iron azaphthalocyanine (FeAzPc-4N), a kind of blue pigment, on activated carbon. This innovative technique allows for molecular-level adsorption, leveraging its redox capabilities. Furthermore, their study showed that the capacitors can withstand 20,000 charge-discharge cycles even under high load conditions of 20 A/gAC, proving suitable for powering LEDs.
“This longer lifespan in comparison to batteries could help reduce waste, allowing the same capacitor to be reused many more times,” states Yabu. “Additionally, the components used in capacitors are significantly less toxic than those in batteries.”
The capacitor electrode developed in this research can boost capacity to that of supercapacitors utilizing CNTs, while using commonly available and low-cost activated carbon, indicating its potential as a next-generation energy storage solution. What’s next for the team? They’re aiming to make the supercapacitor even more powerful.
