New electrode design could boost supercapacitor performance

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Engineers from UCLA and four other institutions have designed a ‘super-efficient and long-lasting’ electrode for supercapacitors. The device’s design – inspired by the structure and function of leaves on tree branches – is said to be more than 10 times more efficient than other designs.

According to the researchers, the electrode design provides the same amount of energy storage and delivers as much power as similar electrodes, despite being much smaller and lighter. In experiments it produced 30% better capacitance on a mass basis compared to the best available electrode made from similar carbon materials. It also showed 30 times better capacitance per area. Further tests showed the electrode produced 10 times more power than other designs and retained 95% of its initial capacitance after more than 10,000 charging cycles.

“We often find inspiration in nature – and plants have discovered the best way to absorb chemicals such as carbon dioxide from their environment,” said UCLA Professor Tim Fisher. “In this case, we used that idea but at a much, much smaller scale.”

The team used two nanoscale structures composed of carbon atoms. The ‘branches’ are arrays of carbon nanotubes some 20 to 30nm in diameter, while the ‘leaves’ are petal-like structures about 100nm wide made of graphene. The leaves were arranged on the perimeter of the nanotube stems, maximising surface area.

The electrode is said to perform well in acidic conditions and in high temperatures.