A Simply Fabricated and Eco-Friendly Supercapacitor for “Greener” Wearables
Researchers have created a high performance, eco-friendly, and elastic supercapacitor that could be a boon for the development of greener wearables.
Sensor technology depends heavily on innovations in the field of microelectronics. Today, much of the field's focus is on capacitors, components that require high power density and charge-discharge speeds, long life cycles, and low costs.
They represent a promising power solution for many electronics applications, especially consumer ones like smartphones and wearables. However, combining high energy density, safety, and eco-friendliness in a single supercapacitor suitable for small devices and applications has been a challenging feat for scientists and engineers.
A team from Skoltech, Aalto University, and Massachusetts Institute of Technology (MIT) has reportedly designed a high-performance, low-cost, environmentally friendly, and stretchable supercapacitor that could be used in wearable electronics.
A New Design for a “Green” Supercapacitor
In their research, the team proposes a new design for a "green" supercapacitor that can be easily fabricated. It consists of a solid-state material based on nitrogen-doped graphene flake electrodes distributed in the NaCl-containing hydrogel electrolyte.
The internal structure of the supercapacitor developed by Skoltech, Aalto University, and MIT researchers. Image credited to Skoltech.ru
To provide flexibility, the structure is placed between two single-walled carbon nanotube film current collectors. Hydrogel in the supercapacitor design enables compact packing and high energy density and allows them to use environmentally friendly electrolytes.
The researchers chose the aqueous hydrogel electrolyte because organic solvents, the alternative for increasing energy density, are hazardous, bad for the environment, and can reduce power density. Aqueous electrolytes do not cause these problems, and they are also more conductive.
Improvements Over Previous Research
According to the team's report, they were able to improve the overall volumetric capacitive performance, high energy density, and power density for their prototype over analogous supercapacitors that have been described in previous research.
"We fabricated a prototype with unchanged performance under the 50% strain after a thousand stretching cycles. To ensure lower cost and better environmental performance, we used a NaCl-based electrolyte. Still, the fabrication cost can be lowered by implementing 3D printing or other advanced fabrication techniques," concluded Skoltech professor Albert Nasibulin.
With people in general now more socially aware and responsible than ever before, the utilization of such "green" components like the research team's supercapacitor could play favorably in consumers' eyes if they are to be used in applications like wearables.