Spongey nanofibre material holds gel electrolyte, helping to reduce battery malfunction and increase energy density
Drexel University researchers have created a “fabric-like material electrode” that could enable the manufacture of safer, faster batteries and supercapacitors.
The group has designed a new supercapacitor, which looks “like a furry sponge infused with gelatin”, and offers a an alternative to the flammable electrolyte solutions that can cause battery malfunction.
Designed by College of Engineering professor Dr Vibha Kalra and her team, the device uses a thick ion-rich gel electrolyte absorbed in a mat of porous carbon nanofibre to produce a solid device. The design was published in a paper in the American Chemical Society journal Applied Materials and Interfaces.
In addition to being non-flammable, the group claims that the design is more durable and offers greater energy storage capacity and charge-discharge lifespan than current, comparable devices. It can also operate at temperatures as high as 300°C, making it suitable for use in hotter or more hazardous environments.
The key to the device is the fibre-like electrode framework. This was created using a process called electrospinning, where a fibrous mat is created extrusion through a rotating electric field — a process that apparently resembles making candy floss. The ionogel is then absorbed in the carbon fibre.
The mat provides a greater surface area for ions from the ionogel to access the electrode, which increases capacity and improves the performance of the energy storage device. It also eliminates the need for many of the scaffolding materials that are essential parts of forming the physical electrode, but don’t play a role in the energy storage process and contribute a good bit to the device’s overall weight.
“State of the art electrodes are composed of fine powders that need to be blended with binding agents and made into a slurry, which is then applied into the device. These binders add dead weight to the device, as they are not conductive materials, and they actually hinder its performance,” Kalra said. “Our electrodes are freestanding, thus eliminating the need for binders, whose processing can account for as much as 20% of the cost of manufacturing an electrode.”
The next step for Kalra’s group will be applying this technique to the production of solid-state batteries as well as exploring its application for smart fabrics.