Lithium ion batteries are in millions of devices in Spain. We carry them in our cell phones, but they are also responsible for powering electric cars, laptops, cordless vacuum cleaners, cordless DIY tools and even the Curiosity robot that NASA has on Mars. In recent years, its capacity and durability have been improved, but it remains limited and depends on the supply of lithium, the deficit of which can trigger a global crisis at any time. That is why there are already those working on technologies that could replace or expand its possibilities, such as supercapacitors, which are already reaching consumer products such as the revolutionary electric bicycle that recharges itself and helps you pedal without getting tired.

Similar to traditional batteries, supercapacitors are also capable of storing energy. They are systems that allow energy to be stored and released very quickly, and the materials that make them up are common (aluminum, carbon, cellulose, polymer...), which means giving up lithium and other components that are difficult to recycle. The latest breakthrough comes from a team of researchers at the University of California, San Diego, who have developed a structural supercapacitor, capable of providing both structural support and energy storage capacity.

This translates, for example, into the possibility of manufacturing cases for mobile phones that, in addition to protecting them against bumps or falls, can drastically extend their autonomy, or parts of the body of an electric car that eliminate the need to install a heavy battery, highly flammable, in the lower area. This is explained in an article published in the specialized magazine Science Advances, where they detail the possibilities that their invention offers when it comes to increasing the autonomy of electronic devices and vehicles without adding weight.

How is this made

The aeronautical industry has been working on the development of structural supercapacitors for years, since weight is one of the main concerns when designing an aircraft and what can greatly limit its capabilities. And although traditional supercapacitors are excellent at storing energy, they lack the mechanical strength necessary to serve as structural components. In the opposite case, there are materials that offer the possibility of sustaining mechanical loads, but are not viable as energy reserves.

To overcome these barriers, the team led by Tina Ng and Xinyu Zhang, professors of electrical and computer engineering at the University of California Jacobs School of Engineering, has changed strategy. Their proposal involves combining different materials to enhance both the mechanical resistance and the electrochemical performance of the supercapacitors.

Two of the researchers working in the materials laboratory of the University of California David Baillot / UC San Diego Omicrono.

Typically, these devices are manufactured by joining two electrode surfaces separated by an electrolyte, which is responsible for facilitating the flow of ions and, therefore, the chemical reaction that allows energy storage. In this case, scientists have made the electrodes with carbon fibers intertwined in a fabric. This already provides considerable structural resistance, but they have also coated it with a mixture of conductive polymer and reduced graphene oxide. materials significantly improve the flow of ions and, therefore, increase the storage capacity.

The other fundamental component of this new supercapacitor is the solid electrolyte, obtained from the union between an epoxy resin and polyethylene oxide, which gives the material greater structural support and favors the mobility of the ions.