Electric double-layer capacitors can extend the battery life of electric vehicles

To develop a new generation of electric cars, solar systems, and other clean energy technologies, researchers need an effective way to store energy. One of the key energy storage devices suitable for these and other applications is supercapacitors, also known as electric double-layer capacitors.

In a recent study, scientists have examined a possible use of a material called zeolite-templated carbon that can be used as an electrode for this type of capacitor. They found that The unique hole-like structure of this material greatly improves the overall performance of the capacitor.

The unique three-dimensional array of nanoholes carved into the zeolitic template carbon enables it to be used as an electrode to produce high performance supercapacitors with high capacity and fast charge times

Researchers Hiroyuki Itoi, Hirotomo Nishihara, Taichi Kogure, and Takashi Kyotani from Tohoku University in Sendai, Japan, have already published their results. Research on high-performance electric double-layer capacitors was published in the recent issue of the Journal of the American Chemical Society.

In order to store energy, the electric double layer capacitor charges ions. These ions migrate from the bulk solution to the electrodes where they are adsorbed. Before reaching the electrode surface, these ions must pass through the narrow nanoholes and be as fast and efficient as possible. Basically speaking, the faster the ions pass through these paths, the faster the capacitor will charge and the higher speed performance will result. In addition, the greater the density of ions adsorbed by the electrode, the greater the amount of charge that can be stored by the capacitor, resulting in high capacitance.

Recently, scientists have been testing materials. They have made these holes of various sizes and structures, striving to achieve both rapid ion transport and high adsorption ion density. However, these two requirements are somewhat contradictory because ions pass through larger nanoholes more rapidly, but large nanoholes result in lower electrode densities and lower adsorbent ion densities.

“In this work, we successfully demonstrated that it is possible to meet these two seemingly contradictory requirements, namely to meet high power density and high-capacity capacitors, using the zeolitic template carbon,” said Nishihara’s website for physicists. Say.

This type of zeolite mineral contains carbon nanopores with a diameter of 1.2 nm, which is smaller than most electrode materials, and has a very ordered structure, while other pores may be disordered and random. The small size of this nanopore allows the adsorption of ions to a very high density, and this ordered structure is described as a diamond-like framework, allowing ions to pass through the nanopore quickly. In a previous study, the researchers found that the nanopores above the zeolite mineralization of the template were less than 1.2 nanometers, and rapid ion transport could not be achieved, indicating that this scale provides the best balance, balancing high-speed performance with high-capacity capacitance.

In the tests, the performance of the zeolitic template carbon exceeded that of other materials, indicating that it can be used as an electrode for high performance electric double layer capacitors.

"We are now trying to further increase the energy density of the zeolitic template carbon, making it reach the same level as a rechargeable battery," said Nishihara. "If such an electric double-layer capacitor is developed for use in mobile devices such as mobile phones, the charging time can be reduced to only a few minutes. Another important application prospect is that electric double-layer capacitors can support electric vehicles' rechargeable batteries. , to extend the battery life. Also for this purpose, achieving a higher energy density is a key issue."