Supercapacitors, akin to batteries, are devices capable of charging rapidly within seconds or minutes. In the pursuit of more efficient energy storage and conversion technologies, supercapacitors have garnered attention for their fast charging and durable energy storage characteristics. However, compared to batteries, supercapacitors have long faced the challenge of lower energy density, making them unsuitable for long-term energy storage. Microporous activated carbon materials, one of the most commonly used electrode materials in commercial supercapacitors, have been of particular interest to researchers.
To overcome this challenge, a groundbreaking study conducted by Professor Alexander Forse's team at the University of Cambridge delved into the relationship between the microporous carbon electrode structure and performance. They discovered that electrodes with a more chemically disordered structure store significantly more energy than highly ordered ones.
This research paves the way for the preparation of high-performance microporous carbon electrodes. The findings were published in Science on April 18.
Microporous activated carbon is an irregularly shaped material. If a sheet of graphene is likened to a smooth white paper, microporous activated carbon is a structure formed by stacking countless crumpled sheets of paper of various sizes and shapes.
"We utilized solid-state nuclear magnetic resonance techniques, combined with computational simulations, to deeply explore the microporous carbon electrodes used in supercapacitors. The results show that the energy storage performance of microporous carbon is closely related to the disorderliness of the material structure. Moreover, in cases of greater disorderliness, the energy storage performance of microporous carbon will be significantly enhanced," explained Liu Xinyu, the first author of the paper and a doctoral student at the University of Cambridge, in an interview with Chinese Science Bulletin.
Liu Xinyu with Professor Clare Grey (left) and Alex Forse (right) from the University of Cambridge.
Liu Xinyu with ordered carbon model (left) and disordered carbon electrode (right) Nathan Pitt photograph
Research has revealed the correlation between the disordered structure of microporous carbon and its performance, overturning traditional beliefs among scientists about improving the performance of carbon-based supercapacitors, and resolving nearly 20 years of controversy in the field regarding the relationship between microporous carbon structure and performance.
Previously, it was widely believed that the size of micropores determined the capacitance of microporous carbon. However, this study confirmed that the degree of disorder in microporous carbon is the key to achieving performance enhancement.
In recent years, supercapacitors, as energy storage devices capable of rapid charging and discharging with extremely high cycling stability, have been widely used in devices requiring frequent charging, such as electric cars, trains, and buses.
"The groundbreaking results of this study provide new insights and methods for the further development of supercapacitor technology. By adjusting the disordered structure of microporous carbon, significant improvements in the energy density of supercapacitors can be achieved in the future, thereby promoting their applications in areas such as electric vehicles and renewable energy storage. The publication of these findings will accelerate the commercialization process of high-performance supercapacitor technology, contributing to the construction of a clean and efficient energy future and helping to achieve the goal of 'carbon neutrality,'" said Liu Xinyu.
Related paper information: https://doi.org/10.1126/science.adn6242
