A team of researchers from the Korea Advanced Institute of Science and Technology (KAIST) has developed a new approach for an energy storage device that can be fully charged in just 20 seconds. The system works with an aqueous electrolyte (water-based solution) which makes it a perfect technology for portable electronic devices that often need to be charged quickly due to current user needs.
Carrying external batteries or going with the charger everywhere has become quite common in our days. Our heavy use of devices makes us ‘burn out’ available battery in no time. To solve this problem, KAIST experts have revolutionized the previous method by which the Aqueous Hybrid Capacitor (AHC) is built, making charging much faster, safer and cheaper.
The magic of graphene
These hybrid capacitors are assembled with a battery that stores energy electrochemically as an electrostatic charge where ions help carry current. The concept of this battery is not new; We have already seen that it has been tried other times; However, on this occasion the scientists used graphene-based polymers instead of metallic conductors , managing to overcome the obstacles of previous Aqueous Hybrid Capacitors that suffered from low power and a short useful life.
Taking into account current technological needs, our devices must not only be compact, powerful, durable and quick to recharge, they should also be respectful with the environment (and preferably not explode if we bite into them).
For these and other reasons, aqueous storage devices, those that contain water-based solutions rather than a toxic or flammable organic pulp, have received a lot of attention as safe and reliable options.
Although it is less flammable than modern lithium batteries and potentially much cheaper, the way the solution carries electrons presents a serious problem. Thanks to this new hybrid capacitor using graphene-based polymers instead of more traditional metallic conductors at the anode and the fabrication of the cathode with a dispersion of metal-oxide nanoparticles, the shortcomings of previous hybrid capacitors are overcome.
The network of tiny carbon fibers at the anode turns out to be much more efficient at transferring electrons to the aqueous solution, allowing batteries with more than 100 times the power density of previous devices, while still maintaining the capacity for more than 100,000 charges.
Better yet, the new liquid electrolyte coupled anodes allow charging from 0 to 100 with just 20 seconds of charging. And all of this is at no cost to personal safety or the economy.
“This eco-friendly technology can be easily manufactured and is highly applicable,” says chemist Jeung Ku Kang. “In particular, its high capacity and high stability, compared to existing technologies, could contribute to the commercialization of aqueous capacitors.”
Since the power supply doesn’t need to be strong, its fast charging speed could make it pair perfectly with photovoltaic cells or other micro-generation power sources.
It will be a while before we see these types of devices outperform lithium ion batteries on the market, but they will certainly find a place in future wearable technology.
Reference: Synthesis of Pseudocapacitive Polymer Chain Anode and Subnanoscale Metal Oxide Cathode for Aqueous Hybrid Capacitors Enabling High Energy and Power Densities along with Long Cycle Life. Il Woo Ock et al. Advanced Enery Materials 2018. DOI: 10.1002 / aenm.201702895
