Development of rechargeable adhesive type batteries

Dr. Yoon Hana at the Energy Conversion and Storage Materials Laboratory of the Korea Energy Research Institute (KIER, President Kim Jong-nam), Professor Kim Young-Jin (Department of Mechanical Engineering, Advanced Institute of Science and Technology Korea) and Professor Kim Seungchul (Department of Optics and Mechatronics Engineering, Pusan ​​National University) jointly developed ‘reconnectable micro-supercapacitors (MSC) * using highly inflamed laser-induced graphene electrodes’ and their research findings were listed in Chemical Engineering Magazine*, one of the world renowned in the field.

* MSCs are ultrathin thin film based supercapacitors that are getting a lot of attention as they are more stable with higher power and energy densities compared to Li thin film batteries.

* * Chemical Engineering Magazine It is considered one of the best international journals in the chemical engineering sector (published by Elsevier, SCI I.F. 8,355)

As the demand for smaller, lighter portable devices and highly functional IoT devices increases, there is an increasing need for new technologies for energy harvesting, storage and management. Portable devices and IoT products are increasingly applied to various sectors of society these days. Therefore, researchers are actively carrying out R&D activities to develop energy storage devices with additional functions in addition to power supply.

The preconditions for portable energy storage devices are that they should be able to change their shapes along with the changing shapes of the human body and movements, while being flexible, safe to use and providing excellent durability. Conventional batteries were not flexible as they were developed to have a cylindrical, prismatic, or bag-like base structure and had limited energy densities. Thus, they had some limitations to apply to next-generation products, such as portable or microdevices that require high flexibility, portability, and actual or volumetric power densities.

In the past, R&D efforts to develop energy storage devices for portable devices were mainly used in Li thin film batteries. Li-thin film micro batteries, which are widely available power supplies for microelectronics on the market, suffer short life cycles, abrupt failures, unstable kinetics at low temperatures, and pose safety concerns when associated with lithium.

Recently, MSCs are gaining great attention as next-generation energy storage devices to replace Li thin-film batteries. In principle, supercapacitors were semi-permanent to use and had many benefits, such as high power densities (10 times more compared to lithium-ion batteries), stability, efficiency, and fast charge / discharge speeds. However, its scope of use was somewhat limited to certain areas due to a low energy density per charge (which was estimated at 1/10 of the Li batteries). Compared to supercapacitors, MSCs have a significantly higher power density than lithium batteries, and power densities are similar or even higher than their rivals. Therefore, they are considered an alternative to high-performance ultra-thin energy storage devices.

The research team successfully developed flexible adhesive-type MSCs that had a flexible structure and can be attached anywhere on objects or surfaces by using ultrashort pulse laser.

The ultrashort pulse laser can instantly generate strong intensity to produce highly inflamed graphene electrodes. By impregnating the adhesive polymer compounds into the highly inflamed graphene interior, the researchers were able to develop adhesive-type MSCs with excellent electrode performance and durability while maintaining adhesiveness.

Dopamine, a functional mimic of the mussel adhesive protein, was introduced as a coating material for flexible adhesive-type MSCs to improve electrochemical performance. The catechol groups in dopamine provide redox-active moieties for pseudo-capacitive electrodes. In doing so, they were able to develop flexible adhesive-type energy storage devices that had high volumetric energy densities similar to that of lithium thin-film batteries with an excellent volumetric power density, 13 times greater than that of their counterparts.

Dr. Hana Yoon of KIER, principal investigator of this study, said: “Our adhesive-type flexible MSCs easily reconnect to next-generation portable devices and IoT devices and are eco-friendly. They are expected to solve many storage technology hurdles. based lithium power. ”

Furthermore, KAIST professor Young-jin Kim, co-investigator of this study, said: “The design technology developed from this study generated a unique swollen graphene with ultrashort pulse laser in a relatively short period of time, while minimizing material loss “This technology has the potential to promote industrial applications of laser-induced graphene in various sectors.”

###

The researchers completed patent applications both at home and abroad. The joint research team between KIER, KAIST, PNU, NTU is currently working on follow-up studies as a leader in the research and development of next-generation energy storage materials and devices.