According to the financial associated press (Shanghai, editor Huang Junzhi), a research team in South Korea has developed a soft, retractable, mechanically deformable lithium battery. The battery could be used in the development of wearable devices, and the researchers also analyzed this possibility by printing the battery on the surface of the clothing.
The project was led by a research team led by Dr. Jeong Gon Son of the Korea Institute of Science and Technology (KIST) Soft Hybrid Materials Research Center, who developed all the materials for lithium batteries, including anodes, cathodes, collectors, electrolytes, and sealants, that are stretchable and printable. The lithium battery developed by the team has high capacity and freeform characteristics suitable for mechanical deformation.
Due to the rapid growth in demand for high-performance wearable devices such as implantable electronic devices such as smart bracelets, pacemakers, and soft wearables for the real virtual world, the development of a soft and stretchable battery, such as human skin and organs, has been of interest to scientists.
The hard-inorganic electrodes of conventional batteries make up most of the volume of the battery and are therefore difficult to stretch. Other components, such as diaphragms and collectors for extracting and transferring charges, must also be stretchable, and liquid electrolyte leakage must also be addressed.
To improve ductility, the team avoided using materials already done in other studies that are unnecessary for energy storage, such as rubber. Then, on the basis of the existing adhesive material, a new soft, stretchable organic gel material was developed and applied. This material firmly holds the active electrode material in place and facilitates the transfer of ions.
In addition, conductive inks are manufactured using materials with excellent tensile and gas-repellent properties. The material will act as a current collector, delivering electrons and encapsulating agents that will work stably even at high voltages and in several deformation states without swelling due to electrolyte absorption.
All components of the team's stretchable lithium-ion battery are said to have mechanical stability, maintaining their performance even after the battery has been repeatedly pulled 1,000 or more times, high tensileity of 50 percent or more, and long-term stability in the air. Moreover, at a drive voltage of 3.3 V or more, its energy storage density (about 2.8 mWh/cm2) is comparable to that of hard lithium-ion batteries on the market.
In addition, the research team printed the electrodes and collector materials they developed directly on both sides of the warm arms made of spandex and coated the material with a stretchable sealant, demonstrating the ability to print stretchable high-voltage organic batteries directly on clothing. Using the resulting battery, the research team was able to continuously power the smartwatch, even when it was worn, removed, or stretched.
Dr. Son of KIST said his team has developed a stretchable lithium-ion battery technology that can either provide structural freedom through the free-form configuration of the battery, or print it on materials such as fabric, and can provide material freedom. It is possible to use existing lithium-ion battery materials, in addition to tensile stability that enables high energy density and mechanical deformation. The product is expected to be used in the development of various wearable or close-fitting devices.