A soft, stretchable and mechanically deformable lithium battery has been developed by a Korean research group. The battery could be utilized in the development of wearable devices. The researchers also analyzed the possibility by printing batteries onto the surface of clothing.
The research group headed by Dr. Jeong Gon Son from the Soft Hybrid Materials Research Center at the Korea Institute of Science and Technology (KIST; President: Seok-Jin Yoon), has declared that they came up with a lithium battery wherein all of the materials, including of the cathode, anode, electrolytes, current collector and encapsulant, are printable and stretchable
The team came up with a lithium battery that exhibits high capacity and free-form characteristics that are ideal for mechanical deformation.
As a result of the increasing demand for high-performance wearable devices like smart bands, implantable electronic devices like soft wearable devices and pace-makers for use in the realistic metaverse, the development of soft and stretchable batteries, like the human skin and organs, have been gaining a lot of interest.
The hard inorganic electrode of a traditional battery consists of the majority of the battery’s volume, thereby making it hard to expand. The other components like the separator and the current collector for drawing and carrying charges must also be expandable, and the problem of liquid electrolyte leakage should also be resolved.
For stretchability to be improved, the research group avoided making use of materials such as had been done in other studies which were unwanted for energy storage, like rubber. Furthermore, a new soft and stretchable organic gel material was engineered and applied depending on the binder material at hand.
This material securely holds the active electrode materials in position and streamlines the transfer of ions. A conductive ink was also fabricated with the help of a material exhibiting outstanding stretchability and gas barrier properties. This material will act as a current collector that transfers electrons and an encapsulant that can work stably even at a high voltage and in several deformed states without swelling as a result of electrolyte absorption.
Furthermore, the battery developed by the researchers was able to integrate present lithium-ion battery materials, as they display outstanding energy storage density (approximately 2.8 mWh/cm2) of a level similar to that of commercially available hard lithium-ion batteries at a driving voltage of 3.3 V or greater.
All of the constituent components of the group’s stretchable lithium-ion battery exhibit the mechanical stability to retain their performance even following repeated pulling of the battery 1,000 or more times, a high stretchability of 50% or above, and long-lasting stability in air.
Additionally, the research group directly printed the electrode and presented collector materials that they had fabricated on either side of an arm warmer made of spandex and employed a stretchable encapsulant to the material.
This illustrates the potential to print a stretchable high-voltage organic battery straight onto clothing. With the help of the consequent battery, the research group was able to constantly power a smartwatch even when it was being put on, taken off, or expanded.
Dr. Son at KIST stated that his group has come up with a stretchable lithium-ion battery technology that offers structural freedom due to the battery’s free-form configuration enabling it to be printed on materials like fabrics, and material freedom as a result of being able to utilize the present lithium-ion battery materials due to the stretch stability enabling mechanical deformation and high energy density.
He also stated that the stretchable energy storage system designed by his team is anticipated to be applicable to the development of several wearable or body-attachable devices.
This study was financially supported by the Mid-Career Research Program of the National Research Foundation of Korea, and the KIST Institutional Program and K-Lab Program funded by the Ministry of Science and ICT (Minister: Hye-Sook Lim).
Hong, S. Y., et al. (2022) Intrinsically Stretchable and Printable Lithium-Ion Battery for Free-Form Configuration. ACS Nano. doi.org/10.1021/acsnano.1c08405.