A South American fruit tree known as the jabuticaba, or Brazilian grapetree, is the inspiration for a new materials solution that has promising implications for the field of wearable electronics.
Researchers at the Ulsan National Institute of Science and Technology (UNIST) in South Korea have presented a hybrid carbon/polymer (HCP) composite that can be cost-effectively developed into a highly stretchable, rechargeable lithium-ion battery (ARLB) based on aqueous electrolytes. The material solves the problem of scalability, which has been a challenge in the quest to develop stretchable electrodes possessing both high electrical conductivity and high mechanical durability.
The bioinspired design of the HCP composite, which resembles the jabuticaba, is composed of hybrid carbon fillers containing carbon nanotubes and carbon black in a simple solution process. It has been found to effectively retain electrical conductivity, even under high strain rates; stable power has been delivered to an LED even under 100 percent strain.
"Our findings are expected to expand the number of stretchable nanocomposites with electrochemical and mechanical properties available for use in a wide variety of applications," said Professor Kwanyong Seo, a member of the school of energy and chemical engineering at UNIST who led the fabrication of stretchable current collectors.
A detailed analysis of the percolation behaviors of the composite’s conductive filler, done using an in-situ SAXS measurement under stretching, revealed that the different types of carbon in the filler led to a formation of highly interconnected cosupporting networks. Professor So Youn Kim, also of the school of energy and chemical engineering, led the in situ SAXS experiments. Kim noted that the study is, “expected to facilitate the design of stretchable nanocomposites with optimized electrochemical and mechanical properties for use in energy storage devices and stretchable electronics.”
The work is published in the January 2018 issue of Advanced Energy Materials.