Mechanistic understanding of monovalent cation transport in eumelanin pigments
Recent research advances in charge conducting materials enable to transform the naturally-occurring materials into a crucial component in many technologies including renewable energy storages or bioelectronics. Among various candidates, eumelanins are the promising charge storage materials by exhibiting hybrid electronic ionic conductivity in a hydrated environment. Chemical and electrochemical properties of eumelanins are relatively well studied, however structure-property relationship is still elusive up to date. Here, we report the mesoscale structure of eumelanins and its impact on the charge transport. X-ray scattering suggests that eumelanin pigments exhibit the semi-crystalline structure with ordered d-spacings. These unique mesoscale structures further influence the charge transport mechanism with the cations of various sizes. Understanding the structures with consequent electrochemical properties suggest that eumelanins may be further tuned to be served as high performance naturally-occurring charge storage material.
- This article is part of the themed collection: Journal of Materials Chemistry B Emerging Investigators