Electrochromic poly(chalcogenoviologen)s as anode materials for high-performance organic radical lithium-ion batteries

A series of electrochromic electron-accepting poly(chalcogenoviologen)s with multiple, stable, and reversible redox centers were used as anodic materials in organic radical lithium-ion batteries (ORLIBs). The introduction of heavy atoms (S, Se, and Te) into the viologen scaffold significantly improved the capacity and cycling stability of the ORLIBs. Notably, the poly(Te-BnV) anode was able to intercalate 20 Li ions and showed higher conductivity and insolubility in the electrolyte, thus contributing to a reversible capacity of 502 mAh g${}^{-1}$ at 100 mA g${}^{-1}$ when the Coulombic efficiency approached 100 %. The charged/discharged state of flexible electrochromic batteries fabricated from these anodic materials could be monitored visually owing to the unique electrochromic and redox properties of the materials. This study opens a promising avenue for the development of organic polymer-based electrodes for flexible hybrid visual electronics. (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)