Conducting Redox Polymer as a Robust Organic Electrode‐Active Material in Acidic Aqueous Electrolyte towards Polymer–Air Secondary Batteries
Kouki Oka, Christian Strietzel, Rikard Emanuelsson, Hiroyuki Nishide, Kenichi Oyaizu, Maria Strømme, Martin Sjödin
Abstract
Abstract Organic materials receive increasing attention as environmentally benign and sustainable electrode‐active materials. We present a conducting redox polymer (CRP) based on poly(3,4‐ethylenedioxythiophene) with naphthoquinone pendant group, which is formed from a stable suspension of a trimeric precursor and an oxoammonium cation as oxidant. This suspension allows us to easily coat the polymer onto a current collector, opening up use of roll‐to‐roll processing or ink‐jet printing for electrode preparation. The CRP showed a full capacity of 76 mAh g −1 even at a high C rate of 100 C in acidic aqueous electrolyte. These properties make the CRP a promising candidate as anode‐active material; a polymer–air secondary battery was fabricated with the CRP as anode, a conventional Pt/C catalyst as cathode, and sulfuric acid aqueous solution as electrolyte. This battery yielded a discharge voltage of 0.50 V and showed good cycling stability with 97 % capacity retention after 100 cycles and high rate capabilities up to 20 C.