All‐Solid‐State Rechargeable Air Batteries Using Dihydroxybenzoquinone and Its Polymer as the Negative Electrode
Makoto Yonenaga, Yusuke Kaiwa, Kouki Oka, Kenichi Oyaizu, Kenji Miyatake
Abstract
Abstract A proof‐of‐concept study was conducted on an all‐solid‐state rechargeable air battery (SSAB) using redox‐active 2,5‐dihydroxy‐1,4‐benzoquinone (DHBQ) and its polymer (PDBM) and a proton‐conductive polymer (Nafion). DHBQ functioned well in the redox reaction with the solid Nafion ionomer at 0.47 and 0.57 V vs. RHE, similar to that in acid aqueous solution. The resulting air battery exhibited an open circuit voltage of 0.80 V and a discharge capacity of 29.7 mAh g DHBQ −1 at a constant current density (1 mA cm −2 ). With PDBM, the discharge capacity was much higher, 176.1 mAh g PDBM −1 , because of the improved utilization of the redox‐active moieties. In the rate characteristics of the SSAB‐PDBM, the coulombic efficiency was 84 % at 4 C, which decreased to 66 % at 101 C. In a charge/discharge cycle test, the capacity remaining after 30 cycles was 44 %, which was able to be significantly improved, to 78 %, by tuning the Nafion composition in the negative electrode.