Immobilizing Poly(vinylphenothiazine) in Ketjenblack‐Based Electrodes to Access its Full Specific Capacity as Battery Electrode Material

Abstract

Organic batteries are considered as environmentally friendly alternative to lithium‐ion batteries due to the application of transition metal‐free redox‐active polymers. One well‐established polymer is poly(3‐vinyl‐N‐methylphenothiazine) (PVMPT) with a fast reversibility of the electrochemical redox reaction at a potential of 3.5 V versus Li|Li+. The oxidized PVMPT is soluble in many standard battery electrolytes, which diminishes its available specific capacity but at the same time can lead to a unique charge/discharge mechanism involving a redeposition process upon discharge. Herein, the influence of different conductive carbon additives and their properties, e.g., specific surface area, pore size distribution, and electrical conductivity, on the dissolution behavior of oxidized PVMPT is investigated. Compared to the state‐of‐the‐art conductive carbon Super C65 employed in many organic battery electrodes, Ketjenblack EC‐300J and EC‐600J reduce the dissolution of the oxidized PVMPT due to better immobilization on the carbon additive and in the resulting 3D structure of the electrode, as assessed by N2‐physisorption, electrochemical, UV–vis spectroscopy and scanning electron microscopy investigations. The studies demonstrate that a dense packing of the carbon particles in the electrode is decisive for the stable immobilization of PVMPT while maintaining its long‐term cycling performance.

Current Trends and Perspectives of Polymers in Batteries

“…Compared to the state-of-the-art conductive carbon Super C65 employed in many organic battery electrodes, Ketjenblack EC-300J and EC-600J resulted in a 3D structure of the electrode. The studies demonstrate that a dense packing of the carbon particles in the electrode is decisive for the stable immobilization of PVMPT while maintaining its long-term cycling performance …”

“…The studies demonstrate that a dense packing of the carbon particles in the electrode is decisive for the stable immobilization of PVMPT while maintaining its long-term cycling performance. 72 A possibility offered by its synthetic versatility is the development of polymers that show several redox groups in the same polymer backbone. This allows that the same polymer material could be used as an anode and cathode simultaneously in a symmetric organic battery configuration.…”

“…The studies demonstrate that a dense packing of the carbon particles in the electrode is decisive for the stable immobilization of PVMPT while maintaining its long-term cycling performance. 72 …”

Tuning Carbon Dioxide Reduction Reaction Selectivity of Bi Single‐Atom Electrocatalysts with Controlled Coordination Environments

“…As the host for Bi SACs, we used commercially available conductive carbon black, Ketjenblack EC-300 J, which is an industrial by-product possessing a low electrical resistivity (0.01-0.1 Ω • cm), high specific surface area (988 m 2 /g), [16] and weak native activity for electrochemical conversion. To synthesize Bi SACs anchored on this carbon support, a solution-based chemical method, [17] followed by inert atmosphere annealing, was used.…”

Unlocking twofold oxidation in phenothiazine polymers for application in symmetric all-organic anionic batteries

“…The crosslinked derivatives were synthesized as previous studies have shown that linear PT-based polymers tend to be soluble in battery electrolytes in their oxidized form. 66,69,70 Linear PSDMPT exhibits a theoretical specific capacity of Qtheo = 148.3 mAh g −1 for a two-electron transfer.…”