Jan Winsberg

Redox‐Flow Batteries: From Metals to Organic Redox‐Active Materials

Abstract Research on redox‐flow batteries (RFBs) is currently experiencing a significant upturn, stimulated by the growing need to store increasing quantities of sustainably generated electrical energy. RFBs are promising candidates for the creation of smart grids, particularly when combined with photovoltaics and wind farms. To achieve the goal of “green”, safe, and cost‐efficient energy storage, research has shifted from metal‐based materials to organic active materials in recent years. This Review presents an overview of various flow‐battery systems. Relevant studies concerning their history are discussed as well as their development over the last few years from the classical inorganic, to organic/inorganic, to RFBs with organic redox‐active cathode and anode materials. Available technologies are analyzed in terms of their technical, economic, and environmental aspects; the advantages and limitations of these systems are also discussed. Further technological challenges and prospective research possibilities are highlighted.

Polymer/zinc hybrid-flow battery using block copolymer micelles featuring a TEMPO corona as catholyte

A well-defined block copolymer was applied in a semi-organic polymer hybrid-flow battery (pHFB). A 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) containing polymer was utilised as cathode active material. Micellar structures of the active material were achieved by utilising a diblock copolymer composed of a polar poly(TEMPO methacrylate) (PTMA) and an unpolar poly(styrene) (PS) block, which enables the formation of core-corona micelles in organic carbonates. The synthesised PTMA-b-PS was electrochemically investigated and subsequently utilised as catholyte in polymer/Zn pHFBs. The constructed flow batteries feature an excellent cycling stability of 1000 consecutive charge/discharge cycles with 95% retention of initial discharge capacity and a stable voltage range of 2 V. Further, the charging process leads to slight changes in the micellar structure combined with an increased solubility.