Poly(TEMPO)/Zinc Hybrid‐Flow Battery: A Novel, “Green,” High Voltage, and Safe Energy Storage System

Abstract

The combination of a polymer-based 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) catholyte and a zinc anode, together with a cost-efficient size-exclusion membrane, builds a new type of semi-organic, "green," hybrid-flow battery, which features a high potential range of up to 2 V, high efficiencies, and a long life time.

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

“…As mentioned before, TEMPO‐based redox‐active materials,32, 33, 166 in particular, are promising charge‐storage materials because of their well‐defined redox behavior. The good long‐term stability is ensured by the hindered recombination of two TEMPO moieties because of steric effects, the delocalization of the radical electron, and an unfavored NO−ON bond formation.…”

“…In the last decade the first steps were taken by the utilization of organic additives such as complexing agents,124, 125 followed by metal‐ligand complexes with organic ligands as charge‐storage materials,58, 96 and subsequently to flow batteries with an inorganic and an organic active material 32, 126. In recent years, organic/halogen,78, 127 and all‐organic RFBs were developed 128, 129.…”

“…From these described polymer‐based organic/inorganic flow batteries, the combination of zinc/organic polymer32, 33, 35 shows the greatest potential for further developments. As mentioned before, TEMPO‐based redox‐active materials,32, 33, 166 in particular, are promising charge‐storage materials because of their well‐defined redox behavior.…”

Redox Flow Batteries: Fundamentals and Applications

“…Compared to the relative small molecules such as hydroquinone and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), large molecules such as AQDS and methyl viologen (MV) are expected to have low-membrane crossover rates. Functionalization of these active organic compounds with polymer backbone chains further enables the battery operation with low-cost size-exclusion membranes [32]. The development 2e À ,2H þ redox reactions pH dependent, ranging from 0.56 to 0.75 [25] 2e À ,2H þ redox reactions 0.2 [26] 2e À ,2H þ redox reactions À0.73 for R ¼ OH [27] Organic radicals About 0.5 V in carbonate electrolyte [28] Organic radicals À0.45 V [29] Organodisulfide About À1 V [30] Table 4.…”

Synthesis of Novel Nitroxide Radical Polymer Materials for Imaging and Energy Storage Applications

“…Similar catholytes were also applied to a poly(TEMPO)/zinc hybrid-flow battery (HFB). 419 HFBs are hybrids between conventional batteries and RFBs, where one of the active species forms a solid-state electrode, while the other is in solution. Zinc is considered to be safer and cheaper than other metals and thus a viable candidate for a sustainable battery system.…”