A challenge in the soaring process of replacing fossil-based power plants with ones based on renewable, but not constantly available, resources is the compensation of grid instabilities. Storage of high amounts of energy can be performed by redox-flow batteries (RFBs), since power and charge of their galvanic cells can be scaled up. RFBs can be based on redox-active metals or polymers. The advantages of polymer-based batteries (e.g. consisting of TEMPO-subunits; TEMPO = 2,2,6,6-tetramethyl-1-piperidinyloxyl) are their low costs, non-toxicity and simple design. To implement polymers for this application, the solubility and the thermal and electrochemical properties must be accurately tuned via changes in composition or microstructure. Rare-earth metal-mediated group-transfer polymerization (REM-GTP) is an efficient tool for precise and living-type synthesis of functional (co)polymers from Michael-type vinyl monomers. Dialkyl vinylphosphonates (DAVPs) are of special interest due to their tailor-made design, pendant group-dependent solubility and non-toxicity. Our group established lanthanocene catalysts with the general structure (Cp3)La(thf) (Cp = cyclopentadienyl, La = Gd-Lu) for a variety of differently substituted DAVPs. Polymerization of di(1-methoxy-2,2,6,6-tetramethylpiperidinyl-4-yl) vinylphosphonate (DMTVP) with (Cp3)Lu(thf) was conducted at room temperature to obtain high-molecular weight PDMTVP with low polydispersity under mild conditions. Subsequent deprotection with meta-chloroperbenzoic acid led to isolation of poly(di(TEMPO-4-yl) vinylphosphonate) (PDTVP) with up to 95% conversion. Spectroscopic and electrochemical properties were investigated using EPR-, SQUID- and CV-measurements. The electric and ionic conductivity was tested with spin-coated PDTVP. In summary, all these measurements indicate the high potential for TEMPO-based vinylphosphonates for application in redox-flow batteries.

Rare-earth metal-mediated synthesis of radical-containing poly(dialkyl vinylphosphonates): Novel materials for battery systems

2019 Fall National Meeting

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