Polymers for aluminium secondary batteries: Solubility, ionogel formation and chloroaluminate speciation

This work deals with the search of polymers apt for preparation solid-like chloroaluminate-based electrolytes. To accomplish this, solubility and gelling ability a large set in deep eutectic solvent AlCl3:urea (uralumina) are studied, followed by characterization electrochemical activity gels. The directly dissolved urea:AlCl3 without auxiliary solvents following fast scalable gel methodology previously reported ultra-high molecular weight (UHMW) polyethylene oxide (PEO). list studied includes diverse chemical structures, different thermal properties aggregation states at mixing temperature 70 °C, defined stability AlCl3:urea. avoid influence on ionogel rheological properties, close to 100,000 g mol−1 have been chosen. considered include poly(ε-caprolactone) (PCL), poly(dimethyl siloxane) (PDMS), poly(vinyl pyrrolidone) (PVP), polyformal, thermoplastic polyurethanes, polymethacrylates, polyacetates elastomer SEBS. It was found that together oxide, only soluble produce electrolytes rules chloroaluminates discussed. stripping/plating Al ionic conductivity PEO, PDMS PCL ionogels cyclic voltammetry impedance spectroscopy. proves be as efficient PEO low polymer concentration, also self-standing electroactive, whereas higher concentration is required structure modification chloroaluminate speciation vibrational spectroscopies, supported DFT calculations.