Single-Ion Flexoionic\nPolymer Energy Harvester under\nOscillatory Flexure

The present paper aims to develop solid polymer electrolyte\nelastomers\nfor energy harvesting and storage devices under dynamic natural environment.\nThe flexoionic elastomer was synthesized by grafting 1-allyl-3-methylimidazolium\nbis(trifluoromethylsulfonyl)imide (AMIMTFSI) to a triblock copolymer\nconsisting of olefinic glycol moieties such as PEG-<i>b</i>-PPG-<i>b</i>-PEG end-capped with methacrylate groups (DMA).\nThe strategy of grafting dissociated AMIM<sup>+</sup> cations to the\npolyglycol triblock copolymer network allows selective (or dominant)\nion polarization by the mobile TFSI<sup>–</sup>anions undergoing\noscillatory motion, the concept of which is similar to single-ion\ntransport as a means of enhancing electrochemical performance in some\nsolid-state polymer electrolyte batteries. The 60:40 PEG-<i>b</i>-PPG-<i>b</i>-PEG-DMA/AMIMTFSI elastomer achieved a high\nflexoelectric coefficient on the order of about 380 μC m<sup>–1</sup> at 1 Hz and a high energy conversion efficiency of\nabout 14.9% under oscillatory bending mode, which opens an opportunity\nfor energy harnessing from rolling tires.