Superionic Quasi-Solid-State Electrolyte for Rechargeable Magnesium–Oxygen Batteries

High Resolution Image Download MS PowerPoint Slide Limited by their life span and capacity, magnesium–oxygen batteries have not reached their full potential. We present a quasi-solid-state electrolyte (QSSE) that significantly enhances their performance. This QSSE combines an optimum amount of polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), succinonitrile (SN) as a plasticizer, and magnesium triflate (Mg(OTf) 2 ) as the salt with the high-conductivity ionic liquid (IL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr 14 TFSI), a magnesium ion mobility booster. The resulting low activation energy (0.215 eV) and high room-temperature ionic conductivity (2.6 mS cm –1 ) of the optimized QSSE facilitate rapid and efficient magnesium-ion transport. Paired with Ru nanoparticle-decorated multiwalled carbon nanotube (Ru/CNT) cathode catalysts, this QSSE-based Mg–O 2 battery achieves a remarkable cyclability of 94 cycles at 100 mA g –1 . This synergistic combination leads the way for commercially viable Mg–O 2 batteries with exceptional stability and high capacity, advancing the path toward sustainable and high-performance energy solutions.