Vasantan Rasupillai DharmarajAyan SarkarJheng-Yi HuangSheng-Chieh HuangChin-Lung KuoChing-Chen WuWen-Sheng ChangHan-Chen ChenYu-Ping LinChao-Cheng KaunRen-Jei ChungRu-Shi Liu2025-04-212025-04-212025-03-20https://scholars.lib.ntu.edu.tw/handle/123456789/728342Limited 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 (Pyr14TFSI), 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-O2 battery achieves a remarkable cyclability of 94 cycles at 100 mA g-1. This synergistic combination leads the way for commercially viable Mg-O2 batteries with exceptional stability and high capacity, advancing the path toward sustainable and high-performance energy solutions.en[SDGs]SDG7journal article10.1021/acsmaterialslett.4c02373