摘要
MXenes have shown record-breaking redox capacitance in aqueous electrolytes,but in a limited voltage window due to oxidation under anodic potential and hydrogen evolution under high cathodic potential.Coupling Ti3C2Tx Xene negative electrode with RuO_(2) or carbon-based positive electrodes expanded the voltage window in sulfuric acid electrolyte to about 1.5 V.Here,we present an asymmetric pseudocapacitor using abundant and eco-friendly vanadium doped MnO_(2) as the positive and Ti_(3)C_(2)Tx MXene as the negative electrode in a neutral 1M Li2SO4 electrolyte.This all-pseudocapacitive asymmetric device not only uses a safer electrolyte and is a much less expensive counter-electrode than RuO_(2),but also can operate within a 2.1 V voltage window,leading to a maximum energy density of 46 Wh/kg.This study also demonstrates the possibility of using MXene electrodes to expand the working voltage window of traditional redox-capable materials.
基金
supported by the National Natural Science Foundation of China(Nos.51972124,51902115,and 51872101)
supported by King Abdullah University of Science and Technology(KAUST)under the KAUST-Drexel Competitive Research Grant(No.OSR-CRG2016-2963 sub 11206).
