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 Ti₃C₂T_x MXene negative electrode with RuO₂ 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 MnO₂ as the positive and Ti₃C₂T_x MXene as the negative electrode in a neutral 1 M Li₂SO₄ electrolyte. This all-pseudocapacitive asymmetric device not only uses a safer electrolyte and is a much less expensive counter-electrode than RuO₂, 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.

MXenes 在水性电解质中显示出破纪录的氧化还原电容，但由于阳极电位下的氧化和高阴极电位下的析氢，在有限的电压窗口中。将 Ti ₃ C ₂ T _x MXene 负极与 RuO ₂或碳基正极偶联，将硫酸电解液中的电压窗口扩大至约 1.5 V。在这里，我们提出了一种使用丰富且环保的钒掺杂 MnO ₂作为不对称赝电容器在中性 1 M Li ₂ SO _{4 中}正极和 Ti ₃ C ₂ T _x MXene 作为负极电解质。这种全伪电容不对称器件不仅使用更安全的电解质，而且是比 RuO ₂便宜得多的反电极，而且可以在 2.1 V 电压窗口内运行，从而产生 46 Wh/kg 的最大能量密度。这项研究还证明了使用 MXene 电极来扩展传统具有氧化还原能力的材料的工作电压窗口的可能性。