3D多孔FeC2O4/石墨烯电极用于高性能2.5 V水系非对称超级电容器

本文制备的三维多孔结构FeC₂O₄/石墨烯复合材料，在不添加粘结剂时可作为超级电容器电极. 复合材料由大孔石墨烯和微介孔FeC₂O₄组成. 通常，水分解电压为1.23 V，对于以水系为电解液的不对称超级电容器，电压窗口限制为2 V. 当以FeC₂O₄/rGO水凝胶作为负极，以纯rGO水凝胶作为正极时，在KOH(1.0 mol/L)电解质中不对称超级电容器电压窗为1.7 V，在中性Na₂SO₄(1.0 mol/L)电解质中可达到2.5 V，相应地，组装的非对称电容器性能优异，能量密度为59.7 Wh/kg. 通过将具有微介孔结构的金属氧化物与石墨烯相结合，制备在不添加导电剂和粘合剂时直接用于组装不对称超级电容器的电极材料.

3D Macro-Micro-Mesoporous FeC2O4/Graphene Hydrogel Electrode for High-Performance 2.5 V Aqueous Asymmetric Supercapacitors

Distinguished from commonly used Fe₂O₃ and Fe₃O₄, a three-dimensional multilevel macromicro-mesoporous structure of FeC₂O₄/graphene composite has been prepared as binderfree electrode for supercapacitors. The as-prepared materials are composed of macroporous graphene and microporous/mesoporous ferrous oxalate. Generally, the decomposition voltage of water is 1.23 V and the practical voltage window limit is about 2 V for asymmetric supercapacitors in aqueous electrolytes. When FeC₂O₄/rGO hydrogel was used as the negative electrode and a pure rGO hydrogel was used as the positive electrode, the asymmetrical supercapacitor voltage window raised to 1.7 V in KOH (1.0 mol/L) electrolyte and reached up to 2.5 V in a neutral aqueous Na₂SO₄ (1.0 mol/L) electrolyte. Correspondingly it also exhibits a high performance with an energy density of 59.7 Wh/kg. By means of combining a metal oxide that owns micro-mesoporous structure with graphene, this work provides a new opportunity for preparing high-voltage aqueous asymmetric supercapacitors without addition of conductive agent and binder.