一步合成Mn3O4@RGO复合材料及其非对称超级电容器的应用

在乙醇胺和水组成的混合溶剂中, Mn(Ac)₂与氧化石墨烯一步反应得到还原石墨烯(RGO)与黑锰矿纳米颗粒(Mn₃O₄)组成的复合材料Mn₃O₄@RGO。以Mn₃O₄@RGO为正极, RGO为负极, 组装得到了具有优良储能性能的非对称型超级电容器Mn₃O₄@RGO//RGO。基于活性物质的总质量, 电容器的最大能量密度可达21.7 Wh/kg, 相应的功率密度为0.5 kW/kg; 同时, 最大功率密度为8 kW/kg时, 对应的能量密度为11.1 Wh/kg。Mn₃O₄@RGO//RGO还表现出良好的循环稳定性, 在经历5000次循环后, 比电容依然保持88.4%。电容器的良好储能性能可归因于在RGO表面生长的高密度Mn₃O₄纳米颗粒和RGO的良好导电性能。

One-pot Synthesis and Application in Asymmetric Supercapacitors of Mn3O4@RGO Nanocomposites

Supercapacitors have attracted dramatic attentions in recent years for their apparent advantages, such as fast charge/discharge rate, high power density and high stability. However, it is still a challenge to improve their energy density for their practical applications. One of the strategies to overcome this drawback is to broaden the working voltage of the devices through assembling asymmetric supercapacitors. Herein, Mn₃O₄@RGO nanocomposites were successfully synthesized by using one-pot approach with Mn(Ac)₂ and GO in the mixed solvent of ethanolamine and water (3:1) without adding any surfactant. The asymmetric supercapacitors (Mn₃O₄@RGO//RGO) assembled with Mn₃O₄@RGO and RGO exhibit excellent performances in energy storage. The asymmetric supercapacitors can achieve a maximum energy density of 21.7 Wh/kg at power density of 500 W/kg and a maximum power density of 8 kW/kg at energy density of 11.1 Wh/kg, based on the total mass of active materials. The Mn₃O₄@RGO//RGO supercapacitors also demonstrated excellent durability retaining 88.4% of their specific capacitances even after 5000 charge/discharge cycles. The excellent performances of Mn₃O₄@RGO//RGO devices in energy storage can be attributed to high density of Mn₃O₄ nanoparticles grown directly on the surfaces of RGO nanosheets, which can dramatically improve the conductivity of materials.