High-Performance Asymmetric Supercapacitor Based on Graphene Hydrogel and Nanostructured MnO2
High-Performance Asymmetric Supercapacitor Based on Graphene Hydrogel and Nanostructured MnO2
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DOI：
10.1021/am300455d
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发表时间：
2012-05-01
影响因子：
9.5
通讯作者：
Duan, Hongwei
中科院分区：
文献类型：
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作者：
Gao, Hongcai;Xiao, Fei;Duan, Hongwei
在中性Na2SO4水溶液中，以具有三维连通孔的石墨烯水凝胶（GH）为负极，以泡沫镍上垂直排列的MnO2纳米板（MnO2- nf）为正极，成功制备了具有高能量和功率密度的非对称超级电容器。由于理想的多孔结构、GH和MnO2-NF的高比电容和倍率能力、两个电极的互补电位窗口，以及聚合物粘合剂和导电添加剂的消除，非对称超级电容器可以在0-2.0 V的宽电位窗口内可逆循环，其艺术能量密度为23.2 Wh kg(-1)，功率密度为1.0 kW kg（-1）。与基于GH （5.5 Wh kg(-1)）和MnO2-NF （6.7 Wh kg(-1)）的对称超级电容器相比，非对称超级电容器的能量密度得到了显著提高。即使在10.0 kW kg（-1）的高功率密度下，非对称超级电容器也可以提供14.9 Wh kg（-1）的高能量密度。非对称超级电容器在5000次循环后电容保持率为83.4%，具有稳定的循环性能。
We have successfully fabricated an asymmetric supercapacitor with high energy and power densities using graphene hydrogel (GH) with 3D interconnected pores as the negative electrode and vertically aligned MnO2 nanoplates on nickel foam (MnO2-NF) as the positive electrode in a neutral aqueous Na2SO4 electrolyte. Because of the desirable porous structure, high specific capacitance and rate capability of GH and MnO2-NF, complementary potential window of the two electrodes, and the elimination of polymer binders and conducting additives, the asymmetric supercapacitor can be cycled reversibly in a wide potential window of 0-2.0 V and exhibits art energy density of 23.2 Wh kg(-1) with a power density of 1.0 kW kg(-1). Energy density of the asymmetric supercapacitor is significantly improved in comparison with those of symmetric supercapacitors based on GH (5.5 Wh kg(-1)) and MnO2-NF (6.7 Wh kg(-1)). Even at a high power density of 10.0 kW kg(-1), the asymmetric supercapacitor can deliver a high energy density of 14.9 Wh kg(-1). The asymmetric supercapacitor also presents stable cycling performance with 83.4% capacitance retention after 5000 cycles.