Three-Dimensional Pompon-like MnO2/Graphene Hydrogel Composite for Supercapacitor

A three-dimensional nanocomposite of pompon-like MnO2/graphene hydrogel was prepared. The 3D graphene hydrogel not only provides a good support to stabilize MnO2 but also facilitate the fast ion mobility and electron transfer. The composite exhibited a good capacitive performance (445.7 F g−1 at 0.5 A g−1) and stability (82.4% retention after 5000 cycles).