Phytic acid modified manganese dioxide/graphene composite aerogel as high-performance electrode materials for supercapacitors

Incorporating manganese dioxide (MnO 2 ) with reduced oxide graphene (RGO) holds great potential as favourable supercapacitor electrodes for energy storage applications. In order to improve the adhesive strength and stability, we synthesized a phytic acid (PA)-linked MnO 2 /RGO aerogel (MnO 2 /P-RGO) through a simple self-assembled hydrothermal and freeze-drying method. Herein, PA as a bridge could accelerate the firm immobilization of MnO 2 on RGO sheets to synthesize the composite aerogel with a three-dimensional (3D) layered porous structure. The 3D MnO 2 /P-RGO composite aerogel as a supercapacitor electrode could achieve the high specific capacitance of 645 F g −1 under the current density of 1 A g −1 and 410 F g −1 at 40 A g −1 . Furthermore, the composite aerogel exhibits remarkable long-term stability, 94.9% of the initial capacitance after 10,000 cycles under the high current density of 20 A g −1 . Moreover, the assembled MnO 2 /P-RGO//RGO asymmetric supercapacitor (ASc) shows the maximum energy density of 59.2 W h kg −1 at 1.48 kW kg −1 and could remain 28.8 W h kg −1 at the maximum power density of 57.6 kW kg −1 . Additionally, the MnO 2 /P-RGO//RGO ASc also exhibits excellent long cycling stability with 91.6% of the initial capacitance after 10,000 cycles at 20 A g −1 , indicating its promising practical application for high-efficiency supercapacitors.