A facile fabrication of MnO2/graphene hybrid microspheres with a porous secondary structure for high performance supercapacitors

• Published in: Journal of solid state electrochemistry 2015-04, Vol.19 (4), p.949-956
• Main Authors: Shang, Yingying, Yu, Ze, Xie, Chao, Xie, Qinxing, Wu, Shihua, Zhang, Yufeng, Guan, Yunfei
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Electrochemistry; Energy Storage; Original Paper; Physical Chemistry
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-014-2691-9

MnO 2 /graphene nanosheets (MnO 2 /GNs) hybrid composite can be prepared by spray-drying technique with either graphene oxide (GO) or hydrazine-reduced graphene as precursor. The characterization results of the as-synthesized composites indicate that MnO 2 and GNs are uniformly distributed and intertangled forming porous microspheres in a diameter of 2–4 μm. This special secondary structure is beneficial for an intimate contact between MnO 2 and GNs accounting for improved conductivity. In addition, the high surface area and abundant porosity enables aqueous electrolyte to penetrate deeply inside the hybrid microspheres, and facilitating the Na + insertion/release process, which increases the utilization of active component resulting in enhanced supercapacitance. MnO 2 /graphene hybrid microspheres exhibit a good cycling performance as the intertangled graphene buffers the volume change of MnO 2 during charge–discharge cycles.