Compounding δ-MnO2 with Modified Graphene Nanosheets for Highly Stable Asymmetric Supercapacitors

Publication date: Available online 17 April 2019Source: Colloids and Surfaces A: Physicochemical and Engineering AspectsAuthor(s): Xiaoshuang Wang, Ling Chen, Shuoqing Zhang, Xiangcheng Chen, Yahao Li, Jingyan Liu, Feng Lu, Yongfu TangAbstractMnO2 is extremely attractive in the energy storage field, but the combination with highly conductive materials to enhance the electrical conductivity is still desired. Here we synthesize the composite of δ-MnO2 and glucose modified graphene nanosheets via a facile hydrothermal process. Graphene is transformed into 3D substrate by short-range self-assembly, on which MnO2 grows densely to construct the composite with both small mesopores (4 nm) and large mesopores (9-50 nm), showing high specific capacitance and ultrastability when used as supercapacitor materials. The synthesized composite exhibits the specific capacitance of 270 F g-1 at 0.5 A g-1, still 168 F g-1 at the high current density of 15 A g-1. Importantly, the kinetics and quantitative analysis confirms the domination of capacitive contribution that enlarges with the scan speed and reaches 87.1% at 100 mV s-1, which accounts for the excellent rate capability. The composite electrode maintains 90.12% of the initial specific capacitance after 50000 cycles at 10 A g-1. The asymmetric supercapacitor assembled with the composite cathode and graphene anode delivers the specific capacitance of 76 F g-1 at 0.5 A g-1. The high energy density of 30.1 Wh kg-1 is prov...
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Category: Chemistry Source Type: research