Nanosized core-shell structured graphene-MnO2 nanosheet arrays as stable electrodes for superior supercapacitorsElectronic supplementary information (ESI) available. See DOI: 10.1039/c7ta02627g

• Main Authors: Jia, He Nan, Lin, Jing Huang, Liu, Yu Lin, Chen, Shu Lin, Cai, Yi Fei, Qi, Jun Lei, Feng, Ji Cai, Fei, Wei-Dong
• Format: Journal Article
• Language: English
• Published: 30.05.2017
• DOI: 10.1039/c7ta02627g
• ISSN: 2050-7488

Directly fabricating vertically standing graphene-manganese dioxide (MnO 2 ) nanoparticle hybrids as electrode materials remains a challenge, especially so without the use of organic binders. Such hybrids should exhibit high electrochemical performance and high stability. To address this challenge, we report a strategy for fabricating nanosized core-shell graphene-MnO 2 nanosheet arrays (G-MnO 2 NAs) for use as electrodes for supercapacitors. The as-grown MnO 2 nanosheets are transformed into core-shell G-MnO 2 nanoparticles by plasma-enhanced chemical vapor deposition. The in situ formed graphene layers act as binders and frameworks, and provide integrity and stability to the overall nanosheet. The resulting core-shell nanoparticles exhibit a high specific surface area and long-term cycling stability. The synergistic effect of the vertically standing intercalated architecture and in situ formed graphene provides a short ion diffusion pathway and a high conductivity. The G-MnO 2 NAs exhibit a high specific capacitance of 1176 F g −1 at 2 mV s −1 , and a long cycling lifetime with negligible capacitance loss after 10 000 cycles. This process for the in situ formation of graphene may be useful for improving the electrochemical performance of other metal oxide-based electrodes. Directly fabricating vertically standing graphene-manganese dioxide (MnO 2 ) nanoparticle hybrids as electrode materials remains a challenge, especially so without the use of organic binders.