Available online at www.sciencedirect.com ScienceDirect Materials Today: Proceedings 3 (2016) 1686–1692 www.materialstoday.com/proceedings 2214-7853© 2015 Elsevier Ltd.All rights reserved. Selection and Peer-review under responsibility of [Conference Committee Members of Recent Advances In Nano Science and Technology 2015. ]. Recent Advances In Nano Science And Technology 2015 (RAINSAT2015) MnO 2 -Vertical graphene nanosheets composite electrodes for energy storage devices Subrata Ghosh*, Bhavana Gupta, K. Ganesan, A. Das, M. Kamruddin, S. Dash, A.K. Tyagi Surface & Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Tamil Nadu, India - 603102 Abstract The vertical graphene nanosheets (VGNs) have attracted considerable attention for energy storage application due to their inherent properties such as morphology, large surface area, high electrical conductivity and three dimensional (3D) open network structures. Here, we report on the growth of VGNs using electron cyclotron resonance - chemical vapor deposition and its electrochemical storage behavior. Further, a near homogeneous dispersion of MnO 2 is coated over VGNs by dip casting to enhance the effective capacitance. Electrochemical charge storage behavior of VGNs and MnO 2 /VGNs composites are investigated using cyclic voltametry and electrochemical impedance spectroscopy (EIS) and also the results are compared. The MnO 2 /VGNs composites exhibit the highest areal capacitance of 5.6 mF/cm 2 , which is 110 times higher than that of VGNs (51.95 μF/cm 2 ) at a scan rate of 50 mV/s. The enhanced capacitance is due to highly conductive 3D network of VGNs which provide fast electron and ion transport and also a large pseudo-capacitance from MnO 2 coating. The EIS results are analyzed with equivalent circuit model which reveals the charge storage mechanism in the materials. Scanning electron microscopy and Raman spectroscopy are also used to understand the morphology and structure – property correlations of the films. These results demonstrate clearly that the MnO 2 /VGNs composite is a potential candidate for energy storage applications. © 2015Elsevier Ltd.All rights reserved. Selection and Peer-review under responsibility of [Conference Committee Members of Recent Advances In Nano Science and Technology 2015.]. Keywords: vertical graphene nanosheets; MnO2; energy storage; impedance spectroscopy * Corresponding author. Tel.: Tel.: +91-44-27480500-22791 E-mail address: subrataghosh.phys@gmail.com