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Abstract Graphene paper is a promising electrode material for use in flexible supercapacitors due to its good electronic conductivity and excellent mechanical characteristics. However, layers of graphene paper have a strong tendency to restack, resulting in a seriously reduced specific surface area and limited electrochemical performance. In this paper, restacked layers of graphene paper are reopened by a vacuum-assisted method, and carbon nanotubes (CNTs) are directly deposited on the enlarged space between the opened graphene layers. Consequently, an ordered carbon composite structure with alternately arranged graphene sheets and CNTs is constructed and exhibits increased specific surface area and a 3D conductive network. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and N 2 adsorption/desorption measurements. The electrochemical performance was tested by galvanostatic charge-discharge test (GDC), electrochemical impedance spectroscopy (EIS) and cyclic voltammograms (CV). The obtained graphene/CNT paper exhibits a remarkably improved capacity of 170.8 F g−1, which is nearly two times higher than that obtained for a regular graphene paper. Highlights • A unique carbonaceous structure with CNTs depositing between the opened layers of graphene is established. • The reopening of the graphene layers can enlarge the layer distance and increase the SSA. • The deposited CNTs can further inhibit the restacking of graphene layers and form a 3D conductive framework. • The prepared MGCP exhibits significantly enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Graphene aerogel is one of the most promising candidates for supercapacitors electrode material because of its high specific surface area and good electronic conductivity. However, the extremely low gravimetric density seriously limits its further practical applications. In this paper, a compression strategy was utilized to increase the gravimetric density by forming a unique highly-curved carbon nanotubes supported graphene porous 3D layer structure. The structure and morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectrum and N 2 adsorption/desorption measurement. Results demonstrate that the highly-curved carbon nanotubes between the graphene layers can prevent the restacking of the graphene layers. The newly formed structure retains the merits of graphene aerogel such as high specific surface area, good electronic conductivity, and porous structure. The electrochemical performance was investigated by a galvanostatic charge-discharge test (GDC) and a specific capacitance of 246.3 F g −1 was achieved, endowing it with great application potential as an supercapacitors electrode material. [ABSTRACT FROM AUTHOR]