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• The ternary metal NiCoGa-LDHs is firstly synthesized by simple hydrothermal method. • The morphology, crystal structure stability and capacitance of NiCoGa-LDHs are systematically studied. • The Ni 1 Co 3 Ga 1 -LDHs@CC electrode exhibits excellent capacitance of 2012.5 F g-1 at 1 A g-1. • The asymmetric supercapacitor (84.22 Wh kg-1) can light multiple LEDs in parallel. Ternary metal layered double hydroxides (LDHs) have been widely used in supercapacitors (SCs) due to their polyvalent state and high electrochemical activity. In this study, Ga (III) doped NiCo layered double hydroxides (NiCoGa-LDHs) electrode material is prepared on carbon cloth (CC) by simple one-step hydrothermal method for the first time. The effects of Ga3+ with different molar ratios on the structure, morphology, crystallinity, ion transport mechanics and electrochemical properties of ternary LDHs electrode materials are systematically investigated. At Ga3+ = 1.0, the as-synthesized Ni 1 Co 3 Ga 1 -LDHs@CC exhibits a special electrochemical capacitance of 2012.5 F g-1 at 1 A g-1 with 57.7% capacitance retention observed at 5.0 A g-1. The synthesis and evaluation of the two bimetallic NiCo-LDHs and NiGa-LDHs are similar in order to demonstrate the performance improvement of gallium heterovalent substitution. And heterovalent substitution of gallium for cobalt ion and nickel ion is proved indirectly. An Asymmetric supercapacitors (ASCs) device is assembled with Ni 1 Co 3 Ga 1 -LDHs@CC as anode and mesoporous carbon (MPC) as cathode, providing a high energy density of 84.22 Wh kg-1 at a power density of 800.1 W kg-1, with excellent cyclic stability. This study provides a new way to improve the electrochemical performance and stability of ternary metal LDHs. [ABSTRACT FROM AUTHOR]

The unique three-dimensional (3D) porous structure of graphite carbon nitride (g-C 3 N 4) and vanadium pentoxide (V 2 O 5) was prepared by an environmentally friendly one-step solvothermal method, and its electrochemical performance was assessed. Importantly, g-C 3 N 4 is a low cost material with excellent chemical stability, and it supports the vertical charge transfer during the charge-discharge process, which promotes electronic transmission along this direction. In addition, V 2 O 5 has good theoretical capacitance and is deemed as a potential electrode material for next-generation supercapacitors. Field emission scanning electron microscopy of the nanocomposite revealed a 3D porous morphology for g-C 3 N 4 (3D PCN) and a spherical morphology for V 2 O 5. This study estimated the viability of the graphite carbon nitride-based nanocomposite PCN@V 2 O 5 as a new catalyst in the supercapacitor (SC) anodes. A series of SC anodes with different catalyst loadings were produced. The electrochemical behavior of the SC anodes was calculated by cyclic voltammetry (CV), charge-discharge and cycling test. When test in electrochemical performance, the ratio of PCN:V 2 O 5 is lower than 1:1 and 3D PCN@V 2 O 5 exhibits a lower specific capacity, the ratio of PCN:V 2 O 5 is higher than 1:1 that most of the pores in 3D porous g-C 3 N 4 are covered that reduces the electron transport rate and results in a lower specific capacity. Overall, 3D PCN@V 2 O 5 has higher specific capacity (457 Fg-1 at 0.5 Ag-1) and better cycling performance (approximately 84% after 500 cycles). This attractive performance indicates that 3D PCN@V 2 O 5 could be used as potential electrode materials for supercapacitors. • A novel 3D porous PCN@V 2 O 5 was prepared by simple chemical precipitation method. • The 3D porous PCN@V 2 O 5 as new electrode materials exhibited great electrochemical properties. • The 3D porous PCN@V 2 O 5 products are potential supercapacitor electrode materials for supercapacitors. [ABSTRACT FROM AUTHOR]