| Compared with battery-type energy storage elements,supercapacitors have a series of advantages such as high power density,excellent fast charge and discharge performance,and long cycle life,which have become current research hotspots.However,compared with battery energy storage elements,its low energy density has limited its application,especially in large-scale electrical equipment.How to solve this limitation has become a popular direction for everyone's research.The electrode material is the key point to determine the performance of supercapacitors,so how to design an electrode with high specific capacitance is the key point to solve the low energy density of supercapacitors.Under the same conditions,the level of charge stored by rubidium capacitor materials is much higher than that of electric double layer materials.Among them,transition metal phosphides and sulfides have higher theoretical specific capacitance and electrochemical activity and have been widely studied.However,its development is limited due to the complicated preparation process,poor rate performance and poor cycle stability.In this paper,the starting point is how to easily and efficiently prepare high-performance transition metal phosphorus and sulfide electrodes.A one-step electrodeposition strategy is adopted to use copper/porous copper oxide(Cu/p-CuO)nanowires and highly conductive carbon cloth(CC).Nickel-cobalt phosphate nanosheet electrodes and nickel-cobalt phosphorus sulfide electrodes were prepared for the substrate.Their morphological characteristics and electrochemical properties were systematically studied.The main contents include:1.A porous ultra-thin NiCo(HPO4)2·3H2O(abbreviated as NiCo-P)nanosheet electrode was prepared on a porous Cu/p-CuO substrate by a one-step electrodeposition method.The experiment proves that the Cu/p-CuO/NiCo-P electrode has a very high specific capacity(1768.5 C g-1 at 2 A g-1)and excellent rate performance(1144.8 C g-1 at 100 A g-1)and electrochemical stability(specific capacitance retention rate reached 92%after 10,000 cycles under 10 A g-1).Because NiCo-P nanosheets and the substrate constitute a three-dimensional(3D)nanoarray structure,the material's "effective specific surface area" has been improved.Moreover,porous CuO nanowires increase the high-speed ion transport pathway and the load of active materials.The capacitance performance of the electrode material prepared by this method is higher than that of most pseudocapacitive materials reported in the literature.In addition,a Cu/p-CuO/NiCo-P//3DPG asymmetric supercapacitor(ASC)device composed of a 3D graphene gel(referred to as 3DPG)exhibits 88.1 Wh kg-1 at a power density of 800.6 W kg-1 High energy density of and significant cycle life(89%retention after 10,000 cycles).2.Two-dimensional(2D)nickel-cobalt-phosphorus sulfide(NiCo-PS)nanosheet electrode was grown on the surface of highly conductive carbon cloth by one-step electrodeposition method.The CC/NiCo-PS electrode was at a current density of 4 A g-1.Showing a specific capacitance of 2744 F g-1,and a specific capacitance of 2267.8 F g-1 and high rate performance(82.6%)at a current density of 100 A g-1.When assembled with an activated carbon electrode to form an ASC device,it has an operating voltage window of 1.6 V and a specific capacitance of 114 F g-1 at a current density of 1 A g-1.The device exhibits an energy density of 40.53 Wh kg-1 at a power density of 694.8 W kg-1,and has significant cycle stability(91.87%retained after 10,000 cycles)... |
PDF Full Text Request