Research On Key Technologies Of Energy Storage And Conversion Devices Based On Nanofabrication Technology

There is no doubt that energy is one of the greatest challenges facing mankind today.Solar energy and wind power are pollution-free and sustainable energy sources,but their conversion and storage efficiency greatly limits their application.Compared with ordinary batteries,supercapacitors have become a new and alternative electrochemical energy storage equipment with the merits of excellent charging and discharging speed,better power density and excellent working life.Carbon materials and transition metal compounds are often used as electrode materials to assemble the supercapacitor device.However,due to the characteristics of these two materials,carbon material has ultra-high electrical conductivity but lesser specific storage and smaller capacity density.On the contrary,the transition metal hydroxides have good specific capacity,energy density and electrochemical stability,but their electrical conductivity is very poor.Transition metal compounds grown in situ on carbon substrates based on nanomachining technology will be an excellent electrode material for supercapacitors.Moreover,its unique structure also provides excellent performance as a frictional layer material for friction nanogenerator(TENG).This has not only increased the selection of TENG friction-layer electrode materials,but also expanded the application field of synthetic materials.The main point of this thesis include:1.Ni_1/3CO_2/3(CO₃)_1/2(OH)·0.11H₂O(NCC)was compounded by reaction of nickel nitrate,cobalt nitrate and urea in the mixed solution of anhydrous ethanol and water at 100?.CNTs@Ni_1/3CO_2/3(CO₃)_1/2(OH)·0.11H₂O(CNTs@NCC)was synthesized by reaction of nickel nitrate,cobalt nitrate,urea,and carbon nanotubes(CNTs)in a mixed solution of anhydrous ethanol and water at 100?.CNTs@NCC was based on CNTs and Ni_1/3CO_2/3(CO₃)_1/2(OH)·0.11H₂O(NCC)generated by the reaction of nickel nitrate,cobalt nitrate and urea was deposited on the surface of CNTs forming a kind of CNTs@NCC composite at the nanometer level.2.The super-capacitors were assembled with NCC and CNTs@NCC as electrode materials.CNTs@NCC//activated carbon(AC)devices showed outstanding specific capacitance in 2 M KOH electrolyte(the specific storage was 102.9 F·g^-1 when the current density was set to 0.5 A·g^-1),and the assembled all-solid super-capacitor also showed larger specific capacitance and longer cycle life.3.CNTs@NCC and NCC were used as friction layer electrode materials to assemble the friction nano-generator,and TENG's collected electrical energy was tested on capacitor charge and discharge by rectifier.TENG assembled in NCC had A short-circuit current of 60?A,A charge density of 80?C·m^-2,and A rectified current of about 50?A at operating frequencies of 5 Hz.Stability tests for TENG were performed at operating frequencies of 5 Hz,and nearly identical outputs were maintained after A cycle of 50,000 weeks.The voltage of the 100?F capacitor can be up to 5 V for 210 s.