Study On The Controllable Synthesis And Electrochemical Energy Storage Behavior Of Cobalt-based Nitride And Its Related Electrode Materials

Since modern society,especially the industrial revolution,the over-consumption on fossil energy resulted in significant energy shortages,scholars continue to conduct extensive research of new energy and its equipment,devoting to achieve sustainable development of energy.Supercapacitors have attracted extensive attention owing to their high power density and good stability.Although supercapacitors have the superiority to batteries for fast charging and discharging speed,their low energy density limits the process of commercial applications.Choosing suitable materials to assemble supercapacitors and increasing the capacitance are the core issue of capacitor applications.As a new type of active material,transition metal nitride possess well conductivity and outstanding stability.In this study,the preparation of cobalt-based nitride materials were carried out,and improved the performance by synergistic cooperation with double-layer hydroxides.We studied their working mechanism and conducted preliminary assembly of the equipment.Research summarized as follows:Ⅰ.Mutiple series of cobalt nitride electrodes were prepared by the method of binary reactive magnetron sputtering,and the electrochemical performance of the thin film electrodes was optimized by adjusting the experimental parameters.The optimized Co3N electrode prepared has an specific capacitance of 79.2 mF cm-2 in 6 M KOH electrolyte,and can still maintain an initial capacity of 78.1%after 15000 cycles,showing its excellent performance and stability.Ⅱ.The CoMn-LDH active substrate was successfully prepared on the carbon paper by a one-step hydrolysis of urea,and then the Co3N active film was deposited on the substrate by binary reactive magnetron sputtering to prepare CoMnLDH@Co3N.The composite material has a coral-like morphology and the specific surface area is greatly improved.The working voltage and current of the composite material have been improved.The specific capacitance in 6 M KOH electrolyte is 283.5 mF cm-2,still remains 81.7%after 15000 cycles.In order to further explore its practical value,a CoMn-LDH@Co3N//CoMn-LDH@Co3N symmetrical capacitor is assembled.When the power density is 2.1 W cm-3,the energy density of the capacitor can reach 45.6 mWh cm-2.When the density increases to 20.0 W cm-3,the energy density of 13.4 mWh cm-2 can still be maintained.