Study On Controllable Preparation Of Transition Metal Nitride Nanocomposite Electrodes And Capacitive Properties Based On Reactive Magnetron Sputtering

Supercapacitors（SCs）possess fast charge/discharge capability,high output power,and long-cycle stability,and have broad application prospects in the field of energy storage.However,the inherent low energy density of SCs is difficult to meet the growing operational demands of various electronic products,which seriously hinders their applications.In recent years,researchers have devoted themselves to the development of supercapacitors with high energy density,mainly focusing on the optimization of the morphology and structure of electrode materials,the improvement of specific surface area,and the selection of appropriate electrolytes.In this paper,the transition metal nitrides Cr N and W₂N were prepared on the hydrothermally synthesized metal-organic frameworks（MOFs）on carbon paper（CP）by reactive magnetron sputtering.,followed by nitrogen-doped porous carbon（NCs）nanoarrays prepared by high-temperature carbonization using MOFs nanoarrays as sacrificial templates.Nitride carriers,the effects of sputtering time and carbonization temperature on the morphology,structure and single-electrode capacitance properties of the composites were mainly studied.In addition,the assembly of symmetric supercapacitors and their capacitive properties were investigated on single-electrode composites.The main research contents and results are as follows:（1）The effects of sputtering time,carbonization temperature and different substrates on the phase and morphology of Cr N films prepared by reactive magnetron sputtering technology were studied.The results show that on the MOFs substrate,the power is600 W,the nitrogen-argon gas flow ratio is 35:20,the total pressure is 0.5 Pa,the sputtering time is 30 min,and the carbonization temperature is 600℃excellent Cr N film.（2）Single-electrode performance tests were performed on the prepared Cr N@NCs@CP composites.The electrode exhibited a specific capacitance of 132.1m F cm^-2 at a current density of 1.0 m A cm^-2 and a specific capacitance of 5.0 m A cm^-2at a current density of 5.0 m A cm^-2.The charge-discharge cycle performance test was carried out under 20 000 cycles,and the capacity retention rate was 95.9%after 20 000cycles.The symmetric supercapacitor achieves an energy density of 5.28μWh cm^-2(2.7 Wh kg^-1)at a power density of 0.41 m W cm^-2.（3）The effects of sputtering time,carbonization temperature and different substrates on the phase and morphology of W₂N thin films prepared by reactive magnetron sputtering were studied.The results show that on the MOFs substrate,the power is 600W,the nitrogen-argon gas flow ratio is 30:2.5,the total pressure is 0.5 Pa,the sputtering time is 45 min,and the carbonization temperature is 600℃excellent W₂N film.（4）Single-electrode performance tests were performed on the prepared W₂N@NCs@CP composites.The electrode exhibited a specific capacitance of 70.2m F cm^-2 at a current density of 1.0 m A cm^-2 and a specific capacitance of 5.0 m A cm-2 at a current density of 5.0 m A cm^-2.The charge-discharge cycle performance test was carried out under 20 000 cycles,and the capacity retention rate was 93.8%after 20 000cycles.The symmetric supercapacitor achieves an energy density of 2.70μWh cm^-2 at a power density of 1.76 m Wcm^-2.In this paper,nano-Cr N and W₂N composites with sheet-like nanoarray morphology were successfully prepared on MOFs@CP by magnetron sputtering.The construction of MOFs nanoarrays improved the specific surface area of the composites and the NCs formed after high temperature carbonization.The synergistic effect of nanoarrays and transition metal nitrides has greatly contributed to the improvement of the capacitance performance of the composite electrode,and provided an experimental basis for the application of other transition metal nitrides in supercapacitors.