Preparation Of MXene Bifunctional Catalyst And Its Application In Zinc-air Battery

With the rapid development of the world’s industrialization,the energy crisis and environmental pollution caused by the consumption of non-renewable resources have become more and more serious.Research on green energy conversion devices is particularly important.Air batteries have received extensive attention and research due to their advantages of environmental protection,high specific capacity,low cost and high safety.However,the main reason restricting its commercial development is the Oxygen Reduction Reaction at the cathode.At present,the high preparation cost of precious metal catalysts mainly based on Pt/C limits its wide application.Therefore,in order to promote the development of catalysts,it is of great significance to develop non-noble metal carbon-based cathode electrocatalysts with low cost and high activity.In this paper,the two-dimensional material MXene is selected as the conductive substrate,and the nitrogen source and carbon source are introduced through in-situ growth to form a three-dimensional array structure based on MXene carbon nanotubes wrapped with metal nanoparticles.The electrocatalytic performance is studied and the catalytic mechanism is proposed.The catalyst is tested in liquid./Practical application of solid zinc-air battery.MXene is prepared by the method of hydrochloric acid and lithium fluoride to generate hydrofluoric acid in situ.Under the action of polyethyleneimine,a three-dimensional conductive network is formed through a directional freezedrying process.The transition metals Fe and Co are uniformly anchored in the conductive network.Auxiliary carbonization to form Fe-Co/CNT@MXene three-dimensional array,multiple active sites Fe-NC,Co-NC and pyridine nitrogen synergistically,through the VASP structure model,DFT to calculate the free energy of reaction to determine the reaction mechanism.And to study the effect of different temperatures and metals on the catalytic performance,and analyze the LSV curve of F e-Co/CNT@MXene-T,where FeCo/CNT@MXene-8 has a half-wave potential of 0.85 V,which is better than commercial Pt/C The half-wave potential of 0.83 V has more excellent catalytic performance,and the prepared catalyst has good stability and methanol resistance.In the 30,000 second test,the attenuation is only 9.8%compared with Pt/C.At the same time,the prepared catalyst has better performance.The assembled liquid zinc-air battery has an open circuit voltage of 1.5V,a specific capacity of 754 mAh g-1 Zn and an energy density of 138 mW cm ’2,and can exhibit a charge-discharge cycle stability of 375 h.To further study the performance of the catalyst in the solid-state flexible zinc-air battery,use polyacrylamide(PAM)as the solid electrolyte to prepare a sandwich solid-state flexible battery with an open circuit voltage of 1.42 V and an energy density of 16mW cm ’2.The battery in series can light up the LED light.And has a longterm cycle stability of 22 h,which provides a good application prospect for the energy supply of flexible devices.