Synthesis And Properties Of Nanocatalysts For Zn-air Battery

Zn-air battery has become one of the hot spots in the field of power battery owing to the advantages of high energy density,low cost,safety and eco-friendly environment.Electrode material is the core factor for Zn-air battery.Especially,cathode catalyst has a decisive influence on the performance of the Zn-air battery.Therefore,the cathode catalyst become the focus of research in the field of Zn-air battery.However,it is difficult for researchers to design and synthsize highly efficient cathode catalyst.So far,noble metal catalyst such as Pt and Ir with the best catalytic activity suffer from scarcity,high cost and single catalytic function,limiting its large-scale commercial application.Hence,it is important to develop non-noble metal catalyst with the advantages of costliness,efficiency and durability in the field of Zn-air battery.Here,transition metal catalyst with the advantages of abundant reserve and low price is one of the best candidates.Unfortunately,low catalytic activity and poor stability prevent the application of this type of catalysts.Thus,this article attempt to design and synthesize a series of nitrogen doped carbon material supported transition metal nanoparticles(M-N/C)bifunctional catalysts with the advantages of low cost,eco-friendly environment,high activity and high durability to change this situation.The corresponding catalysts' synthesis mechanisms were proposed by systematically studying the influence of synthesis conditions on the composition,microstructure,and crystal structure of the catalysts.More importantly,corresponding catalytic mechanism was proposed to guide the synthesis of the catalyst by studying the factors of hetero element doping,bimetallic alloying and ultrathin carbon layers influencing on the catalytic activity of the catalyst,aiming at enhancing the performance of catalyst.Through the systematic study of the catalytic activity of M-N/C catalyst,a Zn-air battery system was constructed using the prepared catalysts as cathode catalyst.Meanwhile,the electrochemical performance of the Zn-air battery was comprehensively tested and analyzed.Then,an exploratory study was carried out in order to the practicle application of Zn-air battery.The obtained results were summarized as follows:(1)Nitrogen doped graphene-like carbon layers wrapped cobalt nanoparticles single transition metal catalsyst and nitrogen,sulfer co-doped graphene-like carbon layers supported carbon nanotubes wrapped cobalt nanoparticles single transition metal catalsyst were successfully prepared by liquid-phase coordination and high-temperature calcination methods in oder.The micromorphology of the catalysts could be effectively adjusted by adjusting the ratio of reactants.Furthermore,the effect of heteroelement doping and micromorphology on the catalytic activity of the catalysts and the performances of the Zn-air battery was systematically studied.(2)On the basis of the above-mentioned single metal catalyst,three kinds of nitrogen doped carbon materials supported binary alloy particle catalysts including FeSb,CoSb and FeCo were designed and synthesized by selecting a reaction precursor with special molecular structure.In generally,the composition and micromorphology of the catalyst can be effectively controlled by changing the reaction condition.And,the composition and micromorphology directly affect the activity of the catalyst.So,the performace of catalyst could be controllable regulated and optimized by the reaction condition.Besides,it has been verified that the bimetallic synergistic effect between binary alloy particles could effectively help to improve the catalytic activity of the catalyst by studying on electrocatalytic property and mechanism.(3)Sum up above catalytic mechanisms and structure features of nitrogen doped carbon materials supported transition metal nanoparticle(M-N/C)catalysts,nitrogen doped ultrathin carbon layers coated metal cobalt nanoparticle catalyst is considered to be the better catalyst with outstanding catalytic performance.The results shown that the external carbon materials were only 3?4 nitrogen doped graphene-like carbon layers,the catalytic activity of catalyst could be affected and adjusted by the micromorphology of the catalyst which could be altered by regulating the heat treatment temperature.Due to the synergistic effect between the external nitrogen doped ultrathin carbon layers and the internal cobalt nanoparticles,the type of catalysts possessed the most outstanding catalytic activity in all prepared catalysts.Besides,the analysis of the synergistic effect had further enriched the research on related catalytic mechanisms.(4)An exploratory study,structural design of 12 V Zn-air battery pack,was carried out for the practical application of Zn-air battery.Meanwhile,the concept,structure and electrochemical performance of Ni-Zn/Zn-air hybrid battery system was explored to further expand the application of hybrid battery in new energy vehicles and other fields.