Controlled Synthesis Of FeCo-NC Materials And Its Application In Aluminum-Air Batteries

Aluminum-air batteries have the advantages of low cost,light weight,high specific energy,environmental friendliness,fast mechanical charging.It expected to become one of the energy technologies of the next generation of electric vehicles.However,the slow ORR of its cathode limits the overall conversion efficiency of the battery(such as power density and energy density).The precious metal platinum and its alloy materials are regarded as the best ORR catalysts,but they have the disadvantages of less resources,high cost and poor durability.Hindering the large-scale application of aluminum-air batteries.Therefore,the development of cost-effective,highly active non-noble metal catalysts to replace platinum-based metal materials for aluminum-air batteries is currently a hot research topic.Transition metal-nitrogen-carbon compounds(M-NC,M=Co,Fe)have excellent ORR activity,low cost,and long life,they have great potential for replacing platinum-based catalysts.In this thesis,through the design,preparation,research of highly active FeCo-NC materials.The structure,morphology and chemical state of FeCo-NC catalyst were analyzed.And the catalyst activity mechanism was thoroughly explored.Subsequently,it was used as a raw material to assemble an aluminum-air battery to explore the overall discharge performance of the aluminum-air battery of the catalyst.The main research are as follows:(1)Design of binary FeCo-NC/CNT composite material:A simple and economical synthesis method was developed.Using inexpensive Fe/Co/Zn salts and formamide as raw materials,a network of interconnected carbon nanotubes generated in situ on the basis of nitrogen-doped carbon materials was used to construct highly dispersed Fe-Co dual sites.Through fine control of Fe/Co composition,the composite materials with high conductivity,large specific surface area and rich pore structure are helpful to improve the performance of ORR.(2)Excellent ORR performance:By optimizing the synthesized bimetallic formamide derivative FeCo-NC(f-FeCo-NC-12),it exhibits excellent ORR performance in alkaline solutions,with an initial potential of up to 1.05 V,half-wave potential.It is as high as 0.91 V,which is 50 mV and 40 mV higher than the initial potential and half-wave potential of the Pt/C catalyst.(3)Significant aluminum-air battery performance:f-FeCo-NC-12 is used to assemble aluminum-air battery,its battery performance is better than Pt/C cathode.The open circuit voltage and specific power are as high as 1.88 V and 188 mW·cm-2.Respectively,and the discharge voltage is about 1.7 V at a current density of 10.0 mA·cm-2.In comparison,the open circuit of the Pt/C catalyst assembled battery the voltage and specific power were 1.82 V and 176.7 mW·cm-2.And the discharge voltage was about 1.64 V at a current density of 10.0 mA.cm-2,both lower than the f-FeCo-NC-12 catalyst.The study found that the application of f-FeCo-NC-12 catalyst instead of Pt/C catalyst in aluminum-air batteries has profound research value.