Preparation Of Novel Cathode Catalyst For Magnesium Air Cell And The Research Of Catalytic Properties

Magnesium-Air fuel cell is considered as a new type of green power to be used in the electric car with rich materials,high mass energy,environmental friendly and easy operation etc.The air electrode has significant influence about the performance in fuel cells.And the performance of the catalyst determines the performance of air electrode.So,developing a new type of catalyst with high efficient has become the important research topic in the fuel cell field.The MnO₂ catalyst with different supports is synthesis through hydrothermal.The composition,structure and microstructure of the catalysts were chara cterized.The results show that the MnO₂ is nanorod structure,and the combinations of MnO₂with MWCNT are different.The different combinations can increase the active site;improve the electrical conduction and oxygen transport.The electrochemical tests show that the reduction potential of MnO₂/MWCNTs is 0.03 V vs.Hg/HgO?50mV higher than MnO₂/C?.And peak power of MAFC is 70.47 mWcm^-2?It proves that catalyst performance of MnO₂/MWCNTs is higher than MnO₂/C.Polybenzimidazole?mPBI,ABPBI?is prepared by melting method.The catalysts?Fe-mPBI,Fe-ABPBI,Co-ABPBI and FeCo-ABPBI?are prepared through pyrolysis the polybenzimidazole and metal salt?FeCl₃·6H₂O,CoCl₂·6H₂O?.The composition,structure and microstructure of the catalysts were characterized.The results show that the catalysts are the nanosheet structure.Through the electrochemical measurements,the results show that reduction potential of Fe-mPBI is 0.03V,and the FeCo-ABPBI is 0.035V.The optimizing preparation condition is mPBI:Fe=1:2,and Fe:Co:ABPBI=1:1:2.The cells peak power density of Fe-mPBI is 67.6mWcm^-2,the FeCo-ABPBI is 71.52mWcm^-2 and the 6wt%Pt/C is 83.7mWcm^-2.The experimental results show that the performance of catalyst by pyrolysis ABPBI is higher than mPBI.The FeCo-ABPBI catalyst have a high performance due to the synergy between bimetallic.In the catalyst,pore structure can enhance the oxygen transport and improve the catalyst performance.The 3D-Fe-ABPBI,3D-Co-ABPBI,and 3D-FeCo-ABPBI catalysts have a porous three-dimensional structure which is prepared by pyrolysis the complexes formed with ABPBI,MgO nano-particles,and metal salt.The composition,structure,microstructure,and pore structure of catalysts were characterized.The results show that the catalyst is nanosheet structure and the hole is mesoporous.The optimizing preparation condition?ABPBI:MgO=1:1,Fe:Co:ABPBI=1:2:5?is obtained by electrochemical,and the best initial reduction potential of 3D-FeCo-ABPBI is 0.06V.The peak power density of assembled MAFC is78.9mWcm^-2.Experiments proved that the synergistic effect of bimetal plays an important role in increasing active site.And the three-dimensional pore structure has the effect of strengthen the oxygen transport.