Preparation Of Carbon Nanotubes Composite And Its Application In Cathode Materials Of Aluminum Ion Batteries And Oxygen Reduction

With the increasing global energy depletion,consumption of fossil energy in the 21st century increases literally.Scientists have recently focused their attention on the research of clean renewable energy.Report on high-performance electrode materials is of great significance in solving energy storage and conversion utilization.Carbon nanotubes have high mechanical strength,high specific surface area,great electrical conductivity and electrochemical stability,thus can be widely used as a supporting material in the field of electrochemistry.In this paper,multi-walled carbon nanotubes（MWCNTs）were used as supporting materials,Co₉S₈ and ZIF-67 were used as active materials,and carbon nanotube composites were prepared by the hydrothermal and calcination processes as electrode materials.The carbon nanotube composites were characterized by XRD,XPS,HR-TEM and TGA.The Co₉S₈/carbon nanotube composite was used as a positive electrode material for an aluminum ion battery,and assembled into a battery in a high purity argon glove box.Through the（LAND）series battery test system,the galvanostatic charge/discharge test was carried out at the current density of 60 mA g^-1.The specific capacity of the Co₉S₈/carbon nanotube electrode material was 79 mAh g^-1;the current density was 120mAg^-1.The specific capacity of the Co₉S₈/carbon nanotube electrode material according to the galvanostatic charge/discharge test was 58 mAhg^-1,and this composite electrode material possessed a good cycle stability.The results shown that the Co₉S₈ was combined well with carbon nanotubes,which could improve the conductivity,specific surface area and battery performance of the Co₉S₈ material.The ZIF-67/carbon nanotube composite was used as an oxygen reduction reaction（ORR）electrode material,whose oxygen reduction reaction electrocatalytic performance was measured by CHI660E electrochemical workstation.The results shown that the half-wave potential of the electrode material was-0.249 V（vs.Ag/AgCl）at a scan rate of 5 mV s^-1 and an electrode rotation rate of 1600 rpm,which was close to the commercial 20 wt%Pt/C catalyst.The ZIF-67 was integrated with well carbon nanotubes,which could improve the conductivity,specific surface area and battery performance of the ZIF-67 material.In addition,reduction of ZIF-67/carbon nanotube composite by sodium borohydride（NaBH₄） reduces the valence state of cobalt（Co）and reduces the electrocatalytic overpotential of oxygen reduction reaction,in order to improve electrocatalytic performance.