The Sulfur-doped Carbon Nanoparticles As Air Cathode For Lithium-oxygen Batteries

With the widespread use of small intelligent devices and the replacement of traditional fuel vehicles by electric vehicles,the performance requirements of batteries are getting higher and higher.Although the batteries currently used meet the energy requirements of some electronic devices,for large electric devices such as new energy vehicles,Higher energy density is required to meet customer mileage requirements.Therefore,lithium-air batteries attract more and more attention as next-generation batteries,because lithium-air batteries have a higher energy density of 11400 Wh kg^-1?with oxygen Calculated to exclude?,almost equal to the energy density of gasoline.In this paper,carbon material is chosen as the cathode substrate because of its light weight,excellent electrical conductivity,low price,and good catalytic performance.It was first applied on fuel cells and found to have good ability to catalyze ORR and OER,but carbon materials.As a lithium-air battery cathode catalyst,the battery discharge potential is too high,by-product production,more importantly,because the capacity attenuation is too fast,so that it can not be practically app lied,it is desirable to change the carbon material properties to reduce the capacity attenuation,usually made of carbon.Nanotubes,or graphene,etc.,a relatively simple method is doping,which changes the original structure of carbon by doping and changes its properties.As a doping element,elemental sulfur is simple to operate and has a rich sulfur storage.In this paper,carbon nanoparticles were prepared by DC arc method,and sulfur-doped carbon nanoparticles were prepared by pipe furnace furnace.The carbon nanomaterials prepared by DC arc method were characterized by XRD and SEM.And EDS characterization,it was confirmed that sulfur was incorporated into carbon,and the sulfur incorporation amount was about 5%.The prepared sulfur-doped carbon nanoparticles were ground and diluted and loaded on carbon paper as a lithium empty battery cathode material.The sulfur-doped carbon cathode and the carbon cathode were electrochemically tested.The CV diagram showed that the ORR activity of the sulfur-doped sulfur was higher than that of the un-sulfur-doped cathode,indicating that the sulfur-doped catalytic property is better than the non-sulfur-doped carbon material.The voltage limit is 2-4.5 V for the first charge and discharge curve.When the current de nsity is limited to 50,150,200 mA·g^-1,the corresponding specific capacities are 3600,2100,1400 mAh·g^-1,respectively.Compared with the un-sulphurized carbon material,the specific capacity and voltage are better at the corresponding current density.Although the current density increases,the electric charge-discharge potential difference increases,but the increase is much smaller than the carbon material.?The potential difference of the sulfur-doped carbon material is about 1.5 V,and the potential difference of the carbon material electrode is about 1.65 V?.This relatively low charge-discharge potential difference indicates that the sulfur doping can improve the catalytic performance of carbon,especially for the oxidogen?ORR?process,improving carbon.The catalytic properties of the material have a significant effect.The sulfur-doped carbon nanomaterial electrode has a current curve of constant current of 100 mA·g^-1 and a defined capacity of 500 mAh·g^-1.The sulfur-doped carbon nanoelectrode circulates for 14cycles,while the carbon nanoelectrode circulates for 11 cycles,indicating its circulation.Sex has improved.The characterization of the electrode sheet in the infrared state of the charge and discharge products indicates that the lithium peroxide of the discharge product can form and decompose with charge and discharge,indicating that it has good cycle ability,and verified the catalytic activity of sulfur-doped carbon,but by XRD and FT-IR indicates that there are also some by-products produced on the load cathode,which may also be responsible for limiting cycle life and charge-discharge specific capacity.Through the analysis of experimental results,it is shown that sulfur-doped carbon can improve the catalytic performance in lithium-air batteries.