Metal Phosphide And Heteroatom Codoped Porous Carbon Material And Its Energy Storage Performance

The shortage of fossil energy and the gradual destruction of the environment have triggered the thinking of the development of human society.In order to meet people’s modern life travel needs and solve environmental problems,the development of new energy sources is urgent.Porous carbon composite materials have been used in many fields due to their structural advantages and good catalytic performance.The porous carbon composite material has a high specific surface area and high porosity.The three-dimensional space displayed inside can be used as a good carrier.In electrochemical energy storage,it acts as an excellent electron transport conductor,ensuring the efficient and rapid progress of the redox reaction.It is of great significance to carry out in-depth research in the field of energy storage.In order to obtain porous carbon composite materials with high performance,researchers have developed many preparation methods:activation method,template method,in-situ synthesis method,ex-situ synthesis method,etc.In this paper,a porous carbon composite material（PPNPCS）co-doped with nickel phosphide and phosphorus atoms was successfully prepared by a one-step method.The porous carbon composite material was composed of multi-level pores with a specific surface area of up to 1650 m² g^-1,By adjusting the ratio of raw materials,the micro-control of the pore structure and the particle size of the metal phosphide metal compound can be achieved.The catalytic activity of nickel phosphide and phosphorus atoms was further investigated.According to the structural advantages of the porous carbon composite itself,it was used as a modified separator material in lithium-sulfur batteries.In this paper,XRD,TEM,SEM,XPS,etc.are used to characterize the structure of the material,and LAND,electrochemical workstation and other electrochemical instruments are used to study the performance of the composite material.The research results show that Ni₂P carbon nanospheres and P are evenly distributed inside and outside the porous carbon material,and the polysulfides in the electrolyte are captured by the polar effects of the two to prevent the shuttle of the polysulfides to the negative electrode.At the same time,the three-dimensional conductive matrix provides enough space to accommodate more polysulfides,and the internal micropores also have a certain physical adsorption effect on the polysulfide intermediates.Benefiting from the synergy of Ni₂P,P element and porous carbon structure,PPNPCS@PP exhibits a high initial capacity(1365 mAh g^-1)and stable long-cycle performance(after 1.0cycle at 1.0 C,it is still Good cycling performance of 496 mAh g^-1).In order to further develop such porous carbon composite materials,In this paper,the same preparation scheme was used to successfully synthesize CoP and P atom co-doped porous carbon composites（PPCPCS）.PPCPCS has the same structural characteristics as PPNPCS.with the same characterization and testing methods,The specific surface area of the porous carbon composite material was as high as 1120-1848 m² g^-1,and active particles with different particle sizes were evenly distributed in the material.The results show that PPCPCS composites with different catalyst contents exhibit different electrochemical activities and stability in different electrolyte solutions.The HER performance was studied under acidic conditions.At a current density of 10 mA cm^-2,the overpotential of PPCPCS-30 was 188 mV and the Tafel slope was 96 mV/dec.The OER performance was explored under alkaline conditions.The over-potential of PPCPCS-30 was 1.46 V at a current density of 10 mA cm^-2,and the Tafel slope was 279 mV/dec.