Study On Preparation And Electrochemical Performances Of Biomass Carbon And Nickel Manganese Compound Based Electrode Materials

The asymmetric supercapacitor(ASC)as the gerneration of supercapacitors,has the advantages of high energy density and high power density.Electrode materials are the key factor to the performance of supercapacitors,now electrode materials have disadvantages such as low energy density of porous carbon materials,high cost of noble metal oxides,and poor stability of conductive polymers.Therefore,the research and development of electrode materials with low-cost and high-performance are the key to the commercialization and sustainable development of supercapacitors.In this study,ginkgo leaf derived nitrogen-doped carbon material was prepared and used as the electrode material in the supercapacitor.Because of hierarchical porous structure and high nitrogen content,ginkgo leaf derived nitrogen-doped carbon material has better electrochemical performances than the un-doped ginkgo leaf derived carbon material,and the maximum specific capacitance can reach 345 F?g-1.In addition,it has been applied as a negative electrode material to fabricate ASC.This ASC achieved a maximum energy density of 44.2 Wh?Kg-1 and a good cycling stability.These performances are superior to those of similar carbon materials reported in some literatures,indicating that this nitrogen-doped carbon material has a good application potential in fabricating high-performance asymmetric supercapacitors.Pseudocapacitive materials have good capacitance output abilities,and are one type of the best candidate materials for ASC.In the face of the practical application in the future,the most critical issue is how to achieve a reasonable constructing of hierarchically ordered hybrid nanostructures through a simple process to facilitate the maximum utilization of active materials and improve the electrochemical performances.To achieve this goal,we developed a one-pot two-stage hydrothermal method to prepare a Ni Mn-LDH@Ni3S2 electrode with nanosheet/nanorod hybrid structure grown in situ on nickel foam.Because the nanosheet surface is rough,and the hybrid array has a rich porous structure,the highest specific capacitance of hybrid electrode reached 2703 F?g-1 at the current density of 3 A?g–1.This should also benefit from the synergistic effect between the Ni Mn-LDH nanosheet and the Ni3S2 nanorod.Furthermore,the maximum energy density of ASC,with this material as the positive electrode and poplar-derived carbon material as the negative electrode materials,can reach up to 57 Wh?Kg-1.And this ASC also show a good cycling stability.