Preparation Of Porous Graphene Aerogel/metal Oxide Composite And Its Supercapacitor Performance

Supercapacitors have high specific energy and specific power,as well as excellent stability and environmental friendliness,so they have a wide range of applications in electric vehicles,power systems,defense industry,communications and electronics.Supercapacitor electrode material is a key factor affecting the performance of supercapacitors.Graphene aerogel?GA?is widely used in super capacitor electrode materials due to its excellent performance.However,the capacity of GA is low.Therefore,this article takes GA as the research object.The performance of GA is mainly improved through the improvement of morphology and structure and the introduction of metal oxides to prepare composite materials,so as to obtain a better graphene aerogel super.Capacitor electrode material.The research work carried out and the results are as follows:?1?This paper uses a hydrothermal reduction method to prepare a graphene aerogel?PGA?material with a porous structure by adding a foaming agent.The morphological characterization showed that the addition of foaming agent increased the specific surface area of PGA,enriched its pore structure,and made it have a better surface morphology.Electrochemical performance tests show that PGA has a significant improvement over capacitors over GA.When the current density is 1 A g^-1,the specific capacitance of PGA is 280 F g^-1,which is 86.7%higher than GA(150 F g^-1),and the cycle stability after 96 cycles is 96%.The improvement of PGA performance is mainly due to the addition of a foaming agent during the reduction process,and the use of bubbles generated by the decomposition of the foaming agent to create holes on the surface of the PGA.The improvement of the morphological structure and the enrichment of the pore structure are conducive to the improvement of specific capacitance.?2?PGA/Co₃O₄composites were prepared using PGA as the substrate.Firstly,the advantages and disadvantages of the two-step hydrothermal method and the step-by-step hydrothermal method were compared,and then the effect of Co₃O₄loading on the properties of PGA/Co₃O₄composites was explored.The morphological characterization shows that nano-sized particles Co₃O₄in the composite are uniformly supported in a three-dimensional network PGA fold structure with a porous structure.Electrochemical performance tests show that the one-step hydrothermal method is superior to the stepwise hydrothermal method,and the composites prepared when the concentration of GO and metal source is 4:1 have the best electrochemical performance.When the current density is 1 A g^-1,the specific capacitance of PGA/Co₃O₄is 520.0 F g^-1,which is 85.7%higher than that of PGA.The specific capacitance retention rate after 1000 cycles of testing is 91.9%.The improvement of composite material performance is mainly due to the introduction of Co₃O₄which brings high Faraday capacitance,and at the same time,the load of Co₃O₄can reduce the agglomeration of PGA,which is conducive to the performance of material.?3?Using a one-step hydrothermal method with PGA as the matrix,compare the effects of different metal oxide loadings on PGA performance.The results show that PGA/Co₃O₄has the highest specific capacitance(520 F g^-1)of the three different composite materials prepared at the same GO:metal source concentration ratio of 4:1,followed by PGA/Ni O(451 F g^-1),PGA/Mn O₂(342 F g^-1)has the lowest specific capacitance.At the same time,the three composite materials have good cycle stability.Comprehensive analysis shows that PGA/Co₃O₄is the best electrode material for supercapacitors when the concentration ratio of GO to metal source is 4:1.