The Preparation Of Carbon-based Material And Application Of Vanadium Battery Electrode Materials

Vanadium Redox Flow Battery(VRB)has recently received considerable attention because of its excellent characterizations,such as long cyclic life,flexible design and high reliability.As one of the key parts of the battery,the electrode provides places for the redox reactions.It has been found that the existed oxygen functional group and the electrical conductive property of the carbonous electrode materials play important roles to promote the redox reaction on the elctrode,thus greatly enhancing the performance of VRB.Herein,through a green and simple synthesis method,which is hydrothermal method,gluconic acid modified graphene and N atom doped multiwall carbon nanotube were synthesized,and further utilized as electrode material for the construction of VRB.Based on the above mentioned,the content of the thesis was summarized as follow:(1)A hydrophilic gluconic acidmodified graohene(GA-GP)was firstly designed and synthesized by a facile and environmentally friendly hydrothermal method.The glucose that added into the reaction system played important role during the synthesis of the graphene.It is not only the reductant of the graphene oxide,but also acted as a precursor of the modifier of the graphene.The structure,morphology and electrochemical properties of the as synthesized GA-GP were characterized by UV-Vis,FT-IR,SEM,XPS and cyclic voltammetry(CV).Because of the conductivity of the graphene,and the oxygen-containing functional groups that existed onto the graphene nanosheet,the GA-GP based VBR exhibited good performance.For instance,the capacity and voltage efficiency of the GA-GP based VBR were 80 mAh and 91.6%,which were much larger than that of the GO based VRB.(2)Using dicyandiamide as a N source,N doped carboxylic acid carbon nanotubes(N-CNT-COOH)was synthesized through a facile hydrothermal method.The echo friendly hydrothermal process can not only achieve the dopping of the heteroatom N into carbon nanotube,but also can well maintain the existed oxygen-containing functional group of CNT-COOH.The structure,morphology and electrochemical properties of the as synthesized N-CNT-COOH were characterized by UV-Vis,FT-IR,SEM,XPS and cyclic voltammetry(CV).Due to the enhanced conductivity of the carbon nanotube,N-CNT-COOH based VBR exhibited better performance than CNT-COOH based VRB.For instance,the capacity,voltage efficiency and energy efficiencyof the N-CNT-COOH based VBR were 51 mAh,91.6%and,90.4%respectively,which were much larger than that of the CNT-COOH based VRB.