Hydrothermal synthesis of reduced graphene oxide for supercapacitor electrode materials and the effect of added sodium alginate on its structure and performance

With the advantages of high power density, long cycle life, and fast charging, supercapacitor has become a research hotspot in recent decades. Graphene is considered as an ideal electrode material for supercapacitors because of its special electrical and mechanical properties. In order to prepare graphene that can be used as supercapacitor electrode materials, various methods are proposed, among which hydrothermal method is mostly used, but graphene prepared using this method always agglomerates seriously and rarely have pores that might be helpful for the increase of electrochemical performance. Therefore, sodium alginate, which has strong hydrogen bonding with graphene oxide and might be helpful to optimize the structure of graphene in the reduction process, should be considered. In this paper, by optimizing the ratio of reducing agent and graphene oxide in hydrothermal reaction, two samples that exhibit better performance were obtained. On this basis, sodium alginate was added in the process of hydrothermal reduction of graphene oxide, and the effect of it on the structure and properties of graphene was explored. The results demonstrate that pore structure is formed and the rate performance is improved obviously by adding sodium alginate.