关键词: 三维石墨烯气凝胶, 硫、氮共掺杂, 全固态超级电容器, 高能量密度, 高稳定性

Abstract:

Graphene is often used as electrode material for symmetric supercapacitors due to its unique advantages of ultra-high conductivity and large specific surface area. However, the Van Der Waals forces between two-dimensional graphene nanosheets easily lead to sheet stacking. Moreover, the supercapacitor assembled with aqueous solution as the electrolyte may undergo a water splitting reaction during the charging process, resulting in a limited charging voltage, which greatly reduces its energy density. Based on this, in this study, sulfur and nitrogen co-doped three-dimensional graphene aerogel electrode materials were prepared by hydrothermal method. The effects of the microscopic morphology, surface chemical properties and hydrothermal reaction time of graphene materials on the electrochemical properties of the materials were investigated. The results showed that S,N-rGO-2 provided with a well-developed pore structure and high contents of heteroatom elements. The specific capacitance was as high as 358.5F/g at a scan rate of 5mV/s, the charging voltage of the all-solid-state supercapacitor assembled with solid electrolyte can reach 1.8V, the specific capacitance was as high as 118.3F/g at a current density of 1A/g and the energy density reached 14.9Wh/kg. The specific capacitance retention rate and Coulombic efficiency were both close to 100% after 10000 charges/discharges. S,N-rGO-2 exhibited excellent electric double-layer capacitance and can be used as the potential supercapacitor electrode material.

Key words: 3D graphene aerogel, S,?N co-doped, all-solid-state supercapacitors, high energy density, high stability