Active supercapacitor material
In the last decade, supercapacitors with an energy density of ~110 Wh L-1 at a power of ~1 kW L-1 were developed and used, utilizing the open framework of graphene-related structures. Our SC-GN3 material combining graphene-type layers with tetrahedral C-C bonds and nitrogen superdoping (16 %) is a new graphene derivative, synthesized from graphite fluoride. SC-GN3 delivers record energy densities of 200 Wh L-1 (power 2.6 kW L-1) and 143 Wh L-1 at 52 kW L-1.
The electrochemical properties of SC-GN3 in a symmetric electrochemical cell using the EMIM-BF4 ionic liquid as the electrolyte are shown below. For benchmarking, the porous carbon (PC) material and Kuraray carbon (KC) material (the latter one widely utilized and used in commercial supercapacitors) were evaluated under identical conditions.
SC-GN3 has superior performance in both volumetric and gravimetric properties, owing to the high mass density of SC-GN3 material.
Volumetric performance and stability of system (SC-GN3 cell has 100% retention after 10 000 cycles at high current density) are particularly important for devices in the modern portable energy storage landscape.
Our SC-GN3 material also performs well in commercially relevant cells, such as the coin cells, which can lighten up a 4V diode.