Kinetic enhanced bio-derived porous carbon tile laminate paper for ultrahigh-rate supercapacitors

Abstract

Porous activated carbon is an attractive supercapacitor electrode material, but its problems, i.e., lengthened ion paths inside large particles, unsatisfactory conductivity caused by the use of insulating binder and rather low packing density, greatly limit their gravimetric/volumetric performance especially at ultrahigh charging rate. Herein, a novel, free-standing, compact carbon paper electrode (0.8 g cm−3) with ultrahigh conductivity (198 S cm−1) and porosity (1098 m2 g−1) is designed by layer-stacking the bio-derived porous carbon tile (CT) with ca. 0.7 μm in wall thickness together with a few of single-walled carbon nanotubes (SWNTs). Ascribed to its kinetically fast ion/charge transfer paths, i.e., ion access shortcuts in plane of quasi-2D layered CTs, interconnected interlayer channels and SWNT-bridged conductive network, this compact laminate electrode delivers remarkable rate performance without sacrificing volumetric capacitance (218 F g−1/174 F cm−3 at 20 A g−1). Significantly, such outstanding rate capability is till maintained in as-assembled symmetric supercapacitor in aqueous (60% capacitance retention at 3000 mV s−1) and organic (60% capacitance retention at 1000 mV s−1) electrolyte, suggesting great promising of our designed carbon electrode for ultrafast charging.