Interface Engineering of Biomass-Derived Carbon used as Ultrahigh-Energy-Density and Practical Mass-Loading Supercapacitor Electrodes

The development of flexible electrodes with high mass loading and efficient electron/ion transport is of great significance but still remains the challenge of innovating suitable electrode structures for high energy density application. Herein, for the first time, lignosulfonate-derived N/S-co-doped graphene-like carbon is in situ formed within an interface engineered cellulose textile through a sacrificial template method. Both experimental and theoretical calculations disclose that the formed pomegranate-like structure with continuous conductive pathways and porous characteristics allows sufficient ion/electron transport throughout the entire structures. As a result, the obtained flexible electrode delivers a remarkable integrated capacitance of 6534 mF cm(-2) (335.1 F g(-1)) and a superior stability at an industrially applicable mass loading of 19.5 mg cm(-2). A pseudocapacitive cathode with ultrahigh capacitance of 7000 mF cm(-2) can also be obtained based on the same electrode structure engineering. The as-assembled asymmetric supercapacitor achieves a high areal capacitance of 3625 mF cm(-2), and a maximum energy density of 1.06 mWh cm(-2), outperforms most of other reported high-loading supercapacitors. This synthesis method and structural engineering strategy can provide materials design concepts and a wide range of applications in the fields of energy storage beyond supercapacitors.