Exfoliating Waste Biomass into Porous Carbon with Multi-Structural Levels for Dual Energy Storage

Waste biomass-derived carbon materials are attracting widespread attention in energy devices due to their renewable environmental protection and heteroatom-rich functionalization. In this work, we propose the preparation of N/O self-doping 3D cage-like porous structures and 2D porous carbon nanosheets by one-step carbonization of activated peanut oil residues with non-toxic K2CO3 at different temperatures (PKs). The fabricated porous carbon materials own a higher specific surface area (1657-2920 m2 g-1), higher nitrogen (1.38-4.41 at. %) and oxygen doping (2.48-4.98 at. %), and higher degree of graphitization. The as-resulted PK-800 possesses a 3D cage-like porous structure, and the electrode at high loads of 12.5 mg cm-2 can achieve an excellent area specific capacitance of 4400 mF cm-2 at 0.5 A g-1. The symmetric components of PK-800 have an ultra-high energy density of 60.31 W h kg-1 at 372 W kg-1 in 1 M TEMATFB/PC. Besides, when applied to the Li-ion battery anode, the prepared highly graphitized 2D porous carbon nanosheets of PK-900 have a high reversible capacity of 580 mA h g-1 at 0.1 A g-1 after 200 cycles. This study proposes a feasible method to activate waste biomass by carbonization in one step and exploit it layer by layer into the desired carbon material for energy storage.

Automated summary

This study proposes a feasible method to activate waste biomass by carbonization in one step and exploit it layer by layer into the desired carbon material for energy storage. The fabricated porous carbon materials possess a higher specific surface area, nitrogen and oxygen doping, and a higher degree of graphitization.