Synthesis free‐template highly micro‐mesoporous carbon nanosheet as electrode materials for boosting supercapacitor performances

Abstract

Porous carbon 2D nanosheets (CNSs) with micro-mesopores interconnected are indispensable for energy conversion systems and storage applications. Herein, we synthesize free-template highly micro-mesoporous carbon nanosheet as electrode material for boosting supercapacitor performances. The activated carbon nanosheets derived from bio-waste were prepared by chemical impregnation followed by high-temperature pyrolysis without hard/soft/salt template-assisted and free-binder adhesives. Garlic skin wastes were selected as a precursor. Furthermore, activated carbon was designed in pellet/coin solids without the addition of binder materials. The porous carbon pellets exhibit a thin 2D nanosheet structure of 15 nm followed by unique wooden labyrinth-like and rod-like structures. The result showed that the impregnation of different chemical concentrations increases the surface area to 273% as high as 1002.920 m2 g−1 with a total volume of 1.3270 cm3 g−1. Moreover, the mesoporosity dominated 66.4%, followed by sub-ultra-micropores. In the symmetric supercapacitor, the carbon nanosheet boosted the specific capacitance almost 3-fold to 320.95 F g−1 in the aqueous electrolyte of 1 M H2SO4. The supercapacitor cell has a high energy density of 43.12 Wh kg−1 and power density of 161.99 W kg−1 at a constant current density of 1.0 A g−1. This work proposes a more effective, green, efficient, and controlled approach to obtain bio-waste-based porous carbon 2D nanosheet with a controlled pore structure for energy conversion and storage systems. Novelty Statement The novelty of this study is a green synthesis has possessed highly micro-mesopores nanosheet bio-waste. 2D nanosheet was prepared free-template and free-binder. Sub-ultra-micropores were confirmed with dominated mesoporosity of 66.8%. Carbon nanosheet boosted specific capacitance almost 3-fold to 320.95 F g−1.