Laser direct writing O/N/S Co-doped hierarchically porous graphene on carboxymethyl chitosan/lignin-reinforced wood for boosted microsupercapacitor

Carbon materials with multiple heteroatoms co-doping and hierarchically porous structures have attracted great attention as promising electrode-active materials for supercapacitors. In this paper, an efficient, green, and low-cost strategy is reported to produce O/N/S co-doped hierarchically porous graphene, using laser direct writing on carboxymethyl chitosan (CMCS)/sodium lignosulphonate (SLS) reinforced wood. The resultant materials possess a typical three-dimensional (3D) framework composed of interconnected micro-, meso- and macropores, a large specific surface area, together with rich heteroatoms doping (13.72 wt% for O, 2.06 wt% for N, and 1.68 wt% for S). These superior features have afforded the as-fabricated microsupercapacitor (MSC) with an excellent areal capacitance of 82.1 mF cm−2 at 0.1 mA cm−2 and correspondingly high energy density of 7.3 μWh cm−2. Moreover, the MSC has good cycling stability (retaining 84.3% of capacitance after 10000 cycles) and favorable modular integration capabilities. Accordingly, this facile preparation of multiple heteroatoms-doped porous graphenes from various renewable and eco-friendly biomass precursors offers promising prospects for low-cost mass production of graphene-based sustainable high-performance electrochemical energy storage.