Sustainable production of Microalgae-Derived turbostratic graphene via flash Joule heating

Sustainable graphene production remains challenging due to the high energy and environmental costs of conventional methods. This study demonstrates a renewable microalgae-based route for flash Joule heating synthesis of turbostratic graphene, elucidating the energy-structure-performance correlation toward low-carbon graphene manufacturing. Among the tested durations, a 500  ms flash yielded the best-performing sample (MDTG-500), which has a low defect density (Raman I_D/I_G = 0.38), a large interlayer spacing (0.344  nm), and a turbostratic few-layer structure confirmed by Raman, XRD, and TEM analyses. MDTG-500 also demonstrates excellent dispersibility, high electrical conductivity (63.8 S cm^-1), strong broadband absorbance (∼89 %), and good thermal stability. When applied in supercapacitors, MDTG-500 exhibits ideal electric double-layer capacitance behavior, with a capacitance retention of 79.8 % from 1-100 mV s^-1, a high areal capacitance of 84 µF cm^-2, and outstanding cycling stability (106 % capacitance retention after 1000 CV cycles). This work provides a sustainable, efficient, and tunable strategy for producing high-purity turbostratic graphene from microalgae, offering new insights into biomass valorization and advanced carbon material design.