Biologically inspired anthraquinone redox centers and biomass graphene for renewable colloidal gels toward ultrahigh-performance flexible micro-supercapacitors.

• Anthraquinone molecules and biomass graphene could be directly self-assembled into renewable colloidal gels in weakly alkaline solutions. • The self-assembly process involves hydrogen bonding, π-π stacking, and electrostatic repulsion. • The colloidal gels not only have the specific capacitance with synergistic effect but exhibit excellent rheological stability for pattern printing. • The printed micro-supercapacitors possess remarkable electrochemical areal performance and outstanding flexibility. • The integration and scalable production of micro-supercapacitors (arrays) by screen printing using the as-formulated renewable inks is demonstrated. Biomass carbon and small redox biomolecules are attractive materials for green, sustainable energy storage devices owing to their environmentally friendly, low-cost, scalable, and novel sources. However, most devices manufactured using these materials have low specific capacitance, poor cycle stability, short lifetime, complexity, and low precision of device fabrication. Herein, we report the directed self-assembly of mononuclear anthraquinone (MAQ) derivatives and porous lignin-based graphene oxide (PLGO) into a renewable colloidal gel through noncovalent interactions. These self-assembled gel electrode materials exhibited high capacitance (484.8 F g⁻¹ at a current density of 1 A g⁻¹) and could be further printed as flexible micro-supercapacitors (FMSCs) with arbitrary patterns and a relatively high resolution on specific substrates. The FMSCs exhibited excellent areal capacitance (43.6 mF cm⁻²), energy and power densities (6.1 μWh cm⁻² and 50 μW cm⁻², respectively), and cycle stability (> 10,000 cycles). Furthermore, the printed FMSCs and integrated FMSC arrays exhibited remarkable flexibility while maintaining a stable capacitance. The proposed approach can be applied to other quinone biomolecules and biomass-based carbon materials. This study provides a basis for fabricating green and sustainable energy storage device architectures with high capacitance, long-term cycling, high scalability, and high precision. [ABSTRACT FROM AUTHOR]