Bacteria promoted hierarchical carbon materials for high-performance supercapacitor

Abstract

To keep up with the appeal for energy-saving and environmental protection, scientists have turned to nature for inspiration in developing relatively green approaches for the fabrication of novel materials. With this in mind, we demonstrate herein a green and facile method for the synthesis of bio-inspired hierarchical carbon materials with nanoscale to microscale porous structures. It is achieved by the combination of the assembly of graphene oxide on the surface of bacteria with a freeze-casting technique. More importantly, the novel multi-level architectures and the bacteria component endow these hierarchical carbon materials with desirable specific surface areas (181.6 m² g⁻¹), rich porosity (0.74 cm³ g⁻¹) and abundant foreign atoms. These structural and compositional advantages result in higher specific capacitance (327 F g⁻¹) compared with previous reported carbon materials at the same current density, as well as large power density and good stability when the as-prepared materials are used as supercapacitor electrode materials in an aqueous electrolyte. The strategy developed in this work provides a good example for making full use of the most-abundant resources endowed by nature, opening up a new insight into designing and producing a wide range of hierarchical structures with highly promising applications in high-performance energy-storage devices.