Towards high performance of supercapacitor: New approach to design 3 D architectured electrodes with bacteria

A novel approach of preparing high performance electrodes for supercapacitors was demonstrated by pyrolyzing the hierarchical composite prepared from organic waste and biological resources. Sponge waste was utilized as a carbon source for preparing the interconnected structured electrode materials with high porosity, and needle-like ZnO particles were directly grown on the sponge in order to effectively capture bacteria cells as well as improve the overall redox reactions. The bacteria (E. coli O157:H7) were isolated on a ZnO/sponge composite to endow electrochemically beneficial inherent nitrogen existing in bacteria, as well as to provide bio-templates with the aids of these structural and material benefits, the carbonized material prepared from the bacteria loaded on the ZnO/sponge composite showed a significantly enhanced specific capacitance of 133 F g⁻¹ (at 0.2 A g⁻¹) and an excellent cycle retention of 89% over long-term cycles (5000 cycles). Our strategy of utilizing recyclable and biomass-derived materials not only can effectively improve the electrochemical performances of supercapacitors but also open an innovative way to address the systemic issues underlying the carbonaceous materials used in supercapacitors.