Microstructured Anodes by Surface Wrinkling for Studies of Direct Electron Transfer Biofilms in Microbial Fuel Cells

Abstract A method for producing hierarchical wrinkled gold surfaces is used to continuously change characteristic microstructure dimensions of a bioanode in a microbial fuel cell, while conserving the total electroactive surface area and material chemistry. Using this approach, the effect of anode topography on power outputs from direct electron transfer from Geobacter sulfurreducens biofilms can be isolated and studied without the competing effects associated with additive manufacturing. Despite having the same electroactive surface area for all structured anodes, tall and well‐spaced features perform best. Anodes with the shortest, most closely packed structures, on the other hand, do not perform any better than planar surfaces with the same footprint and lower electroactive surface area. It is postulated that large interfold spacing provides better electrical contact between the biofilm and the electrode via improved bacterial packing density at the electrode surface. Rigorous attention to structural dimensions rather than total electroactive surface area is proposed as an important direction for future bioanode optimization in microbial fuel cells containing direct electron transfer electroactive biofilms.