My friend and I were discussing the extremely low energy density of modern batteries and read that food has a much higher energy density. Thus, we were considering the possibility of using biological processes to extract energy from food and use that to create an electric potential or do work in some other way.
The electron transport chain creates an electrochemical gradient and thus and electric potential using protons. If some sort of system could be devised to mimic/perform glycolysis and the citric acid cycle and also mimic the ETC membrane and necessary proteins, is it feasible/is there already research on using glucose and cellular respiration (or a similar biological process) to power electrical systems? How would this relate to fossils fuels and what scale could this be useful at?