A glucose bio-battery prototype based on a GDH/poly(methylene blue) bioanode and a graphite cathode with an iodide/tri-iodide redox couple

► The glucose bio-battery consists of a graphite cathode (I-/I3-) and PMB bioanode. ► MWCNTs can improve the deposition amount of PMB and the electrooxidation of NADH. ► A glucose bio-battery with high fill factor (0.706) is achieved. ► The rate-limiting electrode for the bio-battery is identified as the bioanode. ► A maximum power density of 2.43 μW/cm2 at 25 °C is achieved.