Stacked Microfluidic Paper Ethanol Fuel Cell with a Variety of Rapidly Prototyped Electrodes: Optimization and Performance Investigation

Paper devices are cutting-edge platforms for creating miniaturized energy conversion, storage, and sensing devices. In such devices, co-laminar flow and embedded capillaries not only eliminate membranes and external pumps but also allow widespread application. The fabrication, optimization, and characterization of a microfluidic paper ethanol fuel cell (MPEFC) has been demonstrated in the presented study. The MPEFC uses ethanol and sodium hydroxide as fuel and sulfuric acid as electrolytes. Numerous experiments have been conducted to improve the performance of MPEFC by optimizing various electrode types such as laser-induced graphene (LIG), Ag nano-ink/LIG, buckypaper, Ag nano-ink/buckypaper, and two different 3D printed conductive electrodes. Different electrolyte concentrations (NaOH-0.25, 0.5, 1 m) have been studied to understand the impact on ion conductivity. It is observed that the developed MPEFC with multiwalled carbon nanotube -buckypaper as an optimized electrode, 1 M ethanol with 0.5 m NaOH as anolyte, and 1 m H2SO4 as electrolyte delivered the best performance with a current density of 1756.2 mu A cm(-2), and power density of 72.62 mu W cm(-2), at a stable open-circuit voltage of 235 mV with Gr 1 cellulose microchannel with parallel stacked configuration. This work demonstrates the effective enhancement of the output power with inexpensive individual MPEFC.