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

Abstract

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 μA cm−2, and power density of 72.62 μW 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.

Interchangeable Biomass Fuels for Paper-Based Microfluidic Fuel Cells: Finding Their Power Density Limits

“…More details are found in Table . This value is an order of magnitude higher than that found using stacked cells and multiwalled carbon nanotubes in buckypaper as electrodes . This output power is higher than that found for a PμFC fed by ethanol and dichromate (2.74 mW cm –2 ) and lower compared to the same system when equipped with molybdenum oxide nanorods as catalysts (6.32 mW cm –2 ) .…”

“…This value is an order of magnitude higher than that found using stacked cells and multiwalled carbon nanotubes in buckypaper as electrodes. 21 This output power is higher than that found for a PμFC fed by ethanol and dichromate (2.74 mW cm −2 ) 20 and lower compared to the same system when equipped with molybdenum oxide nanorods as catalysts (6.32 mW cm −2 ). 20 Therefore, the ethanol PμFC proposed here adds advantages, since it delivers high power using a nontoxic liquid oxidant, metal-free cathode, and easily found commercial Pt/C NPs at the anode side.…”

“…At least to our knowledge, there are few papers regarding PμFCs fed by methanol and ethanol, − and we could not find PμFCs fed by ethylene glycol or glycerol in the literature. Ethylene glycol is a widely available alcohol that can be obtained from sugars via microorganisms.…”

“…Regarding ethanol usage, Chandra et al built an ethanol/dichromate PμFC equipped with molybdenum oxide nanorods as the anode and cathode, producing 6.32 mW cm –2 of maximum power density . Rao et al also investigated a PμFC fed by ethanol with different experimental configurations and catalysts to achieve ∼0.072 mW cm –2 . It is clear that this research field is promising and unexplored and demands improvement to fit the requirements for practical applications.…”

“…20 Rao et al also investigated a PμFC fed by ethanol with different experimental configurations and catalysts to achieve ∼0.072 mW cm −2 . 21 It is clear that this research field is promising and unexplored and demands improvement to fit the requirements for practical applications.…”