Metal-free Al-air microfluidic paper fuel cell to power portable electronic devices

Paper microfluidic devices are innovative platforms for building miniaturized devices for energy harvesting, energy storage, and sensing applications. Such devices are reported to be used as membraneless microfluidic fuel cells to power portable electronic in a pump-less manner by leveraging the embedded capillaries and co-laminar flow. This paper demonstrates fabrication and characterization of the high-performance metal-free aluminum-air microfluidic paper fuel cell (AAMPFC). Herein, aluminum foil acts as an anode, buckypaper with built-in multiwalled carbon nanotubes (MWCNTs) acts as a cathode and sodium hydroxide (NaOH) works as an electrolyte. The novel AAMPFC is analyzed with various electrolyte concentrations, and maximum output voltage, current density, and power density are recorded. This easy-to-fabricate AAMPFC platform, costing less than US$ 0.5, is further optimized to achieve peak energies by stacking four AAMPFCs (in series and parallel) with various concentrations of electrolyte (NaOH). With parallel configuration, maximum open-circuit potential (OCP), peak current (mA/cm(2)), and power density (mW/cm(2)) of 1.32 V, 50.67 mA/cm(2) and 22.80 mW/cm(2), respectively, are observed with optimized electrolyte, while with series stacked configuration, a stable OCP of 4.10 V is measured. In a series configuration, AAMPFC generated sufficient power to powering a scientific calculator with LCD display for 3 days and 11 LEDs for 10 hours continuously. This research work provides a significant method to enhance the output power with inexpensive parameters (buckypaper, single paper microchannel) to power portable electronic devices. Further, the performance can be enhanced by investigating AAMPFC with various grades of aluminum foil in combination with different grades of porous cellulose papers.

Automated summary

This study presents the fabrication and characterization of a high-performance metal-free aluminum-air microfluidic paper fuel cell (AAMPFC) using aluminum foil and buckypaper with sodium hydroxide as an electrolyte. By optimizing multiple AAMPFCs and configuring with different concentrations of electrolyte, higher output voltage, current density, and power density can be achieved.