Selection of Graphite Pencil Grades for the Design of Suitable Electrodes for Stacking Multiple Single-Inlet Paper-Pencil Fuel Cells

We present a single-inlet paper-pencil based microfluidic fuel cell which works on the capillary driven fluid flow of a mixture of fuel (formic acid) and electrolyte (dilute sulfuric acid) solutions as a single entity. Different types of pencils are used to prepare the graphite electrodes to observe their effect on the fuel cell performance. The graphite electrodes are porous and act as a gas diffusion electrode which breaths in oxygen directly from the quiescent air and out CO2 from the cell. The paper fuel cell also fabricated in different dimensions and connected as cell-stacks to enhance its performance. The paper-pencil device generates maximum open circuit potential of similar to 2.5 V in series combination and maximum current density of similar to 82 mA cm(-2) and power density of similar to 100 mW cm(-2) in parallel combination. Later, rGO-Cu/CuO nanocomposite embedded electrodes are used to observe their effect on the device performance.