A microfluidic direct formate fuel cell on paper

Abstract

We describe the first direct formate fuel cell on a paper microfluidic platform. In traditional membrane-less microfluidic fuel cells (MFCs), external pumping consumes power produced by the fuel cell in order to maintain co-laminar flow of the anode stream and oxidant stream to prevent mixing. However, in paper microfluidics, capillary action drives flow while minimizing stream mixing. In this work, we demonstrate a paper MFC that uses formate and hydrogen peroxide as the anode fuel and cathode oxidant, respectively. Using these materials we achieve a maximum power density of nearly 2.5 mW/mg Pd. In a series configuration, our MFC achieves an open circuit voltage just over 1 V, and in a parallel configuration, short circuit of 20 mA absolute current. We also demonstrate that the MFC does not require continuous flow of fuel and oxidant to produce power. We found that we can pre-saturate the materials on the paper, stop the electrolyte flow, and still produce approximately 0.5 V for 15 min. This type of paper MFC has potential applications in point-of-care diagnostic devices and other electrochemical sensors.

An improved alkaline direct formate paper microfluidic fuel cell

“…B). As expected the higher concentration of 20 % H 2 O 2 with supporting KCl produced a higher power than less concentrated 10% H 2 O 2 with KCl due to its higher reactivity with cathode catalyst . Surprisingly, the presence of the supporting electrolyte in the cathode oxidant stream with 30% H 2 O 2 produced negative voltage.…”

“…We recently demonstrated the first alkaline based paper MFC in which potassium formate and hydrogen peroxide were used as anode fuel and cathode oxidant, respectively . A power density of 2.5 mW/mg Pd was achieved with a single FC.…”

Single-use paper-based hydrogen fuel cells for point-of-care diagnostic applications

“…Furthermore, a fuel cell design inspired by the simplicity and convenience of standard lateral flow test strips has been reported, which makes it suitable for manufacturing using the same mass production methods. [9] The paper fuel cells reported up to date have employed liquid or diluted fuels such as methanol, [9] formic acid, [10,11] formate, [12][13][14] hydrogen peroxide, [15] glucose [16][17][18][19][20][21][22] or urea [23] and have been based on microbial, [23][24][25] enzymatic [16][17][18][19][20][21] or metallic catalysis. [9,[11][12][13]15] Table S1 shows a performance comparison of relevant paper-based fuel cells found in the literature.…”

Fabric‐based alkaline direct formate microfluidic fuel cells

“…While a maximum power density of 2.53 mW/cm 2 was achieved, the devices were fragile when exposed to long periods of fuel submission. Furthermore, only currents at or below 1 mA could be achieved, further limiting their application . The results served as the driving force to design a new, fabric‐based platform with the goal of increased current and durability.…”

“…Non‐flammable, non‐corrosive, and non‐toxic, formate is especially promising for applications involving close contact with the consumer . This oxidation–reduction reaction is given by the following two equations : …”