Single-channel cross-flow stacked electrode microfluid fuel cell

Abstract

The invention discloses a single-channel cross-flow stacked electrode microfluid fuel cell which comprises a cathode cover plate, a self-breathing cathode, a non-conductive porous diaphragm, a flow field plate, a permeable porous anode and a bottom plate, the fuel cell is characterized in that the flow field plate is arranged between the cathode cover plate and the bottom plate, and a main flow channel for fuel to flow is formed in the flow field plate; a cathode air breathing opening is formed in the cathode cover plate; the self-breathing cathode and the permeable porous anode are stacked upand down between the cathode cover plate and the flow field plate; the self-breathing cathode and the permeable porous anode are separated by a non-conductive porous diaphragm; the self-breathing cathode is located below the cathode breathing hole, and the permeable porous anode is embedded into the main runner and corresponds to the carbonaceous self-breathing cathode; the fuel solution penetrates through the non-conductive porous diaphragm in a diffusion manner to reach the self-breathing cathode; the method can be widely applied to the fields of energy, chemical engineering, biochemical detection and the like.

Description

technical field [0001] The invention relates to a microfluidic fuel cell, in particular to a single channel through-flow stacked electrode microfluidic fuel cell. Background technique [0002] In recent years, miniature fuel cells have attracted extensive attention as power sources for portable electronic devices. However, conventional miniature proton exchange membrane fuel cells face a series of problems such as water management, membrane degradation and aging, and fuel permeation. Thanks to the development of microfabrication technology, a membraneless microfluidic fuel cell is proposed. Membrane-free microfluidic fuel cells use the laminar flow of fluid in microchannels to naturally separate fuel and oxidant, remove the proton exchange membrane, and eliminate a series of related problems caused by the membrane, which is conducive to the miniaturization and integration of fuel cells . In addition, microfluidic fuel cells are more flexible in the choice of fuel and oxida...

AI Technical Summary

Problems solved by technology

When the fuel concentration is too high and the flow rate is too low, formate will diffuse to the cathode, and an oxidation reaction will occur at the cathode to generate mixed potential and parasitic current, reducing battery performance

Therefore, in microfluidic fuel cells based on formic acid as fuel, the operating concentration is generally 1-4M, which further limits the improvement of battery performance due to its inability to operate at higher concentrations.

In addition, scholars at home and abroad have proposed a variety of methods including adjusting the flow rate, changing the electrode (battery) structure and arrangement to reduce the impact of fuel permeation on battery performance, such as Bazylak et al. proposed a microfluidic fuel cell with tapered electrodes , using tapered electrodes to adapt to the increase in the width of the diffusion region, this tapered region will increase the distance between the cathode and anode, resulting in an increase in ohmic internal resistance, and it is difficult to precisely control the width of the tapered region

Park et al. proposed a microchannel with an H-shaped cross-section. The fuel and the oxidant are connected by narrow channels to minimize diffusion and mixing. This structure will also reduce the transmission channel of protons (hydroxides), Causes large ohmic internal resistance, and the preparation process of microchannels with H-shaped cross-section is complicated

Sun et al. proposed to add a third fluid between the fuel / oxidant to avoid direct contact between the fuel and the oxidant and reduce fuel penetration, which would increase the complexity of the battery operating system and cause electrolyte waste

To sum up, the current membraneless microfluidic fuel cells are affected by fuel permeation, and cannot operate at high concentrations of fuel, and the way to reduce fuel permeation is more complicated and will bring negative effects

When the fuel and oxidant (electrolyte) enter the microchannel from different inlets to form parallel laminar flow, the traditional membraneless microfluidic fuel cell operation mode cannot completely avoid fuel permeation, and the cell structure with two inlets will also make the cell structure complicated. And consume more pump work, which is not conducive to the high integration of the battery, so that the high-performance output of the battery cannot be achieved and it is difficult to promote the commercial application of membraneless microfluidic fuel cells

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