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Microfluidic Electrochemical Energy Conversion for Artificial Photosynthesis

In this microfluidic water electrolysis device, the channels in which O2 and H2 are generated by splitting water are separated by a chemically inert wall (red). The conduction of protons from one channel to the other, which is required for continuous operation, occurs via a membrane cap (Nafion®), which also prevents the intermixing of the O2 and H2 product streams. All relevant dimensions of the device (e.g. channel/wall width) are adjustable to maximize performance. The system can be easily extended to a photoelectrolyzer by the incorporation of a photovoltaic component as the substrate of devices; this will further enhance its potential for aiding in the development of novel efficient components for solar-fuel generators

The Science

Researchers at the Joint Center for Artificial Photosynthesis have developed a versatile microfluidic test-bed which can be used to optimize the integrated catalysis and mass transport components of electrochemical energy conversion devices. The small size and versatility of the design facilitates the evaluation of new materials under development without the need for scale-up.

The Impact

Energy conversion devices require the parallel functionality of a variety of components for efficient operation. The new microfluidic test-bed allows all functional components to be easily exchanged and tailored for optimization, therefore allowing the performance of integrated devices to be readily assessed. While the initial experiments and modeling were performed for water electrolysis, the concept can be readily extended to solar-fuels generators and fuel-cell devices.



Summary

A novel microfluidic approach for the fabrication of integrated electrochemical energy conversion devices has been developed. Micro-fluidic electrochemical devices provide a simple route to integrate multiple components at small scales; they also provide a platform to readily tune architectures (e.g, channel dimensions). Additional benefits in include a high degree of control over reactant and product flows, low transport limitations due to small channel dimensions, and easy exchange of active materials. The team also developed multi-physics modeling tools that not only provide a quantitative description of the device performance but also can be used to better understand the behavior of the components in the device and ultimately provide insights on avenues for improvements. The approach developed here can be readily extended to other energy conversion systems such as solar-fuel generators and fuel cells and will allow facile testing of new components without the need to scale-up. This can allow for an early-stage assessment of the device’s performance under conditions relevant to operation, and has the potential to significantly accelerate the development of novel efficient components for applications in electrolysis, fuel-cell and artificial photosynthesis.

 
“Integrated microfluidic test-bed for energy conversion devices,” M. A. Modestino, C. A. Diaz-Botia, S. Haussener, R. Gomez-Sjoberg, J. W. Ager and R. A. Segalman, Phys. Chem. Chem. Phys. 15, 7050 (2013). DOI: 10.1039/C3CP51302E