Design of Compact Photoelectrochemical Cells for Water Splitting

Abstract

-Solar driven water splitting can be achieved by coupling electrolyzers with PhotoVoltaics (PV). Integration of both functions in a compact PhotoElectroChemical (PEC) cell is an attractive option but presents significant scientific challenges. In this work, the design of single-and dualcompartment PEC cells for research purposes is discussed. The fabrication of separator-electrode assemblies is an important aspect, and upscaling of these architectures even to centimeter scale is not trivial. The layout of a new dual-compartment compact PEC cell with in-situ monitoring of pH, temperatures, and oxygen and hydrogen evolution for research purposes is presented. Finally, a prospect of future PEC cells for practical applications is presented.Résumé -Conception de cellules photoélectrochimiques compactes pour la décomposition de l'eau -La décomposition de l'eau en utilisant la lumière du soleil s'effectue par couplage d'un électrolyseur aux cellules PhotoVoltaïques (PV). L'intégration des deux fonctions dans une seule cellule PhotoElectroChimique (PEC) compacte est envisagée, mais présente un très grand défi scientifique. Cet article traite la conception des cellules PEC de recherche avec ou sans compartimentation. L'assemblage de séparateurs et d'électrodes est un aspect important, et la fabrication de ces architectures, même à l'échelle centimétrique et n'est pas évidente. La disposition d'une nouvelle cellule compacte PEC à deux compartiments permettant de contrôler in situ l'évolution du pH, de la température, et les concentrations d'oxygène et d'hydrogène est présentée. Enfin, une perspective de futures cellules PEC pour des applications pratiques est présentée.

Minimization of Ionic Transport Resistance in Porous Monoliths for Application in Integrated Solar Water Splitting Devices

“…17,18 There are two common design types. 19,20 In the "wired" design ( Figure 1A) planar anode and cathode have opposed surfaces at close proximity such that the interelectrode distance to be covered by ions in the liquid electrolyte is minimized. 9−11 The "wireless" or "monolithic" layout ( Figure 1B) simplifies cell design by eliminating electrical contacts and wires through integration of all components in a monolithic flat assembly.…”

Polymeric Electrolyte Membrane Photoelectrochemical (PEM-PEC) Cell with a Web of Titania Nanotube Arrays as Photoanode and Gaseous Reactants

“…Solar energy can cover a substantial share of global energy needs, but due to the intermittency and dilute nature of sunlight, storage in energy-dense media, such as hydrogen, is essential. Solar hydrogen can be produced using an electrolyzer powered by photovoltaics (PV) [1,2].…”

“…The potential advantages of PEC cells over the coupled PV-electrolysis system are that they can enable the use of earth abundant, cheap electrode materials and provide a more compact and integrated reactor design [1,2].…”

“…Most of the PEC cells, described so far in the literature, are designed to operate in liquid phases, which have a dual role, serving simultaneously both as the electrolyte and as the oxidation/reduction substrate [1,2]. Inspired by the reactor design of polymeric electrolyte membrane (PEM) electrolyzers and fuel cells [3], few research groups [2,4] have attempted to separate the two electrodes of PEC cells (where the two electrochemical half-reactions take place) with an ionically conductive polymeric membrane. In such systems the membrane acts both as electrolyte and as support for the photoelectrodes.…”

“…In such systems the membrane acts both as electrolyte and as support for the photoelectrodes. This novel strategy seems very promising since it allows the direct separation of the reaction products, while also the polymeric membrane electrolyte does not need to be replenished during long term operation as in the case of liquid electrolytes, which is essential for scaling up PEC devices [1,2].…”