Photochemical water electrolysis is a promising approach for storing intermittant solar energy, but to date demonstrations of this technology have suffered from challenges related to efficiency, cost, and durability. We are interested in exploring alternative electrolyte systems that circumvent the challenges of solar water splitting to afford efficient, robust, and scalable solar energy conversion and storage. To this end, we have characterized crystalline n-type layered chalcogenide semiconductors that can photochemically oxidize halide electrolytes with high efficiency and stability. We have found that illuminated n-WSe2 photoelectrodes, for example, can facilitate HI electrolysis to H2(g) and HI3(aq) at appreciable rates without application of an external electrical bias. We have further developed and characterized a functional example of a "solar flow battery," based on aqueous iodide and anthraquinone redox couples, that integrates solar energy capture, storage, and subsequent liberation of the stored energy with high round-trip (i.e. photons in to electricity out) efficiency. We will discuss the construction and characterization of these systems in detail, as well as opportunities to expand the field of solar-driven galvanic cells.

Unassisted energy storage using layered chalcogenide semiconductors

249th National Meeting (2015)

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