Electrochemical materials for the production and storage of renewable energy [article]

Bryan Russell Wygant, 0000-0003-1924-7831, Austin, The University Of Texas At, C. B. Mullins
2020
The production of electricity from renewable sources, including solar power, is increasingly important as our society seeks to move to cleaner energy sources. Organolead halide perovskites, a class of thin film photovoltaic (PV) materials, are an exciting competitor to traditional Si devices, but suffer from poor material stability. Further, PV power is intermittent, creating a need for efficient energy storage during times when solar power is unavailable. H₂ gas, produced via electrochemical
more » ... ter electrolysis, is a promising way to store this energy in chemical bonds but efficient electrocatalysts are required to drive the reaction. This need for electrocatalysts is particularly acute for the complementary oxygen evolution reaction (OER), the rate-limiting half reaction of electrolysis. Here, we address both halves of the renewable energy problem above, production and storage, and study how the chemistry of PV and OER electrocatalyst materials impacts electrochemical performance and material stability. In regard to production, we studied the performance and stability of quasi-2D Ruddlesden-Popper phase (RPP) perovskites under humid conditions. We found that RPP perovskites are more stable than typical 3D perovskites due to a unique moisture-driven disproportionation mechanism that passivates and protects the surface of the RPP perovskite. This process can also result in the formation of discrete RPP crystallites within the bulk of a perovskite film or device. We also found that changing the composition of the RPP perovskite enables control of the halide diffusion barrier, further impacting material stability. We next investigated energy storage, and studied how elemental composition affected the performance of two transition metal-based OER electrocatalyts. We found that for a Co-containing oxide perovskite, changes in the crystal structure of the catalyst from hexagonal to orthorhombic had little effect on OER performance, while adding small amounts of Fe improved catalytic behavior. Likewise, we found that th [...]
doi:10.26153/tsw/9153 fatcat:egj6ysaws5bhpckxtqrj3zwuza