Replacing conductive carbon black with commercial carbon-coated iron nanoparticles yields an effective contrast-enhancing agent to differentiate between active material, conductive additive, and binder in lithium-ion battery electrodes. Nano-XCT resolved the carbon-binder domain with 126 nm voxel resolution, showing partial coatings around the active material particles and interparticle bridges. In a complementary analysis, SEM/EDS determined individual distributions of conductive additives and binder. Surprisingly, the contrast-enhancing agents showed that the effect of preparation parameters on the heterogeneity of conductive additives was weaker than on the binder. Incorporation of such contrast-enhancing additives can improve understanding of processing-structure-function relationships in a multitude of devices for energy conversion and storage.

Solar-powered electrochemical production of hydrogen through water electrolysis is an active and important research endeavor. However, technologies and roadmaps for implementation of this process do not exist. In this perspective paper, we describe potential pathways for solar-hydrogen technologies into the marketplace in the form of photoelectrochemical or photovoltaic-driven electrolysis devices and systems. We detail technical approaches for device and system architectures, economic drivers, societal perceptions, political impacts, technological challenges, and research opportunities. Implementation scenarios are broken down into short-term and long-term markets, and a specific technology roadmap is defined. In the short term, the only plausible economical option will be photovoltaic-driven electrolysis systems for niche applications. In the long term, electrochemical solar-hydrogen technologies could be deployed more broadly in energy markets but will require advances in the technology, significant cost reductions, and/or policy changes. Ultimately, a transition to a society that significantly relies on solar-hydrogen technologies will benefit from continued creativity and influence from the scientific community.