Hidden Intermediate Phases Unlock New Routes To Solar Fuels And Better Batteries

Researchers at the University of Warwick and the University of Birmingham have revealed that valuable, previously unseen material phases form transiently during the heating-based synthesis of advanced materials. By tracking how molecular precursors transform as they heat, the team captured fleeting intermediate states that could offer new routes to improved solar-fuel devices and battery materials.

What The Team Did

The collaboration used single-source precursors — ‘‘all-in-one’’ starter molecules — and a coordinated suite of advanced techniques to follow transformations in real time. Key methods included solid-state NMR spectroscopy, X-ray diffraction (XRD) and pair distribution function (PDF) analysis. These tools allowed the researchers to map atomic-scale disorder and structural evolution during heating, effectively producing a high-speed freeze-frame of molecular events.

Key Discoveries

Instead of focusing solely on the finished material, the team probed the intermediate stages that typically disappear before the final product forms. They discovered a previously unknown polymorph of bismuth vanadate (β-BiVO4) with a distinct atomic arrangement and a larger band gap than the common form. This altered electronic structure changes how the material absorbs and responds to light, offering a new tuning parameter for devices that harvest solar energy.

In the same experiments the researchers also identified a transient intermediate with a particularly strong affinity for lithium. That stage shows promise for application in lithium-based batteries, potentially enabling faster charging or improved capacity if the phase can be stabilised or exploited.

"When materials are made by heating, researchers normally focus on the final product — the B that comes from A. This study shows there are many interesting stages between A and B, and those hidden steps could be equally important," said Dr Sebastian Pike, Department of Chemistry, University of Warwick.

Why This Matters

These findings shift the emphasis in materials chemistry from end-point synthesis to the thermal pathways that lead there. By steering or arresting the route a compound takes during heating, scientists may be able to discover and exploit otherwise inaccessible structures with useful optical, catalytic or electrochemical properties.

The results were published in Nature Communications on April 30. The authors stress that further work is needed to understand how to stabilise and incorporate these intermediate phases into practical devices, but the study opens a promising new direction for designing next-generation materials for solar fuels, catalysis and energy storage.

Publication: Nature Communications (April 30). Institutions: University of Warwick and University of Birmingham.