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Samples of 70% dark chocolate prepared for study with the USANS instrument at the Spallation Neutron Source. (Credit: ORNL/Genevieve Martin)

Tempering, the heating process that gives chocolate its appealing sheen and creamy texture, is a crucial part of crafting quality chocolate. But, at the molecular level, it gets a little tricky, and when done incorrectly, can render entire batches of chocolate gritty and unappetizing.

The illustrations show how the correlation between lattice distortion and proton binding energy in a material affects proton conduction in different environments. Mitigating this interaction could help researchers improve the ionic conductivity of solid materials.

Ionic conduction involves the movement of ions from one location to another inside a material. The ions travel through point defects, which are irregularities in the otherwise consistent arrangement of atoms known as the crystal lattice. This sometimes sluggish process can limit the performance and efficiency of fuel cells, batteries, and other energy storage technologies.