Lithium-ion batteries can be made smaller using nanoparticles as their tiny size allows for faster charging and greater energy storage – which is useful for smartphones where battery life can be disappointing.
A team of engineers from the Dionne Group at Stanford University in the US exposed palladium nanoparticles to hydrogen gas to test how much the nanoparticles absorbed and released hydrogen atoms.
The palladium nanoparticles act similarly to lithium ion batteries, but instead of ions, hydrogen atoms are used. The movement of hydrogen atoms between the nanoparticles determines how much energy can be stored and used.
Using an environmental-scanning electron microscope, engineers could look inside the nanoparticles to observe hydrogen atoms moving in real time.
The engineers found that icosahedral nanoparticles, which have 20 different sides, stored less energy than cube- or pyramid-shaped nanoparticles.
This experiment also pushes the boundaries of the science behind materials imaging. Robert Sinclair, co-author of the study and professor of materials science and engineering, said: "We could not have envisaged making in situ observations like this at the atomic level even a few years ago, and so what the team has demonstrated and achieved is remarkable."
The ability to peer inside nanoparticles is key to improving energy storage. Jennifer Dionne, principal investigator of the Dionne group, said that looking inside nanoparticles will help in designing "champion materials for next-generation energy storage devices." ®