The breakthrough stems from a new design for high-density lithium metal batteries that carefully controls problematic ion growths, enabling it to maintain its function over hundreds of cycles.

The lithium batteries in use today feature an anode component made out of graphite, but were scientists able to use pure lithium metal instead, it would mark a huge leap in energy storage technology. That's because lithium metal has a theoretical capacity that is around 10 times higher, at around 3,860 mAh/g compared to graphite's 372 mAh/g, which would send electric vehicles much farther on each charge, for example, or enable smartphones to run for a week.

But these batteries generate energy through different chemical reactions, and with these come another set of problems to solve. As a lithium-metal battery is cycled, lithium ions grow unevenly on the anode surface into tentacle-shaped formations known as dendrites. The protrusions can cause the anode to expand and the battery to short or catch fire. A great deal of research focuses on solving this issue.

The authors of this new study approached the problem with a porous carbon structure featuring a hollow core, to serve as the anode. These Li-confinable core–shell hosts, as they're called, are seen as an exciting prospect in this field, with an ability to prevent dendrite growth and volume expansion by stowing the lithium away in a hollow core during cycling. They do, however, suffer from poor electrochemical performance in another way, with undesirable lithium growth still forming on the surface of the structure during operation, something known as top plating.