Lithium ion batteries are widely used because of their impressive storage capacity, but the flammability issue – as evidenced by numerous fires reported by users of the Samsung Galaxy 7 and other electronic devices – remains a problem. Research devoted to this safety concern has largely focused on battery components, such as the common use of flammable liquid electrolyte.

Michigan Technological University scientists approached the problem from a different angle, looking instead at The diamond-tipped probe is incredibly sensitive and must be housed in a compartment that muffles any sort of vibrations. Source: Sarah Bird/Michigan Technological Universitythe significance of lithium’s mechanical behavior in controlling the performance and safety of next-generation batteries. They examined the behavior of the metal at submicron length scales to analyze how lithium mitigates the pressure that naturally develops during charging and discharging a solid-state battery.

Lithium’s reaction to pressure was investigated by indenting films with a diamond-tipped probe to deform the metal. The high strength of lithium at small-length scales, reported earlier by California Institute of Technology researchers, was confirmed. The metal’s ability to rearrange its atomic or ionic structure in response to pressure imposed by the indenter revealed the importance of the speed at which lithium is deformed, which is related to how fast batteries are charged and discharged.

The researchers measured elastic properties of lithium to reflect changes in the physical orientation of its ions, underscoring the need to incorporate lithium’s orientation-dependent elastic properties into all future simulation work. Experimental evidence was also documented indicating lithium may have an enhanced ability to transform mechanical energy into heat at length scales less than 500 nanometers.

A new statistical model explains the conditions under which lithium undergoes an abrupt transition that further facilitates its ability to alleviate pressure. An additional model directly links the mechanical behavior of lithium to the performance of the battery.