Sulphide Li6PS5Br might hold the key towards the break-through in solid-state battery systems, Austrian researchers have found.
According to findings published in the Journal of Physical Chemistry Letters, lithium ions in this type of sulphide move extremely quickly, making it a suitable candidate to become a solid-state electrolyte of the future.
Using lithium nuclear magnetic resonance spectroscopy, researchers from the Christian-Doppler (CD) Laboratory for lithium batteries at Graz University of Technology, have found that ions in sulphide Li6PS5Br oscillate even at ambient temperature with an extremely high frequency. Virtually, the ions perform more than one billion movements per second – qualifying for the role of solid-state ion conductors.
Such mobility has also been shown in other lithium substances, however, many of the materials are not only ionically but also electronically conductive – and thus have to be excluded as solid-state electrolytes.
“The more we know about the nature of the charge carrier transport in solids, the more evident it will become, which materials are the most suitable for the future development of batteries,“ explained Martin Wilkening - one of the research participants.
In a lithium-ion battery, the ions move between both poles of the battery during charging and discharging, passing through structurally different materials. In the case of a solid-state lithium-ion battery, a solid substance, such as a lithium-containing oxide or a sulphide, takes on the role of a conductive electrolyte.
With increasing demands on energy storage for the purposes of electromobility or the ever more power-hungry smartphones and high-performance notebooks, the international research community has been increasingly turning towards solid-state lithium ion batteries.
Compared with the conventional liquid-based lithium-ion batteries, the ‘solids’ offer better thermal stability, longer operational life span and increased safety.