Researchers in Australia believe they have solved one of the key problems holding back the battery of the future, a breakthrough that would allow them to develop cells that could run a smartphone for four days.

Lithium-sulphur batteries can theoretically store six times as much energy as the lithium-ion batteries currently used in phones and electric vehicles, but that extra power can cause them to swell and break.

Mahdokht Shaibani, Matthew Hill and Meysam Mirshekarloo at their Monash University battery lab. Credit:Scott McNaughton

The international research team discovered a simple tweak to the manufacturing process, which they said fixes the problem.

Their patented design was published in Science Advances earlier this week. A stack of battery prototypes have been built in Germany and will be tested in electric cars in the next few months.