The US has taken an important step towards the batteries of the future

Researchers at Oak Ridge National Laboratory (ORNL) within the US Department of Energy have created a new polymer electrolyte that could tackle one of the biggest obstacles facing solid-state batteries: ions moving far too slowly through the electrolyte material.

A central challenge with solid-state batteries is that ions must travel through a solid electrolyte. However, many candidate materials are either overly brittle or do a poor job of conducting charge. ORNL’s new polymer material, by contrast, aims to combine the flexibility associated with polymers with exceptionally high ionic conductivity. According to the scientists, in a particular configuration the ions can move billions of times faster than the surrounding structure of the material.

The effect hinges on carefully tuning the polymer’s make-up using a lithium salt and introducing specific molecular groups known as bipolar ions. These groups create highly polar regions inside the material, where small “ion pockets” form. When the concentration is set correctly, the pockets link up into channels, allowing ions to pass through the electrolyte quickly and with minimal resistance.

The team believes the finding could represent an important step towards more dependable solid-state batteries. Next, they plan to examine how the polymer works at the molecular level using supercomputers and artificial intelligence.