Stabilising mat offers hope for commercialising lithium sulphur batteries

Lithium sulphur batteries have been touted for many years as a potential replacement for lithium ion technology, because the chemistry of the lithium sulphur system would allow more energy to be stored in a single battery. However, the same chemistry is also proved a stumbling block, as the sulphur tends to migrate away from the electrode by forming complex polysulphide compounds. This results in the superior energy density degrading after first few recharge cycles.

The challenge for researchers has been to find a way to stabilise the Li-S electrode without either adding weight to the battery or making it too complex to manufacture. Researchers from Drexel University College of Engineering in Philadelphia are now claiming a breakthrough that could result in a battery with a capacity four times higher than similarly sized lithium ion unit.

Developed in the laboratory run by Vibha Kalra, the breakthrough comes in the form of a porous titanium monooxide nanofibre mat, somewhat resembling a bird's nest. This forms part of the cathode of the battery. "This is a significant development because we have found that our titanium monoxide-sulphur cathode is both highly conductive and able to bind polysulphides via strong chemical interactions, which means it can augment the battery’s specific capacity while preserving its impressive performance through hundreds of cycles," Kalra said.