Lithium sulphur (Li-S) batteries hold more than twice the energy density of lithium ion and would provide more than double the range of current EVs – up to 450 kilometers on a single charge. Sulphur is also a waste product, is non-toxic, safe and inexpensive – so what’s been the hold up? Lithium sulphur batteries deteriorate after just a few cycles of charging and discharging. Seems that polysulfide dissolution leads to a ‘gunk’ build up on the anode. Ideally any EV battery pack should have a cycle life of at least a 1,000 cycles.
However, researchers at Lawrence Berkeley Labs in California have modified these cells using graphene oxide. Together with other changes to the battery design and new electrolyte it would appear they have overcome the issues surrounding the sulphur chemistry that was causing the problem. It now looks as if the batteries are capable of at least 1,500 cycles without deterioration. On top of the cycle breakthrough the new electrolyte that was used allows the battery to operate at a higher rate resulting in increased charge speed and more power delivery during discharge. The Li-S battery is also safer as ionic liquids are non-volatile and non-flammable.
This is early days with costs and applications still uncertain. The next steps in the development are to further increase the cell energy density, improve cell performance under extreme conditions, and scale up to larger cells. It does seem however with a bit of graphene magic thrown in to the mix the technological breakthrough of better battery technology is a major step closer.
Read more on these developments – click here.