One of the more promising materials is sulfur ... capacity after undergoing 25,000 charge/recharge cycles—a noticeable improvement over typical lithium-ion batteries, which tend to degrade ...

This incredible energy density comes from sulfur’s ability to undergo multi-electron redox reactions with lithium during charge and discharge ... This improves ionic conductivity, even at ...

She says that while the sulfur-based batteries are more environmentally friendly and less toxic than lithium-ion batteries, they are not used in mass production because they don't hold a charge.