Lithium-ion batteries are currently winning the rechargeable battery wars. But for how long? Sodium-ion batteries, while not as energy dense or as long-lasting are cheaper (around 25-30% cheaper) and use materials that are considerably easier to source.
Scientists in this article have gone even further in their pursuit of lower costs, noting a toxic member of the carrot family, Hogweed, can be used to make a decent hard carbon to support the battery's electrochemical performance. What's more, if you run out, it is a fast-growing plant!