High-capacity and reliable rechargeable batteries are a critical component of many devices and even modes of transport. They play a key role in the shift to a greener world. A wide variety of elements are used in their production, including cobalt, the production of which contributes to some environmental, economic, and social issues. A team now presents a viable alternative to cobalt which in some ways can outperform state-of-the-art battery chemistry. It also survives a large number of recharge cycles, and the underlying theory can be applied to other problems.