Lithium-ion batteries are central to clean energy storage. To achieve their high energy densities, they commonly use cathodes based on transition metal oxides. However, these cathodes are manufactured using the toxic, teratogenic processing solvent N-methyl-2-pyrrolidone (NMP), which faces increasing regulatory restrictions. To phase out the use of NMP, more benign processing solvents are needed.

Now, writing in Nature Communications, Sang-Young Lee, Won Bo Lee, Junghwan Kim and colleagues introduce a water-based processing solution that enables the sustainable manufacturing of lithium battery cathodes, without giving up their commercial electrochemical performance.