Elucidating the crystal structures of the intercalation phases in KxCrSe2 (0=

The quest for affordable and sustainable energy storage has driven increasing interest in potassium-ion batteries (KIBs). However, metal chalcogenides have been largely overlooked as KIB cathodes due to the prevalence of side reactions during the intercalation process. Our recent research has demonstrated the feasibility of reversible K+ ion intercalation into CrSe2, achieving near-theoretical capacity in the resulting battery. This marks a significant advancement in the application of chalcogenides in KIB research. While the results are promising, challenges remain, including enhancing cycling stability and understanding structural changes during potassium intercalation. In operando studies are key in this regard, requiring access to synchrotron radiation since our laboratory attempts could not provide sufficient resolution and a reasonable 2θ range to elucidate the crystal structure changes occurring during the intercalation process.