Prussian Blue Analogue‐Derived ZnO/ZnFe 2 O 4 Core‐Shell Nanospheres as High‐Performance Anodes for Lithium‐Ion and Potassium‐Ion Batteries

Herein, core‐shell nanostructured ZnO/derived from self‐sacrifice template method with Prussian blue analogue (i. e., Zn 3 [Fe(CN) 6 ] 2 ) as precursor has been successfully synthesized by controlling the calcination temperatures and heating rates. The formation mechanism of core‐shell nanostructures has been explored through the morphology transformation under different synthetic conditions. Impressively, ZnO/ZnFe 2 O 4 hybrid material with core‐double shell nanostructure shows good cycling performance as anodes of lithium‐ion batteries (1137 mAh g −1 at 1 A g −1 after 80 cycles) and potassium‐ion batteries (217 mAh g −1 at 0.1 A g −1 after 400 cycles). The excellent performances can be attributed to the unique core‐double shell nanostructure as well as synergistic effects of ZnO and ZnFe 2 O 4 . The results indicate that the strategy of designing nanostructures could successfully improve the electrochemical performances of ZnO/ZnFe 2 O 4 and effectively expand the commercial application of transition metal oxides.