PRUSSIAN BLUE ANALOGUE HAVING CORE-SHELL STRUCTURE, PREPARATION METHOD THEREFOR AND SODIUM-ION SECONDARY BATTERY CONTAINING PRUSSIAN BLUE ANALOGUE

The present application relates to a prussian blue analog having a core-shell structure, which has a core and a cladding layer that clads the core, whereinthe chemical formula of the core is the following Formula 1, NaxP[R(CN)6]δ·zH2O Formula 1wherein the P and R are each independently selected from at least one of transition metal elements, 0