Mn-HCF@Fe-HCF Core–Shell Architecture: Enhancing Structural Stability and Electrochemical Performance of Sodium-Ion Batteries.

To overcome the structural failure of Manganese-based Prussian blue analogue (Mn-HCF) as a cathode material of sodium ion batteries caused by Mn ion dissolution induced by Jahn–Teller effect, we coated Mn-HCF with iron-based Prussian blue (Fe-HCF) to prepare the core–shell Mn-HCF@Fe-HCF cathode material for sodium ion batteries through co-precipitation method. The research results indicate that this structure effectively blocks the direct contact between Mn-HCF and electrolyte, thereby minimizing the dissolution of Mn 3 + in the electrolyte and significantly improving the cycling stability and rate performance. The discharge capacity of this material at a current density of 0.1 C (14 mA g − 1) is 129.7 mAh g − 1 . It still has a capacity of 87.4 mAh g − 1 at a current density of 2 C (280 mA g − 1) , and still has a capacity retention rate of 84.3% (91 mAh g − 1) after 100 cycles at a current density of 0.5 C (70 mA g − 1). Compared with the capacity retention rate of 51.5% of Mn-HCF 100 cycles before coating, the cycle stability of Mn-HCF@Fe-HCF is greatly improved. The Mn-HCF@Fe-HCF material was successfully prepared through a simple coprecipitation method. When applied in sodium-ion batteries, the Mn-HCF@Fe-HCF exhibited a remarkable cycle stability of 129.7 mAh g–1 at 0.1 C, along with an impressive rate performance of 104.2 mAh g–1 at 1 C. [ABSTRACT FROM AUTHOR]