Dissolution Inhibition Strategy Stabilizes Manganese Prussian Blue Analogs for High-Energy Sodium-Ion Batteries

Abstract

The manganese Prussian blue analogs (Mn-PBAs) are regarded as scalable, low-cost, and high-energy cathodes for sodium-ions batteries (SIBs). Unfortunately, Mn-PBAs suffer from severe dissolution, particularly of manganese (Mn), which has been shown will exacerbate the structural collapse of cathode materials and electrolyte decomposition, significantly reducing the cycling stability of Mn-PBAs-based batteries. Herein, an innovative dissolution inhibition strategy is proposed by utilizing solvents that inherently exhibit lower solubility for Mn-PBAs as the electrolyte. This approach successfully establishes a Mn-PBAs dissolution-diffusion inhibition interface, thereby kinetically preventing the dissolution of Mn-PBAs and addressing the associated issues. The interaction energy between Mn-PBAs and the electrolyte, along with analyses of mean square displacement and van Hove function curves, theoretically validates the successful construction of this inhibition interface. In the new electrolyte, the Mn-PBAs can provide a specific capacity of ≈154 mAh g⁻¹ (≈510 Wh kg⁻¹) and can be cycled at a current density of 2 C for >1000 cycles, demonstrating excellent electrochemical performance in the new electrolyte. This pioneering work can forge new avenues for stabilizing high-energy Mn-PBAs and holds substantial promise for practical applications.