KI-Assisted Formation of Spindle-like Prussian White Nanoparticles for High-Performance Potassium-Ion Battery Cathodes

Prussian white (PW) is considered as a promising cathode material for potassium-ion batteries (KIBs) due to its low cost and high theoretical capacity. However, the high water content and structural defects and the strict synthesis conditions of PW lead to its unsatisfactory cycling performance and low specific capacity, hindering its practical applications. Herein, a template-engaged reduction method is proposed, using MIL-88B(Fe) as a self-template and KI as the reducing agent to prepare K-rich PW with low defects and water content. Furthermore, the hierarchical porous spindle-like morphology can be inherited from the precursor, furnishing sufficient active sites and reducing the ion diffusion path. Consequently, when applied as a KIB cathode material, spindle-like PW (K1.72Fe[Fe(CN)(6)](0.96)0.342H(2)O) manifested remarkable potassium storage properties. Notably, a full cell assembled by the spindle-like PW cathode and graphite anode exhibited a large energy density of similar to 216.7 Wh kg(-1), demonstrating its huge potential for energy storage systems.

Automated summary

A template-engaged reduction method was proposed to prepare Prussian white with low defects and water content. The spindle-like morphology inherited from the precursor provided sufficient active sites and reduced the ion diffusion path, resulting in remarkable potassium storage properties.