Method for size-controlled synthesis of transition metal cyanide coordination compound

Abstract

Embodiments describe a scalable method for synthesizing Prussian White transition metal cyanide coordination compounds (TMCCC) of the general formula NaFe[Fe(CN)]n HO for use in battery electrodes. This method involves the controlled decomposition of sodium hexacyanoferrate decahydrate using formic acid, where particle size distribution is precisely controlled by modulating nucleation and growth. The process also includes a sodiation step using an aqueous buffer and a reducing agent. The synthesized materials exhibit high capacity and enable the commercialization of sodium-ion batteries, with the added benefit of byproduct processing. The method ensures precise regulation of particle size and morphology, leading to structural uniformity, and allows for tailoring tap density to optimize volumetric energy density. The resulting TMCCC demonstrates zero to low vacancy content and has a confirmed monoclinic phase.