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

A method of producing a target Prussian White transition metal cyanide coordination compound (TMCCC) of the general formula NaxFey[Fe(CN)6]1-z n H2O, wherein 0<x≤2.0, y=1.0, 0≤z<0.2, 0≤n<3.0, comprising the steps of:

• (a) admixing sodium hexacyanoferrate (II) decahydrate and water to produce the initial reaction mixture;
• (b) adding a first quantity of formic acid to the reaction mixture obtained in (a) in a period of time at a temperature T to produce the reaction mixture at its second stage;
• (c) holding the reaction mixture obtained in (b) for a period of time at a temperature T to produce reaction mixture at its third stage;
• (d) adding to the reaction mixture obtained in (c) a second quantity of formic acid over a period of time at a temperature T to produce reaction mixture at its fourth stage;
• (e) holding the reaction mixture obtained in (d) for a period of time at a temperature T to produce reaction mixture at its final stage;
• (f) filtering and solvent washing the reaction product obtained in (e) to obtain a TMCCC;
• (g) admixing a buffer and said TMCCC obtained in (f) to produce a reaction mixture;
• and
• (h) contacting the reaction mixture obtained in (g) with a sulfur-containing reducing agent to produce the target Prussian White TMCCC;
• (i) filtering and solvent washing the reaction product obtained in (h) to produce a fully sodiated TMCCC;
• and
• (j) drying the reaction product obtained in (i) to produce a dry powder of said fully sodiated TMCCC.