Water softening intercalation materials

A device for removing ions from a solution, the device comprising:

• first and second intercalation electrodes forming a compartment configured to stream the solution, the first and second intercalation electrodes including first and second intercalation materials, respectively, the first and/or second intercalation materials including a binary transition metal Prussian blue analogue compound, a ternary transition metal Prussian blue analogue compound, or a combination thereof, the binary transition metal Prussian blue analogue compound having a general formula:
• AxByCz[Fe(CN)6], where A=Li, Na, or K;
• B=Mn, Fe, Ni, Cu, or Zn;
• C=Mn, Fe, Ni, Cu, or Zn);
• 0≤x≤1;
• 0≤y≤1;
• and 0≤z≤1, and the ternary transition metal Prussian blue analogue compound having the general formula:
• AxByCzDw[Fe(CN)6], where A=Li, Na, or K;
• B=Mn, Fe, Ni, Cu, or Zn;
• C=Mn, Fe, Ni, Cu, or Zn;
• D=Mn, Fe, Ni, Cu, or Zn;
• 0≤x≤1;
• 0≤y≤1;
• 0≤z≤1;
• 0≤w≤1, the first and second intercalation electrodes configured to receive an electric bias of current or voltage applied by a power supply such that the first and second intercalation electrodes reversibly store and release ions from the solution.

A device for removing ions from a solution, the device comprising:

• an anion exchange membrane and a carbon-based electrode in a first layer-to-layer configuration with each other;
• a cation exchange membrane and an intercalation host in a second layer-to-layer configuration with each other, the intercalation host including an intercalation material, and the intercalation material including a binary transition metal Prussian blue analogue compound, a ternary transition metal Prussian blue analogue compound, or a combination thereof, the binary transition metal Prussian blue analogue compound having a general formula:
• AxByCz[Fe(CN)6], where A=Li, Na, or K;
• B=Mn, Fe, Ni, Cu, or Zn;
• C=Mn, Fe, Ni, Cu, or Zn);
• 0≤x≤1;
• 0≤y≤1;
• and 0≤z≤1, and the ternary transition metal Prussian blue analogue compound having the general formula:
• AxByCzDw[Fe(CN)6], where A=Li, Na, or K;
• B=Mn, Fe, Ni, Cu, or Zn;
• C=Mn, Fe, Ni, Cu, or Zn;
• D=Mn, Fe, Ni, Cu, or Zn;
• 0≤x≤1;
• 0≤y≤1;
• 0≤z≤1;
• 0≤w≤1;
• and
• a compartment formed in between the anion exchange membrane and the cation exchange membrane and configured to stream the solution.