Prussian Blue K2Fe[Fe(CN)6] Powder for K-Ion Battery Cathode, 20 g/bottle, CPIBCPB

K2Fe[Fe(CN)6] (Potassium Iron Hexacyanoferrate), the stoichiometric, potassium-rich form of Prussian Blue (PB), is a highly competitive cathode material for Potassium-Ion Batteries (KIBs/PIBs). Because potassium (K+) has a large ionic radius (1.38 Å compared to Li+'s 0.76 Å), standard dense interstitial host structures like layered oxides or olivines suffer from severe lattice strain and sluggish kinetics when cycling potassium. Prussian Blue solves this via its uniquely accommodating open-framework architecture.

K2Fe[Fe(CN)6] acts as a two-electron transfer cathode material, yielding highly favorable capacities and voltages: (1) ~3.0 V vs. K/K+: Associated with the oxidation/reduction of the High-Spin Fe^{2+}/ Fe}^{3+} sites (N-coordinated). (2) ~4.0 V vs. K/K+: Associated with the oxidation/reduction of the Low-Spin Fe^{2+}/ Fe^{3+} sites (C-coordinated). The combined redox action delivers an average discharge voltage profile between 3.3 V and 3.6 V, enabling highly competitive material-level energy densities (~500 Wh/kg).

Part Number	CPIBCPB (C-PIB-C-PB)
Chemical Composition	K: 30.5 wt%   Fe: 45.0 wt%
Particle Size Distribution	D10 = 1.2 um;  D50 = 3.9 um;   D90 = 10.6 um
Tap Density	1.10 g/cm3
Specific Area	0.66 m2/g
pH	9.7
XRD
First Discharging Capacity	~136 mAh/g (0.1 C, 2.0-4.2 V)   Cathode: KPB: SP: PVDF = 90 : 5 : 5 Anode: Potassium metal Electrolyte: 1 mol/L KPF6 in EC:PC = 1:1.

Notes: (1) Please store the KPB powder in a dry area (glovebox is preferred)

References: 

1. S. Chong, et al. Potassium ferrous ferricyanide nanoparticles as a high capacity and ultralong life cathode material for nonaqueous potassium-ion batteries, J. Mater. Chem. A, 2017,5, 22465-22471
2. A. Tyagi, et al. Opportunities in Na/K [hexacyanoferrate] frameworks for sustainable non-aqueous Na+/K+ batteries, Sustainable Energy Fuels, 2022,6, 550-595