Prussian white analogues as promising cathode for non-aqueous potassium-ion batteries

We prepared Prussian white analogues-KxMFe(CN)(6)center dot mH(2)O (M = Fe, Co, Ni, or Cu). These compounds are investigated as cathode materials for potassium-ion batteries with a non-aqueous electrolyte. Each of these materials exhibits different K-ion storage properties with reversible capacity values ranging from 35 to 110 mAh g(-1), at high potentials above 3.2 V vs. K+/K. Among them, FeFe-Prussian white, K1.68Fe1.09Fe(CN)(6)center dot 2.1H(2)O, exhibits the highest reversible capacity of 110 mAh g(-1) and stable cycling performance in contrast to rapid capacity fading of other analogues. Our results demonstrate a remarkable potential of this family of cathode materials for the emerging potassium-ion batteries. (C) 2017 Elsevier B.V. All rights reserved.