Tuning Intercalation Sites in Nickel Hexacyanoferrate Using Lattice Nonstoichiometry
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- 作者：Xiaogang Hao and Daniel T. Schwartz
- 刊名：Chemistry of Materials
- 出版年：2005
- 出版时间：November 15, 2005
- 年：2005
- 卷：17
- 期：23
- 页码：5831 - 5836
- 全文大小：122K
- 年卷期：v.17,no.23(November 15, 2005)
- ISSN：1520-5002
文摘
Reversible intercalation/deintercalation of K+ in nickel hexacyanoferrate (NiHCF) thin films occurs intwo energetically distinct, largely noninteracting, sites whose proportions are set by lattice nonstoichiometry.Principal component analysis (PCA) is used to correlate the stoichiometry of NiHCF, measured usingenergy-dispersive X-ray spectroscopy (EDS), with intercalation processes measured via cyclic voltammetry(CV). NiHCF voltammograms are well-known to exhibit two reversible peaks for K+-containingelectrolytes; each peak represents a different local cation intercalation/deintercalation environment. PCAof 59 different CV-EDS data sets shows (to first order) that the relative sizes of the two CV peaks areproportional to the lattice nonstoichiometry, but the peak locations (energies) are largely independent ofstoichiometry. Intercalation sites in stoichiometric lattices are energetically favored compared to sitesassociated with defects (
G 
-10 kJ/mol K+). The proportionality of CV peak sizes, and lack of peakshifting with lattice nonstoichiometry, indicates the different intercalation sites are largely noninteracting.Weak site-site interactions allow easy tuning of intercalation properties via lattice stoichiometry, thoughthe best sensing or separation performance will likely be achieved in either defect-free lattices or highlynonstoichiometric lattices where, in each case, a single type of intercalation site is dominant. Processingconditions for creating a wide range of NiHCF lattice stoichiometries are presented.
G -10 kJ/mol K+). The proportionality of CV peak sizes, and lack of peakshifting with lattice nonstoichiometry, indicates the different intercalation sites are largely noninteracting.Weak site-site interactions allow easy tuning of intercalation properties via lattice stoichiometry, thoughthe best sensing or separation performance will likely be achieved in either defect-free lattices or highlynonstoichiometric lattices where, in each case, a single type of intercalation site is dominant. Processingconditions for creating a wide range of NiHCF lattice stoichiometries are presented.