Cobalt Hexacyanoferrate as Cathode Material for Na+ Secondary Battery

We investigated structural and electrochemical properties of thin film electrodes of cobalt hexacyanoferrate, Na x Co[Fe(CN) 6 ] 0.90 2.9H 2 O, against $x$. The compound exhibits a high capacity of 135 mAh/g and an average operating voltage of 3.6 V against Na, with a good cyclability. The discharge...

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Published inApplied physics express Vol. 6; no. 2; pp. 025802 - 025802-3
Main Authors Takachi, Masamitsu, Matsuda, Tomoyuki, Moritomo, Yutaka
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.02.2013
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Summary:We investigated structural and electrochemical properties of thin film electrodes of cobalt hexacyanoferrate, Na x Co[Fe(CN) 6 ] 0.90 2.9H 2 O, against $x$. The compound exhibits a high capacity of 135 mAh/g and an average operating voltage of 3.6 V against Na, with a good cyclability. The discharge curve exhibits two plateaus at ${\approx}3.8$ and ${\approx}3.4$ V, which are ascribed to the reduction processes of Fe 3+ and Co 3+ , respectively. The ex situ X-ray diffraction (XRD) profiles reveal the robust nature of the host framework against Na + intercalation/deintercalation. Thus, cobalt hexacyanoferrate is a promising candidate for the cathode material of sodium-ion secondary battery (SIB).
Bibliography:Discharge curves of thin-film electrode of Na x Co[Fe(CN) 6 ] 0.90 2.9H 2 O measured at 0.6, 6, 40, and 60 C. The film thickness is 1.1 μm. The inset shows the jungle-gym-type host framework of Prussian blue analogues. Small spheres represent Co and Fe, while bars represent CN - . XRD pattern of Na x Co[Fe(CN) 6 ] 0.90 2.9H 2 O against $x$. Values in parentheses represent indexes in the face-centered cubic setting. (a) Discharge curves of thin-film electrode of Na x Co[Fe(CN) 6 ] 0.90 2.9H 2 O against $x$. (b) Lattice constant ($a$) of Na x Co[Fe(CN) 6 ] 0.90 2.9H 2 O against $x$. Open and closed circles denote data points obtained in the charge and discharge processes, respectively. Solid and broken lines in (b) indicate the results of the least-squares fittings in plateaus I and II, respectively. Cycle number dependence of charge (closed circles) and discharge (open circles) capacities ($Q$) of thin-film electrode of Na x Co[Fe(CN) 6 ] 0.90 2.9H 2 O. The charge rate is at 0.6 C. The film thickness is 1.1 μm. The inset shows charge/discharge curves of the thin-film electrode of Na x Co[Fe(CN) 6 ] 0.90 2.9H 2 O.
ISSN:1882-0778
1882-0786
DOI:10.7567/APEX.6.025802