Kagomé lattices as cathode: Effect of particle size and fluoride substitution on electrochemical lithium insertion in sodium- and ammonium Jarosites
Highly crystalline sodium and ammonium Jarosites, NaFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6} and NH{sub 4}Fe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}, have been synthesized employing hydrothermal synthesis routes. The structures consist of anionic layers of vertex-sharing FeO{sub 6} octahedra and SO{sub 4} tetrahedral units with interlayer space occupied by Na and ammonium ions, respectively. The corner-sharing FeO{sub 6} octahedral units form six and three rings similar to hexagonal tungsten bronze sheets also known as kagomé lattice. These sodium and ammonium Jarosites are thermally stable up to 400 °C and undergo facile electrochemical lithium insertion through the reduction of Fe{sup 3+} to Fe{sup 2+}. Galvanostatic charge–discharge indicates that up to 2.25 and 2 lithium ions per formula unit can be inserted at an average voltage of 2.49 and 2.26 V to the sodium and the ammonium Jarosites, respectively, under slow discharge rate of C/50. The cycle-life and experimental achievable capacity show strong dependence on particle sizes and synthesis conditions. A small amount of fluoride substitution improves both achievable capacity and average voltage. - Graphical abstract: Discharge capacity of jarosite phases as a function of particle size and fluoride substitution. - Highlights: • Synthesis of natro- and ammonium Jarosites. • Jarosites as cathodes for lithium ion batteries. • Li-ion electrochemistry of Jarosites. • Mössbauer spectroscopy of Jarosites.
- OSTI ID:
- 22658058
- Journal Information:
- Journal of Solid State Chemistry, Vol. 242, Issue Part 2; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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