Kagomé Lattices as Cathode: Effect of Particle Size and Fluoride Substitution on Electrochemical Lithium Insertion in Sodium- and Ammonium Jarosites

Author

Prashanth Sandineni
Hooman Yaghoobnejad Asl
Amitava Choudhury, Missouri University of Science and TechnologyFollow

Abstract

Highly crystalline sodium and ammonium Jarosites, NaFe₃(SO₄)₂(OH)₆ and NH₄Fe₃(SO₄)₂(OH)₆, have been synthesized employing hydrothermal synthesis routes. The structures consist of anionic layers of vertex-sharing FeO₆ octahedra and SO₄ tetrahedral units with interlayer space occupied by Na and ammonium ions, respectively. The corner-sharing FeO₆ 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 Fe³⁺ to Fe²⁺. 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 2.26V 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.

Recommended Citation

P. Sandineni et al., "Kagomé Lattices as Cathode: Effect of Particle Size and Fluoride Substitution on Electrochemical Lithium Insertion in Sodium- and Ammonium Jarosites," Journal of Solid State Chemistry, vol. 242, no. Part 2, pp. 78 - 86, Elsevier, Oct 2016.

The definitive version is available at https://doi.org/10.1016/j.jssc.2016.02.022

Department(s)

Chemistry

Keywords and Phrases

Bronze; Cathodes; Electric discharges; Electrochemistry; Electrodes; Fluorine compounds; Ions; Iron oxides; Lithium; Lithium compounds; Lithium-ion batteries; Particle size; Electrochemical lithium insertion; Fluoride substitutions; Galvanostatic charge discharges; Hexagonal tungsten bronzes; Jarosites; Ssbauer spectroscopies; Strong dependences; Synthesis conditions; Hydrothermal synthesis; Cathodes; Electrochemistry; Hydrothermal synthesis; Jarosites; Li-ion battery; Mossbauer spectroscopy

International Standard Serial Number (ISSN)

0022-4596

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 Elsevier, All rights reserved.

Publication Date

01 Oct 2016