Lithium ions conduction in Li_2xMn_1-xPS₃ films

Abstract

Li_2xMn_1-xPS₃ films have been synthesized by exfoliating MnPS₃ through the successive intercalations of K⁺ and Li⁺ ions. Their dielectric response has been measured from 80 to 350 K in the frequency range of (10²–10⁶) Hz. The obtained data have been analyzed in terms of both complex permittivity ε* and the ac conductivity σ_ac. The frequency dependence of σ_ac has been interpreted in terms of the Jonscher’s law, whose exponent n decreases by increasing temperature. The n values lie between 0.479 and 0.501 and are typical of materials in which the ac conductivity is due to multiple hops of carriers. By analyzing the σ_dc temperature dependence, the observed dielectric response has been attributed to the intercalated lithium ions, and the Li_2xMn_1-xPS₃ films have been classified as hopping charge carrier systems.

Keywords:

• thin films
• chemical synthesis
• dielectric response
• dielectric spectroscopy

Acknowledgements

The authors wish to thank Dr G. Squadrito of the Instituto di Tecnologie Avanzate per l’Energia (ITAE) “Nicola Giordano” of Consiglio Nazionale delle Ricerche for having carried out the reported SEM images.