• Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/026/07/0673-0681

    • Keywords

       

      Lithium microbattery; tungsten oxysulphide; thin film; X-ray photoelectron spectroscopy (XPS); sputtering.

    • Abstract

       

      Several WO𝑦S𝑧 tungsten oxysulphide thin films were tested as positive electrodes for lithium microbatteries. The amorphous WO1.05S2 thin film was found very promising. A capacity decrease occurred during the first few cycles, after which the films were able to intercalate reversibly up to 1.1 lithium ion per formula unit under high regime (75 𝜇A/cm2). They were tested for 250 charge–discharge cycles, between 3.0 V and 1.2 V. X-ray photoelectron spectroscopy measurements were performed on different compounds in both intercalated (Li1WO1.05S2, Li2.7WO1.05S2 and Li3.8WO1.05S2) and partially de-intercalated (Li1WO1.05S2) states in order to understand the redox processes occurring during the first discharge–charge cycle. The analysis of both the W4𝑓 and the S2𝑝 peaks has shown that the redox processes involve not only the tungsten atoms but also sulphur atoms. At the beginning of the intercalation, W6+ was first partially reduced into W5+, and then into W4+, but the important stage was the reduction of W4+ into W0. In W0, the electron binding energy was very close to that of metallic tungsten. At the same time, S$^{2-}_2$ ions were partially reduced into S2- ions. But only the reduction process of tungsten atoms appeared to be totally reversible.

    • Author Affiliations

       

      I Martin-Litas1 P Vinatier1 A Levasseur1 J C Dupin2 D Gonbeau2

      1. Institut de Chimie de la Matière Condensée de Bordeaux CNRS and Ecole Nationale Supérieure de Chimie et de Physique de Bordeaux, 16, avenue Pey Berland, 33607 Pessac cedex, France
      2. Laboratoire de Physico–Chimie Moléculaire (UMR 5624), Université de Pau et des Pays de l’Adour, 2, avenue du dex 9, France
    • Dates

       
  • Bulletin of Materials Science | News

    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.