Electrochemical properties of tungsten oxysulphide thin films as positive electrodes for lithium microbatteries

Bulletin of materials science

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

[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$$Institut de Chimie de la Matière Condensée de Bordeaux CNRS and Ecole Nationale Supérieure de Chimie et de Physique de Bordeaux, 16, avenue Pey Berland, 33607 Pessac cedex, FranceInstitut de Chimie de la Matière Condensée de Bordeaux CNRS and Ecole Nationale Supérieure de Chimie et de Physique de Bordeaux, 16, avenue Pey Berland, 33607 Pessac cedex, France$$;Laboratoire de Physicoâ€�?�Chimie Moléculaire (UMR 5624), Université de Pau et des Pays de l’Adour, 2, avenue du dex 9, France$$Laboratoire de Physicoâ€�?�Chimie Moléculaire (UMR 5624), Université de Pau et des Pays de l’Adour, 2, avenue du dex 9, FranceLaboratoire de Physicoâ€�?�Chimie Moléculaire (UMR 5624), Université de Pau et des Pays de l’Adour, 2, avenue du dex 9, France$$

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

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

Several WO_ð‘�?S_ð‘�? tungsten oxysulphide thin films were tested as positive electrodes for lithium microbatteries. The amorphous WO_1.05S₂ 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 chargeâ€�?�discharge cycles, between 3.0 V and 1.2 V.X-ray photoelectron spectroscopy measurements were performed on different compounds in both intercalated (Li₁WO_1.05S₂, Li_2.7WO_1.05S₂ and Li_3.8WO_1.05S₂) and partially de-intercalated (Li₁WO_1.05S₂) states in order to understand the redox processes occurring during the first dischargeâ€�?�charge cycle. The analysis of both the W4ð‘�?? and the S2ð‘�? 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 S^2- ions. But only the reduction process of tungsten atoms appeared to be totally reversible.

【 授权许可】

Unknown