Letter to the editor Structure and electrical properties of a new thio-phosphorus oxynitride glass electrolyte Nerea Mascaraque a , Hiromichi Takebe b , Gregory Tricot c , José Luis G. Fierro d , Alicia Durán a , Francisco Muñoz a, ⁎ a Instituto de Cerámica y Vidrio (CSIC), Kelsen 5, Cantoblanco, 28049 Madrid, Spain b Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577, Japan c LASIR UMR CNRS 8516, Université de Lille 1, 59655 Villeneuve d'Ascq Cedex, France d Instituto de Catálisis y Petroquímica (CSIC), Marie Curie 2, Cantoblanco, 28049 Madrid, Spain abstract article info Article history: Received 13 June 2014 Received in revised form 8 September 2014 Accepted 10 September 2014 Available online xxxx Keywords: Solid electrolytes; Ionic conductivity; Oxynitride glasses; Sulfur; NMR For the first time, a thio-phosphorus oxynitride glass containing nitrogen and sulfur, LiPOSN, has been prepared by a melting process in two steps and its manipulation is possible in air without any decomposition. The anionic substitution of oxygen by sulfur and nitrogen in the phosphate glass structure has been confirmed by 1D 31 P solid state NMR and XPS. The 2D 31 P DQ-SQ experiment indicates that S bearing phosphate groups are integrated into the global phosphate network and do not form clusters. Through the study of the properties of this glass, it was verified a decrease of the glass transition temperature, due to the depolymerization of the phosphate network when lithium sulfide is introduced into the oxynitride glass, along with a pronounced increase of the ionic con- ductivity, that suggest that this glass can be considered as a new highly conductive and corrosion resistant glass electrolyte. © 2014 Elsevier B.V. All rights reserved. Phosphate glasses used as solid state electrolytes in lithium batteries [1–3] must present a high ionic conductivity, negligible electronic con- ductivity, thermal and chemical stability and compatibility with the electrodes. Nowadays, Li 2 S-P 2 S 5 -P 2 O 5 glasses are the materials with the highest ionic conductivity and better performance to be used as solid electrolytes. Many authors have reported on these materials in thin films [4], powders [5] and bulk glasses [6]. Minami and Ohtomo [7,8] demonstrated that the introduction of P 2 O 5 and Li 2 O in the system of Li 2 S-P 2 S 5 produces an increase of the ionic conductivity. The sulfide- based electrolytes generally present lithium ion conductivity higher by several orders of magnitude with respect to oxide-based electrolytes. However, the main disadvantage of Li 2 S-materials is their poor chemical durability, which leads to their degradation in air. One way to improve the durability may be the introduction of nitrogen [9,10] that also in- creases the ionic conductivity [11–13] and thermal stability [10]. So, it would be expected that phosphate glasses presenting both sulfur and nitrogen may give rise to materials with a higher ionic conductivity and a suitable chemical durability. In this preliminary work, a new glass with composition Li 1.62 PO 2.84 S 0.11 N 0.32 was prepared through a melting process in two steps developed by Mascaraque et al. [14] for obtaining LiPOFN glasses. The properties were studied by Differential Thermal Analysis (DTA) and Impedance Electrochemical Spectroscopy (EIS) in order to determine the glass transition temperature (T g ) and the ionic conductivity (σ). The structural characterization was performed by 1D 31 P magic angle spinning nuclear magnetic resonance (MAS-NMR), 2D 31 P double quantum-single quantum (DQ-SQ) MAS-NMR and X-ray photoelectron spectroscopy (XPS). The structural results confirm the anionic substitu- tion of sulfur in the LiPON glass network as well as a substantial increase of ionic conductivity. The process of obtaining the thio-phosphorus oxynitride glass, Li 1.62 PO 2.84 S 0.11 N 0.32 , started from the parent glass 55Li 2 O·45P 2 O 5 [11], prepared from appropriate batch of reagent grade materials: Li 2 CO 3 (99% ACS Reagent, Aldrich) and (NH 4 ) 2 HPO 4 (99% ACS, Reagent, Merck), calcined for 1 day in porcelain crucibles in an electric furnace up to 400 °C, then melted for 2 h at 850 °C, and casted onto brass plates to quench the melt. The glass was nitrided following a thermal treat- ment under flowing anhydrous ammonia [15] at 750 °C for 5 h. The thio-phosphorus oxynitride glass was then prepared through a second melting step of the oxynitride glass (Li 1.22 PO 2.60 N 0.34 ) mixed with re- agent grade material Li 2 S (99%, Merck). The batch was melted in a vitre- ous carbon crucible covered with a silica tube under nitrogen flow at 650 °C during 30 min, as described in [16,17]. After melting, the crucible is broken to obtain the sample (Li 1.62 PO 2.84 S 0.11 N 0.32 ). Nitrogen and sulfur elemental analysis was carried out using a LECO CHNS-932. The errors of nitrogen and sulfur analysis are ±0.3 and ±0.2 mol%, respectively. The starting nitrogen content of sulfur- Journal of Non-Crystalline Solids 405 (2014) 159–162 ⁎ Corresponding author. E-mail address: fmunoz@icv.csic.es (F. Muñoz). http://dx.doi.org/10.1016/j.jnoncrysol.2014.09.011 0022-3093/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Journal of Non-Crystalline Solids journal homepage: www.elsevier.com/ locate/ jnoncrysol LETTER TO THE EDITOR