Important Aspects on the Fabrication and             Characterization of Lithium-Sulfur Batteries 

Natalia A. Cañas,1 Norbert Wagner,1 and K. Andreas Friedrich1,2

1 German Aerospace Center, Stuttgart, Institute of Technical Thermodynamics
Pfaffenwaldring 38-40,70569, Stuttgart, Germany.
2 University of Stuttgart, Institute for Thermodynamic and Thermal Engineering,
Pfaffenwaldring 6, 70569, Stuttgart, Germany.
natalia.canas@dlr.de

The lithium sulfur (Li-S) battery is a promising system for the future generation of rechargeable batteries. The main advantages of this type of cell are the high theoretical capacity (1675 Ah∙kg−1), high energy density (2500 Wh∙kg−1) and low cost of sulfur. However, degradation of the cathode is difficult to alleviate because of the complex electrochemistry of the Li-S system. In these work, simple approaches on the battery fabrication and it influences on the stability of the cell are presented. Furthermore, these investigations aim to understand the critical issues associated with the electrochemical processes occurring in Li-S batteries, establishing methods and procedures necessary to investigate this system. The result obtained through the use of the following characterization techniques are compared and analyzed: (a) X-ray diffraction for detection and quantification of crystalline products Li2S and S8 [1], (b) electrochemical impedance spectroscopy for analysis of electrolyte resistance, charge transfer resistance in the electrodes, and reaction and dissolution Li2S and S8 [2], (c) UV-Vis spectroscopy for detection and quantification of dissolved species (mainly polysulfides) [3], (d) Atomic force microscopy for surface analysis and formation of isolating layers, (e) Thermal analysis (TG/DSC) and mass spectroscopy to study the degradation of components and morphological changes on the cathode.

[1] N. A. Cañas, S. Wolf, N. Wagner, K. A. Friedrich. J. of Power Sources, 226 (2013) 313-319.
[2] N.A. Cañas, K. Hirose, N. Wagner, B. Pascucci, N. Wagner, K.A Friedrich, R. Hiesgen, Electrochim. Acta, 97 (2013) 42-51.
[3] N.A. Cañas, D. N. Fronczek, N. Wagner, A. Latz, K.A Friedrich, submitted to J. Phys. Chem. C.
[4] R. Hiesgen, S. Sörgel, R.Costa, L.Carlé, I. Galm, N. Cañas, B. Pascucci and K. A. Friedrich. Beilstein J. of Nanotechnology 2013, 4, 611-624.