Electrochemical Characterization of Carbon/Sulfur as Lithium-Sulfur Battery Cathodes?,

M. ORTIZ, A. VISINTIN AND S. REAL

Congreso; 20th Topical Meeting of the International Society of Electrochemistry, Advances in Lithium and Hydrogen Electrochemical Systems for Energy Conversion and Storage; 2017

International Society of Electrochemistry

Nowadays, rechargeable batteries with high energy density are required for our society, due to the needsof cleaner and more efficient energy systems and, with the objective of supplying the increasingtechnological demands. Commercial lithium batteries are systems based on intercalation compounds thatare able to delivering specific energies, about 150-200 WhKg-1, one-third of their theoretical energy(≈ 600 Wh kg-1). The reversible capacity for these intercalation compounds results difficult to beincreased. Consequently, the need to explore new cathodes formed by lighter materials and involvingelectrochemical reactions of more than one electron becomes very important. An element as sulfur wouldbe satisfying these conditions (with a theoretical capacity of 1675 mAhg-1 and a specific energy of 2600WhKg-1) [1,2]. The lithium-sulfur battery has been investigated by different groups in past decades;however, there are serious drawbacks, which have not yet been overcome and limit the practicaldevelopment of this system [3]. Moreover, sulfur is much more abundant, inexpensive, and non-toxiccompared to the transition-metal oxide cathodes.We present, in this study, the preparation of composites with carbon and sulfur materials in a singlefabrication process: using S2C as the solvent. The characterization of the prepared material was performedusing optical techniques (X-ray diffraction, scanning electron microscopy and transmission) and itselectrochemical performance in lithium-sulfur batteries was studied using electrochemical techniquessuch as: charge-discharge cycles, galvanostatic discharges to different currents and cyclic voltammetry.The prepared composite materials delivered higher capacities during the first cycles (≈800 mAhg-1) andthen they were stabilized at values around 60% of the initial capacity. Furthermore, carbonelectrochemical response was not observed; these results indicate that its main function is to acteffectively as an electron-conducting material and support of the matrix.