Ordered Distribution of S in a Multi Walled Carbon Nanotubes/Sulfur Composite Cathodes for Li/S Batteries

The Li- S batteries has pronounced as an excellent alternative in Li batteries, mainly due to its high theoretical specific capacity and energy density. However, the practical application of rechargeable Li/S batteries has several problems due to the low utilization of the active material and low efficiency during charge and discharge cycles. This work proposes the use of MWCNT as support material for the S in this type of batteries. Among the advantages offered by the use of MWCNT like more specific area, there is the prevention of the dissolution of polisufides with long chain, which can cause passivation of the anode and reduce the life cycle of the battery. Functionalization of MWCNT improves the amount of active sites on their surface, therefore, deposition of S in the MWCNT is homogeneous and controlled, allowing increasing of its electrochemical properties. In this work a characterization of this distribution is effectuated using electrochemical techniques, EIS (Electrochemical Impedance Spectroscopy), CV (Cyclic Voltammetry), in organic electrolyte. The surface characterization was made with AFM (Atomic Force Microscopy). Techniques of superficial characterization as LEIS (Localized Electrochemical Impedance Spectroscopy) and SECM (Scanning Electrochemical Microscopy) helps to relate the electrochemical behavior and, the superficial arrangement in this materials.