Development of three dimentioal free standing carbon nanofiber cathode for the Lithium - Sulfur (LiS) battries
Muhammad Saif Maqsood, Deutsches Textilforschungszentrum Nord-West gGmbH , Krefeld, GermanyEui-young Shin, Deutsches Textilforschungszentrum Nord-West gGmbH , Krefeld, Pascal Sous , ZBT, Duisburg, Wael Ali, Deutsches Textilforschungszentrum Nord-West gGmbH , Krefeld, Andreas Wego, Deutsches Textilforschungszentrum Nord-West gGmbH , Krefeld, Jochen S. Gutmann, Physikalische Chemie Universität Duisburg Essen, Essen,
In contrast to Lithium batteries, Lithium sulfur (LiS) batteries have up to three times higher energy density and a significantly low cost due to the use of inexpensive sulfur in the cathode. However, sulfur has low conductivity and needs carbon as a conductive agent in the cathode. In addition, LiS batteries suffer from volume expansion of sulfur electrode and shuttle effect during charge and discharge cycles resulting in a low number of overall cycles. In this study, three-dimensional porous and nonporous carbon nanofibers (CNFs) were prepared from electrospun polyacrylonitrile nanofibers. Prepared CNFs were then used in LiS batteries in two configurations; in the first configuration, CNFs were coated with Lithium sulfide (Li2S) and used as standalone cathode, in the second as an interlayer between Lithium sulfide (Li2S) coated-cathode and separator. Furthermore, the effects of carbonization temperature and porosity of CNFs on the performance of LiS batteries have been investigated. It was found that the carbonization temperature of CNFs plays a critical role in achieving superior cell performance. Electrochemical measurements show that CNFs cathode can achieve a discharge capacity of up to 550 mAh/g at 1C rate with a coulomb efficiency of above 98% after 250 charge and discharge cycles.