Abstract
A much higher cell voltage of ca. 2.5 V than that of the typical Li-S battery was successfully achieved by combining the 5 V-class, spinel-type LiNi0.5Mn1.5O4 (LNMO) as a cathode and the rubber-derived sulfur composite as an anode. The cycling performance of the cell was improved by the PVDF coating only the cathode and coating both the cathode and anode, in which the discharge capacity retention increased from ca. 45 % to ca. 60 %. On the other hand, there was no difference in the cycling performance between the cell with the PVDF coating only the anode and the cell without the PVDF coating both the cathode and anode. There was no difference between the cycling performance of the half-cell of the LNMO cathode with the PVDF coating and without the PVDF coating, indicating that the PVDF coating on the cathode side does not prevent degradation of the electrolyte solution on the cathode surface. These results suggest that the PVDF coatings of the cathode surface play an important role as a protective layer in preventing the direct contact and side reaction between the polysulfides and cathode surface, thus leading to improvement of the cycling performance.
