Effect of Ball Milling on Electrochemical Properties of Sulfur/Polyacrylonitrile (SPAN) Cathode in Li/S Battery

Ball-milling process was applied to increase sulfur content in sulfur/polyacrylonitrile (SPAN) composites and improve electrochemical properties of Li/S batteries. In contrast to as-received PAN, pre-heated PAN was pulverized by the ball-milling, resulting in the continuous size reduction with increasing the milling time. Sulfur contents in SPAN composites synthesized with a pre-heated and milled PAN were increased with prolonging the milling time and the maximum content reached 44.5% for the milling time of 10 h. Li/S cells with SPAN electrodes delivered the first discharge capacities of 1356, 1409, 1512, and 1610 mAh/g-sulfur for milling times of 0, 1, 5, and 10 h. The 10 h-milled SPAN electrode with the highest sulfur content exhibited poor initial efficiency and low capacity retention at 100 cycles, whereas from a comprehensive viewpoint of the specific capacity and capacity retention, the 6 h-milled SPAN electrode exhibited the best electrochemical performance due to the suitable size and sulfur content.