Polyamidoamine dendrimer modified Ketjen Black mixed sulfur coated cathode for enhancing polysulfides adsorbability in Li-S batteries

Abstract

Lithium sulfur (Li-S) batteries were considered the next generation of energy devices with the greatest development potential because of their large theoretical capacity and high energy density. However, many challenges exist in the research field of Li-S batteries, such as low utilization rate of active substances and inferior cycling performance. Here, a simple and feasible preparation strategy was applied to fabricate the composite cathode of polyamidoamine (PAMAM) dendritic macromolecule polymer modified the Ketjen Black mixed sublimated sulfur (PAMAM@KB@S). Benefiting from the improved polysulfides adsorbability due to the abundant functional groups which originate from PAMAM, PAMAM@KB@S composites with 3.94 mg sulfur-loading at a current density of 0.5 C exhibit a high initial specific discharge capacity of 894.3 mAh g−1 and maintain a specific discharge capacity of 455.7 mAh g−1 after 200 cycles. And the average Coulombic efficiency of PAMAM@KB@S electrode (96.7%) within 200 cycles is higher than that of KB@S electrode (88.5%).