Sulfonic groups stemmed ionic shield for polysulfides towards high performance Li–S batteries

Abstract

Lithium-sulfur (Li–S) batteries possess great attention for energy storage owing to its high theoretical capacity and energy density compared to the state-of-the-art lithium-ion technology. However, the commercialization of Li–S battery is still at bottleneck due to the several technical problems, of which polysulfide shuttle effect is the major challenge. To minimize the shuttling of polysulfides by confining them within the cathode compartment, a novel lithium ion conducting organic polymer lithium poly(2-acrylamido-2-methyl-1-propanesulfonate) (LPAMPS) coated Celgard separator (LPAMPS@CG) was designed by simple doctor blade coating technique. The negatively charged –SO3̄ groups present in LPAMPS coating works as an electrostatic shield for soluble polysulfide anions through coulombic repulsion without inhibiting the transport of Li+. The Li–S cell containing LPAMPS@CG not only reduces shuttling effect but also enhances the electrolyte wettability, interfacial property and ionic conductivity. The cell with LPAMPS@CG separator delivered an initial discharge capacity of 1486 mAh g−1 at 0.1C, and a discharge capacity of 1061 mAh g−1 was retained after 200 cycles. Furthermore, the cells containing LPAMPS@CG exhibited excellent rate capability and anti-self-discharge rate.