Suppressing sulfur crosstalk lowers the bar of lithium metal anode for practical Li-S pouch cells

Abstract

The obscure cause of early failure in lithium-sulfur batteries has long hindered their practicality. In this work, the shortboard factor has been ascertained as the lithium metal anode. Capacity-type sulfur cathode amplifies the intrinsic dendrite growth of Li metal through higher capacity requirements (> 8 mAh/cm2). More significantly, sulfur crosstalk seriously destroys the chemical-electrochemical stability of Li metal and directly leads to the unexpected capacity diving, which has been identified as more dominant and crucial. Herein, to lower the bar of the Li metal anode for the practicality of Li-S batteries, we proposed a hybrid sulfur-rich cathode to suppress the sulfur crosstalk. Our innovations reduced the lithium porosity by 26.7 % and the lithium corrosion rate by 27.4 % after cycling. As a result, our demonstrated pouch cells achieved superior energy densities of 460 Wh/kg and 985 Wh/L, and a stable cycle life above 75 cycles with an excellent capacity retention of 80 %. Our work is anticipated to provide a meticulous and thorough view to let the community rethink how to realize the practicality of Li-S batteries.