title: Long-Life and High-Areal-Capacity Li-S Batteries Enabled by a Light-Weight Polar Host with Intrinsic Polysulfide Adsorption.
abstract: Lithium-sulfur batteries are attractive electrochemical energy storage systems due to their high theoretical energy density and very high natural abundance of sulfur. However, practically, Li-S batteries suffer from short cycling life and low sulfur utilization, particularly in the case of high-sulfur-loaded cathodes. Here, we report on a light-weight nanoporous graphitic carbon nitride (high-surface-area g-C3N4) that enables a sulfur electrode with an ultralow long-term capacity fade rate of 0.04% per cycle over 1500 cycles at a practical C/2 rate. More importantly, it exhibits good high-sulfur-loading areal capacity (up to 3.5 mAh cm(-2)) with stable cell performance. We demonstrate the strong chemical interaction of g-C3N4 with polysulfides using a combination of spectroscopic experimental studies and first-principles calculations. The 53.5% concentration of accessible pyridinic nitrogen polysulfide adsorption sites is shown to be key for the greatly improved cycling performance compared to that of N-doped carbons.
authors: Department of Chemistry and the Waterloo Institute for Nanotechnology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors: Quan
authors: Q
authors: Pang
authors: Department of Chemistry and the Waterloo Institute for Nanotechnology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors: Linda F
authors: LF
authors: Nazar
keywords: graphitic carbon nitride; light-weight; lithium−sulfur battery; long cycle life; polysulfide adsorption