Diminishing Self-Discharge of High-Loading Li-S Batteries with Oxygen-rich Biomass Carbon Interlayers.

Abstract

Lithium-sulfur batteries (Li-S) have possessedgratifying developmentin the past decadedue to their high theoretical energy density. However, the severe polysulfide shuttling provokes undesirable self-discharge effect, leading to low energy efficiency in Li-S batteries.Herein, an interlayer composed of oxygen-rich carbon nanosheets (OCN) derived from bagasse is elaborated to suppress the shuttle effect and reduce the resultant self-discharge effect. The OCN interlayer is able to physically block the shuttling behavior of polysulfides and its oxygen-rich functional groups can strongly interact with polysulfides via O-S bonds to chemically immobilize mobile polysulfides. The self-discharge test for seven days further shows that the self-discahrge rate is diminished by impressive 93%. As a result, Li-S batteries with the OCN interlayer achieve an ultrahigh discharge specific capacity of 710 mAh g-1at a high mass loading of 7.18mg.Thework provides a facile method for designing functional interlayersand opens a new avenue for realizing Li-S batteries with high energy efficiency.