An effective polysulfides bridgebuilder to enable long-life lithium-sulfur flow batteries

Polysulfides shuttle, although is not the only one, but definitely the most prominent problem which hinders the commercialization of lithium-sulfur cells. Herein, a functionally designed SiO2 tethered 1-methyl-1-propylpiperidinium chloride (SiO2-PPCl) ionic liquid nanoparticle is adopted as a bridgebuilder between the carbon carrier and lithium polysulfides (LPS) to modulate shuttle issues. The SiO2-PPCl exerts effective adhesion to both polar LPS and nonpolar carbon carrier material by its special function groups, which make it act as a bridge between them, therefore, the dissolved LPS are prevented from migrating to lithium anode effectively, and the corresponding LPS shuttle is controllable by simply tuning the ratio of SiO2-PPCl to sulfur. This strategy is demonstrated in a lithium sulfur suspension flow cell in which the shuttle effect is more serious because large quantity of electrolyte is adopted, and over 1000 cycles is achieved with high coulombic efficiency of 99%. Verified in a laboratory flow cell equipment, the approach of exploiting polysulfides bridgebuilder to control LPS shuttle manifests its feasibility and offers a new direction to develop lithium-sulfur batteries.