Abstract
The lithium–sulfur battery is promising as an alternative to conventional lithium-ion technology due to the high energy density of both sulfur and lithium metal electrodes. An extended lifetime has been demonstrated, but two notable challenges still exist to realize its full potential: to overcome the undesired high electrolyte/sulfur ratio required for the catholyte-type mechanism that governs most cell configurations, and to inhibit Li dendrite growth and its parasitic reaction with the electrolyte that results in cell degradation. Here, we demonstrate that by tuning the electrolyte structure, the challenges at both electrodes can be tackled simultaneously. Specifically, the sulfur speciation pathway transforms from a dissolution–precipitation route to a quasi-solid state conversion in the presence of a lowered solvent activity and an extended electrolyte network, curtailing the need for high electrolyte volumes. Ab initio calculations reveal the nature of the network structure. With such an optimized structure, the electrolyte allows dendrite-free Li plating and shows a 20-fold reduction in parasitic reactions with Li, which avoids electrolyte consumption and greatly extends the life time of a low electrolyte/sulfur (5 µl mg–1) sulfur cell.
Original language | English |
---|---|
Pages (from-to) | 783-791 |
Number of pages | 9 |
Journal | Nature Energy |
Volume | 3 |
Issue number | 9 |
DOIs | |
State | Published - Sep 1 2018 |
Externally published | Yes |
Funding
This research was supported as part of the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the US Department of Energy, Office of Science, Basic Energy Sciences. L.F.N. also thanks the NSERC for generous support via their Canada Research Chair and Discovery Grant programmes. We appreciate helpful discussions with T. Watkins and K. Zavadil.