A novel quasi-solid state electrolyte with highly effective polysulfide diffusion inhibition for lithium-sulfur batteries

Abstract

Polymer solid state electrolytes are actively sought for their potential application in energy storage devices, particularly lithium metal rechargeable batteries. Herein, we report a polymer with high concentration salts as a quasi-solid state electrolyte used for lithium-sulfur cells, which shows an ionic conductivity of 1.6 mS cm−1 at room temperature. The cycling performance of Li-S battery with this electrolyte shows a long cycle life (300 cycles) and high coulombic efficiency (>98%), without any consuming additives in the electrolyte. Moreover, it also shows a remarkably decreased self-discharge (only 0.2%) after storage for two weeks at room temperature. The reason can be attributed to that the electrolyte can suppress polysulfide anions diffusion, due to the high ratio oxygen atoms with negative charges which induce an electrical repulsion to the polysulfide anions, and their relatively long chains which can provide additional steric hindrance. Thus, the polysulfide anions can be located around carbon particles, which result in remarkably improved overall electrochemical performance, and also the electrolyte have a function of suppress the formation of lithium dendrites on the lithium anode surface.

Upgrading traditional liquid electrolyte via in situ gelation for future lithium metal batteries

“…6B ) attributed to massive solvent oxidation and decomposition. Theoretically, the instability of liquid-phase DOL/DME to a large extent originates from the DOL with an unstable cyclic structure ( 38 , 39 ), which implies that, after a ring-opening polymerization process where the cyclic DOL is, in advance, stabilized in the long-chain linear structure, the tolerance of electrolyte toward electrochemical progress under high voltage could be improved. As proof, the linear sweep voltammetry (LSV) curve presented in Fig.…”

Editors' Choice—Understanding Chemical Stability Issues between Different Solid Electrolytes in All-Solid-State Batteries

“…3,40,65 Furthermore, several studies in the field of Li/S battery research demonstrated that polysulfides can be dissolved in PEO, showing high mobility in Li/S cells with SPEs. [66][67][68] It can therefore be assumed that removal of the LSPS decomposition products, i.e., of Li-ions and polysulfides, into the polymer is a driving force for the oxidation of LSPS, following the principle of Le Chatelier.…”

Ionic Liquid Functionalized Gel Polymer Electrolytes for Stable Lithium Metal Batteries

“…The LE (DOL/DME) started to become unstable at 4.00 V and showed a serious decomposition at about 4.20 V [23] . The instability of LE largely originates from the relatively unstable cyclic structure of DOL [24] . In the case of GEL, the onset potential for the decomposition was found to be higher than 4.00 V pointing to the encapsulation of electrolyte within the GEL structure.…”