Shielding Polysulfide Intermediates by an Organosulfur‐Containing Solid Electrolyte Interphase on the Lithium Anode in Lithium–Sulfur Batteries

Abstract

The lithium–sulfur (Li–S) battery is regarded as a promising high‐energy‐density battery system, in which the dissolution–precipitation redox reactions of the S cathode are critical. However, soluble Li polysulfides (LiPSs), as the indispensable intermediates, easily diffuse to the Li anode and react with the Li metal severely, thus depleting the active materials and inducing the rapid failure of the battery, especially under practical conditions. Herein, an organosulfur‐containing solid electrolyte interphase (SEI) is tailored for the stabilizaiton of the Li anode in Li–S batteries by employing 3,5‐bis(trifluoromethyl)thiophenol as an electrolyte additive. The organosulfur‐containing SEI protects the Li anode from the detrimental reactions with LiPSs and decreases its corrosion. Under practical conditions with a high‐loading S cathode (4.5 mgS cm−2), a low electrolyte/S ratio (5.0 µL mgS−1), and an ultrathin Li anode (50 µm), a Li–S battery delivers 82 cycles with an organosulfur‐containing SEI in comparison to 42 cycles with a routine SEI. This work provokes the vital insights into the role of the organic components of SEI in the protection of the Li anode in practical Li–S batteries.

In situ Construction of Robust Biphasic Surface Layers on Lithium Metal for Lithium–Sulfide Batteries with Long Cycle Life

“…To demonstrate the effect of the robust BSLs on inhibiting the side reactions between Li‐metal anode and LiPSs, we examined the electrochemical performance of Li‐Li symmetrical cells with 1 M LiTFSI‐DOL/DME electrolyte containing 50 mM Li 2 S 8 chemicals (Figure 3). With Li 2 S 8 in the electrolyte, the symmetrical cells with BSLs‐Li electrodes presented stable voltage profiles over 1200 h with little hysteresis at 1 mA cm −2 , which is significantly better than those of pristine Li and DMSO‐treated Li electrodes (Figure 3 a; Figure S14) [22] . We also studied the performance of Li‐Li symmetrical batteries under high current densities and lithium‐stripping capacities (i.e., 2 mAh cm −2 at a current density of 2 mA cm −2 , and 3 mAh cm −2 at a current density of 3 mA cm −2 ).…”

“…With Li 2 S 8 in the electrolyte,t he symmetrical cells with BSLs-Li electrodes presented stable voltage profiles over 1200 hw ith little hysteresis at 1mAcm À2 ,w hich is significantly better than those of pristine Li and DMSO-treated Li electrodes (Figure 3a;F igure S14). [22] We also studied the performance of Li-Li symmetrical batteries under high current densities and lithium-stripping capacities (i.e., 2mAh cm À2 at ac urrent density of 2mAcm À2 ,and 3mAh cm À2 at acurrent density of 3mAcm À2 ). Ther esults show that Li-Li symmetrical cells with BSL-coated Li electrodes can stably circulate for more than 300 hours (Figure S15), which is much better than that of cells without the BSLs.This suggests that the BSLs are robust and provide ap rotective shield to inhibit the LiPSs shuttling effect in Li-S batteries.T oi llustrate the underlying mechanism, we further examined electrochemical impedance spec-tra (EIS) of these symmetric cells (Figure 3b,c).…”

A Natural Polymer Captor for Immobilizing Polysulfide/Polyselenide in Working Li–SeS2 Batteries

“…The Li metal of the cell with CF@CNTs-NPP interlayer possesses the lowest sulfur and almost undetectable selenium mass content. All above results suggest that the CF@CNTs-NPP interlayer can effectively block the dissolution and shuttling of soluble Li 2 S n /Li 2 Se n so as to largely alleviate the depletion of LiNO 3 and the corrosion of fresh Li, contributing to stable SEI and significantly improved lifespan of Li–SeS 2 batteries under practical conditions [ 74 – 76 ].…”

Material design and structure optimization for rechargeable lithium-sulfur batteries

“…As well as the inorganic salts and inorganic solid nanoparticles mentioned previously, some organic additives for Li anode protection have been also demonstrated in Li-S batteries. 223,224 For example, a novel sulfur-containing polymer of poly(sulfurrandom-triallylamine) with a sulfur content of 90 wt % (PST-90) was regarded as a Review high-performance additive to protect the Li metal anode in Li-S batteries. 217 In PST-90, numerous sulfur chains are connected with organic components to form a 3D interconnected network.…”