A Polysulfide‐Immobilizing Polymer Retards the Shuttling of Polysulfide Intermediates in Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries are regarded as one of the most promising candidates for next‐generation rechargeable batteries. However, the practical application of lithium–sulfur (Li–S) batteries is seriously impeded by the notorious shuttling of soluble polysulfide intermediates, inducing a low utilization of active materials, severe self‐discharge, and thus a poor cycling life, which is particularly severe in high‐sulfur‐loading cathodes. Herein, a polysulfide‐immobilizing polymer is reported to address the shuttling issues. A natural polymer of Gum Arabic (GA) with precise oxygen‐containing functional groups that can induce a strong binding interaction toward lithium polysulfides is deposited onto a conductive support of a carbon nanofiber (CNF) film as a polysulfide shielding interlayer. The as‐obtained CNF–GA composite interlayer can achieve an outstanding performance of a high specific capacity of 880 mA h g−1 and a maintained specific capacity of 827 mA h g−1 after 250 cycles under a sulfur loading of 1.1 mg cm−2. More importantly, high reversible areal capacities of 4.77 and 10.8 mA h cm−2 can be obtained at high sulfur loadings of 6 and even 12 mg cm−2, respectively. The results offer a facile and promising approach to develop viable lithium–sulfur batteries with high sulfur loading and high reversible capacities.

Rational Design of Binders for Stable Li‐S and Na‐S Batteries

“…The abovementioned linear binders such as PEO, [76] PVA, [44] PEI, [77] and CMC, [30] also show polysulfide-anchoring ability because of the existence of the lone electron pairs on O and N of the molecules. [79] Later on, other linear polymers including sulfonated poly(ether ether ketone), [80] poly(vinylidene difluoride-trifluoroethylene), [81] poly(3,4-ethyle nedioxythiophene):polystyrene sulfonate (PEDOT:PSS), [82] polyamide-6, chitosan sulfate ethylamide glycinamide, [83] benzimidazole-containing poly(arylene ether ketone), and sulfonated poly(arylene ether ketone-co-benzimidazole) [84] also have been reported to show good polysulfide anchoring ability. [78] This hydrophilic property is favorable considering environmental friendliness.…”

A Freestanding Flexible Single‐Atom Cobalt‐Based Multifunctional Interlayer toward Reversible and Durable Lithium‐Sulfur Batteries

“…The high discharge plateau is related with the generation of high‐order soluble polysulfides, which is the origin of the shuttle effect. The low discharge plateau corresponds to the formation of insoluble Li 2 S x ( x = 1, 2), commonly possessing sluggish reaction kinetics . The high‐ and low‐voltage plateau capacities are calculated from the discharge curves and denoted as Q H and Q L , respectively.…”

Let It Catch: A Short‐Branched Protein for Efficiently Capturing Polysulfides in Lithium–Sulfur Batteries

“…The upper discharge plateau is relevant to the conversion of cyclo‐S 8 to soluble long‐chain polysulfides (Li 2 S n , 4 ≤ n ≤ 8) and the lower plateau is attributed to the further reduction of long‐chain polysulfides to insoluble sulfides of Li 2 S n ( n = 1, 2) . Therefore, tracking the change of capacity for both stages is important for understanding of the loss of sulfur species and redox reactions . The capacities of the upper and lower voltage plateaus are extracted from the discharge voltage profiles in Figure 3a and denoted as Q H and Q L , respectively.…”

“…The previous efforts have demonstrated the effectiveness of two primary classes of biopolymers, proteins, and polysaccharides, for absorbing the polysulfides in Li–S batteries. The polar groups inside these biopolymer molecules have been believed to be the main reason for binding with polysulfides . It is noted that, biopolymers have structural and compositional diversities, which bring about significant impacts on their properties and functions .…”