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

Abstract

SeS2 has become a promising cathode material owing to its enhanced electrical conductivity over sulfur and higher theoretical specific capacity than selenium; however, the working Li–SeS2 batteries have to face the practical challenges from the severe shuttling of soluble dual intermediates of polysulfide and polyselenide, especially in high-SeS2-loading cathodes. Herein, a natural organic polymer, Nicandra physaloides pectin (NPP), is proposed to serve as an effective polysulfide/polyselenide captor to address the shuttling issues. Informed by theoretical calculations, NPP is competent to provide a Lewis base-based strong binding interaction with polysulfides/polyselenides via forming lithium bonds, and it can be homogeneously deposited onto a three-dimensional double-carbon conductive scaffold to finally constitute a polysulfide/polyselenide-immobilizing interlayer. Operando spectroscopy analysis validates the enhanced polysulfide/polyselenide trapping and high conversion efficiency on the constructed interlayer, hence bestowing the Li–SeS2 cells with ultrahigh rate capability (448 mAh g−1 at 10 A g−1), durable cycling lifespan (≈ 0.037% capacity attenuation rate per cycle), and high areal capacity (> 6.5 mAh cm−2) at high SeS2 loading of 15.4 mg cm−2. Importantly, pouch cells assembled with this interlayer exhibit excellent flexibility, decent rate capability with relatively low electrolyte-to-capacity ratio, and stable cycling life even under a low electrolyte condition, promising a low-cost, viable design protocol toward practical Li–SeS2 batteries.

High Energy Density Aqueous Zinc–Chalcogen (S, Se, Te) Batteries: Recent Progress, Challenges, and Perspective

“…In this way, combining S and Se to rationally balance the flaw but complementary feature of these two elements has been investigated to enhance battery performance, which is represented as selenium-sulfur composite (Se x S y ) electrode. [153,154] Till now, a large quantity of work has been devoted to develop the Li-Se x S y , [155,156] Na-Se x S y , [157,158] and K-Se x S y batteries, [159,160] while the reaction mechanism and electrochemical properties of Zn-Se x S y aqueous batteries are rarely reported to our knowledge.…”

Advances in Selenium Sulfides Cathodes for Lithium/Selenium–Sulfur Batteries

“…The porous nanofiber construction also improves the flexibility and ensures uninterrupted channels for fast ionic and electronic transfer (Figure a). In another study, Wu’s team developed a 3D dual-carbon framework comprising CNTs enveloped in nitrogen-rich carbon foam (CF@CNTs, Figure b) . Created to act as the host for both the SeS 2 cathode and the Li metal anode, this structure yielded reliable electrochemical behavior.…”

“…(b) Schematics of the fabrication of CF@CNTs-NPP. Reproduced with permission from ref . Copyright 2021 Shanghai Jiao Tong Univ Press.…”

A carbon mixed selenium sulfide separator coating for lithium‐sulfur battery life enhancement

“…Recently, it has been shown that doping a small amount of Se into S molecules improves the electronic conductivity of sulfur molecules, and the formation of Se−S bonds between them stabilizes the composite sulfur cathode, thus improving the electrochemical performance of Li−S batteries [36] . SeS 2 has become a new type of lithium‐ion battery cathode due to its high specific capacity of sulfur and good electrical conductivity of selenium [37–41] . In this work, we prepared SeS 2 /KB modified battery separators by compounding a small amount of SeS 2 with KB and introducing it into the positive side of lithium‐sulfur secondary battery separators.…”

“…[36] SeS 2 has become a new type of lithium-ion battery cathode due to its high specific capacity of sulfur and good electrical conductivity of selenium. [37][38][39][40][41] In this work, we prepared SeS 2 /KB modified battery separators by compounding a small amount of SeS 2 with KB and introducing it into the positive side of lithiumsulfur secondary battery separators. The physical barrier effect on polysulfide formed by the pore-like structure of KB stacking, coupled with the chemical trapping effect of SeS 2 on polysulfide, the two synergistically can effectively prevent the shuttle effect on sulfide and promote the long-term stable cycle of lithium-sulfur batteries.…”