As a critical role in battery systems, polymer binders have been shown to efficiently suppress the lithium polysulfide shuttling and accommodate volume changes in recent years. However, preparation processes and safety, as the key criterions for Li‐S batteries' practical applications, still attract less attention. Herein, an aqueous multifunction binder (named PEI‐TIC) is prepared via an easy and fast epoxy‐amine ring‐opening reaction (10 min), which can not only give the sulfur cathode a stable mechanical property, a strong chemical adsorption and catalytic conversion ability, but also a fire safety improvement. The Li‐S batteries based on the PEI‐TIC binder display a high discharge capacity (1297.8 mAh g−1), superior rate performance (823.0 mAh g−1 at 2 C), and an ultralow capacity decay rate of 0.035% over more than 800 cycles. Even under 7.1 mg cm−2 S‐loaded, the PEI‐TIC electrode can also achieve a high areal capacity of 7.2 mA h g−1 and excellent cycling stability, confirming its application potential. Moreover, it is also noted that TG‐FTIR test is performed for the first time to explore the flame‐retardant mechanism of polymer binders. This work provides an economically and environmentally friendly binder for the practical application and inspires the exploration of the flame‐retardant mechanism of all electrode components.
Lithium-sulfur (Li-S) batteries are the promising next-generation secondary energy storage systems, because of their advantages of high energy density and environmental friendliness. Among numerous cathode materials, organosulfur polymer materials have received extensive attentions because of their controllable structure and uniform sulfur distribution. However, the sulfur content of most organosulfur polymer cathodes is limited (S content <60%) due to the addition of large amounts of conductive agents and binders, which adversely affects the energy density of Li-S batteries. Herein, a hyperbranched sulfur-rich polymer based on modified polyethyleneimine (Ath-PEI) named carbon nanotubeentangled poly (allyl-terminated hyperbranched ethyleneimine-random-sulfur) (CNT/Ath-PEI@S) was prepared by sulfur polymerization and used as a Li-S battery cathode. The high intrinsic viscosity of Ath-PEI provided considerable adhesion and avoided the addition of PVDF binder, thereby increasing the sulfur content of cathodes to 75%. Moreover, considering the uniform distribution of elemental sulfur by the polymer, the utilization of sulfur was successfully improved, thus improving the rate capability and discharge capacity of the battery. The binder-free, sulfur-rich polymer cathode exhibited ultra-high initial discharge capacity (1520.7 mAh g −1 at 0.1 C), and high rate capability (804 mAh g −1 at 2.0 C). And cell-level calculations show that the electrode exhibits an initial capacity of 942.3 mAh g −1 electrode , which is much higher than those of conventional sulfur-polymer electrodes reported in the literature.
Lithium–sulfur (Li-S) batteries are considered as among the most promising electrochemical energy storage devices due to their high theoretical energy density and low cost. However, the inherently complex electrochemical mechanism in Li-S batteries leads to problems such as slow internal reaction kinetics and a severe shuttle effect, which seriously affect the practical application of batteries. Therefore, accelerating the internal electrochemical reactions of Li-S batteries is the key to realize their large-scale applications. This article reviews significant efforts to address the above problems, mainly the catalysis of electrochemical reactions by specific nanostructured materials. Through the rational design of homogeneous and heterogeneous catalysts (including but not limited to strategies such as single atoms, heterostructures, metal compounds, and small-molecule solvents), the chemical reactivity of Li-S batteries has been effectively improved. Here, the application of nanomaterials in the field of electrocatalysis for Li-S batteries is introduced in detail, and the advancement of nanostructures in Li-S batteries is emphasized.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.