Search

Lithium‐sulfur (Li‐S) batteries have received tremendous academic and industrial attentions owing to their ultrahigh energy density. However, technical challenges including lithium dendrite formation, polysulfide shuttling and sluggish sulfur reaction kinetics limit their cycle life, rate capability and areal capacity, especially at practically high sulfur loadings. Here, coordination‐engineered graphite carbon nitrides is proposed to effectively address these challenges. On the anode a layer of novel N‐rich graphitic carbon nitride (g‐C3N5) is applied, in which tricoordinated N atoms display strong affinity to Li+, to guide lithium deposition and efficiently inhibit dendrite formation. Besides, a layer of defective g‐C3N5 carrying highly active bicoordinated N vacancies and cyano N atoms is applied on the cathode, which significantly adsorb polysulfides and catalyze the reversible conversion, as well as the nucleation and dissolution of Li2S thereby outcompeting polysulfide shuttling and raising kinetics at high sulfur loading. This coordination‐engineering strategy based on g‐C3N5 enables Li‐S batteries exhibiting high stability and low capacity‐fading‐rate (0.03% per cycle) in 400 cycles at the high current rate of 4 C, as well as Li‐S pouch cells showing a high areal capacity of 11.69 mAh cm−2 at a high sulfur loading of 9.02 mg cm−2, demonstrating the feasibility of Li‐S batteries in practical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The in-situ gel of SPE ensures interface compatibility and scalable preparation. • InPc was conducive to improving ionic conductivity and suppressing shuttle effect. • InPc induces a protective layer on the surface of the lithium. • The resulting pouch Li-S cell delivered an energy density of 325.5 Wh kg−1. Lithium-sulfur batteries (LSBs) are currently being investigated as a potential candidate for high-energy–density rechargeable batteries. However, the notorious shuttle effect and uncontrolled dendrite growth posed problems for the practical applications of LSBs. Here, a new solid polymer electrolyte (SPE) was developed by in-situ polymerization of 1,3-dioxolane (DOL) in the presence of a multifunctional indium phthalocyanine (PDOL@InPc). The InPc endows the SPE with improved ionic conductivity and merit inhibition of the shuttle effect, in addition to being an effective additive for inducing uniform Li deposition by reconstructing the electric field at the interface. The characteristics of ionic migration in PDOL@InPc were quantified, and agreement between experiment and simulation established a relationship between macroscopic characteristics and molecular-level processes. The interfacial side reaction was controlled by the PDOL@InPc electrolyte, which also improved the distribution of the Li+ flux for dense Li deposition. Li symmetrical batteries designed with PDOL@lnPc can withstand a current density of up to 0.5 mA cm−2 and cycle reliably for 1500 h. The PDOL@InPc electrolyte displayed a high ionic conductivity at room temperature of 3.7 mS cm−1 and a significant Li+ transference number of 0.63. The resulting Li-S battery (Li|PDOL@lnPc|Sulfur) delivered a significant 325.5 Wh kg−1 of energy density at 0.2 C (1 C = 1000 mA g−1) at the level of the multilayer-pouch cell under an extremely low electrolyte of 3.5 g g−1 Sulfur and high loading of 8.0 mg cm−2. This work provides a feasible strategy for the widespread implementation of LSBs with increased safety and a longer lifetime. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) battery has attracted remarkable attention owing to its high theoretical energy density. However, its commercialization is still hampered by the rapid capacity degradation which mainly originates from the polysulfides shuttle between the anode and cathode. In this paper, a functional multiwall carbon nanotube/sulfonated polyaniline (MWCNT/SPANI) modified separator is designed to enhance the electrochemical performance of the Li-S batteries with high sulfur loading. The MWCNT/SPANI-coated separator is highly permselective to Li + but rejects the transportation of polysulfide anions. Besides, the MWCNT/SPANI coating can also work as an upper current collector and provides channels for electron and ion transport to enhance the sulfur utilization and ensure the reactivation of trapped active materials. With the ion selective MWCNT/SPANI-coated separator, the electrochemical performance of the Li-S batteries based on cathodes with high sulfur loading (5 mg cm −2 ) and high sulfur content (72 wt%) has been significantly improved. It delivers a reversible capacity of 913 mA h g −1 at the current density of 100 mA g −1 after 100 cycles, much higher than that of the cells with pristine Celgard separator. Hence, the ion selective MWCNT/SPANI modified separator is promising for developing high-performance Li-S batteries employing cathodes with high sulfur loading and high sulfur content. [ABSTRACT FROM AUTHOR]

In this work, a lithium-ion sulfur battery has been constructed by employing the sulfurized polyacrylonitrile (S@pPAN) cathode, prelithiated SiO x /C anode and commercial carbonate-based electrolyte. Compared with the traditional lithium-sulfur battery, the replacement of lithium metal with prelithiated SiO x /C anode and the use of commercial carbonate-based electrolyte ensure the high safety of the new battery. Meanwhile, the lithium-ion sulfur battery also possesses the advantage of high energy density. It delivers a high reversible capacity of 616 mA h g −1 after 100 cycles with an average working voltage of about 1.6 V, corresponding to a high energy density of 661 W h kg −1 , which is more than double that of the commercial lithium-ion batteries. The fabrication of the lithium-ion sulfur battery provides an effective way to solve the safety problems of the available lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]