Polysulfide intercalation in bilayer-structured graphitic C3N4: a first-principles study. Issue 48 (4th December 2017)

• Record Type: Journal Article
• Authors: Li, Sinan; Yang, Shaobin; Shen, Ding; Sun, Wen; Shan, Xueying; Dong, Wei; Chen, Yuehui; Zhang, Xu; Mao, Yongqiang; Tang, Shuwei
• Is Part Of: Physical chemistry chemical physics. Volume 19:Issue 48(2017)
• Page Start: 32708
• Page End: 32714
• Publication Date: 2017-12-04
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp05334g
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : A graphitic C3 N4 bilayer can stabilize polysulfides (PSs) by using a micropore-scale interlayer as a promising anchoring material, and improve sulfur utilisation. Abstract : Lithium–sulfur (Li–S) batteries have attracted increasing attention due to their high theoretical capacity, being a promising candidate for portable electronics, electric vehicles and large-scale energy storage. The interactions of bilayer structured graphitic C3 N4 (bi-C3 N4 ) with S8, lithium polysulfides (LiPSs), 1, 3-dioxolane, 1, 2-dimethoxyethane and tetrahydrofuran ether-based solvents have been studied using first-principles calculations. It has been found that the (micropore-scale) interlayer of bi-C3 N4 shows intimate contact and strong binding with S8 and LiPSs due to the formation of chemical Li–N bonds. The incorporation of soluble LiPSs by the wrinkled layers of bi-C3 N4 with 5.5–7.2 Å interlayer pores can suppress the shuttling effect. The interlayer ultramicropores with interlayer distances of <4 Å can accommodate the small Li2 S2 and Li2 S molecules, and impede the irreversible reaction between the solvents and the LiPSs. The calculated energy gap of bi-C3 N4 decreases to be narrow during lithiation. Our results can provide a guideline for promoting the electrochemical performance of microporous g-C3 N4 /sulfur composites for Li–S batteries.