含氮/氧双元素碳催化剂调整硫正极在碳酸丙烯酯电解液中的氧化还原路径

doi:10.1016/S1872-2067(24)60096-3

催化学报 ›› 2024, Vol. 63: 224-233.DOI: 10.1016/S1872-2067(24)60096-3

含氮/氧双元素碳催化剂调整硫正极在碳酸丙烯酯电解液中的氧化还原路径

余灵辉^a^,^b^,^c^,^*(), 张恒^a, Luyuan Paul Wang^b, Samuel Jun Hoong Ong^b, 席识博^d, 陈博^b, 郭瑞^e, 汪婷^f, 杜永华^g, 陈伟^e, Ovadia Lev^h, 徐梽川^b^,ⁱ^,^*()

^a武汉纺织大学化学与化工学院, 湖北武汉 430200, 中国
^b南洋理工大学材料科学与工程学院, 新加坡
^c武汉纺织大学生物质纤维与生态染整湖北省重点实验室, 湖北武汉 430200, 中国
^d新加坡科技研究局, 化学品、能源和环境可持续性研究所, 新加坡
^e新加坡国立大学化学系, 新加坡
^f厦门大学环境与生态学, 福建厦门 361102, 中国
^g布鲁克海文国家实验室, 国家同步加速器光源II, 纽约, 美国
^h耶路撒冷希伯来大学化学研究所, 耶路撒冷, 以色列
ⁱ卓越研究与技术企业校园, 新加坡-HUJ研究创业联盟, 新加坡
^j南洋理工大学跨学科研究生院, 能源研究院, 新加坡

收稿日期:2024-05-04 接受日期:2024-06-26 出版日期:2024-08-18 发布日期:2024-08-19
通讯作者: *电话: 电子信箱: xuzc@ntu.edu.sg (徐梽川),lhyu@wtu.edu.cn (余灵辉).

Catalytically altering the redox pathway of sulfur in propylene carbonate electrolyte using dual-nitrogen/oxygen-containing carbon

Linghui Yu^a^,^b^,^c^,^*(), Heng Zhang^a, Luyuan Paul Wang^b, Samuel Jun Hoong Ong^b, Shibo Xi^d, Bo Chen^b, Rui Guo^e, Ting Wang^f, Yonghua Du^g, Wei Chen^e, Ovadia Lev^h, Zhichuan J. Xu^b^,ⁱ^,^*()

^aSchool of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430200, Hubei, China
^bSchool of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
^cHubei Key Laboratory of Biomass Fibers & Eco-Dyeing & Finishing, Wuhan Textile University, Wuhan 430200, Hubei, China
^dInstitute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research in Singapore (A*STAR), 1 Pesek Road, Jurong Island 627833, Singapore
^eDepartment of Chemistry, National University of Singapore, Singapore 117543, Singapore
^fCollege of the Environment & Ecology, Xiamen University, Xiamen 361102, Fujian, China
^gNational Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
^hThe Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
ⁱSingapore-HUJ Alliance for Research and Enterprise, NEW-CREATE Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore138602, Singapore
^jEnergy Research Institute@NTU, ERI@N, Interdisciplinary Graduate School, Nanyang Technological University, Singapore 639798, Singapore

Received:2024-05-04 Accepted:2024-06-26 Online:2024-08-18 Published:2024-08-19
Contact: *E-mail: xuzc@ntu.edu.sg (Z. Xu),lhyu@wtu.edu.cn (L. Yu).

摘要/Abstract

摘要：

锂硫电池(LSB)的能量密度比现有的商业锂离子电池高数倍, 具有很好的应用前景. 然而, LSB的发展也面临着巨大挑战. LSB通常使用与硫电极兼容性较好的醚类电解液, 但在充放电过程中, 硫电极产生的多硫化锂中间体会溶解在醚类电解液中, 产生穿梭效应, 导致LSB的循环性能差、库仑效率低和自放电严重. 碳酸酯类电解液在商业锂离子电池中被广泛应用, 因此也是LSB比较理想的电解液. 一些碳酸酯溶剂具有较低的多硫化锂溶解度, 这为克服LSB的穿梭效应提供了可能性. 然而, 在碳酸酯类电解液中, 硫电极与电解液会发生副反应, 导致无法正常充放电. 为此, 大量工作集中在优化电极和碳酸酯类电解液, 以提高兼容性, 虽然已取得显著进展, 但是仍然存在较多问题, 例如, 复合物中硫的载量通常在40%左右或更低, 以及优化的电解液昂贵等. 因此, 提高LSB与碳酸酯类电解液的兼容性仍是当前的挑战.

本文报道了一种可克服硫电极在碳酸酯类电解液中发生副反应的催化反应机理. 选用多硫化锂溶解度较低的碳酸丙烯酯(PC)为电解液, 溶度为常规的1 mol L^‒1, 复合物载硫量可达52%. 研究了两种孔径分布和孔隙率相似, 但表面官能团不同的微孔宿主碳对硫的电化学活性的影响. 结果表明, 两种宿主碳对硫的电化学活性具有明显不同的影响. 使用含氮的宿主碳时, 硫电极的可逆比容量高于800 mAh g^‒1 (电流密度: 100 mA g^‒1); 而使用不含氮的宿主碳时, 相同电流密度下, 可逆比容量只有约200 mAh g^‒1. 对比研究表明, 含氮官能团显著提高了硫电极的电化学性能, 排除了较高的容量是由于微孔限域的影响. X-射线吸收光谱结果表明, 使用含氮宿主碳时, 硫在放电过程中能被还原为多硫化锂, 并且稳定存在于电解液中, 可进一步被还原为Li₂S; 而使用不含氮的宿主碳时, 则未检测到多硫化锂或者Li₂S的生成. 这主要是因为使用不含氮宿主碳的电极中的多硫化锂在碳酸酯类电解液中发生副反应而无法稳定存在. 由此可见, 宿主碳上含氮的官能团能与多硫化锂相互作用, 形成稳定中间体, 阻止多硫化锂与电解液间的副反应. 密度泛函理论计算结果表明, 石墨化氮+COOH、吡啶氮+COOH、吡啶氮+COH, 以及吡咯氮+C=O这四种同时含有氮和氧的官能团与多硫化锂之间存在更强的相互作用, 这为提升硫电极与碳酸酯类电解液的兼容性提供了理论支持. 催化机理与PC低多硫化锂溶解度的特性结合起来, 使得LSB在PC电解液中无明显的穿梭效应, 并且能够稳定地充放电循环.

综上, 宿主碳上氮/氧功能团与多硫化锂之间的相互作用, 可以阻止多硫化锂与PC电解液之间的副反应, 使得多硫化锂能够稳定存在于PC电解液中, 从而在充放电过程中实现电化学氧化还原反应. 本文为LSB使用碳酸酯类电解液提供了一条有效的途径.

关键词: 储能, 锂硫电池, 催化氧化还原反应, 多孔碳材料, 碳酸酯电解液

Abstract:

Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries (LSBs) because of their successful implementation in commercial Li-ion batteries. The low-polysulfide-solubility feature of some carbonate solvents also makes them very promising for overcoming the shuttle effects of LSBs. However, regular sulfur electrodes experience undesired electrochemical mechanisms in carbonate electrolytes due to side reactions. In this study, we report a catalytic redox mechanism of sulfur in propylene carbonate (PC) electrolyte based on a comparison study. The catalytic mechanism is characterized by the interactions between polysulfides and dual N/O functional groups on the host carbon, which largely prevents side reactions between polysulfides and the carbonate electrolyte. Such a mechanism coupled with the low-polysulfide-solubility feature leads to stable cycling of LSBs in PC electrolyte. Favorable dual N/O functional groups are identified via a density functional theory study. This work provides an alternative route for enabling LSBs in carbonate electrolytes.

Key words: Energy storage, Lithium-sulfur battery, Catalytic redox reaction, Porous carbon, Carbonate electrolyte

余灵辉, 张恒, Luyuan Paul Wang, Samuel Jun Hoong Ong, 席识博, 陈博, 郭瑞, 汪婷, 杜永华, 陈伟, Ovadia Lev, 徐梽川. 含氮/氧双元素碳催化剂调整硫正极在碳酸丙烯酯电解液中的氧化还原路径[J]. 催化学报, 2024, 63: 224-233.

Linghui Yu, Heng Zhang, Luyuan Paul Wang, Samuel Jun Hoong Ong, Shibo Xi, Bo Chen, Rui Guo, Ting Wang, Yonghua Du, Wei Chen, Ovadia Lev, Zhichuan J. Xu. Catalytically altering the redox pathway of sulfur in propylene carbonate electrolyte using dual-nitrogen/oxygen-containing carbon[J]. Chinese Journal of Catalysis, 2024, 63: 224-233.

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链接本文: https://www.cjcatal.com/CN/10.1016/S1872-2067(24)60096-3

https://www.cjcatal.com/CN/Y2024/V63/I8/224

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Fig. 1. Morphological analysis of N/O-C and N2 (77 K) adsorption analysis of N/O-C and O-C. SEM (a) and TEM (b) images of N/O-C. Adsorption isotherms (c) and corresponding pore size distributions (d).

Fig. 2. Preparation and properties of S52@N/O-C. (a) Schematic of preparation of S52@N/O-C from porous carbon (N/O-C). (b) XRD patterns of pristine sulfur and S52@N/O-C. (c,d) Electrochemical properties of S52@N/O-C. (c) The first five charge/discharge profiles in the PC electrolyte. (d) Rate capability in the PC electrolyte. (e) First two charge/discharge profiles in the diglyme electrolyte. (f) Rate capability and cyclability in the PC electrolyte.

Fig. 3. Properties of S20@N/O-C and S20@O-C. (a) XRD patterns. (b) TEM image of S20@N/O-C. Elemental mapping of S20@N/O-C for carbon (c), nitrogen (d), and sulfur (e). (f) TEM image of S20@O-C. Elemental mapping of S20@O-C for carbon (g) and sulfur (h).

Fig. 4. Electrochemical properties of S20@N/O-C and S20@O-C in PC electrolyte. First five charge/discharge profiles (a) and rate capability (b) of S20@N/O-C. (c) First five charge/discharge profiles of S20@O-C. (d) Rate capability and cyclability of S20@N/O-C.

Fig. 5. XANES study in the PC electrolyte. (a) Sulfur K-edge XANES spectra of S20@N/O-C electrodes at different lithiation states. (b) Sulfur K-edge XANES spectra of fresh S20@N/O-C electrodes and S20@N/O-C electrodes at discharged states at 1.0 V. (c) Points chosen for the XANES measurements of S20@N/O-C. (d) Sulfur K-edge XANES spectra of S20@O-C electrodes at different lithiation states. (e) Points chosen for the XANES measurements of S20@O-C. 1D, 1C, 2D, and 2C in the legends of (c,e) stand for the first discharge, first charge, second discharge, and second charge, respectively.

Fig. 6. XPS spectra of N/O-C. (a) C 1s; (b) N 1s.

Fig. 7. DFT calculations. Optimized adsorption structures (top view) of Li2S8 adsorbed on graphite (a), carbon with COOH (b), carbon with graphitic nitrogen (GN) and COOH (c), carbon with pyridinic nitrogen (PDN) and COOH (d), carbon with PDN and COH (e), and carbon with pyrrolic nitrogen (PRN) and C=O (f). (g) Adsorption energies of Li2S8 on different functional groups of carbon. More optimized adsorption structures can be found in Fig. S10 and Fig. S11.

Fig. 8. Schematic showing a catalytic redox mechanism of sulfur in the presence of N/O-containing carbon in carbonate electrolyte, comparing the mechanism when using a regular sulfur electrode.

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含氮/氧双元素碳催化剂调整硫正极在碳酸丙烯酯电解液中的氧化还原路径

Catalytically altering the redox pathway of sulfur in propylene carbonate electrolyte using dual-nitrogen/oxygen-containing carbon

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[1]	刘小妮, 刘晓斌, 李彩霞, 杨波, 王磊. 缺陷工程在金属基电池中的研究进展[J]. 催化学报, 2023, 45(2): 27-87.
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