鋰硫電池在過去十年逐漸成為儲能領域的研究焦點之一。究其原因，除了它著名的高理論能量密度和低成本材料外，其循環性能的改進也鼓勵了許多研究人員致力於將其盡早推向市場。為了不使高能量鋰硫電池失去其低成本及環境友善之優勢，本研究以製程成熟的碳紙基材作為研究平台，探究四款在結構、導電性，及吸附能力等微觀性質具有顯著差異的商品如何在具實用價值之電池組裝參數下展現各自優勢與劣勢。文獻指出，不僅是硫利用率，其他關鍵電池組裝參數，如硫含量、硫載量，以及電解液對硫比，影響鋰硫電池能量密度甚鉅。藉由合理的三維疊層及浸潤的陰極構裝法，在9.4 μL mg−1的低電解液對硫比下，具有12.7 mg cm−2之高硫載量的眾碳紙陰極能夠展現高達8.8–16.2 mW h cm−2之面積能量密度，以及高達228–918 mW h g−1之重量能量密度。四款碳紙的測試結果，凸顯了質量傳輸對於將碳紙用作集流體的重要性，以及整個陰極當中活性物質用量是否充足之問題。能夠具有最高陰極重量能量密度之基材設計不見得必須擁有最佳導電性，但須擁有輕質且具彈性的結構、良好吸附能力，與能促進電極／電解液介面順暢質傳的物理性質。

The literature points out that the preferred design for sulfur cathodes in lithium–sulfur batteries is a three-dimensional conductive network that is manufactured on a large scale at a low cost, holds a sufficient amount of active materials, and retains structural flexibility simultaneously. However, to date, nearly no report clarifies which factors, such as conductivity, adsorption capability, and morphology of sulfide deposits, affect lithium–sulfur batteries’ performance more. Therefore, this paper selects four commercial carbon-fiber products with manufacturing maturity and low prices but with significant differences in structure, conductivity, and adsorption capability for comparison. By analyzing the relation between the cathodes’ electrochemical performances and microscopic properties, it is investigated how the four products play their merits and demerits under practical cell-assembly parameters. The results show that, for the unmodified carbon-fiber substrates, a suitable freestanding three-dimensional carbon current collector does not need a superior conductivity but must have a lightweight and flexible structure to maintain a high gravimetric energy density based on the entire cathode. Moreover, a good adsorption capability or physical properties facilitating long-term smooth mass transport at the electrode/electrolyte interface, such as micro- and nano-scale liquid channels, are essential to cyclability improvement. In the future, the modification or redesign direction of the substrate is to improve the conductivity or catalytic activity further and mitigate the electrolyte consumption while maintaining as many of the advantages mentioned above as possible.

[1] M. Armand, J.-M. Tarascon, “Building better batteries,” Nature, 451, 652–657, 2008.
[2] B. Galkin, J. Kibilda, L. A. DaSilva, “UAVs as mobile infrastructure: Addressing battery lifetime,” IEEE Commun. Mag., 57, 132–137, 2019.
[3] S.-H. Chung, A. Manthiram, “Current status and future prospects of metal–sulfur batteries,” Adv. Mater., 31, 1901125, 2019.
[4] J. Lei, T. Liu, J. J. Chen, M. S. Zheng, Q. Zhang, B. W. Mao, Q. F. Dong, “Exploring and understanding the roles of Li2Sn and the strategies to beyond present Li-S batteries,” Chem, 6, 2533–2557, 2020.
[5] L. Trahey, F. R. Brushett, N. P. Balsara, G. Ceder, L. Cheng, Y. M. Chiang, N. T. Hahn, B. J. Ingram, S. D. Minteer, J. S. Moore, K. T. Mueller, L. F. Nazar, K. A. Persson, D. J. Siegel, K. Xu, K. R. Zavadil, V. Srinivasan, G. W. Crabtree, “Energy storage emerging: A perspective from the joint center for energy storage research,” Proc. Natl. Acad. Sci. U.S.A., 117, 12550–12557, 2020.
[6] R. F. Service, “Lithium-sulfur batteries poised for leap,” Science, 359, 1080–1081, 2018.
[7] B. Dunn, H. Kamath, J.-M. Tarascon, “Electrical energy storage for the grid: A battery of choices,” Science, 334, 928–935, 2011.
[8] Y. Jin, G. M. Zhou, F. F. Shi, D. Zhuo, J. Zhao, K. Liu, Y. Y. Liu, C. X. Zu, W. Chen, R. F. Zhang, X. Y. Huang, Y. Cui, “Reactivation of dead sulfide species in lithium polysulfide flow battery for grid scale energy storage,” Nat. Commun., 8, 462, 2017.
[9] Y. Yang, G. Y. Zheng, Y. Cui, “A membrane-free lithium/polysulfide semi-liquid battery for large-scale energy storage,” Energy Environ. Sci., 6, 1552–1558, 2013.
[10] 蔡蘊明, “【2019諾貝爾化學獎】鋰離子電池, ” O. Ramström, “Scientific background on the nobel prize in chemistry 2019: Lithium-ion batteries, ” Member of the Nobel Committee for Chemistry, 2019, https://teaching.ch.ntu.edu.tw/nobel/2019/.
[11] J. B. Goodenough, “How we made the Li-ion rechargeable battery,” Nat. Electron., 1, 204–204, 2018.
[12] J. Asenbauer, T. Eisenmann, M. Kuenzel, A. Kazzazi, Z. Chen, D. Bresser, “The success story of graphite as a lithium-ion anode material – fundamentals, remaining challenges, and recent developments including silicon (oxide) composites,” Sustain. Energy Fuels, 4, 5387–5416, 2020.
[13] S. Nanda, A. Bhargav, A. Manthiram, “Anode-free, lean-electrolyte lithium-sulfur batteries enabled by tellurium-stabilized lithium deposition,” Joule, 4, 1121–1135, 2020.
[14] X. Zhang, Y. G. Yang, Z. Zhou, “Towards practical lithium-metal anodes,” Chem. Soc. Rev., 49, 3040–3071, 2020.
[15] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, J.-M. Tarascon, “Li–O2 and Li–S batteries with high energy storage,” Nat. Mater., 11, 19–29, 2011.
[16] J.-G. Zhang, W. Xu, J. Xiao, X. Cao, J. Liu, “Lithium metal anodes with nonaqueous electrolytes,” Chem. Rev., 120, 13312–13348, 2020.
[17] Standard pouch cell from OXIS energy, https://oxisenergy.com/products/
[18] J. L. Guo, J. P. Liu, “A binder-free electrode architecture design for lithium–sulfur batteries: A review,” Nanoscale Adv., 1, 2104–2122, 2019.
[19] T. Tang, Y. Hou, “Chemical confinement and utility of lithium polysulfides in lithium sulfur batteries,” Small Methods, 4, 1–20, 2020.
[20] X. F. Yang, X. Li, K. G. Adair, H. M. Zhang, X. L. Sun, “Structural design of lithium–sulfur batteries: From fundamental research to practical application,” Electrochem. Energ. Rev., 1, 239–293, 2018.
[21] R. Steudel, T. Chivers, “The role of polysulfide dianions and radical anions in the chemical, physical and biological sciences, including sulfur-based batteries,” Chem. Soc. Rev., 48, 3279–3319, 2019.
[22] J. L. Guo, H. Y. Pei, Y. Dou, S. Y. Zhao, G. S. Shao, J. P. Liu, “Rational designs for lithium-sulfur batteries with low electrolyte/sulfur ratio,” Adv. Funct. Mater., 2010499, 2021.
[23] H. Noh, J. Song, J.-K. Park, H.-T. Kim, “A new insight on capacity fading of lithium–sulfur batteries: The effect of Li2S phase structure,” J. Power Sources, 293, 329–335, 2015.
[24] S. Drvarič Talian, G. Kapun, J. Moškon, A. Vizintin, A. Randon-Vitanova, R. Dominko, M. Gaberšček, “Which process limits the operation of a Li–S system?,” Chem. Mater., 31, 9012–9023, 2019.
[25] S.-H. Chung, C.-H. Chang, A. Manthiram, “Progress on the critical parameters for lithium–sulfur batteries to be practically viable,” Adv. Funct. Mater., 28, 1801188, 2018.
[26] T. Danner, A. Latz, “On the influence of nucleation and growth of S8 and Li2S in lithium-sulfur batteries,” Electrochim. Acta, 322, 134719, 2019.
[27] J. H. Yan, X. B. Liu, B. Y. Li, “Capacity fade analysis of sulfur cathodes in lithium–sulfur batteries,” Adv. Sci., 3, 1600101, 2016.
[28] Z.-W. Zhang, H.-J. Peng, M. Zhao, J.-Q. Huang, “Heterogeneous/homogeneous mediators for high-energy-density lithium–sulfur batteries: Progress and prospects,” Adv. Funct. Mater., 28, 1707536, 2018.
[29] T. Zhang, M. Marinescu, S. Walus, P. Kovacik, G. J. Offer, “What limits the rate capability of Li-S batteries during discharge: Charge transfer or mass transfer?,” J. Electrochem. Soc., 165, A6001–A6004, 2018.
[30] S. J. Kim, Y. Jeoun, J. Park, S. H. Yu, Y. E. Sung, “Design considerations for lithium–sulfur batteries: Mass transport of lithium polysulfides,” Nanoscale, 12, 15466–15472, 2020.
[31] L. Kong, J.-X. Chen, H.-J. Peng, J.-Q. Huang, W. Zhu, Q. Jin, B.-Q. Li, X.-T. Zhang, Q. Zhang, “Current-density dependence of Li2S/Li2S2 growth in lithium–sulfur batteries,” Energy Environ. Sci., 12, 2976–2982, 2019.
[32] X.-B. Cheng, R. Zhang, C.-Z. Zhao, F. Wei, J.-G. Zhang, Q. Zhang, “A review of solid electrolyte interphases on lithium metal anode,” Adv. Sci., 3, 1500213, 2016.
[33] Y. T. Liu, S. Liu, G.-R. Li, X.-P. Gao, “Strategy of enhancing the volumetric energy density for lithium–sulfur batteries,” Adv. Mater., 33, 2003955, 2021.
[34] A. Manthiram, Y. Fu, S.-H. Chung, C. Zu, Y.-S. Su, “Rechargeable lithium–sulfur batteries,” Chem. Rev., 114, 11751–11787, 2014.
[35] S. S. Zhang, “A new finding on the role of LiNO3 in lithium-sulfur battery,” J. Power Sources, 322, 99–105, 2016.
[36] S. S. Zhang, J. A. Read, “A new direction for the performance improvement of rechargeable lithium/sulfur batteries,” J. Power Sources, 200, 77–82, 2012.
[37] S. Z. Huang, Z. H. Wang, Y. Von Lim, Y. Wang, Y. Li, D. H. Zhang, H. Y. Yang, “Recent advances in heterostructure engineering for lithium–sulfur batteries,” Adv. Energy Mater., 11, 2003689, 2021.
[38] G. Benveniste, H. Rallo, L. Canals Casals, A. Merino, B. Amante, “Comparison of the state of lithium-sulphur and lithium-ion batteries applied to electromobility,” J. Environ. Manage., 226, 1–12, 2018.
[39] A. K. C. Estandarte, J. C. Diao, A. V. Llewellyn, A. Jnawali, T. M. M. Heenan, S. R. Daemi, J. J. Bailey, S. Cipiccia, D. Batey, X. W. Shi, C. Rau, D. J. L. Brett, R. Jervis, I. K. Robinson, P. R. Shearing, “Operando Bragg coherent diffraction imaging of LiNi0.8Mn0.1Co0.1O2 primary particles within commercially printed NMC811 electrode sheets,” ACS Nano, 15, 1321–1330, 2020.
[40] S. S. Sharma, A. Manthiram, “Towards more environmentally and socially responsible batteries,” Energy Environ. Sci., 13, 4087–4097, 2020.
[41] Precipitated sulfur preparation, https://en.wikipedia.org/wiki/Sulfur_(pharmacy)
[42] Price of the commercial sulfur powder, https://www.alfa.com/zh-cn/catalog/010785/
[43] Price of the commercial NMC811 powder, www.msesupplies.com/collections/lithium-ion-battery-materials/nmc811
[44] X. Ji, K. T. Lee, L. F. Nazar, “A highly ordered nanostructured carbon-sulphur cathode for lithium-sulphur batteries,” Nat. Mater., 8, 500–506, 2009.
[45] R. P. Fang, S. Y. Zhao, Z. H. Sun, D.-W. Wang, H.-M. Cheng, F. Li, “More reliable lithium-sulfur batteries: Status, solutions and prospects,” Adv. Mater., 29, 1606823, 2017.
[46] H.-J. Peng, J.-Q. Huang, X.-B. Cheng, Q. Zhang, “Review on high-loading and high-energy lithium–sulfur batteries,” Adv. Energy Mater., 7, 1700260, 2017.
[47] J. X. Song, M. L. Gordin, T. Xu, S. R. Chen, Z. X. Yu, H. Sohn, J. Lu, Y. Ren, Y. H. Duan, D. H. Wang, “Strong lithium polysulfide chemisorption on electroactive sites of nitrogen-doped carbon composites for high-performance lithium-sulfur battery cathodes,” Angew. Chem. Int. Ed., 54, 4325–4329, 2015.
[48] S. Xin, L. Gu, N.-H. Zhao, Y.-X. Yin, L.-J. Zhou, Y.-G. Guo, L.-J. Wan, “Smaller sulfur molecules promise better lithium-sulfur batteries,” J. Am. Chem. Soc., 134, 18510–18513, 2012.
[49] C. Luo, H. L. Zhu, W. Luo, F. Shen, X. L. Fan, J. Q. Dai, Y. J. Liang, C. S. Wang, L. B. Hu, “Atomic-layer-deposition functionalized carbonized mesoporous wood fiber for high sulfur loading lithium sulfur batteries,” ACS Appl. Mater. Interfaces, 9, 14801–14807, 2017.
[50] J. H. Chen, H. M. Zhang, H. J. Yang, J. Y. Lei, A. Naveed, J. Yang, Y. Nuli, J. L. Wang, “Towards practical Li–S battery with dense and flexible electrode containing lean electrolyte,” Energy Storage Mater., 27, 307–315, 2020.
[51] Y. B. He, Z. Chang, S. C. Wu, H. S. Zhou, “Effective strategies for long-cycle life lithium–sulfur batteries,” J. Mater. Chem. A, 6, 6155–6182, 2018.
[52] A. Benítez, Á. Caballero, E. Rodríguez-Castellón, J. Morales, J. Hassoun, “The role of current collector in enabling the high performance of Li/S battery,” ChemistrySelect, 3, 10371–10377, 2018.
[53] S. Waluś, C. Barchasz, R. Bouchet, J.-F. Martin, J.-C. Leprêtre, F. Alloin, “Investigation of non-woven carbon paper as a current collector for sulfur positive electrode—understanding of the mechanism and potential applications for Li/S batteries,” Electrochim. Acta, 211, 697–703, 2016.
[54] L. Zhu, H. J. Peng, J. Liang, J. Q. Huang, C. M. Chen, X. F. Guo, W. C. Zhu, P. Li, Q. Zhang, “Interconnected carbon nanotube/graphene nanosphere scaffolds as free-standing paper electrode for high-rate and ultra-stable lithium-sulfur batteries,” Nano Energy, 11, 746–755, 2015.
[55] A. Schneider, C. Suchomski, H. Sommer, J. Janek, T. Brezesinski, “Free-standing and binder-free highly N-doped carbon/sulfur cathodes with tailorable loading for high-areal-capacity lithium-sulfur batteries,” J. Mater. Chem. A, 3, 20482–20486, 2015.
[56] B. D. McCloskey, “Attainable gravimetric and volumetric energy density of Li–S and Li ion battery cells with solid separator-protected Li metal anodes,” J. Phys. Chem. Lett., 6, 4581–4588, 2015.
[57] D. P. Lv, J. m. Zheng, Q. Y. Li, X. Xie, S. Ferrara, Z. M. Nie, L. B. Mehdi, N. D. Browning, J.-G. Zhang, G. L. Graff, J. Liu, J. Xiao, “High energy density lithium–sulfur batteries: Challenges of thick sulfur cathodes,” Adv. Energy Mater., 5, 1402290, 2015.
[58] W. J. Xue, Z. Shi, L. M. Suo, C. Wang, Z. Q. Wang, H. Z. Wang, K. P. So, A. Maurano, D. W. Yu, Y. M. Chen, L. Qie, Z. Zhu, G. Y. Xu, J. Kong, J. Li, “Intercalation-conversion hybrid cathodes enabling Li–S full-cell architectures with jointly superior gravimetric and volumetric energy densities,” Nat. Energy, 4, 374–382, 2019.
[59] J. N. Wang, G. R. Yang, J. Chen, Y. P. Liu, Y. K. Wang, C. Y. Lao, K. Xi, D. W. Yang, C. J. Harris, W. Yan, S. J. Ding, R. V. Kumar, “Flexible and high‐loading lithium–sulfur batteries enabled by integrated three‐in‐one fibrous membranes,” Adv. Energy Mater., 9, 1902001, 2019.
[60] L. L. Shi, S.-M. Bak, Z. Shadike, C. Q. Wang, C. J. Niu, P. Northrup, H. K. Lee, A. Y. Baranovskiy, C. S. Anderson, J. Qin, S. Feng, X. D. Ren, D. Y. Liu, X. Q. Yang, F. Gao, D. P. Lu, J. Xiao, J. Liu, “Reaction heterogeneity in practical high-energy lithium-sulfur pouch cells,” Energy Environ. Sci., 13, 3620–3632, 2020.
[61] M. Rana, S. A. Ahad, M. Li, B. Luo, L. Wang, I. Gentle, R. Knibbe, “Review on areal capacities and long-term cycling performances of lithium sulfur battery at high sulfur loading,” Energy Storage Mater., 18, 289–310, 2019.
[62] M. Shaibani, M. S. Mirshekarloo, R. Singh, C. D. Easton, M. C. D. Cooray, N. Eshraghi, T. Abendroth, S. Dörfler, H. Althues, S. Kaskel, A. F. Hollenkamp, M. R. Hill, M. Majumder, “Expansion-tolerant architectures for stable cycling of ultrahigh-loading sulfur cathodes in lithium-sulfur batteries,” Sci. Adv., 6, eaay2757, 2020.
[63] W. J. Deng, J. Phung, G. Li, X. L. Wang, “Realizing high-performance lithium-sulfur batteries via rational design and engineering strategies,” Nano Energy, 82, 105761, 2021.
[64] B. Zhang, J. Wu, J. Gu, S. Li, T. Yan, X.-P. Gao, “The fundamental understanding of lithium polysulfides in ether-based electrolyte for lithium–sulfur batteries,” ACS Energy Lett., 6, 537–546, 2021.
[65] N. B. Emerce, D. Eroglu, “Effect of electrolyte-to-sulfur ratio in the cell on the Li-S battery performance,” J. Electrochem. Soc., 166, A1490–A1500, 2019.
[66] L. Huang, J. J. Li, B. Liu, Y. H. Li, S. H. Shen, S. J. Deng, C. W. Lu, W. K. Zhang, Y. Xia, G. X. Pan, X. L. Wang, Q. Q. Xiong, X. H. Xia, J. P. Tu, “Electrode design for lithium–sulfur batteries: Problems and solutions,” Adv. Funct. Mater., 30, 1910375, 2020.
[67] H. Mao, L. Liu, L. Shi, H. Wu, J. X. Lang, K. Wang, T. X. Zhu, Y. Y. Gao, Z. H. Sun, J. Zhao, G. X. Gao, D. Y. Zhang, W. Yan, S. J. Ding, “High loading cotton cellulose-based aerogel self-standing electrode for Li–S batteries,” Sci. Bull., 65, 803–811, 2020.
[68] C. Zhang, W. Lv, Y. Tao, Q.-H. Yang, “Towards superior volumetric performance: Design and preparation of novel carbon materials for energy storage,” Energy Environ. Sci., 8, 1390–1403, 2015.
[69] S.-H. Chung, A. Manthiram, “Designing lithium–sulfur batteries with high-loading cathodes at a lean electrolyte condition,” ACS Appl. Mater. Interfaces, 10, 43749–43759, 2018.
[70] S.-H. Chung, A. Manthiram, “Designing lithium-sulfur cells with practically necessary parameters,” Joule, 2, 710–724, 2018.
[71] Q. Pang, X. Liang, C. Y. Kwok, L. F. Nazar, “Advances in lithium–sulfur batteries based on multifunctional cathodes and electrolytes,” Nat. Energy, 1, 16132, 2016.
[72] C. Y. Chang, X. Pu, “Revisiting the positive roles of liquid polysulfides in alkali metal–sulfur electrochemistry: From electrolyte additives to active catholyte,” Nanoscale, 11, 21595–21621, 2019.
[73] L. Ma, K. E. Hendrickson, S. Wei, L. A. Archer, “Nanomaterials: Science and applications in the lithium–sulfur battery,” Nano Today, 10, 315–338, 2015.
[74] S. Z. Xiong, K. Xie, Y. Diao, X. B. Hong, “Characterization of the solid electrolyte interphase on lithium anode for preventing the shuttle mechanism in lithium–sulfur batteries,” J. Power Sources, 246, 840–845, 2014.
[75] Y. Z. Fu, Y.-S. Su, A. Manthiram, “Highly reversible lithium/dissolved polysulfide batteries with carbon nanotube electrodes,” Angew. Chem. Int. Ed., 52, 6930–6935, 2013.
[76] D.-J. Lee, M. Agostini, J.-W. Park, Y.-K. Sun, J. Hassoun, B. Scrosati, “Progress in lithium–sulfur batteries: The effective role of a polysulfide-added electrolyte as buffer to prevent cathode dissolution,” ChemSusChem, 6, 2245–2248, 2013.
[77] M. F. Mathias, J. Roth, J. Fleming, W. Lehnert, “Diffusion media materials and characterisation,” in Handbook of fuel cells: Fundamentals, technology, applications, John Wiley & Sons, Ltd, Chichester, UK, 2010.
[78] L. X. Miao, W. K. Wang, K. G. Yuan, Y. H. Yang, A. B. Wang, “A lithium–sulfur cathode with high sulfur loading and high capacity per area: A binder-free carbon fiber cloth–sulfur material,” Chem. Commun., 50, 13231–13234, 2014.
[79] X. W. Wang, T. Gao, F. D. Han, Z. Ma, Z. A. Zhang, J. Li, C. S. Wang, “Stabilizing high sulfur loading Li–S batteries by chemisorption of polysulfide on three-dimensional current collector,” Nano Energy, 30, 700–708, 2016.
[80] H. Kim, Y.-J. Lee, S.-J. Lee, Y.-S. Chung, Y. Yoo, “Fabrication of carbon papers using polyacrylonitrile fibers as a binder,” J. Mater. Sci., 49, 3831–3838, 2014.
[81] Y. Q. Chen, C. Jiang, C. D. Cho, “An investigation of the compressive behavior of polymer electrode membrane fuel cell’s gas diffusion layers under different temperatures,” Polymers, 10, 971, 2018.
[82] C.-H. Hung, C.-H. Chiu, S.-P. Wang, I.-L. Chiang, H. Yang, “Ultra thin gas diffusion layer development for PEMFC,” Int. J. Hydrogen Energy, 37, 12805–12812, 2012.
[83] The technology transfer of activated carbon-fiber cloth, https://pcm.tipo.gov.tw/PCM2010/PCM/commercial/04/FCU.aspx
[84] The description about fast resin penetration, http://c-hung.com/product_d.php?lang=tw&tb=1&id=42
[85] The discription about the gas-diffusion-layer product of carbon 3, https://www.avcarb.com/product-page-mgl/
[86] The discription about the gas-diffusion-layer product of carbon 4, http://www.ce-tech.com.tw/upload_files/Catalogue/CeTech_Catalogueprint_210204.pdf
[87] A. Ozden, S. Shahgaldi, X. Li, F. Hamdullahpur, “A review of gas diffusion layers for proton exchange membrane fuel cells—with a focus on characteristics, characterization techniques, materials and designs,” Prog. Energy Combust. Sci., 74, 50–102, 2019.
[88] Y. Chen, C. Jiang, C. Cho, “Characterization of effective in-plane electrical resistivity of a gas diffusion layer in polymer electrolyte membrane fuel cells through freeze–thaw thermal cycles,” Energies, 13, 145, 2019.
[89] X. W. Yu, A. Manthiram, “A class of polysulfide catholytes for lithium–sulfur batteries: Energy density, cyclability, and voltage enhancement,” Phys. Chem. Chem. Phys., 17, 2127–2136, 2015.
[90] W. Giurlani, E. Berretti, M. Innocenti, A. Lavacchi, “Measuring the thickness of metal coatings: A review of the methods,” Coatings, 10, 1211, 2020.
[91] D. Shindo, T. Oikawa, “Energy dispersive X-ray spectroscopy,” in Analytical electron microscopy for materials science, Springer Japan, Tokyo, 81–102, 2002.
[92] M. A. B. Whitaker, “The Bohr-Moseley synthesis and a simple model for atomic X-ray energies,” Eur. J. Phys., 20, 213–220, 1999.
[93] D. E. Newbury, N. W. M. Ritchie, “Performing elemental microanalysis with high accuracy and high precision by scanning electron microscopy/silicon drift detector energy-dispersive X-ray spectrometry (SEM/SDD-EDS),” J. Mater. Sci., 50, 493–518, 2014.
[94] D. E. Newbury, N. W. M. Ritchie, “Is scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) quantitative?,” Scanning, 35, 141–168, 2013.
[95] J. Konopka, “Calibrating standardless quantitative EDS results with limited standards,” Microsc. Microanal., 20, 1722–1723, 2014.
[96] J. Konopka, “Quantitative analysis of heterogenous samples by SEM/EDS,” Microsc. Microanal., 21, 1633–1634, 2015.
[97] J. Konopka, “Options for quantitative analysis of light elements by SEM/EDS,” in Technical Note 52523, ThermoFisherScientific, 2013.
[98] C. Hammond, The basics of crystallography and diffraction, Oxford, 2001.
[99] M. El Hannach, T. Soboleva, K. Malek, A. A. Franco, M. Prat, J. Pauchet, S. Holdcroft, “Characterization of pore network structure in catalyst layers of polymer electrolyte fuel cells,” J. Power Sources, 247, 322–326, 2014.
[100] A. Kumar, H. M. Jena, “Preparation and characterization of high surface area activated carbon from Fox nut (Euryale ferox) shell by chemical activation with H3PO4,” Results Phys., 6, 651–658, 2016.
[101] M. Thommes, K. Kaneko, A. V. Neimark, J. P. Olivier, F. Rodriguez-Reinoso, J. Rouquerol, K. S. W. Sing, “Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC technical report),” Pure Appl. Chem., 87, 1051–1069, 2015.
[102] M. W. Iqbal, A. K. Singh, M. Z. Iqbal, J. Eom, “Raman fingerprint of doping due to metal adsorbates on graphene,” J. Phys.: Condens. Matter, 24, 335301, 2012.
[103] A. C. Ferrari, J. C. Meyer, V. Scardaci, C. Casiraghi, M. Lazzeri, F. Mauri, S. Piscanec, D. Jiang, K. S. Novoselov, S. Roth, A. K. Geim, “Raman spectrum of graphene and graphene layers,” Phys. Rev. Lett., 97, 187401, 2006.
[104] M. A. Pimenta, G. Dresselhaus, M. S. Dresselhaus, L. G. Cançado, A. Jorio, R. Saito, “Studying disorder in graphite-based systems by Raman spectroscopy,” Phys. Chem. Chem. Phys., 9, 1276–1291, 2007.
[105] S. Niyogi, E. Bekyarova, M. E. Itkis, H. Zhang, K. Shepperd, J. Hicks, M. Sprinkle, C. Berger, C. N. Lau, W. A. DeHeer, E. H. Conrad, R. C. Haddon, “Spectroscopy of covalently functionalized graphene,” Nano Lett., 10, 4061–4066, 2010.
[106] L. Bokobza, J.-L. Bruneel, M. Couzi, “Raman spectra of carbon-based materials (from graphite to carbon black) and of some silicone composites,” C-J Carbon Res, 1, 77–94, 2015.
[107] S. F. Pei, H. M. Cheng, “The reduction of graphene oxide,” Carbon, 50, 3210–3228, 2012.
[108] J. Banaszczyk, A. Schwarz, G. De Mey, L. Van Langenhove, “The van der Pauw method for sheet resistance measurements of polypyrrole-coated para-aramide woven fabrics,” J. Appl. Polym. Sci., 117, 2553–2558, 2010.
[109] J. R. Wang, M. M. Wang, N. Q. Ren, J. M. Dong, Y. X. Li, C. H. Chen, “High-areal-capacity thick cathode with vertically-aligned micro-channels for advanced lithium ion batteries,” Energy Storage Mater., 39, 287–293, 2021.
[110] J. Sun, H. R. Jiang, M. C. Wu, X. Z. Fan, C. Y. H. Chao, T. S. Zhao, “A novel electrode formed with electrospun nano- and micro-scale carbon fibers for aqueous redox flow batteries,” J. Power Sources, 470, 228441, 2020.
[111] S.-H. Chung, A. Manthiram, “Rational design of statically and dynamically stable lithium–sulfur batteries with high sulfur loading and low electrolyte/sulfur ratio,” Adv. Mater., 30, 1705951, 2018.
[112] T.-H. Ko, W.-S. Kuo, C.-H. Hu, “Raman spectroscopic study of effect of steam and carbon dioxide activation on microstructure of polyacrylonitrile-based activated carbon fabrics,” J. Appl. Polym. Sci., 81, 1090–1099, 2001.
[113] X. S. Huang, “Fabrication and properties of carbon fibers,” Materials, 2, 2369–2403, 2009.
[114] J. Mittal, H. Konno, M. Inagaki, O. P. Bahl, “Denitrogenation behavior and tensile strength increase during carbonization of stabilized PAN fibers,” Carbon, 36, 1327–1330, 1998.
[115] S. Wu, Y. Q. Liu, Y. C. Ge, L. P. Ran, K. Peng, M. Z. Yi, “Surface structures of PAN-based carbon fibers and their influences on the interface formation and mechanical properties of carbon-carbon composites,” Compos. Part A Appl. Sci. Manuf., 90, 480–488, 2016.
[116] T.-H. Ko, W.-S. Kuo, Y.-H. Chang, “Microstructural changes of phenolic resin during pyrolysis,” J. Appl. Polym. Sci., 81, 1084–1089, 2001.
[117] J. K. McLaughlin, W. H. Chow, L. S. Levy, “Amorphous silica: A review of health effects from inhalation exposure with particular reference to cancer,” J Toxicol Environ Health, 50, 553–566, 1997.
[118] X. Q. Zhang, Y. Zhong, X. H. Xia, Y. Xia, D. H. Wang, C. A. Zhou, W. J. Tang, X. L. Wang, J. B. Wu, J. P. Tu, “Metal-embedded porous graphitic carbon fibers fabricated from bamboo sticks as a novel cathode for lithium-sulfur batteries,” ACS Appl. Mater. Interfaces, 10, 13598–13605, 2018.
[119] Z. G. Xie, W. Guan, F. Y. Ji, Z. R. Song, Y. L. Zhao, “Production of biologically activated carbon from orange peel and landfill leachate subsequent treatment technology,” J. Chem., 2014, 1–9, 2014.
[120] A. Sayah, F. Habelhames, A. Bahloul, B. Nessark, Y. Bonnassieux, D. Tendelier, M. El Jouad, “Electrochemical synthesis of polyaniline-exfoliated graphene composite films and their capacitance properties,” J. Electroanal. Chem., 818, 26–34, 2018.
[121] N. M. S. Hidayah, W.-W. Liu, C.-W. Lai, N. Z. Noriman, C.-S. Khe, U. Hashim, H. C. Lee, “Comparison on graphite, graphene oxide and reduced graphene oxide: Synthesis and characterization,” AIP Conf Proc, 1892, 150002, 2017.
[122] S. Wang, Z.-H. Chen, W.-J. Ma, Q.-S. Ma, “Influence of heat treatment on physical–chemical properties of PAN-based carbon fiber,” Ceram. Int., 32, 291–295, 2006.
[123] S.-S. Tzeng, K.-H. Hung, T.-H. Ko, “Growth of carbon nanofibers on activated carbon fiber fabrics,” Carbon, 44, 859–865, 2006.
[124] Z. Q. Li, C. J. Lu, Z. P. Xia, Y. Zhou, Z. Luo, “X-ray diffraction patterns of graphite and turbostratic carbon,” Carbon, 45, 1686–1695, 2007.
[125] Y. V. Larichev, P. M. Yeletsky, V. A. Yakovlev, “Study of silica templates in the rice husk and the carbon–silica nanocomposites produced from rice husk,” J. Phys. Chem. Solids, 87, 58–63, 2015.
[126] N. T. Nguyen, D. H. Nguyen, D. D. Pham, V. P. Dang, Q. H. Nguyen, D. Q. Hoang, “New oligochitosan-nanosilica hybrid materials: Preparation and application on chili plants for resistance to anthracnose disease and growth enhancement,” Polym. J., 49, 861–869, 2017.
[127] T. Liu, X. L. Sun, S. M. Sun, Q. H. Niu, H. Liu, W. Song, F. T. Cao, X. C. Li, T. Ohsaka, J. F. Wu, “A robust and low-cost biomass carbon fiber@SiO2 interlayer for reliable lithium-sulfur batteries,” Electrochim. Acta, 295, 684–692, 2019.
[128] W. Maulina, R. Kusumaningtyas, Z. Rachmawati, Supriyadi, A. Arkundato, L. Rohman, E. Purwandari, “Carbonization process of water hyacinth as an alternative renewable energy material for biomass cook stoves applications,” IOP Conf. Ser.: Earth Environ. Sci, 239, 2019.
[129] W. Liu, Q. Yang, Z. L. Yang, W. J. Wang, “Adsorption of 2,4-D on magnetic graphene and mechanism study,” Colloids Surf. A, 509, 367–375, 2016.
[130] H. X. Xu, B. Gao, H. Cao, X. Y. Chen, L. Yu, K. Wu, L. Sun, X. Peng, J. J. Fu, “Nanoporous activated carbon derived from rice husk for high performance supercapacitor,” J. Nanomater., 2014, 714010, 2014.
[131] A. H. Wazir, I. W. Kundi, “Synthesis of graphene nano sheets by the rapid reduction of electrochemically exfoliated graphene oxide induced by microwaves,” J. Chem. Soc. Pak., 38, 11–16, 2016.
[132] C. D. Zappielo, D. M. Nanicuacua, W. N. L. d. Santos, D. L. F. d. Silva, L. H. Dall’Antônia, F. M. d. Oliveira, D. N. Clausen, C. R. T. Tarley, “Solid phase extraction to on-line preconcentrate trace cadmium using chemically modified nano-carbon black with 3-mercaptopropyltrimethoxysilane,” J. Braz. Chem. Soc., 27, 1715–1726, 2016.
[133] M. Bera, Chandravati, P. Gupta, P. K. Maji, “Facile one-pot synthesis of graphene oxide by sonication assisted mechanochemical approach and its surface chemistry,” J Nanosci Nanotechnol, 18, 902–912, 2018.
[134] L. Zhang, L.-Y. Tu, Y. Liang, Q. Chen, Z.-S. Li, C.-H. Li, Z.-H. Wang, W. Li, “Coconut-based activated carbon fibers for efficient adsorption of various organic dyes,” RSC Adv., 8, 42280–42291, 2018.
[135] Y. S. Xin, T. S. Li, F. L. Xu, M. M. Wang, “Multidimensional structure and enhancement performance of modified graphene/carbon nanotube assemblies in tribological properties of polyimide nanocomposites,” RSC Adv., 7, 20742–20753, 2017.
[136] V. Hernández-Morales, R. Nava, Y. J. Acosta-Silva, S. A. Macías-Sánchez, J. J. Pérez-Bueno, B. Pawelec, “Adsorption of lead (II) on SBA-15 mesoporous molecular sieve functionalized with –NH2 groups,” Microporous Mesoporous Mater., 160, 133–142, 2012.
[137] M. Z. Corazza, B. F. Somera, M. G. Segatelli, C. R. T. Tarley, “Grafting 3-mercaptopropyl trimethoxysilane on multi-walled carbon nanotubes surface for improving on-line cadmium(II) preconcentration from water samples,” J Hazard Mater, 243, 326–333, 2012.
[138] P. Rajkumar, K. Diwakar, R. Subadevi, R. M. Gnanamuthu, F.-M. Wang, M. Sivakumar, “Micro-/mesoporous nature of carbon nanofiber/silica matrix as an effective sulfur host for rechargeable lithium–sulfur batteries,” J. Phys. D: Appl. Phys., 53, 265501, 2020.
[139] K. S. W. Sing, “Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (recommendations 1984),” Pure Appl. Chem., 57, 603–619, 1985.
[140] K. Sing, “The use of nitrogen adsorption for the characterisation of porous materials,” Colloids Surf. A, 187, 3–9, 2001.
[141] S.-H. Chung, A. Manthiram, “A natural carbonized leaf as polysulfide diffusion inhibitor for high-performance lithium–sulfur battery cells,” ChemSusChem, 7, 1655–1661, 2014.
[142] Z. J. Gong, Q. X. Wu, F. Wang, X. Li, X. P. Fan, H. Yang, Z. K. Luo, “A hierarchical micro/mesoporous carbon fiber/sulfur composite for high-performance lithium-sulfur batteries,” RSC Adv., 6, 37443–37451, 2016.
[143] C. Barchasz, J.-C. Leprêtre, F. Alloin, S. Patoux, “New insights into the limiting parameters of the Li/S rechargeable cell,” J. Power Sources, 199, 322–330, 2012.
[144] X. Qian, J. H. Zhi, L. Q. Chen, J. J. Zhong, X. F. Wang, Y. G. Zhang, S. L. Song, “Evolution of microstructure and electrical property in the conversion of high strength carbon fiber to high modulus and ultrahigh modulus carbon fiber,” Compos. Part A Appl. Sci. Manuf., 112, 111–118, 2018.
[145] T. Jeon, Y. C. Lee, J.-Y. Hwang, B. C. Choi, S. Lee, S. C. Jung, “Strong lithium-polysulfide anchoring effect of amorphous carbon for lithium-sulfur batteries,” Curr. Appl Phys., 22, 94–103, 2021.
[146] L. W. Yang, H. T. Li, Q. Li, Y. Wang, Y. X. Chen, Z. G. Wu, Y. X. Liu, G. K. Wang, B. H. Zhong, W. Xiang, Y. J. Zhong, X. D. Guo, “Research progress on improving the sulfur conversion efficiency on the sulfur cathode side in lithium–sulfur batteries,” Ind. Eng. Chem. Res., 59, 20979–21000, 2020.
[147] M. L. Yu, Z. Y. Wang, Y. W. Wang, Y. F. Dong, J. S. Qiu, “Freestanding flexible Li2S paper electrode with high mass and capacity loading for high-energy Li–S batteries,” Adv. Energy Mater., 7, 1700018, 2017.
[148] R. V. Salvatierra, A.-R. O. Raji, S.-K. Lee, Y. Ji, L. Li, J. M. Tour, “Silicon nanowires and lithium cobalt oxide nanowires in graphene nanoribbon papers for full lithium ion battery,” Adv. Energy Mater., 6, 1600918, 2016.
[149] Y.-J. Yen, S.-H. Chung, “Lean-electrolyte lithium–sulfur electrochemical cells with high-loading carbon nanotube/nanofiber–polysulfide cathodes,” Chem. Commun., 57, 2009–2012, 2021.
[150] L. Luo, S.-H. Chung, A. Manthiram, “A trifunctional multi-walled carbon nanotubes/polyethylene glycol (MWCNT/PEG)-coated separator through a layer-by-layer coating strategy for high-energy Li–S batteries,” J. Mater. Chem. A, 4, 16805–16811, 2016.
[151] S.-H. Chung, C.-H. Chang, A. Manthiram, “A carbon-cotton cathode with ultrahigh-loading capability for statically and dynamically stable lithium–sulfur batteries,” ACS Nano, 10, 10462–10470, 2016.
[152] L. S. Li, R. Jacobs, P. Gao, L. Y. Gan, F. Wang, D. Morgan, S. Jin, “Origins of large voltage hysteresis in high-energy-density metal fluoride lithium-ion battery conversion electrodes,” J. Am. Chem. Soc., 138, 2838–2848, 2016.
[153] Z. Z. Du, X. J. Chen, W. Hu, C. H. Chuang, S. Xie, A. J. Hu, W. S. Yan, X. H. Kong, X. J. Wu, H. X. Ji, L.-J. Wan, “Cobalt in nitrogen-doped graphene as single-atom catalyst for high-sulfur content lithium–sulfur batteries,” J. Am. Chem. Soc., 141, 3977–3985, 2019.
[154] F. Y. Fan, Y.-M. Chiang, “Electrodeposition kinetics in Li-S batteries: Effects of low electrolyte/sulfur ratios and deposition surface composition,” J. Electrochem. Soc., 164, A917–A922, 2017.
[155] C.-H. Chang, S.-H. Chung, A. Manthiram, “Transforming waste newspapers into nitrogen-doped conducting interlayers for advanced Li–S batteries,” Sustain. Energy Fuels, 1, 444–449, 2017.
[156] M. Zhao, B. Q. Li, H. J. Peng, H. Yuan, J. Y. Wei, J. Q. Huang, “Lithium–sulfur batteries under lean electrolyte conditions: Challenges and opportunities,” Angew. Chem. Int. Ed., 59, 12636–12652, 2020.
[157] A. Gupta, A. Manthiram, “Unifying the clustering kinetics of lithium polysulfides with the nucleation behavior of Li2S in lithium–sulfur batteries,” J. Mater. Chem. A, 9, 13242–13251, 2021.
[158] A. Hoefling, D. T. Nguyen, P. Partovi-Azar, D. Sebastiani, P. Theato, S.-W. Song, Y. J. Lee, “Mechanism for the stable performance of sulfur-copolymer cathode in lithium-sulfur battery studied by solid-state NMR spectroscopy,” Chem. Mater., 30, 2915–2923, 2018.
[159] H. Yamin, A. Gorenshtein, J. Penciner, Y. Sternberg, E. Peled, “Lithium sulfur battery: Oxidation/reduction mechanisms of polysulfides in thf solutions,” J. Electrochem. Soc., 135, 1045–1048, 1988.
[160] C. Barchasz, F. Molton, C. Duboc, J.-C. Leprêtre, S. Patoux, F. Alloin, “Lithium/sulfur cell discharge mechanism: An original approach for intermediate species identification,” Anal. Chem., 84, 3973–3980, 2012.
[161] C. J. Jafta, A. Hilger, X.-G. Sun, L. X. Geng, M. Y. Li, S. Risse, I. Belharouak, I. Manke, “A multidimensional operando study showing the importance of the electrode macrostructure in lithium sulfur batteries,” ACS Appl. Energy Mater., 3, 6965–6976, 2020.
[162] X. J. Gao, X. F. Yang, Q. Sun, J. Luo, J. N. Liang, W. H. Li, J. W. Wang, S. Z. Wang, M. S. Li, R. Y. Li, T.-K. Sham, X. L. Sun, “Converting a thick electrode into vertically aligned “thin electrodes” by 3D-printing for designing thickness independent Li-S cathode,” Energy Storage Mater., 24, 682–688, 2020.
[163] Y. V. Mikhaylik, J. R. Akridge, “Low temperature performance of Li/S batteries,” J. Electrochem. Soc., 150, 306–311, 2003.
[164] D. R. Deng, F. Xue, C.-D. Bai, J. Lei, R. Yuan, M. S. Zheng, Q. F. Dong, “Enhanced adsorptions to polysulfides on graphene-supported bn nanosheets with excellent Li–S battery performance in a wide temperature range,” ACS Nano, 12, 11120–11129, 2018.
[165] F. Y. Fan, W. C. Carter, Y. M. Chiang, “Mechanism and kinetics of Li2S precipitation in lithium–sulfur batteries,” Adv. Mater., 27, 5203–5209, 2015.
[166] S. Kalybekkyzy, A. Mentbayeva, M. V. Kahraman, Y. Zhang, Z. Bakenov, “Flexible S/DPAN/KB nanofiber composite as binder-free cathodes for Li-S batteries,” J. Electrochem. Soc., 166, A5396–A5402, 2019.
[167] J. Song, S. J. Lee, Y. Kim, S. S. Kim, K. T. Lee, N. S. Choi, “Thermal reactions of lithiated and delithiated sulfur electrodes in lithium-sulfur batteries,” ECS Electrochem. Lett., 3, A26–A29, 2014.
[168] N. Azimi, Z. Xue, I. Bloom, M. L. Gordin, D. Wang, T. Daniel, C. Takoudis, Z. Zhang, “Understanding the effect of a fluorinated ether on the performance of lithium–sulfur batteries,” ACS Appl. Mater. Interfaces, 7, 9169–9177, 2015.
[169] M. Agostini, J.-Y. Hwang, H. M. Kim, P. Bruni, S. Brutti, F. Croce, A. Matic, Y.-K. Sun, “Minimizing the electrolyte volume in Li-S batteries: A step forward to high gravimetric energy density,” Adv. Energy Mater., 8, 1801560, 2018.
[170] M. D. Murbach, V. W. Hu, D. T. Schwartz, “Nonlinear electrochemical impedance spectroscopy of lithium-ion batteries: Experimental approach, analysis, and initial findings,” J. Electrochem. Soc., 165, A2758–A2765, 2018.
[171] T. Osaka, T. Momma, D. Mukoyama, H. Nara, “Proposal of novel equivalent circuit for electrochemical impedance analysis of commercially available lithium ion battery,” J. Power Sources, 205, 483–486, 2012.
[172] D. Andre, M. Meiler, K. Steiner, H. Walz, T. Soczka-Guth, D. U. Sauer, “Characterization of high-power lithium-ion batteries by electrochemical impedance spectroscopy. II: Modelling,” J. Power Sources, 196, 5349–5356, 2011.
[173] C. H. Long, L. B. Li, M. Zhai, Y. H. Shan, “Facile preparation and electrochemistry performance of quasi solid-state polymer lithium–sulfur battery with high-safety and weak shuttle effect,” J. Phys. Chem. Solids, 134, 255–261, 2019.
[174] J. Conder, C. Villevieille, S. Trabesinger, P. Novák, L. Gubler, R. Bouchet, “Electrochemical impedance spectroscopy of a Li–S battery: Part 1. Influence of the electrode and electrolyte compositions on the impedance of symmetric cells,” Electrochim. Acta, 244, 61–68, 2017.
[175] Z. F. Deng, Z. Zhang, Y. Q. Lai, J. Liu, J. Li, Y. X. Liu, “Electrochemical impedance spectroscopy study of a lithium/sulfur battery: Modeling and analysis of capacity fading,” J. Electrochem. Soc., 160, A553–A558, 2013.
[176] L. X. Yuan, X. P. Qiu, L. Q. Chen, W. T. Zhu, “New insight into the discharge process of sulfur cathode by electrochemical impedance spectroscopy,” J. Power Sources, 189, 127–132, 2009.
[177] G. Saldaña, J. I. San Martín, I. Zamora, F. J. Asensio, O. Oñederra, “Analysis of the current electric battery models for electric vehicle simulation,” Energies, 12, 2750, 2019.
[178] A. Lasia, “Impedance of the faradaic reactions in the presence of mass transfer,” in Electrochemical impedance spectroscopy and its applications, Springer New York, New York, NY, 85–125, 2014.
[179] T. Zhang, M. Marinescu, L. O'Neill, M. Wild, G. Offer, “Modeling the voltage loss mechanisms in lithium–sulfur cells: The importance of electrolyte resistance and precipitation kinetics,” Phys. Chem. Chem. Phys., 17, 22581–22586, 2015.
[180] F. X. Yin, J. Ren, G. Y. Wu, C. W. Zhang, Y. G. Zhang, “Polypyrrole nanowires with ordered large mesopores: Synthesis, characterization and applications in supercapacitor and lithium/sulfur batteries,” Polymers, 11, 277, 2019.
[181] M. Coşkun, Ö. Polat, F. M. Coşkun, Z. Durmuş, M. Çağlar, A. Türüt, “The electrical modulus and other dielectric properties by the impedance spectroscopy of LaCrO3 and LaCr0.90Ir0.10O3 perovskites,” RSC Adv., 8, 4634–4648, 2018.
[182] R. Suarez-Hernandez, G. Ramos-Sánchez, I. O. Santos-Mendoza, G. Guzmán-González, I. González, “A graphical approach for identifying the limiting processes in lithium-ion battery cathode using electrochemical impedance spectroscopy,” J. Electrochem. Soc., 167, 100529, 2020.
[183] A. J. Bard, L. R. Faulkner, Electrochemical methods: Fundamentals and applications, John Wiley & Sons, New York, 386, 2001.
[184] H. Chu, J. Jung, H. Noh, S. Yuk, J. Lee, J. H. Lee, J. Baek, Y. Roh, H. Kwon, D. Choi, K. Sohn, Y. Kim, H. T. Kim, “Unraveling the dual functionality of high‐donor‐number anion in lean‐electrolyte lithium‐sulfur batteries,” Adv. Energy Mater., 10, 2000493, 2020.