Intercalation Phase Engineering of Transition Metal Dichalcogenides by Professor Zhiyuan Zeng

NTU MSE Seminar Hosted by Assistant Professor Jie Shen

Abstract

Intercalation of atoms, ions, and molecules is an effective means of tuning the properties of two-dimensional materials, while in situ imaging and spectroscopy provide powerful tools for deciphering intercalation dynamics and mechanisms.^1,2 Firstly, we developed a lithium ion battery intercalation & exfoliation method with detailed experimental procedures for the mass production of 11 2D transition metal dichalcogenides (TMDs) and inorganic nanosheets, such as MoS₂, WS₂, TiS₂, TaS₂, ZrS₂, graphene, h-BN, NbSe₂, WSe₂, Sb₂Se₃ and Bi₂Te₃, among them 3 TMDs achieved mono- or double layer yield > 90%.³ The Li insertion can be monitored and finely controlled in the battery testing system, so that the galvanostatic discharge process is stopped at a proper Li content to avoid decomposition of the intercalated compounds. Secondly, we discovered that small current and high cut-off voltage (0.005 A g-1, 0.9 V) produces pure 2H WS₂ bilayers. while large current and low cut-off voltage (0.02 A g-1, 0.7 V) leads to 1T’ WS₂ monolayers.⁴ For lithium intercalation mechanism, the state-of-the-art In-Situ Liquid Phase TEM is an ideal technique for identifying the phase changes during intercalation process.⁵ Combining with in-situ XAS, XRD and Raman, etc, the underlying intercalation phase engineering mechanism were elucidated to achieve phase-switchable preparation of TMDs.⁶ For the application, the unconventional phase of TMDs generated via intercalation exhibited much improved physical and chemical properties, such as superconducting devices, humidity sensor,⁴ thermoelectric generator,⁶ heavy metal removal,⁷ ion separation,^8-11 aquatic biota detection,¹² etc.

References: 
[1] R. Yang†, L. Mei†, Z. Lin†, et al., Q. Lu*, J. Li*, Z. Y. Zeng*, Nat. Rev. Chem., 2024, 8, 410.
[2] R. Yang, et al., D. Voiry, Q. Lu, J. Li*, Z. Y. Zeng*, Nat. Synth., 2023, 2, 101-118.
[3] R. Yang, L. Mei, et al., H. S. Shin*, D. Voiry*, Z.Y. Zeng*, Nat. Protoc., 2022, 17, 358-377.
[4] L. Mei, Z. Gao, R. Yang, et al., J. Li*, X. Yu*, Z. Y. Zeng*, Nat. Synth., 2025, 4, 303-313.
[5] R. Yang, L. Mei, Y. Fan, et al., J. Yang, J. Li*, Z. Y. Zeng*, Nat. Protoc., 2023, 18, 555-578.
[6] Q. Zhang, et al., X. C. Zeng*, K. P. Loh*, Z. Y. Zeng*, Natl. Sci. Rev., 2026, accepted.
[7] L. Mei, M. Sun, et al., B. Huang*, L. Gu*, D. Voiry, Z. Y. Zeng*, Nat. Commun., 2024, 15, 7770.
[8] T. Ying, N. Onofrio, et al., C. Y. Tang*, D. Voiry*, Z. Y. Zeng*, Adv. Mater., 2025, 37, e04781.
[9] T. Ying, Y. Xiong, et al., C. Y. Tang, J. Fan, Z. Y. Zeng*, Adv. Mater., 2024, 36, 2403385.
[10] L. Mei, et al., D. Voiry, H. Wang*, A. B. Farimani*, Z. Y. Zeng*, Adv. Mater., 2022, 34, 2201416. 
[11] Y. Zhang, et al., B. Huang*, Z. Y. Zeng*, Nano Lett., 2026, DOI: 10.1021/acs.nanolett.5c04248.
[12] L. Mei, et al., Z. Y. Zeng*, K. M. Y. Leung*, Natl. Sci. Rev., 2026, DOI: 10.1093/nsr/nwag055.

Biography

Professor Zhiyuan Zeng
City University of Hong Kong

Prof. Zhiyuan Zeng received his BSc, MPhil and PhD from Central South University, Zhejiang University and Nanyang Technological University in 2006, 2008 and 2013, respectively. After 4 years as a Postdoctoral Fellow at Lawrence Berkeley National Laboratory (LBNL) and 2 years as an Engineer working in Applied Materials Inc. (Silicon Valley), he joined the Department of Materials Science and Engineering, City University of Hong Kong as an Assistant Professor in 2019, and was promoted to Associate Professor in 2024, and then Professor in 2026. His research interests are intercalation phase engineering of transition metal dichalcogenides for phase-switchable preparation of TMDs, including conventional and unconventional phases, which greatly improved the electronic and environmental application performance. He has published 181 SCI papers (132 IF>10) including Nat. Mater., Nat. Rev. Chem., Nat. Synth., Nat. Protoc., Nat. Commun, Natl. Sci. Rev., etc, with 29521 citations and H-index of 76. He was the "2018 Youth Thousand Talents Plan" awardee, and he was also awarded the 2023/2024 Young Collaborative Research Grant (YCRG, 4,832,040 HKD) by the University Grants Committee (UGC) of Hong Kong. He has been listed as the Highly Cited Researcher (Top 1%, Clarivate Analytics) 5 times in 2024-2018. He was also awarded the Lifetime Fellow by IAAM, and CENG Research Excellence Awards for Junior Faculty by CityUHK in 2025.