{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/130132"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/130132","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Nanoscale defect engineering and mapping for cathode materials of multivalent ion batteries","abstract":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01","abstract_html":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01","abstract_has_math":false,"creators":["Tang, Zhichu"],"institution":"University of Illinois Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science & Engr","degree_department":null,"school":null,"contributors":["Chen, Qian","Zuo, Jian-Min","Braun, Paul V.","Yang, Hong"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-07-07","date_published":"2025-07-07","updated_at":"2026-07-22T22:25:06Z","subjects":["Defect Engineering","Zn-ion Battery","Energy Storage","4d-stem","Nanomaterial Characterization"],"languages":["en","eng"],"rights":["Copyright 2025 Zhichu Tang"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/130132","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Chen, Qian","Zuo, Jian-Min","Braun, Paul V.","Yang, Hong"]},{"key":"dc:creator","label":"Author","values":["Tang, Zhichu"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-07-07","2025-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science & Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Defect Engineering","Zn-ion Battery","Energy Storage","4d-stem","Nanomaterial Characterization"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2025 Zhichu Tang"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/130132"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01","The student, Zhichu Tang, accepted the attached license on 2025-06-27 at 09:32.","The student, Zhichu Tang, submitted this Dissertation for approval on 2025-06-27 at 09:50.","This Dissertation was approved for publication on 2025-07-07 at 15:59.","DSpace SAF Submission Ingestion Package generated from Vireo submission #22374 on 2025-10-25 at 15:52:51","Aqueous multivalent ion batteries, particularly Zn-ion batteries (ZIBs), represent a promising next-generation solution for grid-scale energy storage. However, their practical application is hindered by the lack of suitable cathode materials that can support reversible Zn-ion intercalation, as well as an incomplete understanding of their fundamental reaction mechanisms. This thesis aims to address these challenges by advancing nanoscale characterization techniques and offering fundamental insights into how particle size reduction and stacking fault (SF) engineering enhance Zn-ion diffusion within the spinel lattice. Chapter 1 provides a brief introduction to manganese-based oxides as cathode materials for ZIBs and outlines the remaining scientific and technical challenges. Chapter 2 investigates the influence of particle size on the phase transition pathways of λ-MnO2 during Zn-ion insertion, along with water-induced side reactions. We find that although Zn-ion insertion is enhanced in nanoparticles (NPs), their extraction from the spinel lattice is still difficult, leading to poor cycling stability. To address this limitation, Chapter 3 presents a novel method to improve the cycling performance of λ-MnO2 NPs in ZIBs by introducing SFs via thermal treatment. These SF defects are identified and quantified at nanometer resolution using four-dimensional scanning transmission electron microscopy (4D-STEM). Collocated 4D-STEM and electron energy loss spectroscopy (EELS) mapping reveals SFs enable reversible Zn-ion insertion and extraction in the spinel lattice. The thermal-induced phase transition pathway and the underlying mechanism by which SFs promote Zn-ion extraction are discussed in Chapter 4. We further extend the 4D-STEM technique and associated data-mining methods to other battery systems, demonstrating the effect of Na+ on Li-Na ion exchange in LiFePO4 through strain mapping. Finally, Chapter 5 summarizes the key findings and proposes future research directions, emphasizing the potential of integrating 4D-STEM with in-situ liquid-phase transmission electron microscopy to investigate ion transport and structural evolution in real time. These advances provide a powerful platform for the fundamental study and rational design of intercalation-type cathode materials for next-generation energy storage systems."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Nanoscale defect engineering and mapping for cathode materials of multivalent ion batteries"]}]}],"canonical_facts":{"dc:contributor":["Chen, Qian","Zuo, Jian-Min","Braun, Paul V.","Yang, Hong"],"dc:creator":["Tang, Zhichu"],"dc:date":["2025-07-07","2025-08"],"dc:description":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01","The student, Zhichu Tang, accepted the attached license on 2025-06-27 at 09:32.","The student, Zhichu Tang, submitted this Dissertation for approval on 2025-06-27 at 09:50.","This Dissertation was approved for publication on 2025-07-07 at 15:59.","DSpace SAF Submission Ingestion Package generated from Vireo submission #22374 on 2025-10-25 at 15:52:51","Aqueous multivalent ion batteries, particularly Zn-ion batteries (ZIBs), represent a promising next-generation solution for grid-scale energy storage. However, their practical application is hindered by the lack of suitable cathode materials that can support reversible Zn-ion intercalation, as well as an incomplete understanding of their fundamental reaction mechanisms. This thesis aims to address these challenges by advancing nanoscale characterization techniques and offering fundamental insights into how particle size reduction and stacking fault (SF) engineering enhance Zn-ion diffusion within the spinel lattice. Chapter 1 provides a brief introduction to manganese-based oxides as cathode materials for ZIBs and outlines the remaining scientific and technical challenges. Chapter 2 investigates the influence of particle size on the phase transition pathways of λ-MnO2 during Zn-ion insertion, along with water-induced side reactions. We find that although Zn-ion insertion is enhanced in nanoparticles (NPs), their extraction from the spinel lattice is still difficult, leading to poor cycling stability. To address this limitation, Chapter 3 presents a novel method to improve the cycling performance of λ-MnO2 NPs in ZIBs by introducing SFs via thermal treatment. These SF defects are identified and quantified at nanometer resolution using four-dimensional scanning transmission electron microscopy (4D-STEM). Collocated 4D-STEM and electron energy loss spectroscopy (EELS) mapping reveals SFs enable reversible Zn-ion insertion and extraction in the spinel lattice. The thermal-induced phase transition pathway and the underlying mechanism by which SFs promote Zn-ion extraction are discussed in Chapter 4. We further extend the 4D-STEM technique and associated data-mining methods to other battery systems, demonstrating the effect of Na+ on Li-Na ion exchange in LiFePO4 through strain mapping. Finally, Chapter 5 summarizes the key findings and proposes future research directions, emphasizing the potential of integrating 4D-STEM with in-situ liquid-phase transmission electron microscopy to investigate ion transport and structural evolution in real time. These advances provide a powerful platform for the fundamental study and rational design of intercalation-type cathode materials for next-generation energy storage systems."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/130132"],"dc:language":["en","eng"],"dc:rights":["Copyright 2025 Zhichu Tang"],"dc:subject":["Defect Engineering","Zn-ion Battery","Energy Storage","4d-stem","Nanomaterial Characterization"],"dc:title":["Nanoscale defect engineering and mapping for cathode materials of multivalent ion batteries"],"dc:type":["text"],"thesis:degree_discipline":["Materials Science & Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:06Z"}