Gukhyun Lim, Min Kyung Cho, Jaewon Choi, Ke-Jin Zhou, Dongki Shin, Seungyun Jeon, Minhyung Kwon, A-Re Jeon, Jinkwan Choi, Seok Su Sohn, Minah Lee, Jihyun Hong
{"title":"通过调整表面重构途径实现富锂富锰阴极容量衰减与电压衰减的去耦合","authors":"Gukhyun Lim, Min Kyung Cho, Jaewon Choi, Ke-Jin Zhou, Dongki Shin, Seungyun Jeon, Minhyung Kwon, A-Re Jeon, Jinkwan Choi, Seok Su Sohn, Minah Lee, Jihyun Hong","doi":"10.1039/d4ee02329c","DOIUrl":null,"url":null,"abstract":"Exploiting oxygen anion redox in Li-/Mn-rich layered oxides (LMR-NMCs) offers the highest capacity among cathode materials for Li-ion batteries (LIBs). However, its long-term utilization is challenging due to continuous voltage and capacity decay caused by irreversible phase transitions involving cation disordering and oxygen release. While extensive studies have revealed the thermodynamic origin of cation disordering, the mechanisms of oxygen loss and consequent lattice densification remain elusive. Moreover, mixed spinel-rocksalt nanodomains formed after cycling complicate the degradation mechanism. Herein, we reveal a strong correlation between phase transition pathways and oxygen stability at the particle surface in LMR-NMCs through a comparative study using electrolyte modification. By tailoring surface reconstruction pathways, we control overall phase and electrochemistry evolution mechanisms. Removing polar ethylene carbonate from the electrolyte significantly suppresses irreversible oxygen loss at the cathode-electrolyte interface, preferentially promoting the in-situ layered-to-spinel phase transition while avoiding typical rocksalt phase formation. The in-situ formed spinel-stabilized surface enhances charge transfer kinetics through three-dimensional ion channels, maintaining reversible Ni, Mn, and O redox capability over 700 cycles, as revealed by electron microscopy, X-ray absorption spectroscopy, and resonant inelastic X-ray scattering. Deep delithiation and lithiation enabled by the surface spinel phase accelerate the bulk layered-to-spinel phase transition, inducing thermodynamic voltage fade without capacity loss. Conversely, conventional electrolytes induce layered-to-rocksalt surface reconstruction, impeding charge transfer reactions, which causes simultaneous capacity and (apparent) voltage fades. Our work decouples thermodynamic and kinetic aspects of voltage decay in LMR-NMCs, establishing the correlation between surface reconstruction, bulk phase transition, and the electrochemistry of high-capacity cathodes that exploit cation and anion redox couples. This study highlights the significance of electrochemical interface stabilization for advancing Mn-rich cathode chemistries in future LIBs.","PeriodicalId":72,"journal":{"name":"Energy & Environmental Science","volume":null,"pages":null},"PeriodicalIF":32.4000,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Decoupling Capacity Fade and Voltage Decay of Li-rich Mn-rich Cathodes by Tailoring Surface Reconstruction Pathways\",\"authors\":\"Gukhyun Lim, Min Kyung Cho, Jaewon Choi, Ke-Jin Zhou, Dongki Shin, Seungyun Jeon, Minhyung Kwon, A-Re Jeon, Jinkwan Choi, Seok Su Sohn, Minah Lee, Jihyun Hong\",\"doi\":\"10.1039/d4ee02329c\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Exploiting oxygen anion redox in Li-/Mn-rich layered oxides (LMR-NMCs) offers the highest capacity among cathode materials for Li-ion batteries (LIBs). However, its long-term utilization is challenging due to continuous voltage and capacity decay caused by irreversible phase transitions involving cation disordering and oxygen release. While extensive studies have revealed the thermodynamic origin of cation disordering, the mechanisms of oxygen loss and consequent lattice densification remain elusive. Moreover, mixed spinel-rocksalt nanodomains formed after cycling complicate the degradation mechanism. Herein, we reveal a strong correlation between phase transition pathways and oxygen stability at the particle surface in LMR-NMCs through a comparative study using electrolyte modification. By tailoring surface reconstruction pathways, we control overall phase and electrochemistry evolution mechanisms. Removing polar ethylene carbonate from the electrolyte significantly suppresses irreversible oxygen loss at the cathode-electrolyte interface, preferentially promoting the in-situ layered-to-spinel phase transition while avoiding typical rocksalt phase formation. The in-situ formed spinel-stabilized surface enhances charge transfer kinetics through three-dimensional ion channels, maintaining reversible Ni, Mn, and O redox capability over 700 cycles, as revealed by electron microscopy, X-ray absorption spectroscopy, and resonant inelastic X-ray scattering. Deep delithiation and lithiation enabled by the surface spinel phase accelerate the bulk layered-to-spinel phase transition, inducing thermodynamic voltage fade without capacity loss. Conversely, conventional electrolytes induce layered-to-rocksalt surface reconstruction, impeding charge transfer reactions, which causes simultaneous capacity and (apparent) voltage fades. 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Decoupling Capacity Fade and Voltage Decay of Li-rich Mn-rich Cathodes by Tailoring Surface Reconstruction Pathways
Exploiting oxygen anion redox in Li-/Mn-rich layered oxides (LMR-NMCs) offers the highest capacity among cathode materials for Li-ion batteries (LIBs). However, its long-term utilization is challenging due to continuous voltage and capacity decay caused by irreversible phase transitions involving cation disordering and oxygen release. While extensive studies have revealed the thermodynamic origin of cation disordering, the mechanisms of oxygen loss and consequent lattice densification remain elusive. Moreover, mixed spinel-rocksalt nanodomains formed after cycling complicate the degradation mechanism. Herein, we reveal a strong correlation between phase transition pathways and oxygen stability at the particle surface in LMR-NMCs through a comparative study using electrolyte modification. By tailoring surface reconstruction pathways, we control overall phase and electrochemistry evolution mechanisms. Removing polar ethylene carbonate from the electrolyte significantly suppresses irreversible oxygen loss at the cathode-electrolyte interface, preferentially promoting the in-situ layered-to-spinel phase transition while avoiding typical rocksalt phase formation. The in-situ formed spinel-stabilized surface enhances charge transfer kinetics through three-dimensional ion channels, maintaining reversible Ni, Mn, and O redox capability over 700 cycles, as revealed by electron microscopy, X-ray absorption spectroscopy, and resonant inelastic X-ray scattering. Deep delithiation and lithiation enabled by the surface spinel phase accelerate the bulk layered-to-spinel phase transition, inducing thermodynamic voltage fade without capacity loss. Conversely, conventional electrolytes induce layered-to-rocksalt surface reconstruction, impeding charge transfer reactions, which causes simultaneous capacity and (apparent) voltage fades. Our work decouples thermodynamic and kinetic aspects of voltage decay in LMR-NMCs, establishing the correlation between surface reconstruction, bulk phase transition, and the electrochemistry of high-capacity cathodes that exploit cation and anion redox couples. This study highlights the significance of electrochemical interface stabilization for advancing Mn-rich cathode chemistries in future LIBs.
期刊介绍:
Energy & Environmental Science, a peer-reviewed scientific journal, publishes original research and review articles covering interdisciplinary topics in the (bio)chemical and (bio)physical sciences, as well as chemical engineering disciplines. Published monthly by the Royal Society of Chemistry (RSC), a not-for-profit publisher, Energy & Environmental Science is recognized as a leading journal. It boasts an impressive impact factor of 8.500 as of 2009, ranking 8th among 140 journals in the category "Chemistry, Multidisciplinary," second among 71 journals in "Energy & Fuels," second among 128 journals in "Engineering, Chemical," and first among 181 scientific journals in "Environmental Sciences."
Energy & Environmental Science publishes various types of articles, including Research Papers (original scientific work), Review Articles, Perspectives, and Minireviews (feature review-type articles of broad interest), Communications (original scientific work of an urgent nature), Opinions (personal, often speculative viewpoints or hypotheses on current topics), and Analysis Articles (in-depth examination of energy-related issues).