Zhi Zhu, Shuanglong Xu, Zhenjie Wang, Xiaohui Yan, Guiyin Xu, Yimeng Huang, Yuping Wu, Yin Zhang and Ju Li
{"title":"避免电化学压痕:具有超稳定高压循环功能的 CNT-cocooned钴酸锂电极","authors":"Zhi Zhu, Shuanglong Xu, Zhenjie Wang, Xiaohui Yan, Guiyin Xu, Yimeng Huang, Yuping Wu, Yin Zhang and Ju Li","doi":"10.1039/D4EE00722K","DOIUrl":null,"url":null,"abstract":"<p >Charging LiCoO<small><sub>2</sub></small> (LCO) to above 4.5 V induces crystal cracking and seriously deteriorates the battery cycle life. Decreasing the range of the LCO misfit strain during deep de-lithiation is useful for preventing cracks, but this is not always achievable. Here, we demonstrate that the limited electrochemical contact area between electronically conductive carbon and the LCO crystal causes “electrochemical indentations” (ECIs) during charging and discharging. Particularly in fast charging, the high local Δ<em>c</em><small><sub>Li</sub></small> gradient in LCO would cause a local volume of the surficial lattice to shrink while the rest of the crystal is still under stretching, and hence, drive the ECI to cause cracking. Increasing the electrochemical contact area would reduce the ECI and cracking risk. Therefore, we developed a free-standing CNT-LCO electrode in which all of the LCO particles were intimately wrapped with a dense CNT cocoon to establish a larger true electrical contact area. The simulations demonstrated that the radial Δ<em>c</em><small><sub>Li</sub></small> and ECI decreased significantly in the cocooned LCO particles. The cocooned LCO electrode maintained good morphology and retained 94% of its energy density after 400 cycles when charged to 4.55 V. By removing the need for a current collector and binder, the volumetric energy density of the CNT-LCO cathode reached 3200 Wh L<small><sup>−1</sup></small> (electrode).</p>","PeriodicalId":72,"journal":{"name":"Energy & Environmental Science","volume":null,"pages":null},"PeriodicalIF":32.4000,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/ee/d4ee00722k?page=search","citationCount":"0","resultStr":"{\"title\":\"Avoiding electrochemical indentations: a CNT-cocooned LiCoO2 electrode with ultra-stable high-voltage cycling†\",\"authors\":\"Zhi Zhu, Shuanglong Xu, Zhenjie Wang, Xiaohui Yan, Guiyin Xu, Yimeng Huang, Yuping Wu, Yin Zhang and Ju Li\",\"doi\":\"10.1039/D4EE00722K\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Charging LiCoO<small><sub>2</sub></small> (LCO) to above 4.5 V induces crystal cracking and seriously deteriorates the battery cycle life. 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The simulations demonstrated that the radial Δ<em>c</em><small><sub>Li</sub></small> and ECI decreased significantly in the cocooned LCO particles. The cocooned LCO electrode maintained good morphology and retained 94% of its energy density after 400 cycles when charged to 4.55 V. 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Avoiding electrochemical indentations: a CNT-cocooned LiCoO2 electrode with ultra-stable high-voltage cycling†
Charging LiCoO2 (LCO) to above 4.5 V induces crystal cracking and seriously deteriorates the battery cycle life. Decreasing the range of the LCO misfit strain during deep de-lithiation is useful for preventing cracks, but this is not always achievable. Here, we demonstrate that the limited electrochemical contact area between electronically conductive carbon and the LCO crystal causes “electrochemical indentations” (ECIs) during charging and discharging. Particularly in fast charging, the high local ΔcLi gradient in LCO would cause a local volume of the surficial lattice to shrink while the rest of the crystal is still under stretching, and hence, drive the ECI to cause cracking. Increasing the electrochemical contact area would reduce the ECI and cracking risk. Therefore, we developed a free-standing CNT-LCO electrode in which all of the LCO particles were intimately wrapped with a dense CNT cocoon to establish a larger true electrical contact area. The simulations demonstrated that the radial ΔcLi and ECI decreased significantly in the cocooned LCO particles. The cocooned LCO electrode maintained good morphology and retained 94% of its energy density after 400 cycles when charged to 4.55 V. By removing the need for a current collector and binder, the volumetric energy density of the CNT-LCO cathode reached 3200 Wh L−1 (electrode).
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).