Zexin Lin, Zhihao Deng, Xianrun Cao, Lu Guo, Feifei Zhang, Sheng Liu, Juezhi Yu and Gangfeng Ouyang
{"title":"分子滴定策略:利用内置电场检测 LiFePO4 中的锂扩散系数","authors":"Zexin Lin, Zhihao Deng, Xianrun Cao, Lu Guo, Feifei Zhang, Sheng Liu, Juezhi Yu and Gangfeng Ouyang","doi":"10.1039/D5CP00481K","DOIUrl":null,"url":null,"abstract":"<p >Electrometric titration techniques have long been used to measure the Li<small><sup>+</sup></small> diffusion coefficients of electrode materials. However, the influence of electrode additives, cell assembly methods, and in particular, inaccurate assessments of the reaction area often lead to unreliable results. Here, we propose a molecular titration technique (MTT) to measure the lithium diffusion coefficient (<em>D</em><small><sub>Li</sub></small>) in LiFePO<small><sub>4</sub></small>. This MTT alleviates the tedious electrode preparation procedure, circumvents the influence of additives, reduces the real reaction area errors, and shortens the testing time, making the testing more precise and efficient than the traditional titration techniques. In detail, [Fe(CN)<small><sub>6</sub></small>]<small><sup>3−</sup></small> solution is used to oxidize LiFePO<small><sub>4</sub></small> to Li<small><sup>+</sup></small> and FePO<small><sub>4</sub></small>, while the potential change rate (<em>r</em><small><sub>p</sub></small>) of the solution is recorded. Then, a built-in electric field (BIEF) electron transferring model is established, and the relationship between <em>D</em><small><sub>Li</sub></small> and <em>r</em><small><sub>p</sub></small> is formulated using the Huggins–Weppner equation. Eventually, the de-lithiation diffusion coefficient of Li<small><sub>1−<em>x</em></sub></small>FePO<small><sub>4</sub></small> (1 ≤ <em>x</em> ≤ 0) is measured to be 1–8 × 10<small><sup>−15</sup></small> cm<small><sup>2</sup></small> s<small><sup>−1</sup></small> based on the recorded data and established formulae.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":" 19","pages":" 9954-9961"},"PeriodicalIF":2.9000,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"A molecular titration strategy: utilizing a built-in electric field to measure the lithium diffusion coefficient in LiFePO4†\",\"authors\":\"Zexin Lin, Zhihao Deng, Xianrun Cao, Lu Guo, Feifei Zhang, Sheng Liu, Juezhi Yu and Gangfeng Ouyang\",\"doi\":\"10.1039/D5CP00481K\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Electrometric titration techniques have long been used to measure the Li<small><sup>+</sup></small> diffusion coefficients of electrode materials. However, the influence of electrode additives, cell assembly methods, and in particular, inaccurate assessments of the reaction area often lead to unreliable results. Here, we propose a molecular titration technique (MTT) to measure the lithium diffusion coefficient (<em>D</em><small><sub>Li</sub></small>) in LiFePO<small><sub>4</sub></small>. This MTT alleviates the tedious electrode preparation procedure, circumvents the influence of additives, reduces the real reaction area errors, and shortens the testing time, making the testing more precise and efficient than the traditional titration techniques. In detail, [Fe(CN)<small><sub>6</sub></small>]<small><sup>3−</sup></small> solution is used to oxidize LiFePO<small><sub>4</sub></small> to Li<small><sup>+</sup></small> and FePO<small><sub>4</sub></small>, while the potential change rate (<em>r</em><small><sub>p</sub></small>) of the solution is recorded. Then, a built-in electric field (BIEF) electron transferring model is established, and the relationship between <em>D</em><small><sub>Li</sub></small> and <em>r</em><small><sub>p</sub></small> is formulated using the Huggins–Weppner equation. Eventually, the de-lithiation diffusion coefficient of Li<small><sub>1−<em>x</em></sub></small>FePO<small><sub>4</sub></small> (1 ≤ <em>x</em> ≤ 0) is measured to be 1–8 × 10<small><sup>−15</sup></small> cm<small><sup>2</sup></small> s<small><sup>−1</sup></small> based on the recorded data and established formulae.</p>\",\"PeriodicalId\":99,\"journal\":{\"name\":\"Physical Chemistry Chemical Physics\",\"volume\":\" 19\",\"pages\":\" 9954-9961\"},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2025-04-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physical Chemistry Chemical Physics\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://pubs.rsc.org/en/content/articlelanding/2025/cp/d5cp00481k\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physical Chemistry Chemical Physics","FirstCategoryId":"92","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2025/cp/d5cp00481k","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
A molecular titration strategy: utilizing a built-in electric field to measure the lithium diffusion coefficient in LiFePO4†
Electrometric titration techniques have long been used to measure the Li+ diffusion coefficients of electrode materials. However, the influence of electrode additives, cell assembly methods, and in particular, inaccurate assessments of the reaction area often lead to unreliable results. Here, we propose a molecular titration technique (MTT) to measure the lithium diffusion coefficient (DLi) in LiFePO4. This MTT alleviates the tedious electrode preparation procedure, circumvents the influence of additives, reduces the real reaction area errors, and shortens the testing time, making the testing more precise and efficient than the traditional titration techniques. In detail, [Fe(CN)6]3− solution is used to oxidize LiFePO4 to Li+ and FePO4, while the potential change rate (rp) of the solution is recorded. Then, a built-in electric field (BIEF) electron transferring model is established, and the relationship between DLi and rp is formulated using the Huggins–Weppner equation. Eventually, the de-lithiation diffusion coefficient of Li1−xFePO4 (1 ≤ x ≤ 0) is measured to be 1–8 × 10−15 cm2 s−1 based on the recorded data and established formulae.
期刊介绍:
Physical Chemistry Chemical Physics (PCCP) is an international journal co-owned by 19 physical chemistry and physics societies from around the world. This journal publishes original, cutting-edge research in physical chemistry, chemical physics and biophysical chemistry. To be suitable for publication in PCCP, articles must include significant innovation and/or insight into physical chemistry; this is the most important criterion that reviewers and Editors will judge against when evaluating submissions.
The journal has a broad scope and welcomes contributions spanning experiment, theory, computation and data science. Topical coverage includes spectroscopy, dynamics, kinetics, statistical mechanics, thermodynamics, electrochemistry, catalysis, surface science, quantum mechanics, quantum computing and machine learning. Interdisciplinary research areas such as polymers and soft matter, materials, nanoscience, energy, surfaces/interfaces, and biophysical chemistry are welcomed if they demonstrate significant innovation and/or insight into physical chemistry. Joined experimental/theoretical studies are particularly appreciated when complementary and based on up-to-date approaches.