Mitigating Interfacial Degradation by Tuning the Diluent–Anion Affinity for Long-Cycling Lithium Metal Batteries.
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| Title: | Mitigating Interfacial Degradation by Tuning the Diluent–Anion Affinity for Long-Cycling Lithium Metal Batteries. |
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| Authors: | Wu, Hongcheng1,2 (AUTHOR) hongchengwu@shu.edu.cn, Ran, Jiangnan1,2 (AUTHOR), Dou, Youxian2 (AUTHOR), Yang, Dalin2 (AUTHOR), Wu, Guangye2 (AUTHOR), Zheng, Qiang1 (AUTHOR) qzheng@shu.edu.cn |
| Source: | Materials (1996-1944). Jun2026, Vol. 19 Issue 12, p2605. 14p. |
| Subjects: | Electrolytes, Solvation, Chemical affinity, Lithium cells, Electrode efficiency, Deterioration of materials |
| Abstract: | Highlights: TeCA with weak intermolecular interaction achieves a compressed solvation structure by mitigating diluent–FSI− interaction. TeCA-LHCE shows good flame retardancy and cost advantages compared with commercial carbonate electrolytes. TeCA-LHCE electrolyte can reduce the fluorine content in the electrolyte, thereby better complying with PFAS regulations. TeCA-LHCE enables 99.23% average CE over 500 cycles in Li||Cu cell and stable cycling over 800 h in Li||Li symmetric cells. Full cells employing TeCA-LHCE achieve improved cycling stability at 4.3 V and wide-temperature adaptability. Ionic liquid-based localized high-concentration electrolytes, leveraging their intrinsically nonflammable safety characteristics and wide electrochemical windows, have emerged as strong contenders for next-generation lithium metal battery electrolytes. However, because such systems are anion-rich, the electrolyte bulk phase tends to form solvation structures dominated by bulky anionic clusters along with an excess of free anions, which triggers persistent and uncontrollable anion decomposition at the interphase. To address this issue, we adopt a strategy of constructing a compressed solvation structure by introducing a weakly interacting chlorinated diluent (TeCA), which helps form a compact solvation environment and alleviates excessive anion decomposition at electrode interphases. In this work, 1,1,2,2-tetrachloroethyl acetate (TeCA) was introduced as a weakly coordinating chlorinated diluent into an ionic-liquid localized high-concentration electrolyte (LHCE) to regulate the Li+-FSI− solvation environment. By combining Raman spectroscopy, molecular dynamics simulations, and electrochemical characterization, the TeCA-LHCE system was found to exhibit altered ion-cluster configurations, improved oxidation tolerance, and enhanced interfacial stability under high-voltage conditions. The as-prepared TeCA-LHCE electrolyte presents improved electrochemical performance in comparison with TTE-LHCE and the baseline electrolyte (BE). The Li||Cu half-cell employing TeCA-LHCE achieved a high Coulombic efficiency above 99% over 500 cycles and formed a uniform and dense lithium deposition layer without obvious dendritic growth. When paired with a high-loading NCM811 cathode (10 mg cm−2), the TeCA-LHCE-based Li||NCM811 full cell delivered significantly improved cycling stability and rate capability under a high cutoff voltage of 4.3 V. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | Highlights: TeCA with weak intermolecular interaction achieves a compressed solvation structure by mitigating diluent–FSI− interaction. TeCA-LHCE shows good flame retardancy and cost advantages compared with commercial carbonate electrolytes. TeCA-LHCE electrolyte can reduce the fluorine content in the electrolyte, thereby better complying with PFAS regulations. TeCA-LHCE enables 99.23% average CE over 500 cycles in Li||Cu cell and stable cycling over 800 h in Li||Li symmetric cells. Full cells employing TeCA-LHCE achieve improved cycling stability at 4.3 V and wide-temperature adaptability. Ionic liquid-based localized high-concentration electrolytes, leveraging their intrinsically nonflammable safety characteristics and wide electrochemical windows, have emerged as strong contenders for next-generation lithium metal battery electrolytes. However, because such systems are anion-rich, the electrolyte bulk phase tends to form solvation structures dominated by bulky anionic clusters along with an excess of free anions, which triggers persistent and uncontrollable anion decomposition at the interphase. To address this issue, we adopt a strategy of constructing a compressed solvation structure by introducing a weakly interacting chlorinated diluent (TeCA), which helps form a compact solvation environment and alleviates excessive anion decomposition at electrode interphases. In this work, 1,1,2,2-tetrachloroethyl acetate (TeCA) was introduced as a weakly coordinating chlorinated diluent into an ionic-liquid localized high-concentration electrolyte (LHCE) to regulate the Li+-FSI− solvation environment. By combining Raman spectroscopy, molecular dynamics simulations, and electrochemical characterization, the TeCA-LHCE system was found to exhibit altered ion-cluster configurations, improved oxidation tolerance, and enhanced interfacial stability under high-voltage conditions. The as-prepared TeCA-LHCE electrolyte presents improved electrochemical performance in comparison with TTE-LHCE and the baseline electrolyte (BE). The Li||Cu half-cell employing TeCA-LHCE achieved a high Coulombic efficiency above 99% over 500 cycles and formed a uniform and dense lithium deposition layer without obvious dendritic growth. When paired with a high-loading NCM811 cathode (10 mg cm−2), the TeCA-LHCE-based Li||NCM811 full cell delivered significantly improved cycling stability and rate capability under a high cutoff voltage of 4.3 V. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 19961944 |
| DOI: | 10.3390/ma19122605 |
