Akkisetty Bhaskar, Dimogiannis Konstantinos, Searle Joanne, Rogers David, Newton Graham N, Johnson Lee R
Nottingham Applied Materials and Interfaces Group, School of Chemistry, University of Nottingham, Nottingham NG7 2TU, U.K.
School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
ACS Appl Mater Interfaces. 2022 Aug 17;14(32):36551-36556. doi: 10.1021/acsami.2c06502. Epub 2022 Aug 5.
Development of sodium anodes, both hard carbon (HC) and metallic, is dependent on the discovery of electrolyte formations and additives able to stabilize the interphase and support Na transport. Halogen salt additives are known to lower the energy barrier for the Na-ion charge transfer at the interface and facilitate stable Na plating/stripping in a symmetric cell configuration. Here, a halogen-rich additive for the sodium-ion battery electrolyte, 2-chloro-1,1,2-trifluoroethyl difluoromethyl ether (enflurane), is reported. Enflurane offers a simple molecular alternative to salt-based additives. The additive is also shown to improve the cycling performance of sodium metal electrodes. Our analysis demonstrates that enflurane is preferentially reduced at the HC electrode over propylene carbonate and is incorporated into the solid electrolyte interphase (SEI). The result is a thin, halogen-rich SEI that offers better charge transport properties and stability during cycling compared to that formed in the additive-free electrolyte. Additionally, enflurane inhibits polarization of metallic sodium electrodes, and when included in HC half-cells at 10 v/v %, it improves the reversible specific capacity and stability.
硬碳（HC）和金属钠阳极的开发取决于能否发现能够稳定界面并支持钠传输的电解质形成物和添加剂。已知卤素盐添加剂可降低界面处钠离子电荷转移的能垒，并有助于在对称电池配置中实现稳定的钠电镀/剥离。在此，报道了一种用于钠离子电池电解质的富含卤素的添加剂，即2-氯-1,1,2-三氟乙基二氟甲基醚（恩氟烷）。恩氟烷为盐基添加剂提供了一种简单的分子替代物。该添加剂还被证明可改善金属钠电极的循环性能。我们的分析表明，与碳酸丙烯酯相比，恩氟烷在HC电极上优先被还原，并被纳入固体电解质界面（SEI）。结果是形成了一层薄的、富含卤素的SEI，与在无添加剂电解质中形成的SEI相比，它在循环过程中具有更好的电荷传输性能和稳定性。此外，恩氟烷可抑制金属钠电极的极化，当以10 v/v%的比例包含在HC半电池中时，它可提高可逆比容量和稳定性。
