Gambe Yoshiyuki, Kobayashi Hiroaki, Honma Itaru
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
ACS Appl Mater Interfaces. 2025 Jan 15;17(2):3316-3323. doi: 10.1021/acsami.4c16866. Epub 2025 Jan 3.
Sodium croconate, a high-voltage organic cathode material, can be applied to high-energy-density and cost-effective organic sodium-ion batteries (OSIBs) as an alternative to traditional lithium-ion batteries. However, organic molecular cathodes generally dissolve into the electrolyte, leading to poor cyclability. Thus, an electrolyte that can address the present limitations and further facilitate the fabrication of highly reversible OSIBs must be developed. To address this gap in the literature, in this study, we demonstrate an acetonitrile (AN)-based highly concentrated electrolyte (HCE) with sodium bis(fluorosulfonyl)imide (NaFSI). This electrolyte has an ionic conductivity of 12.1 mS cm, which is higher than those of previously reported HCEs. Moreover, the developed HCE (NaFSI:AN molar ratio of 1:2.7) exhibits a high Na transference number of 0.49. A full-cell OSIB bearing this electrolyte demonstrates high-power operation with improved capacity retention. The solvent-free electrolyte with the solvation structure of the [2Na-FSI] aggregate suppresses the dissolution of organic molecules, leading to their high performance.
环丙烯酸钠是一种高压有机阴极材料，作为传统锂离子电池的替代品，可应用于高能量密度且经济高效的有机钠离子电池（OSIB）。然而，有机分子阴极通常会溶解在电解质中，导致循环性能较差。因此，必须开发一种能够解决当前局限性并进一步促进高可逆性有机钠离子电池制造的电解质。为了填补文献中的这一空白，在本研究中，我们展示了一种基于乙腈（AN）的含双（氟磺酰）亚胺钠（NaFSI）的高浓度电解质（HCE）。这种电解质的离子电导率为12.1 mS/cm，高于先前报道的高浓度电解质。此外，所开发的高浓度电解质（NaFSI:AN摩尔比为1:2.7）表现出0.49的高钠迁移数。采用这种电解质的全电池有机钠离子电池展示了高功率运行以及改善的容量保持率。具有[2Na - FSI]聚集体溶剂化结构的无溶剂电解质抑制了有机分子的溶解，从而使其具有高性能。
