Modulating Double-Layer Solvation Structure via Dual-Weak-Interaction for Stable Sodium-Metal Batteries

Tianze Shi, Ruilin Hou, Linlin Zheng, Hangyu Lu, Chengrong Xu, Xinyi Sun, Ping He, Shukui Li, Haoshen Zhou, Shaohua Guo*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Sodium-metal batteries are the most promising low-cost and high-energy-density new energy storage technology. However, the sodium-metal anode has poor reversibility, which can be optimized by constructing the robust solid electrolyte interphase (SEI). Here, a concept of dual-weak-interaction electrolyte (DWIE) is demonstrated, its double-layer solvation structure is composed of weakly solvated tetrahydrofuran as the inner layer, and dipole interaction are introduced in the outer layer by dibutyl ether. This double-layer solvation structure dominated by contact ion pairs and aggregates can promote to deriving of inorganic-rich SEI film, resulting in smooth and dendrite-free sodium-metal deposition. By adjusting the molecular configuration of dibutyl ether to diisobutyl ether, the dipole interaction is further enhanced, resulting in stronger weakly solvating effect. Thus, the Na||Cu cells using the optimized DWIE achieved a high Coulombic efficiency of 99.22%, surpassing most electrolyte design strategies. Meanwhile, at 5C, the Na3V2(PO4)3 (NVP)||Na cell achieves stable cycling exceeding 3000 cycles. Even under rigorous conditions of ≈8.8 mg cm−2 NVP loading and 50 µm thickness Na, the full cell can achieve a long cycling lifespan of 217 cycles. The pioneering concept paves the way for crafting readily achievable, cost-effective, and eco-friendly electrolytes tailored for SMBs, and offers potential applications in other battery systems.

Original languageEnglish
Article number2405803
JournalAdvanced Energy Materials
Volume15
Issue number20
DOIs
Publication statusPublished - 27 May 2025
Externally publishedYes

Keywords

  • dipole interaction
  • dual-weak-interaction electrolyte
  • electrode-electrolyte interface
  • inorganic-rich SEI
  • sodium-metal batteries

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