Authors: Hongyu Lv, Qian Yao, Cheng Zheng, Yanan Sun, Zhao Qian, Zhikai Wei, Fang Xie, Rajeev Ahuja, Jian Yang
Published: 2025-05-27
Source: Full article
AbstractSodium‐ion batteries (SIBs) are attractive for large‐scale energy storage and have to work at a wide temperature range. Compared to the performance at room temperature, the low‐temperature performance of SIBs is always poor. Herein, tetrahydrofuran (THF) and 2‐methyltetrahydrofuran (MTHF) are mixed as a model of weak solvating effect to improve the low‐temperature performance. In the mixed electrolyte, the anion‐dipole expulsion and steric hindrance in the solvation sheath increase, which weakens the cation‐dipole attraction and reduces the desolvation energy. Meanwhile, the weak dipole‐dipole interaction between THF and MTHF lowers the electrolyte viscosity and improves the ionic conductivity. The change in the solvation structure also results in an entropy increase, facilitates the cleavage of P‐F in PF6