高等学校化学学报

高等学校化学学报

• 研究论文 • 上一篇    

碳酸酯类溶剂对钠离子电池硬碳负极电化学性能影响机制

陶睿敏,李添奕,茹梦令,陈爽,崔永莉   

  1. 中国矿业大学材料与物理学院
  • 收稿日期:2025-10-15 修回日期:2025-11-18 网络首发:2025-11-21 发布日期:2025-11-21
  • 通讯作者: 崔永莉 E-mail:cuiyongli@cumt.edu.cn
  • 基金资助:
    中国矿业大学国家级重点支持大学生创新训练计划项目（批准号：S202510290276）和中国矿业大学大型仪器设备开放共享基金资助（批准号：DYGX-2025-62）资助

The Influence Mechanism of Carbonate Solvents on the Electrochemical Performance of Hard Carbon Anodes in Sodium-Ion Batteries

TAO Ruimin，LI Tianyi，RU Mengling, CHEN Shuang, CUI Yongli   

  1. College of Materials and Physics, China University of Mining and Technology
  • Received:2025-10-15 Revised:2025-11-18 Online First:2025-11-21 Published:2025-11-21
  • Contact: CUI Yongli E-mail:cuiyongli@cumt.edu.cn
  • Supported by:
    Supported by the China University of Mining and Technology's National Key Support Program for undergraduate Innovation Training Project（No. S202510290276）and the Open Sharing Fund for the Large-scale Instruments and Equipments of China University of Mining and Technology (No. DYGX-2025-6)

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摘要： 本文针对锂离子电池硬碳负极，设计以六氟磷酸钠（NaPF6）为钠盐，在碳酸乙烯酯（EC）基溶剂中添加碳酸丙烯酯（PC）和碳酸二甲酯（DMC）作为混合溶剂的电解液，探究不同溶剂协同组合对硬碳负极电化学性能影响及其影响机制。采用分子动力学模拟（MD）分析了电解液溶剂化结构和钠离子在电解液中扩散系数；通过电导率测试，充放电、循环性能和倍率性能测试对比分析了硬碳负极在EC基电解液中的电化学性能，并通过循环伏安（CV）、恒电流间歇滴定技术（GITT）及电化学阻抗谱（EIS）分析钠离子存储动力学行为，并通过扫描电子显微镜(SEM)、透射电在显微镜（TEM）和X射线光电子能谱(XPS)等对硬碳表面形貌和成分进行分析。结果表明，DMC和PC协同作用可以显著提高电解液的离子电导率和钠离子扩散速率、优化溶剂化结构，减少有机副产物并增加阴离子配位，促进SEI膜中无机物生成，有效降低SEI膜阻抗和电荷传递阻抗，同时提高钠离子在HC中扩散系数，使硬碳负极在1 M NaPF6-EC/PC/DMC电解液中具有相对优越的倍率性能和充放电循环性能，在50 mA g-1下首圈容量362mAh g-1，50次循环后，容量衰减到353.4 mAh g-1，容量保持率为97.6%。因此EC/PC/DMC混合溶剂是钠离子电池硬碳负极最具有应用前景的溶剂之一。

关键词: 钠离子电池, 电解液, 溶剂, 电化学性能, 电化学行为

Abstract: In the article, the electrolytes of mixed solvents for the hard carbon negative of sodium-ion batteries were designed, using sodium hexafluorophosphate (NaPF6) as the sodium salt and adding propylene carbonate (PC) and dimethyl carbonate (DMC) in an ethylene carbonate (EC) based solvent. The effect and mechanism of different solvent synergistic combinations on the electrochemical performance of hard carbon negative were explored. The sodium solvation structure and the diffusion coefficient of sodium ions in the electrolyte were analyzed by Molecular dynamics simulation (MD). The electrochemical performance of hard carbon negative electrode in EC based electrolyte was compared and analyzed through conductivity tests, charge-discharge tests, cycling performance tests, and rate capability tests. The kinetic behavior of sodium ions storage was also analyzed by cyclic voltammetry (CV), alvanostatic intermittent titration (GITT), and electrochemical impedance spectroscopy (EIS). The surface morphology and composition of hard carbon anodes before and after cycling were made by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), and so on. As a result, the synergistic effect of DMC and PC can significantly improve the ionic conductivity of the electrolyte and diffusion coefficient of sodium ions in electrolyte, optimize the solvation structure, reduce organic by-products and increase anion coordination, promote the generation of inorganic substances in the SEI film, effectively reduce the SEI film impedance and charge transfer impedance, and improve the diffusion coefficient of sodium ions in HC. Therefore, the hard carbon anode demonstrates superior rate capability and cycling performance in the 1 M NaPF6-EC/PC/DMC electrolyte at 50 mA g-1, 362mAh g-1 initial capacity, and the capacity decays to 353.4 mAh g-1 with a capacity retention rate of 97.6% after 50 cycles. Thereby, EC/PC/DMC mixed solvents are one of the most promising solvents for the HC anode of sodium ion batteries

Key words: Sodium ion battery；Electrolyte；Solvent, Electrochemical performance；Electrochemical behavior

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