Unraveling the Mechanism of Different Kinetics Performance between Ether and Carbonate Ester Electrolytes in Hard Carbon Electrode,Advanced Functional Materials

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Unraveling the Mechanism of Different Kinetics Performance between Ether and Carbonate Ester Electrolytes in Hard Carbon Electrode
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2022-09-22 , DOI: 10.1002/adfm.202209523
Xiaoli Yi _{1,

2} , Xinhai Li _{1,

2,

3} , Jing Zhong _{1,

2} , Siwu Wang _{1,

2} , Zhixing Wang _{1,

2,

3} , Huajun Guo _{1,

2,

3} , Jiexi Wang _{1,

2,

3} , Guochun Yan _{1,

2,

3}

Affiliation

Ether electrolytes exhibit better rate kinetics than carbonate ester electrolytes when used in several kinds of anode materials, especially in hard carbon (HC) for sodium-ion batteries (SIBs). However, the mechanism causing the remarkable kinetics difference is still unclear. Here, a three-electrode system is used first to eliminate the influence of polarization from the Na counter electrode. Then, there is systematic exploration from three steps of the electrode reaction process (Na⁺ storage in HC; de-solvation; Na⁺ migration through solid electrolyte interphase (SE), and the underlying mysteries are uncovered. For Na⁺ storage in the bulk of the HC, it is found that two systems show the same storage mechanism and Na metallic nanoparticles will appear when discharged to 0.1 V. In addition, faster de-solvation of the ether electrolyte is uncovered by three-electrode temperature-dependent EIS and solvation free energies calculation. Moreover, the difference of the SEI layers is unraveled by X-ray photoelectron spectroscopy etching, scanning electron microscopy, and differential electrochemical mass spectrometry. Most importantly, by discriminating the impacts of the SEI layers and de-solvation behavior, it can be concluded that the de-solvation process is the rate-controlling step of the electrode reaction process and is the main factor causing the kinetics differences between the two electrolytes. The research provides a clear mechanism to illuminate fast kinetics for ether electrolytes, which will promote its application in SIBs.

中文翻译：

揭示硬碳电极中醚和碳酸酯电解质不同动力学性能的机制

当用于多种负极材料时，醚类电解质表现出比碳酸酯电解质更好的速率动力学，尤其是在钠离子电池 (SIB) 的硬碳 (HC) 中。然而，导致显着动力学差异的机制仍不清楚。在这里，首先使用三电极系统来消除 Na 反电极极化的影响。然后，从电极反应过程的三个步骤（Na ⁺在HC中的存储；去溶剂化；Na ⁺通过固体电解质界面（SE）的迁移）进行系统探索，揭开其中的奥秘。对于Na ⁺在大量的 HC 中存储，发现两个系统显示相同的存储机制，当放电至 0.1 V 时会出现 Na 金属纳米粒子。此外，三电极温度发现醚电解质更快的去溶剂化 -相关的 EIS 和溶剂化自由能计算。此外，通过 X 射线光电子能谱蚀刻、扫描电子显微镜和微分电化学质谱法揭示了 SEI 层的差异。最重要的是，通过区分SEI层和脱溶剂化行为的影响，可以得出结论，脱溶剂化过程是电极反应过程的速率控制步骤，是导致两者动力学差异的主要因素电解质。

更新日期：2022-09-22

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