Evolution of the Dynamic Solid Electrolyte Interphase in Mg Electrolytes for Rechargeable Mg-Ion Batteries
Evolution of the Dynamic Solid Electrolyte Interphase in Mg Electrolytes for Rechargeable Mg-Ion Batteries
复制标题
DOI：
10.1021/acsami.2c13037
复制
发表时间：
2022-10-07
影响因子：
9.5
通讯作者：
Sa, Niya
中科院分区：
文献类型：
--
作者：
Fan, Shengqi;Cora, Saida;Sa, Niya
在镁电解质/电极界面处的微观固体电解质中间相（SEI）的形成和演变较少报道，并且需要完全理解以克服镁阳极-电解质处的相容性挑战。本文采用现场电化学石英晶体微天平（EQCM-D）、电化学阻抗谱（EIS）、场发射扫描电镜（FESEM）、能量色散X射线谱（EDS）和傅里叶变换红外光谱（FTIR）等方法研究了镁电解液/电极界面的SEI演化。结果显示显着不同的界面演化的两个镁电解质系统的研究，非卤素镁（TFSI）2在THF中的电解质与DMA作为共溶剂（nhMg-DMA电解质）与含卤素的全苯基络合物（APC）电解质。nhMg-DMA电解质报告了极小的SEI形成沿着由于电解质重构过程而在初始电化学循环中的显著库仑损失。有趣的是，在稍后的电化学循环中观察到更复杂的SEI生长，伴随着归因于新形成的与Mg 2+的配位环境的改善的可逆Mg沉积，并最终导致电化学沉积的Mg 0的更均匀的形态，其保持富含MgF 2的界面。相比之下，APC电解质在其初始电化学循环时显示出广泛的SEI形成，随后在电化学循环时发生SEI溶解过程，伴随着提高的库仑效率，痕量水和氯化物物质被去除。因此，其导致在进一步电化学循环时的SEI稳定化进展，从而导致电化学沉积的Mg 0的升高的电荷传输动力学和上级纯度。这些杰出的发现增加了对镁界面上SEI形成和演变的理解，并为未来的镁离子电池设计铺平了道路。
Formation and evolution of the microscopic solid electrolyte interphase (SEI) at the Mg electrolyte/electrode interface are less reported and need to be completely understood to overcome the compatibility challenges at the Mg anode-electrolyte. In this paper, SEI evolution at the Mg electrolyte/electrode interface is investigated via an in situ electrochemical quartz crystal microbalance with dissipation mode (EQCM-D), electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectrometry (FTIR). Results reveal remarkably different interfacial evolutions for the two Mg electrolyte systems that are studied, a non halogen Mg(TFSI)2 electrolyte in THF with DMA as a cosolvent (nhMg-DMA electrolyte) versus a halogen-containing all-phenyl complex (APC) electrolyte. The nhMg-DMA electrolyte reports a minuscule SEI formation along with a significant Coulomb loss at the initial electrochemical cycles owing to an electrolyte reconstruction process. Interestingly, a more complicated SEI growth is observed at the later electrochemical cycles accompanied by an improved reversible Mg deposition attributed to the newly formed coordination environment with Mg2+ and ultimately leads to a more homogeneous morphology for the electrochemically deposited Mg0 , which maintains a MgF2-rich interface. In contrast, the APC electrolyte shows an extensive SEI formation at its initial electrochemical cycles, followed by a SEI dissolution process upon electrochemical cycling accompanied by an improved coulombic efficiency with trace water and chloride species removed. Therefore, it leads to SEI stabilization progression upon further electrochemical cycling, resulting in elevated charge transport kinetics and superior purity of the electrochemically deposited Mg0. These outstanding findings augment the understanding of the SEI formation and evolution on the Mg interface and pave a way for a future Mg-ion battery design.