Fluorinated ether decomposition in localized high concentration electrolytes
Fluorinated ether decomposition in localized high concentration electrolytes
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氟化醚在局部高浓度电解质中分解
DOI：
10.1016/j.jpowsour.2022.232299
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发表时间：
2023
影响因子：
9.2
通讯作者：
Marbella, Lauren E.
中科院分区：
文献类型：
--
作者：
May, Richard;Hestenes, Julia C.;Munich, Naiara A.;Marbella, Lauren E.
局部高浓度电解质（LHCE）是一类有前途的电池材料，能够实现锂金属阳极的稳定循环。在这里，我们报告使用的operandemagnetic resonance（NMR）光谱观察电解质分解过程中的锂剥离/电镀，并确定在LHCEs上的锂金属电池性能的各个组件的影响。全氟19 F溶液NMR数据表明，双（氟磺酰基）酰亚胺（FSI−）盐和双（2，2，2-三氟乙基）醚（BTFE）稀释剂分子在固体电解质界面（SEI）形成中起关键作用。商业软包电池的三电极电化学阻抗谱（EIS）也显示LHCE和标准高浓度电解质（HCE）之间的界面电阻的差异，这可以通过将BTFE和BTFE反应产物并入SEI中来解释。基于固体核磁共振和X射线光电子能谱表征，我们发现BTFE稀释剂分解形成CF2-和CF 3-含有片段内的LiF-丰富的SEI沉积在阳极表面上。与HCE相比，在LHCE中循环之后，电池的阴极（这里为LiNi0.8Mn0.1Co0.1O2）侧上的CEI还含有更高量的LiF和捕获的LiFSI，这归因于稀释剂分解并且与阴极处的较低阻抗相关。总的来说，这项工作提供了一个新的框架，考虑高度氟化醚分子，而不是纯粹作为稀释剂在LHCE的功能，这些氟化醚表现出可调的界面反应性，可以利用控制锂沉积行为。
Localized high concentration electrolytes (LHCEs) are a promising class of battery materials to enable stable cycling of the lithium metal anode. Here, we report the use ofoperandonuclear magnetic resonance (NMR) spectroscopy to observe electrolyte decomposition during Li stripping/plating and identify the influence of individual components in LHCEs on Li metal battery performance. Data fromoperando19F solution NMR indicates that both bis(fluorosulfonyl)imide (FSI−) salt and bis(2,2,2-trifluoroethyl) ether (BTFE) diluent molecules play a key role in solid electrolyte interphase (SEI) formation. Three-electrode electrochemical impedance spectroscopy (EIS) of commercial pouch cells also shows differences in interfacial resistances between LHCE and standard high concentration electrolytes (HCEs) that may be explained by incorporation of BTFE and BTFE reaction products into the SEI. Based on solid-state NMR and X-ray photoelectron spectroscopic characterization, we find that BTFE diluents decompose to form CF2- and CF3-containing fragments within a LiF-rich SEI deposited on the anode surface. The CEI on the cathode (here, LiNi0.8Mn0.1Co0.1O2) side of the battery also contains higher quantities of LiF and trapped LiFSI after cycling in the LHCE compared to a HCE that are attributed to diluent decomposition and correlated with lower impedance at the cathode. Overall, this work provides a new framework to consider highly fluorinated ether molecules—instead of functioning purely as diluting agents in LHCEs, these fluorinated ethers exhibit tunable interfacial reactivity that can be leveraged to control Li deposition behavior.
影响因子：
20.4
作者：
Cao, Xia;Zou, Lianfeng;Zhang, Ji-Guang
通讯作者：
Zhang, Ji-Guang
影响因子：
3.7
作者：
Ilott, Andrew J.;Jerschow, Alexej
通讯作者：
Jerschow, Alexej