Tuning the solution structure of electrolyte for optimal solid-electrolyte-interphase formation in high-voltage lithium metal batteries

作     者：Juner Chen Tingyu Liu Lina Gao Yumin Qian Yaqin Liu Xueqian Kong Juner Chen;Tingyu Liu;Lina Gao;Yumin Qian;Yaqin Liu;Xueqian Kong

作者机构：Center for Chemistry of High-Performance&Novel MaterialsDepartment of ChemistryZhejiang UniversityHangzhou 310027China Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang ProvinceSchool of EngineeringWestlake University18 Shilongshan RoadHangzhou 310024China Institute of Advanced TechnologyWestlake Institute for Advanced Study18 Shilongshan RoadHangzhou 310024China Key laboratory of advanced optoelectronic quantum architecture and measurementministry of educationSchool of PhysicsBeijing Institute of Technology100081 BeijingChina Department of ChemistryZhejiang UniversityHangzhou 310027ZhejiangChina 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2021年第30卷第9期

页      面：178-185页

核心收录：

学科分类：0808[工学-电气工程] 081704[工学-应用化学] 08[工学] 0817[工学-化学工程与技术] 

基　　金：financial support from the National Natural Science Foundation of China (21922410) the Zhejiang Provincial Natural Science Foundation (R19B050003 and LQ21B030006) the Scientific Research Fund of Zhejiang Provincial Education Department (Y201839549) the Zhejiang University K.P. Chao’s High Technology Development Foundation (2018RC009) the Postdoctoral Science Foundation of Zhejiang Province (ZJ2020079) 

主　　题：Electrolyte Solution structure Li metal battery First principle molecular dynamics Solid-electrolyte-interphase 

摘      要：The continuous reduction of electrolytes by Li metal leads to a poor lifespan of lithium metal batteries(LMBs). Low Coulombic efficiency(CE) and safety concern due to dendrite growth are the challenging issues for LMB electrolyte design. Novel electrolytes such as highly concentrated electrolytes(HCEs) have been proposed for improving interphase stability. However, this strategy is currently limited for high cost due to the use of a large amount of lithium salts as well as their high viscosity, reduced ion mobility, and poor wettability. In this work, we propose a new type of electrolyte having a moderate concentration. The electrolyte has the advantage of HCEs as the anion is preferentially reduced to form inorganic solidelectrolyte-interphase(SEI). Such optimization has been confirmed through combined spectroscopic and electrochemical characterizations and supported with the first-principle molecular dynamics simulation. We have shown the intrinsic connections between solution structure and their electrochemical stability. The 2.0 M LiDFOB/PC electrolyte, as predicted by our characterizations and simulations, allows stable charge–discharge of LNMO|Li cells at 5C for more than 1500 cycles. The 2.0 M electrolyte generates a dense layer of SEI containing fluoro-oxoborates, Li_(3)BO_(3), LiF, Li_(2)CO_(3), and some organic species effectively passivating the lithium metal, as confirmed by electron microscopy, X-ray photoelectron spectroscopy,and solid-state nuclear magnetic resonance.