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Updated: Jun 14, 2025
Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature
Published on: December 20, 2016
Gibbs Free Energy Regulation to Decrease Desolvation Barrier for Ultralow-Temperature Lithium Metal Batteries at
Ke-Feng Ren1, Yun-Fei Du2, Jia-Xin Guo2
1Jiangsu Key Laboratory of New Energy Devices & Interface Science, School of Chemistry and Materials Science, Nanjing University of Information Science and Technology, Nanjing, Jiangsu, 210044, China.
Abstract:
Sluggish desolvation kinetics of Li ions cause poor lifespan of Li metal batteries at ultralow temperatures. Herein, the rapid desolvation process is achieved by reducing the change of Gibbs free energy (△G) at the electrode-electrolyte interfaces. The low desolvation barrier can be attained by higher entropy change (△S) and lower enthalpy change (△H). In the Gibbs-free-energy-driven electrolyte with multiple anions, the complex solvation structures are constructed, which release more group states during the desolvation process, thus increasing △S. The weak ion-dipole interaction of Li ion-solvent is designed to decrease △H. Hence, a lower desolvation barrier is realized. Besides, anion-induced solvation structure can form inorganic-rich solid electrolyte interphase. These synergistically enhance the plating kinetics and guide the uniform Li deposition at low temperatures. An impressive capacity retention of 95.5% can be maintained in Li||LiNi0.5Co0.2Mn0.3O2 cells with a high cathode loading of 3.0 mAh cm-2 after 210 cycles at -20°C. Even at an ultralow temperature of -40°C, the cells can stably operate for 220 cycles with a capacity retention of 87.7%. The Gibbs free energy regulation offers an innovative perspective for the design of low-temperature electrolytes with rapid interfacial kinetics.
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