Apr 24, 2024
5:00pm - 7:00pm
Flex Hall C, Level 2, Summit
Hyuntae Lee1,Hyeongguk An1,Hongjun Chang2,Janghyuk Moon2,Sujong Chae3,Hongkyung Lee1
Daegu Gyeongbuk Institute of Science and Technology1,Chung Ang University2,Pukyong National University3
Hyuntae Lee1,Hyeongguk An1,Hongjun Chang2,Janghyuk Moon2,Sujong Chae3,Hongkyung Lee1
Daegu Gyeongbuk Institute of Science and Technology1,Chung Ang University2,Pukyong National University3
With the growing reliance on battery-operated vehicles, addressing the safety concerns associated with lithium plating, exacerbated by high cell polarization during extremely fast charging (XFC) of Li-ion batteries, becomes imperative. This research probes into the effects of Li<sup>+</sup> desolvation and the solid-electrolyte interphase (SEI) chemistry on cell polarizations through the use of linear carbonate (LC)-based, high-concentration LiPF<sub>6</sub> electrolytes (LPCEs). Within the LC group, dimethyl carbonate (DMC) is identified as the most thermodynamically favorable for enhancing desolvation kinetics, thus reducing the charge-transfer resistance at the graphite anode. To facilitate effective graphite passivation and accelerated Li<sup>+</sup> transport through the SEI, fluoroethylene carbonate (FEC) is employed to form a thin, fluorinated SEI layer. This enhances the XFC cycling stability in graphite||NMC622 full cells (3.0 mAh cm<sup>−2</sup>; N/P ratio = 1.1), achieving a remarkable 94.3% capacity retention after 500 cycles under a 10-minute charging regime. Compared to traditional electrolytes, the excellent XFC performance is further substantiated in a practical 1.2-Ah pouch cell, showcasing a tripling in capacity retention over 200 cycles and effectively mitigating Li plating-induced cell swelling. Unraveling the intricate mechanisms of cell polarization, as dictated by the electrolyte chemistry, furnishes pivotal insights for developing future electrolyte designs for XFC capabilities of Li-ion batteries.