Designing a Li-Metal Battery to Surviving in Practical Operating Condition for Electric Vehicle Applications

Abstract

We propose a new breakthrough in realizing a practical Li-metal battery capable of fast charging while delivering a high energy density. To stabilize the Li metal anode, the electrolyte, consisting of 1M LiPF6 and 0.05M lithium difluoro(oxalate)borate (LiDFOB) dissolved in the mixture of ethyl methyl carbonate (EMC) and fluoroethylene carbonate (FEC) solution, ensures a stable robust solid electrolyte interphase (SEI) layer on the anode surface. LiNO3 pretreatment of the Li-metal anode adds a prior Li2O-rich SEI layer that provides the mechanical strength to maintain the SEI layer from breakdown against to dendritic Li growth at extremely high charge current density. Meanwhile, Al-doped full-concentration-gradient Li[Ni0.75Co0.10Mn0.15]O2 cathode provides the necessary cycling stability at a high cathode loading level. Integrating these components produced a LMB that allowed a high areal capacity of 4.1 mAh cm-2 and accomplished an unprecedented cycling stability over 300 cycles at a high current density of 3.6 mA cm-2. In addition, proposed LMB can further extended when moderate capacity loading of 2.0 mAh cm-2 under ultra-fast charging-discharging conditions; specifically, the LMB showed excellent long-term cycling stability up to 500 cycles under charge at 3.6 mA cm-2 (30 min) but discharge with 9 mA cm-2 (12 min). We believe that our findings presented herein provide new perspectives for the development of practical LMBs that satisfy the capacity and charging rate requirements for future electric vehicles.Reference1. J.-Y. Hwang, S.-J. Park, C. S. Yoon and Y.-K. Sun, Energy Environ. Sci., 2019, 12, 2174.2. S.-J. Park, J.-Y. Hwang, C. S. Yoon, H.-G. Jung and Y.-K. Sun, ACS Appl. Mater. Interfaces, 2018, 10, 17985.3. Y.-K. Sun, Z. Chen, H.-J. Noh, D.-J. Lee, H.-G. Jung, Y. Ren, S. Wang, C. S. Yoon, S.-T. Myung and K. Amine, Nat. Mater., 2012, 11, 942.