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

摘要

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 IM LiPF_6 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. LiNO_3 pretreatment of the Li-metal anode adds a prior Li_2O-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[Ni_(0.75)Co_(0.10)Mn_(0.15)]O_2 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.