Customizing a Li–metal battery that survives practical operating conditions for electric vehicle applications†
We propose a new breakthrough in realizing a practical Li–metal battery (LMB) capable of fast charging while delivering a high energy density. We used an electrolyte consisting of 1 M LiPF6 and 0.05 M lithium difluoro(oxalate)borate dissolved in a mixture of ethyl methyl carbonate and fluoroethylene carbonate to ensure the formation of a stable and robust solid electrolyte interphase (SEI) layer on the anode surface. Pretreatment of the Li–metal anode with LiNO3 adds a prior Li2O-rich SEI layer that provides the required mechanical strength to prevent premature SEI layer breakdown. An Al-doped full-concentration-gradient Li[Ni0.75Co0.10Mn0.15]O2 cathode provides the necessary cycling stability at a high cathode loading. By integrating these components, we produced an LMB that allowed a high areal capacity of 4.1 mA h cm−2 with an unprecedented cycling stability over 300 cycles at a high current density of 3.6 mA cm−2 (full charge–discharge in 2 h). We believe that the findings presented herein provide new perspectives for the development of practical LMBs that satisfy the capacity and charging rate requirements for future electric vehicles.