Electrolyte interface design for regulating Li dendrite growth in rechargeable Li-metal batteries: A theoretical study

Abstract

Lithium metal (Li) is an ideal anode for designing high-energy Li metal batteries (LMBs) due to its high specific capacity (3860 mAh g-1) and lowest electrochemical potential. However, the practical use of Li is currently impeded by uncontrollable dendritic growth during repeated Li plating and stripping, causing serious safety hazards such as electrical short circuits. To regulate Li growth behavior, various solid electrolyte interfaces (SEIs) have been explored. Despite intensive efforts, further understanding of the dendritic growth mechanism is still required. In this respect, herein, we clarify the origin and growth mechanism of Li dendrites by evaluating the critical role of an artificial SEI using a finite element method. Based on our theoretical study, we suggest that the relatively low ionic conductivity of the SEI layer is responsible for facilitating the growth of Li dendrites and the growth can be effectively suppressed by employing an artificial SEI with a higher ionic conductivity. The highconductivity artificial SEI regulates local current distributions, directly affecting the growth of Li dendrites as determined by measuring the current density, exchange current density, and geometry. Our findings provide new insight into the design of artificial SEIs for improving the cycling performance of advanced LMBs.