IN-SITU TRANSMISSION ELECTRON MICROSCOPY OBSERVATION OF LITHIUM HAIR GROWTH

摘要

Lithium metal has a theoretical specific capacity of 3800 mAh/grnand the lowest potential of -3.04 V vs. standard hydrogen electrode.rnIt has been used for investigating the next generation batteries suchrnas Li-S and Li-air batteries. The extremely high capacity of thesernbatteries relies on the high specific capacity of the anode lithium.rnHowever, there are unsolved problems for lithium to be practical.rnThe dendrite growth in the electrochemical charge/discharge processrnis one of them. The growth of the dendrite often leads to a shortrncircuit and can be fatal. The use of Li in batteries has been studiedrnextensively in the past 40 years both experimentally andrntheoretically. And many attempts were made to suppress therndendritic growth of lithium. It is reported that adding non-lithiumrncation with lower reduction potential than lithium to the electrolyterncan promote uniform lithium deposition by accumulation of non-Lirncations to the sharp lithium tips (seeds of lithium dendrites) repellingrnthe Li+ for further amplification of the tip. The modification of thernsurface by hollow nano carbon spheres was demonstrated to preventrnthe dendrite formation. The surface structure in nano-scale is a keyrnto understand the lithium dendrite formation/growth. In-siturntransmission electron microscopy is a powerful tool that can observernthe nano-scale phenomena in real time. In this work we conducted insiturnTEM experiment to understand the lithium dendrite formationrnmechanism.