Tuesday, 21 June 2016
Riverside Center (Hyatt Regency)
Lithium metal having the lowest reduction potential (-3.04 V vs. SHE) and high specific capacity (~3800 mAh g-1
) have not been successfully implemented in commercial lithium secondary batteries (LSBs) due to the formation of lithium dendrite, resulting in inhibited battery performance and instability. However, to accomplish the mileage and high energy requirements of electric vehicles and energy storage systems, the above drawbacks of lithium metal need to be solved for it to be implemented in LSBs. Hence, based on our experimental findings on the dependency of current flow on metal surface morphology, we adopted a mathematical model to simulate and optimise the metal surface morphology of different shapes to locate dendrite-free regions. To reflect the simulation results, the electrochemical performance of cells assembled with and without controlled lithium metal surface was experimentally conducted. Field-emission scanning electron microscope (FE-SEM, S-4800, Hitachi) was also used to confirm dendrite formation on lithium metal surface during charge and discharge.
The simulation results showed difference in current flow according to the different shaped patterns on the metal surface. An optimized patterned surface morphology is presented to prevent the dendrite formation. From our experimental results, we found out that cells with controlled Li metal surface morphology exhibited improved long-term cycling performance. From the FE-SEM images, the pattern holes are readily filled with liquid like and granular forms of Li-metal without any dendrite growth during the Li deposition process.
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This work was supported by the international Collaborative Energy Technology R&D Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No. 20158510050020).