Electrodeposited lithium on copper foil as electrodes in lithium metal batteries

Summary:

One of the main challenges of today is the storage of electrical energy. Besides the well-established system of Li-ion batteries, metallic lithium electrodes are promising due to the high specific capacity of lithium (3860 mAh/g) and its very low negative electrochemical potential (-3.040 V vs. SHE). [1] However, lithium tend to form dendrites, which causes serious safety issues because of internal short circuits. Additionally, during cycling the dendrites can lose contact to the electrodes to form inactive (“dead”) lithium, which lowers the amount of active material within the cell.[1] Because of the limited rollability of lithium to form thin foils [2], often an excess of lithium up to 300% is used [3]. This compensates the loss of active materials but increases the risk of internal short circuits.
In contrast to that, electrodeposited lithium offers the possibility to adjust and minimize the amount of lithium within the cell. However, there is a range of operation conditions that influences the quality of the lithium deposition. In our group, an electrolyte system for the dendrite-free deposition of lithium was developed [4]. Based on this, suitable operation conditions were developed, to optimize the deposition process and to identify conditions were dendrite formation is suppressed. Additionally, cycling tests were performed to investigate the morphology changes of the electrodeposited Lithium during cycling.

[1] D. Lin, Y. Liu, Y. Cui, Nat. Nanotechnol., 12 (2017) 194–206.
[2] G.-M. Raynaud, G. Regazzoni, G. Nussbaum, Process for Obtaining Lithum-Based Thin Sheets and Its Application to the Production of Negative Plates for Accumulators, US005102475, 1992.
[3] D. Eroglu, K.R. Zavadil, K.G. Gallagher, J. Electrochem. Soc., 162 (2015) A982–A990.
[4] S. Sörgel, JEPT – J. Electrochem. Plat. Technol. (2018) „Electrodeposited Dendrite-Free, Nano-Columnar 3D Lithium Anodes and Their Application in Lithium Sulfur Batteries with 3D Sulfur Cathodes“, published June 6, 2018.