Description:
<jats:p> Li metal could be the ideal anode for rechargeable battery technologies, due to its negative redox potential (ca. -3 V vs. SHE), high specific capacity (3860 mAh g<jats:sup>−1</jats:sup>), and low density (0.534 g cm<jats:sup>−3</jats:sup>) [1-3]. Recent advances show a new design concept where there are no initial active materials in the anode (no carbon, Si, or Li metal) and the corresponding Li quantity is directly deposited on the current collector during charging. This approach will result in important practical advantages such as enhanced volumetric and gravimetric specific energies, ease of manufacturing and reduced complexity/safety concerns of the recycling process (ideally Li is completely removed in the discharged state). However, the applicability of the Li-metal batteries is constrained by the nonuniform lithium deposition, accompanied by dendrite growth and the formation of dead lithium during long-term cycling, which lead to low Coulombic efficiency and even cell failure [2]. The initial structure and morphology of the Li deposit has a vital influence on the later progression of the Li layer [4]. This underpins the importance of a fundamental understanding of the electrodeposition process. However, the presence of a solid-electrolyte interphase (SEI) makes such investigations difficult, since after the transport of the Li ions through the SEI, a subsequent charge transfer and nucleation growth process at the substrate-SEI interface, instead of substrate-liquid electrolyte interface occurs. This contribution will discuss lithium electrodeposition in a sulfolane based, localized high concentrated electrolyte system. Possible phase formation mechanisms as well as kinetic and thermodynamic aspects during the initial stages of the process are studied by classical electrochemical methods (Fig. 1, left). Furthermore, the mass-charge balance during deposition and stripping was monitored (Fig. 1, right) via in-situ microgravimetry (electrochemical quartz crystal microbalance). In the contribution we will discuss these transients in terms of lithium layer growth and SEI formation.</jats:p>
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<jats:bold>References:</jats:bold>
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<jats:p>[1] X. Cheng et al., (2017) Chemical Reviews, 117 (15), p. 10403-10473.</jats:p>
<jats:p>[2] J. Cui et al., (2017) Chinese Chemical Letters, 28 (12), p. 2171-2179.</jats:p>
<jats:p>[3] Z. Hu et al., (2020) Frontiers in chemistry 8, p. 409.</jats:p>
<jats:p>[4] A. Pei et al., (2017) Nano Letters, 17 (2), p. 1132–1139.</jats:p>
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<jats:p>Figure 1</jats:p>
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