Silicon (Si) is one of the most promising candidates for application as high‐capacity negative electrode (anode) material in lithium ion batteries (LIBs) due to its high specific capacity. However, evoked by huge volume changes upon (de)lithiation, several issues lead to a rather poor electrochemical performance of Si‐based LIB cells. The Coulombic efficiency (CEff) during the first cycle(s), especially when using nano‐sized Si, is relatively low, due to the formation of the solid electrolyte interphase (SEI). Pre‐lithiation approaches can increase the CEff by compensating active lithium losses during the first cycle(s). Here, we evaluate the beneficial impact of pre‐lithiated Si/C electrodes for their application in NCM111||Si/C cells by comparing two approaches, i. e., electrochemical pre‐lithiation and pre‐lithiation by direct contact to Li metal foil. The SEI composition and surface morphology of pre‐lithiated Si/C electrodes as well as the impact of reducing active Li losses on individual electrode potentials over cycling are revealed. For long‐term cycling, both pre‐lithiation techniques lead to a distinct improvement of the overall capacity as well as the CEff for the first 40 cycles due to i) the pre‐formed SEI and ii) a Li reservoir within the anode. Depletion of the active Li from NCM111 is significantly reduced and we can confirm that both pre‐lithiation techniques improve the cycling performance of NCM111||Si/C cells in an almost equal manner.

Due to its low cost, high abundance and non-toxicity zinc metal is a very promising electrode material for rechargeable batteries. The main drawback of using zinc in aqueous alkaline solutions is the formation of zinc dendrites, which lead to cell failure, and a low coulombic efficiency. In this study the suppression of dendritic zinc growth by applying either pure 1-ethylimidazolium trifluoromethane sulfonate or 1-ethylimidazolium trifluoromethane sulfonate / water mixtures with zinc trifluoromethane sulfonate as electrolyte formulations was examined. The surface morphology of the deposited zinc is significantly influenced by the amount of water present in the electrolyte. Cyclic voltammetry measurements showed a less negative reduction potential of zinc with increasing water content. Additionally, the presence of air in the electrolyte proved to be another factor influencing the cyclic voltammetry results. Furthermore, galvanostatic cycling data showed a lowering of the overpotential and constant potentials during long-term cycling of 100 cycles if water is present in the electrolyte, and SEM micrographs confirmed that the surface structure remains compact even after long-term cycling.

Polymer electrolytes are attractive candidates to boost the application of rechargeable lithium metal batteries. Single-ion conducting polymers may reduce polarization and lithium dendrite growth, though these materials could be mechanically overly rigid, thus requiring ion mobilizers such as organic solvents to foster transport of Li ions. An inhomogeneous mobilizer distribution and occurrence of preferential Li transport pathways eventually yield favored spots for Li plating, thereby imposing additional mechanical stress and even premature cell short circuits. In this work, we explored ceramic-in-polymer hybrid electrolytes consisting of polymer blends of single-ion conducting polymer and PVdF-HFP, including EC/PC as swelling agents and silane-functionalized LATP particles. The hybrid electrolyte features an oxide-rich layer that notably stabilizes the interphase toward Li metal, enabling single-side lithium deposition for over 700 h at a current density of 0.1 mA cm–2. The incorporated oxide particles significantly reduce the natural solvent uptake from 140 to 38 wt % despite maintaining reasonably high ionic conductivities. Its electrochemical performance was evaluated in LiNi0.6Co0.2Mn0.2O2 (NMC622)||Li metal cells, exhibiting impressive capacity retention over 300 cycles. Notably, very thin LiNbO3 coating of the cathode material further boosts the cycling stability, resulting in an overall capacity retention of 78% over more than 600 cycles, clearly highlighting the potential of hybrid electrolyte concepts.