Influence of electrolyte composition on high energy lithium metal cells

Lithium metal electrodes are known for problematic formation of lithium dendrites and poor cyclability, especially in liquid-based electrolytes. Severe SEI formation along with lithium and electrolyte consumption are responsible for sudden failure of lithium metal cells, this phenomenon being more pronounced with highly loaded electrodes and deep stripping/plating cycles. In this paper, the goal was to compare the commonly used carbonate-based electrolytes with ether-based formulations, which are usually employed in lithium/sulfur systems, as well as to quantify the effect of frequently used additives on the behavior of lithium metal, using a relatively simple characterization methodology. In particular, the objective is to focus on the effect of electrolyte composition on the fading of lithium metal electrode, while preventing the use of contaminating high capacity positive electrodes such as layered oxide as well as sulfur cathodes. LiFePO4/Li and symmetric Li/Li cells were assembled to investigate the behavior of lithium metal electrode in different electrolyte media, while high loading positive electrodes were employed to study the lithium electrode into a high energy density cell design.