Stable cycling of organic electrolyte rechargeable lithium metal anode batteries with fluorine-free solvents

Researchers have reported multiple systems and strategies towards the goal of stable and high energy density rechargeable lithium-based batteries. Established rechargeable battery applications, including powering electric vehicles, have been dominated by conventional graphite negative electrodes due to low cost and high cycle stability. However, the energy density of graphite negative electrode cells is limited, and substituting lithium metal as the negative electrode active material would significantly increase cell energy density. Unfortunately, many established organic electrolytes used for graphite-containing systems are not compatible with extended cycling of lithium metal, and lead to severe capacity fade. Prior research efforts have addressed lithium metal cycling limitations through modifying the electrolyte and/or current collector, but many of these strategies end up sacrificing energy density advantages at the cell level, or involve relatively complex or expensive components. Herein, batteries with lithium metal negative electrodes paired with LiNi 0.8 Co 0.1 Mn 0.1 O 2 active material cathodes with moderate areal capacity of ∼1.5 mAh cm −2 were fabricated and evaluated using an electrolyte formulation that included readily available salts and solvents. The solvents were comprised of 1,2-dimethoxyethane and ethylene carbonate, and solutes were LiPF 6 and LiNO 3 . For the most promising electrolytes, cell capacity retentions of 85% after 1000 charge/discharge cycles were achieved, showing promise for this system to achieve long cycle lifetime lithium metal anode cells.