A\nQuasi-Solid-State Polymer Lithium–Metal Battery\nwith Minimal Excess Lithium, Ultrathin Separator, and High-Mass Loading\nNMC811 Cathode

Solid-state batteries\nwith lithium metal anodes are considered\nthe next major technology leap with respect to today’s lithium-ion\nbatteries, as they promise a significant increase in energy density.\nExpectations for solid-state batteries from the automotive and aviation\nsectors are high, but their implementation in industrial production\nremains challenging. Here, we report a solid-state lithium–metal\nbattery enabled by a polymer electrolyte consisting of a poly(DMADAFSI)\ncationic polymer and LiFSI in Pyr<sub>13</sub>FSI as plasticizer.\nThe polymer electrolyte is infiltrated and solidified in the pores\nof a commercial LiNi<sub>0.8</sub>Mn<sub>0.1</sub>Co<sub>0.1</sub>O<sub>2</sub> (NMC811) cathode with up to 2.8 mAh cm<sup>–2</sup> nominal areal capacity and in the pores of a 25 μm thin commercial\n polypropylene separator. Cathode and separator are finally laminated\ninto a cell in combination with a commercial 20 μm thin lithium\nmetal anode. Our demonstration of a solid-state polymer battery cycling\nat full nominal capacity employing exclusively commercially available\ncomponents available at industrial scale represents a critical step\nforward toward the commercialization of a competitive all-solid-state\nbattery technology.