The Li/NaK/LLZTO/NaK/Li cells consistently exhibit CCDs > 0.5 mA cm -2 within the areal capacity limits (3 -30 mAh cm -2 ) regardless of whether the applied stack pressure is 1.5 MPa or < 75kPa, or whether the Li metal was first pressed to the LLZTO at elevated temperature. The stable cycling of the Li/NaK/LLZTO/NaK/Li cells at these extreme areal capacity values with minimal cell polarization show that when the Na-K liquid is present, neither of these preprocessing steps is necessary. We interpret that the Na-K alloy serves simultaneously as an electrochemically inert liquid current collector that fills any Li voids that may form, homogenizing both the stripping and plating current, and as a Li + transport medium that facilitates intimate ionic transport between the solid Li metal and LLZTO electrolyte. Together, these effects overcome the contact impedance problem for ionic transport that is common at solid metal -solid electrolyte interfaces. Despite the solubility for Li in the Na-K system being rather low, (on the order ~ 1 x 10 -4 mole fraction ), the Na-K alloy is clearly capable of appreciable Li transport at the relevant length scale, since the first half-cycle of the cells, during which the Na-K liquid is wetting between the Li metal and solid electrolyte, exhibits low polarization. We observed similar CCD values (Fig. ) for two Na-K liquid compositions, 0.25K-0.75Na and 0.68K-0.32Na (by mole), even though the Li solubility in the liquid is a factor of four higher for the latter liquid composition.