Fig. 5: Electrochemical and physiochemical characterisations of symmetric Li-Mg∣∣Li-Mg cells.

A Chronopotentiometric stripping showing potential as a function of areal capacity at 0.31 mA cm−2, 30 ∘C, 5 MPa. B Zoom from A on 5% Mg curve potential increase region. C Extracted capacity before 5 V limit for self-symmetric cells of varying alloy content. Model predictions for constant diffusivity in red and variable diffusivity in blue. D Ex situ cross-sectional SEM image of Li+5at%Mg - Li6PS5Cl interface after chronopotentiometry, prepared by plasma focused ion beam milling.