Figure 1. a) Phase diagrams of Li-M (M=Hg, Ag, Au and Zn, respectively). The regions where Hg, Ag, Au and Zn dissolved are denoted as (Li), δ(Li), (Li) and β(Li); b) a schematic of Li|substrate cell and the formation of Li-rich solid solution alloys upon Li deposition; c) Li plating profiles of four cells at 2 mA cm-2 and 5 mAh cm-2.
Figure 2. Morphology and structure evolution with different Li plating capacities at 2 mA cm-2. a) The cross-sectional SEM images of LiHg electrodes with areal capacity of 0.0, 2.3, 3.1, 5.0, 9.0 and 55.0 mAh cm-2; b) the electrochemical profiles and corresponding ex-situ XRD patterns with controlled Li capacities; c) the schematic illustration of morphology evolution of LiHg substrate upon Li deposition.
Figure 3. Composition analyses for the sample with a plating capacity of 5 mAh cm-2. a) The SEM image and corresponding EDS mapping of Hg; b) EELS spectrum of Li signal for the FIB sample; c, d) XPS spectra of Hg and Li of the FIB sample; e, f) HAADF image and corresponding EDS mapping image from HR-TEM; g, h) the low, high HAADF images and corresponding EDS mapping from the Cs-corrected TEM model, where Hg agglomeration are clarified as bright domains in the dark Li zones due to the super energy exposure of Cs-corrected TEM and significantly different atomic weight of the two elements.
Figure 4. a–c) The cross- and top-sectional SEM images and corresponding EDS mapping images with Li deposition capacity of 0 mAh cm-2 and 5 mAh cm-2: a) Ag foil, b) Au foil and c) Zn foil. d) The schematic diagram of the morphology evolution from pristine electrode to the subsequent plating process for Ag, Au and Zn.
Figure 5. a) The histogram of theoretical diffusion equal distance R and diffusion coefficient D of Ag, Au, Zn and Hg in the Li-rich solid solution phases; b) the schematic upon Li atoms deposition on different substrate foils (Ag, Au, Zn foil and LiHg film).
Figure 6. The electrochemical performance of cells assembled with Zn foil and LiHg film electrodes with a prelithiation capacity of 4 mAh cm-2. a) Stripping/plating-time curves at 2 mA cm-2 and 2 mAh cm-2; b–d) Coulombic efficiencies and corresponding stripping/plating curves at 2 mA cm-2 and 2 mAh cm-2; e–g) LiHg film|LFP and Zn foil|LFP full cell performance: e) cycling performance, f) and g) capacity-voltage curves at various cycles.