All-Solid-State Batteries with Pre-plated Ultrathin Lithium Metal Enabled by No Pressure Holding and Characterized by...

All-solid-state batteries with ultrathin lithium metal, close to the anode-free solid-state batteries, could achieve high energy density. However, it is not trivial to plate an ultrathin lithium metal layer on a Cu current collector (Cu-CC). In situ electron paramagnetic resonance (EPR) imaging showed that the pre-plating on Cu-CC in a Li-In|Li₆PS₅Cl|Cu cell without pressure holding produced a lithium metal layer with a small area. However, when a Li-In|Li₆PS₅Cl|Cu cell was held under a considerable pressure, this cell would produce a lithium metal layer with a large area. The Cu-CC with the ultrathin lithium metal layer of a small surface could be extracted and then assembled with LiNiO₂ and Li₆PS₅Cl to achieve better electrochemical performance compared to that of a large surface, because a small area of the lithium metal layer would lead to fewer side reactions and less consumption of lithium ions. This work suggests the importance of the control of the lithium plating and the observation of lithium plating by in situ EPR imaging.