Effect of Silver Particle Distribution in a Carbon Nanocomposite Interlayer on Lithium Plating in Anode-Free All-Solid-State Batteries

Solid-state batteries can outperform lithium-ion batteries in energy per unit mass or volume when operating with a Li metal anode. However, Li anodes pose significant manufacturing challenges. Anode-free cells avoid these challenges by plating metallic Li at the anode on the first charge, but subsequent nonuniform cyclic stripping and plating decrease the Coulombic efficiency and encourage Li dendrites and early cell failure. We report a new spray-printed nanocomposite bilayer of silver/carbon black (Ag/CB) between anodic current collectors and a Li6PS5Cl solid electrolyte comprising an Ag-rich region at the current collector and a CB-rich region at the solid electrolyte. Compared with previous Ag/CB mixtures, this bilayer promoted more uniform Li anode plating and improved cycling. Cells with a high-Ni oxide cathode had an initial discharge capacity of >190 mAh/g and a Coulombic efficiency of >98% over 100 cycles. Improved Li plating uniformity with the structured Ag/CB interlayer was confirmed by using secondary-ion mass spectrometry (SIMS) imaging.