A schematic of a single cell of a conventional, liquid-based lithium-ion battery (LiB) and a solid-state LiB. The conventional LiB comprises an anode composed of a Cu current collector and an active anode material (graphite), a separator soaked in an organic electrolyte, and a cathode composed of a Al current collector and an active cathode material, for example, LiCo2, as shown here. The solid-state LiB comprises a similar cathode, a solid electrolyte, and an anode composed of a Li-ion plate and Cu current collector. The anode-electrolyte interphase (SEI) and cathode-electrolyte interphase (CEI) for both LiBs are represented as pink and blue transparent layers, respectively. The tabs are shown protruding from the top of the current collectors. Both LiB cells show all components as fully lithiated, with directional Li+ movement during (dis)charge indicated with arrows.