Screen-Printed Li Arrays with Reinforced Interphase as Ultrathin Anodes for High-Energy-Density Liquid- and Solid-State Batteries.

High-energy-density lithium metal batteries, either liquid or solid state, require ultrathin Li anodes, but their implementation is hindered by poor Li processability in fabrication and inhomogeneous Li plating behaviours upon cycling. This work addresses these challenges through a mask-patterned discrete array using a molten salt-derived Li nanocomposite. The screen-printing strategy circumvents the poor wettability of molten Li on copper that causes high Li|Cu contact angle and non-uniform Li spreading, thus fabricating ultrathin Li foils with equivalent thicknesses below 30 μm. Concurrently, the molten salt-derived inorganic nanoparticles in Li favour homogeneous Li deposition and induce inorganic-rich solid electrolyte interphase to jointly suppress active Li consumption. The resulting Li array (10-28 μm) anodes demonstrate remarkable performance in both liquid- and solid-state systems, achieving high energy densities up to 504 Wh kg-1/1071 Wh L-1 and stable cycling over 260 cycles with high-loading cathodes. This integrated approach resolves both fabrication and cycling challenges of ultrathin Li anodes and offers an alternative solution for high-performance liquid-/solid-state batteries.