Toward Anode-less Lithium Metal Batteries Enabled by Garnet-Based Composite Polymer Electrolytes

A promising strategy for next-generation energy storage involves boosting the energy density through innovative cell architectures. Among these architectures, anode-less Li metal batteries stand out for their potential to eliminate excess Li, thus maximizing energy density and simplifying manufacturing. Most anode-less systems rely on liquid or inorganic solid electrolytes, each with safety and scalability limitations. This work demonstrates the feasibility of an anode-less system enabled by garnet-based composite polymer electrolytes with high ionic conductivity (∼1.4 mS cm^–1 at 50 °C). A Cu–In current collector on the anode side was optimized to promote uniform Li nucleation and alloy formation. Full cells exhibited stable cycling for 200 cycles, with an average Coulombic efficiency of 96.2%. Although this work did not target high capacity, it provides a crucial proof of concept, highlighting the practical viability of a polymer-based anode-less Li metal battery for future high-energy-density battery systems.