Anode‐Free Li‐Metal Battery Based on Sustainable Sulfolane Electrolyte: Performance–Anode Structure Correlation

Anode‐free concept can fully utilize the unmatched theoretical specific energy of lithium‐metal battery. However, the low stability of the anode interface, including both the morphology of Li metal and the solid electrolyte interphase (SEI), hinders the practical battery implementation and creates safety concerns. In this work, sulfolane‐based localized high‐concentration electrolyte (LHCE) is applied as a sustainable and applicable electrolyte for anode‐free Li‐metal batteries (AFLMBs). The effects of important factors, including type of anode current collector, electrolyte properties, and cycling conditions, are explored in terms of clarifying their impact on the structural and functional properties of LFP‖Cu cells. Flammability tests indicate that the electrolyte is nonflammable by direct ignition under the applied conditions, which is highly beneficial for the safety and sustainability of the AFLMB. The performance of SL‐based LHCE is tested for Li plating–stripping reaction on Cu‐engineered substrates, where the microporous Cu substrates display major improvement, which can be attributed to their enlarged active surface area and open and highly interconnected porous structure. The influence of the key operation parameters, state of charge, depth of discharge, and current density is explored, and useful correlations of these factors with the anode structural properties and battery cycling stability are established.