Mesh-Supported Porous\nFilm as a Reservoir for Insoluble\nAdditives and Facilitator of Stable Li Accommodation in Li-Metal Anodes

An anode structure is proposed for Li-metal secondary\nbatteries.\nThe anode structure comprises a porous film that serves as a reservoir\nto continuously supply electrolyte-insoluble additives and a mesh-type\nspacer that mechanically supports the film and also provides space\nfor stable Li storage. Specifically, LiNO<sub>3</sub>, an effective\nadditive for controlling the solid–electrolyte interphase (SEI)\nlayer of the Li-metal anode but barely soluble in commercial electrolytes\nusing carbonate-based ester solvents, is embedded in the polymer film\nfor achieving its continuous supply. The film is prepared to be porous\nto ensure Li-ion transport. However, the increased film porosity and\nhigh additive content degrade the physical stability and flexibility\nof the film. To counteract this, a polymer mesh is integrated into\nthe film as a mechanical support, realizing a high LiNO<sub>3</sub> loading and high film porosity, which are crucial for sufficient\nLiNO<sub>3</sub> supply and Li-ion transport kinetics. Additionally,\nthe polymer mesh provides a fixed-height space for Li accommodation,\nmaintaining a consistent electrode thickness during charge/discharge\nprocesses. This integrated anode structure, realized through a low-cost\nand simple process, addresses the technical challenges of SEI layer\ncontrol and electrode thickness stabilization in Li-metal anodes,\noffering a practical solution for Li-metal secondary batteries.