Anhydrous n methylpyrrolidone

P84® (BTDA-TDI/MDI) co-polyimide was supplied by HP Polymer GmbH. Anhydrous N-methylpyrrolidone (NMP, 99.5% purity) and tetrahydrofuran (THF, 99.5% purity) were purchased from Sigma-Aldrich (Madrid, Spain). Anhydrous ethanol (EtOH, ≥99.8% purity) was purchased from Prolabo. Hexane and methanol were purchased from Fisher Scientific (Madrid, Spain). All materials were used without further purification.

For the synthesis of ZIF-8, 2-methylimidazole (Hmim) (99% purity) and zinc nitrate hexahydrate (99+% purity) were purchased from Alfa Aesar and absolute ethanol (99.8+% purity) was purchased from Fisher Scientific. For the fabrication of the HF membranes, Fumion AP poly(2,2′-(m-phenylene))-5,5′-bisbenzimidazole (PBI, M_w = 48 000 g mol⁻¹) was supplied by Fumatech BWT GmbH. Polyvinylpyrrolidone (PVP) K30, anhydrous N-methylpyrrolidone (NMP, 99.5% purity) and lithium chloride (LiCl) were purchased from Sigma-Aldrich. n-Hexane and methanol were purchased from Fisher Scientific.

A coin-type cell (CR2032, Rotech, Inc., Gwangju, Republic of Korea) was used to evaluate the electrochemical performance of the anode materials. To prepare the binder solution, polyvinylidene fluoride (average MW 534,000 by GPC, powder, Sigma-Aldrich) was dissolved in anhydrous N-methylpyrrolidone (99.5%, Sigma-Aldrich) for 24 h (12 wt%). A slurry was prepared by dispersing the active material and conductive C (Super P, 99+%, metal basis, Alfa Aesar) in the binder-dissolved solution such that the weight ratio of the active material, binder, and conductive C was 70:15:15, respectively, followed by stirring at 150 rpm for 24 h. The prepared slurry was casted on Cu foil, followed by drying in a vacuum oven at 70 °C for 24 h. The dried working electrode was punched into a circular shape (diameter: 1.25 cm). A typical loading amount of the electrode material was 1.5 mg. Polyethylene and Li foil (99.9%, metal basis, 0.75 mm thickness, Alfa Aesar) were used as the separator and counter electrode, respectively. Additionally, 1.5 mL of the electrolyte (1 M LiPF₆ dissolved in ethylene carbonate/diethylene carbonate, 1:1, v/v) was added during cell assembly. The cells were assembled in an Ar-gas-filled glovebox.