PEEK-WC / nanosponge membranes for lithium anode protection in rechargeable Li-O2 batteries

Dextrin-based nanosponges (NS) are hyper-cross-linked polymers characterized by the ability to encapsulate a great variety of substances in liquid phase.More important, dextrin-based nanosponges are nanostructured within a three-dimensional network. Here, an amorphous modified polyetheretherketone (PWC) and nanosponges (NS) derived from cross-linking dextrin and b-ciclodextrins, are used to prepare flat sheet membranes. The presence of nanosponges in membrane changes PWC features. PWC/NS membrane displays very low oxygen permeability, good ionic conductivity and assure a suitable interfacial stability with Li metal. For such properties, the membrane is suitable to protect highly reactive Li metal anode from oxygen crossover, dendrite formation and from side reactions due to oxygenated DMSO based electrolyte. Li-O2 lab-scale cells are assembled with the membrane sandwiched between Li and separator soaked by electrolyte, with continuous oxygen flow of 3 ml /min at the cathode side. XRD analysis demonstrates that the membrane does not interfere with formation and decomposition of Li2O2. Membranes assure long cell cycle life at reversible capacity and better capacity retention during cycling in full discharge / charge conditions.