Designing photocured macromolecular matrices for stable potassium batteries

The preparation and characterization of the first photocured gel polymer electrolyte for potassium batteries is presented. The use of UV-induced radical polymerization aims at developing a sustainable and rapid way to produce polymer electrolytes without using further processes to separate solvents and by-products. The gel polymer electrolyte displays a high ionic conductivity (17 mS cm-1 at 20 degrees C) and an electrochemical stability window up to 3.7 V (vs. K+/K), maintaining excellent stability within the battery working potential range. The thermal resistance is suitable for potassium battery application and the glass transition temperature is low enough to ensure a good macromolecular mobility of the polymer chains. Due to the highly crosslinked structure, the gel polymer electrolyte is mechanically robust and able to hinder the formation of potassium dendrites, i.e. one of the main issues to be faced for this energy storage technology, allowing the unprecedented achievement of 600 cycles with a capacity retention of 58%.