The working electrodes were prepared by mixing 90 wt% of HC, 5 wt% of carbon Super P (Alfa Aesar ≥99%) as a conducting material, and 5 wt% of polyvinylidene (PVDF, MSESupplies ≥99.6 %) as a binder in N-Methylpyrrolidone (NMP, MSESupplies ≥99.9%, anhydrous). The resulting slurry was cast on aluminum foil (MTI ≥99.3%) using a 200 µm doctor blade. The film was first dried at 100ºC using a hot-plate for approximately one hour and then vacuum-dried overnight at 100ºC to fully remove NMP. The electrode film was punched into 14 mm diameter disks for the coin cells.