Glass microfibre filter

Symmetric two-electrode cells were fabricated to analyse the charge-storage capabilities of electrodes based on EFAC1 and EFAC2 in an aqueous, 6 M KOH electrolyte. The electrode inks were prepared by mixing the CFs (70%) with PVDF (20%) and Carbon Black (10%) with a total weight of 0.4 g in 4 mL NMP. PVDF acts as a binder, while Carbon Black is a conductivity enhancement agent. The homogeneous ink was cast on Ni foil (current collector) using a doctor blade setup and dried in an oven. The average thickness of the films was 40 μm. Circular electrodes of 12 mm diameter were obtained using a steel punch. The effective mass of active material on each electrode was ~ 2.4 mg. Two electrodes with very similar active material masses were chosen and pressed at 6.9 MPa. Before assembly, 14 mm glass microfibre filter (Whatman) separators were soaked in a 6 M KOH electrolyte. CR2032 coin cell cases were used for the fabrication of supercapacitors. The assembled cells were pressed at 5.2 MPa using a crimper and the cells were left for 24 h to allow the electrodes to sufficiently soak the electrolyte before measurement. The schematic representation of waste polyurethane elastomer-based CF electrode assembled in a symmetric two-electrode cell is shown in Fig. 1.Figure 1

Schematic representation of waste polyurethane elastomer-based CF electrode for a symmetric two-electrode cell.

One microlitre of 5,6,-³H uracil (1 µCi) was added to 1 ml culture samples and incubated at 37°C with agitation for 20 h. Two hundred microlitres of this culture was placed in 3 ml 7% ice-cold CCl₃COOH and incubated at 0°C for 20 min, followed by filtration through a glass microfibre filter (Whatman). Precipitated cells were washed with 3 ml 7% CCl₃COOH and 6 ml 96% ethanol. Filters were placed in 10 ml scintillation mixture; impulse counts were determined by LS analyser (Beckman Instruments) and expressed as counts per minute (cpm).

The electrodes were assembled in ‘coffee bag'-type cells all assembled under argon atmosphere (<0.1 p.p.m. O₂/H₂O). The electrodes were separated by glass microfibre filters (Whatman) with a few droplets of 1 mol l⁻¹ LiPF₆ (EC:DMC 1:1, Novolyte) electrolyte. All the electrochemical tests were performed galvanostatically within a voltage window of 4.3 and 2.5 V versus Li/Li+ using an Autolab PGSTAT302N potentiostat/galvanostat.