Electrophoretic deposition of TiO₂-CNTs nanocomposite for cathode applications in Li-S batteries

Over the last few decades, scientific research in the field of lithium-sulfur batteries (LSBs) has been surmounted because of their high theoretical capacity (1675 mAhg^-1) and energy density (2500 Whkg^-1). However, its practical application is behind the critical challenge associated with the irreversible dissolution of lithium polysulfide (LPSs) into the electrolyte which causes the shuttle effect. In the present study, titanium dioxide with carbon nanotubes (CNTs-TiO₂) nanocomposite was co-deposited on a carbon fiber paper to trap the long-chain polysulfide effectively. To fabricate the 3D cathode, a layer of CNTs-TiO₂ was deposited using a binder-free electrophoretic deposition (EPD) method. Elemental sulfur impregnation was carried out at 200 °C using the vapor-infusion technique. The prepared nano-composite presented outstanding electrochemical performance because of the synergistic effect of conductive CNTs and polar TiO₂. The CNTs-TiO2/S nanocomposite cathode displayed the high initial discharge capacity of 1300 mAhg^-1at 0.1C. The sample with 50% CNT showed higher capacity retention over prolonged cycling. The result indicated that the prepared cathode has a high potential for LSB cathode.