Improved performance of electrodes based on carbonized olive stones/S composites by impregnating with mesoporous TiO2 for advanced Li—S batteries

• Activated carbon from olive stones with mesoporous TiO2S as cathode is reported.
• Comparing same cell without TiO2 a performance improvement of 60% is obtained.
• Higher specific capacity values were delivered at current densities 1 C, 2 C and 4 C.
• Post-mortem characterizations confirm TiO2 sorbent properties vs Li polysulfides.

Carbons obtained from biomass have attracted a lot of attention for use as electrodes for Li-ion batteries. Less attention has been paid to their use in LiS batteries in spite of the higher energy densities. Here, we optimized the electrochemical properties of an activated carbon (OSAC) obtained from olive stones with the help of mesoporous TiO2. The OSAC@TiO2/S hybrid composite exhibited improved electrochemical performance compared with the OSAC/S composite. The presence of TiO2 increased the delivered capacity of the cell by more than 60%, and the rate capability was notably improved. The cell could operate at current densities of 3350 mA g−1 (2 C), releasing an average capacity of 500 mAh g−1 with a coulombic efficiency close to 100%. This improvement in the electrochemical performance is attributed to the sorbent properties of TiO2 towards Li polysulfides and its facility to insert Li, which enhances the electronic and ionic conductivity of the hybrid composite.