## 3 Results and Discussion
### Electrochemical Characterization  
The materials prepared through the colloidal solution, by either CS or SDR technique, have been used for cathode preparation. The electrode was prepared by mixing together in a mortar the active material, powder of super S carbon and Teflon in the form of ribbon in 40:50:10 weight ratio. Successively the resulting mixture was laminated obtaining a tape from which 1 cm\({}^{2}\) round electrodes were punched. In a typical preparation, the electrode weight was about 7.5 mg, which means a sulfur loading of about 3 mg/cm\({}^{2}\) for CS and SDR materials and of 1.4 mg/cm\({}^{2}\) for core-shell S-TiO\({}_{2}\) material. For electrochemical characterizations, a T shape cell with lithium metal as anode, LTFSI lithium bis(trifluoro methane sulfonyl imide) 1 M in DME:DEGDME (dimethoxy ethane diethylene glycol dimethyl ether) 1:1 by volume andas the electrolyte and the material to be tested as cathode, was assembled. Two wool glass separators soaked with the electrolyte solution were used. All tests were performed in a voltage range from 1.6 to 2.8 V and using a constant specific current of 167.5 mA/g (C/10, where C is the theoretical capacity). Figure 9a shows the discharge curves relative to the first, third, fifth and tenth cycle for a material obtained through CS. Figure 8: Diffractometric pattern of S-TiO\({}_{2}\) particles. Figure 9: (**a**) Discharge curves at theoretical capacity (C)/10 for CS material; (**b**) discharge curves at C/10 for SDR material. It is possible to recognize the typical trend of a Li-S cell with the presence of two distinct plateaus at different potential. The material had an initial capacity of 570 mAh/g, namely about 34% of the sulfur theoretical capacity. This value gradually decreased, reaching 70 mAh/g at the end of the tenth cycle, which means that the electrode lost 82% of its capacity during the first 10 cycles. Figure 10a shows the charging curves for the previously mentioned cycle. It can be noted that the capacity value relative to the first cycle was equal to 540 mAh/g, so it was lower than the value obtained during the discharge. This indicates that, once formed, Li\({}_{2}\)S is not fully oxidized and does not completely participate in the subsequent electrochemical reactions. Furthermore, it is possible that the polysulphides in solution were reduced chemically to the anode to form a passivating layer on the metallic lithium. In Figures 9b and 10b, respectively, the curves of discharge and charge-sweeps relative to the first, third, fifth and tenth cycle for a material obtained through SDR are represented. The electrode showed a specific capacity for the first cycle of 1510 mAh/g, which represents 90.1% of theoretical capacity. This value dropped to 623 mAh/g during the third cycle to be around 197 mAh/g at the end of the tenth cycle. The high value of capacity during the first cycle demonstrates the effectiveness of using nanostructured materials for Li-S cell. In order to perform a fair comparison, the electrochemical materials were tested for 100 cycles under the same conditions. The results obtained are presented in Figure 11a,b, respectively, from which it clearly shows that the loss of capacity continues even after the tenth cycle for both materials: In detail, the cell passes from 70 mAh/g to 22 mAh/g losing 1.23% of initial value per cycle for the material obtained by CS, and from 197 mAh/g to 70 mAh/g with an average rate of loss equal to 1.53% per cycle for the material obtained by SDR. After the 20 th cycle, the capacities were maintained substantially unchanged. In both cases the loss of capacity in the third discharge sweep was 55% with respect to the first one. Figure 11: Trend as a function of cycle number (**a**) CS, (**b**) SDR. Figure 10: (**a**) Charge curves at C/10 for CS material; (**b**) charge curves at C/10 for SDR material.