  Composite materials achieved by including transition-metal oxides with
different structures and morphologies in sulfur are suggested as scalable
cathodes for high-energy lithium-sulfur (Li-S) batteries. The composites
contain 80 wt.% sulfur and 20 wt.% of either MnO2 or TiO2, leading to a sulfur
content in the electrode of 64 wt.% and revealing a reversible, fast, and lowly
polarized conversion process in the cell with limited interphase resistance.
The S-TiO2 composite exhibits an excellent rate capability between C/10 and 2C,
and a cycle life extended over 400 cycles at 2C, owing to the effects of the
nanometric TiO2 additive in boosting the reaction kinetics. Instead, the
micrometric sized particles of MnO2 partially limit the electrochemical
activity of S-MnO2 to the current rate of 1C. Nevertheless, both S-MnO2 and
S-TiO2 withstand a sulfur loading up to values approaching 6 mgcm-2, and
deliver an areal capacit ranging from about 4.5 to 5.5 mAhcm-2 at C/5. The
excellent performances of the metal oxide-sulfur electrodes, even at high
active material loading, and the possible scalability of the synthetic pathway
adopted in the work suggest that the composites are viable cathodes for
next-generation Li-S batteries with high energy density and efficient
electrochemical process.

Materials Science;Chemical Physics