A MOF-derived composite with multi-functional effects for high-performance Li–S batteries, especially its Co–N dual-catalyzing for S redox.

Highly ordered TiO 2 single-crystalline nanowire arrays have been fabricated within the pores of anodic aluminum oxide (AAO) template by a cathodically induced sol−gel method. Raman spectra confirmed that the nanowires are composed of pure anatase TiO 2 . TEM investigations indicated that these nanowires have a uniform tetragonal single-crystal structure. Finally, a possible growth mechanism of the TiO 2 nanowires is discussed.

High utilization and loading of sulfur in cathodes holds the key in the realization of Li-S batteries. We here synthesized a CoN mesoporous sphere, which was made up of nanosheets, via an easy and convenient method. This material presents high affinity, speedy trapping, and absorbing capacity for polysulfides and acts as a bifunctional catalysis for sulfur redox processes; therefore it is an ideal matrix for S active material. With such a mesoporous sphere used as a sulfur host in Li-S batteries, extraordinary electrochemistry performance has been achieved. With a sulfur content of 72.3 wt % in the composite, the CoN@S delivered a high specific discharge capacity of 1659 mAh g at 0.1 C, almost reaching its theoretic capacity. Also, the battery exhibited a large reversible capacity of about 1100 mAh g at 0.5 C and 1000 mAh g at 1 C after 100 cycles. At a high rate of 2 C and 5 C, after 300 cycles, the discharge capacity finally stabilized at 805 and 585 mAh g. Even at a 94.88% sulfur content, the cathode can still deliver an extremely high specific discharge capacity of 1259 mAh g with good cycle performance.