Ultralong, as long as ∼1 mm, orthorhombic vanadium pentoxide (V 2 O 5 ) nanowires were synthesized using a hydrothermal method. Free-standing and binder-free composite paper was prepared on a large scale by a two-step reduction method using free-standing V 2 O 5 nanowires as the skeleton and reduced graphene oxide (rGO) nanosheets as the additive. Such a free-standing V 2 O 5 /rGO composite paper as a cathode for lithium ion batteries possesses both structural integrity and extraordinary electrochemical performance. The reversible specific areal capacity of the V 2 O 5 /rGO composite paper electrode is 885 μAh/cm 2 at 0.09 mA/cm 2 , much higher than that of the pure V 2 O 5 nanowire paper electrode (570 μAh/cm 2 ). It also shows excellent cycling performance at high rates with 30.9% loss of its initial capacities after 1000 cycles at a current rate of 0.9 mA/cm 2 . The excellent performance was attributed to the improved electronic conductivity and Li + ion transport from the rGO addition.

The oxidation behavior of 316L stainless steel exposed at 400, 600 and 800°C air for 100, 500 and 1000 h was investigated using different characterization techniques. Weight gain obeys a parabolic law, but the degree of deviation of n index is increasingly larger with the increase of temperature. A double oxide film, including Cr 2 O 3 and Fe 2 O 3 oxide particles in outer and FeCr 2 O 4 oxides in inner, is observed at 400°C. As regards to samples at 600°C, a critical exposure period around 100 h exists in the oxidation process, at which a compact oxide film decorated with oxide particles transforms to a loose oxide layer with a pore-structure. In addition, an oxide film containing Fe-rich outer oxide layer and Cr-rich inner oxide layer is observed at 600°C for 500 and 1000 h. Spallation of oxide scale is observed for all samples at 800°C regardless of exposure periods, resulting in different oxidation morphologies, and the degree of spallation behavior is getting worse. A double oxide film with the same chemical composition as 600°C is observed, and the thickness increases over exposure periods.

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