Ti@δ-MnO₂ core-shell nanowire arrays as self-supported electrodes of supercapacitors and Li ion batteries

δ-MnO₂ is a promissing electrode material of supercapacitors and Li ion batteries (LIBs) owing to its low cost, layer structure and composite valence of Mn. However, the unfavorable electronic conductivity of δ-MnO₂ restricts its rate capability in both of the two devices. Herein, a vertically standing Ti nanowire array modified with δ-MnO₂ nanoflakes is prepared by a electrodeposition method, and the electrochemical properties of Ti@δ-MnO₂ nanowire arrays in supercapacitors and LIBs are investigated. The results show that, the arrays have a capacity of 195 F g^-1 at 1.0 A g^-1 and can cycle more than 10000 rounds at 10 A g^-1 as electrodes of supercapacitors. On the other hand, the arrays behave good rate capability as LIB cathodes, which can release a capacity of 70 mAh g^-1 at 10C rate charge/discharge. We suggest that, the good electronic conductivity owing to the core-shell structure and the facilitated mass transport supplied by the array architecture are responsible for the enhanced rate performances in the two devices.