We demonstrate the significance of nanostructuring on the reversible Li-insertion into octahedral sites of the nickel substituted spinel Li[Ni0.5Mn1.5]O-4. One dimensional nanofibers (50-250 nm diameter) of the Li[Ni0.5Mn1.5]O-4 were prepared by a single spinneret electrospinning and their performance was compared with powders synthesized via a conventional solid state approach. Li-diffusion coefficient of electrospun fibers was an order of magnitude higher (5.8 x 10(-11) cm(2) s(-1)) than that of conventional powders (1.22 x 10(-12) cm(2) s(-1)). Galvanostatic studies revealed a much improved capacity and rate performance for electrospun fibers. The fibers delivered a reversible capacity of similar to 87 mAh g(-1) after 150 cycles at 1C rate compared to negligible capacity for solid-state prepared material. Finally, the performance of this nanostructured spinel phase as an anode in aqueous rechargeable Li-ion system was demonstrated to require a strongly alkaline electrolyte. (C) 2015 Elsevier B.V. All rights reserved.