Nanostructured Fe3O4 nanoparticles were prepared by a simple sonication assisted co-precipitation method. Transmission electron microscopy, X-ray diffraction and BET surface area analysis confirmed the formation of ∼20nm crystallites that constitute ∼200nm nanoclusters. Galvanostatic charge–discharge cycling of the Fe3O4 nanoaprticles in half cell configuration with Li at 100mAg−1 current density exhibited specific reversible capacity of 1000mAhg−1. The cells showed stability at high current charge–discharge rates of 4000mAg−1 and very good capacity retention up to 200 cycles. After multiple high current cycling regimes, the cell always recovered to full reversible capacity of ∼1000mAhg−1 at 0.1C rate.