Highly dispersive and uniform α-MoO 3 nanoparticles were successfully synthesized by a facile sol–gel method using triblock copolymer as a dispersing agent. The morphology, structure and chemical state of the product were characterized by FESEM, TEM, XRD, XPS and FT-IR. Galvanostatic charge/discharge test demonstrated high initial discharge capacities of 964 and 1192mAhg −1 at different current densities. At a current density of 20mAg −1 , the lithium-ion insertion was up to 6.4Li + /Mo which was higher than its theoretical value. This higher embedding quantity led to higher discharge capacity, which was significant to lithium-ion battery. Moreover, the discharge curves assisted by the differential capacity curves proved that the lithium-ion intercalation/deinercalation into the α-MoO 3 host structure underwent a two-step mechanism.