The invention relates to a nanostructured material.The material is a nanostructured carbonaceous material composed of agglomerates of small needles of Li.sub.1+.alpha.V.sub.3O.sub.8 and of .beta.-Li.sub.xV.sub.2O.sub.5 (0.1.ltoreq..alpha..ltoreq.0.25 and 0.03.ltoreq.x.ltoreq.0.667) surrounded by a noncontinuous layer of spherical carbon particles.It is obtained by a process consisting in preparing a carbonaceous precursor gel by bringing carbon, .alpha.-V.sub.2O.sub.5 and a Li precursor into contact in amounts such that the ratio of the [V.sub.2O.sub.5]/[Li] concentrations is between 1.15 and 1.5 and that the (carbon)/(carbon+V.sub.2O.sub.5+Li precursor) ratio by weight is from 10 to 15 and in subjecting the gel to a heat treatment comprising a 1st stage at 80.degree. C.-150.degree. C. for 3-12 h and a 2nd stage between 300.degree. C. and 350.degree. C. for 10 min to 1 hour, under an nitrogen or argon atmosphere.Applications: positive electrode active material.