NOVELTY - The method comprises heating a reaction mixture comprising a first metal salt and a second metal salt at a temperature of 150-200 degrees C for 2 hours in a sealed reactor. The reaction mixture is formed by mixing a solution comprising a first metal salt with a solution comprising a second metal salt. The method further comprises: adjusting a pH of the solution comprising the first metal salt by adding an acid or base, adjusting a pH of the solution comprising the second metal salt by adding an acid or base, and/or adjusting a pH of the reaction mixture by adding an acid or base.    USE - The method is useful for synthesizing size and/or morphologically controlled nanostructures, which is useful in an energy storing device such as lithium-insertion battery (all claimed).    ADVANTAGE - The nanostructures have uniform nanoparticle size and uniform morphology thus reducing stress concentrations and stabilizing charge distribution in the energy storage device.    DETAILED DESCRIPTION - The method comprises heating a reaction mixture comprising a first metal salt and a second metal salt at a temperature of 150-200 degrees C for 2 hours in a sealed reactor. The reaction mixture is formed by mixing a solution comprising a first metal salt with a solution comprising a second metal salt. The method further comprises: adjusting a pH of the solution comprising the first metal salt by adding an acid or base, adjusting a pH of the solution comprising the second metal salt by adding an acid or base, and/or adjusting a pH of the reaction mixture by adding an acid or base; and adding specific polymers to the solution comprising the first metal salt, adding specific polymers to the solution comprising the second metal salt and/or adding specific polymers to the reaction mixture. A concentration of the first metal salt is equal or greater than or 3 times lesser than to the concentration of the second metal salt. The pH of the solution comprising the first metal salt, the pH of the solution of comprising the second metal salt and/or the pH of the reaction mixture are adjusted with nonaqueous or aqueous acid. The pH of the solution comprising the first metal salt is adjusted with nonaqueous polyprotic acid. The pH of the reaction mixture is adjusted with aqueous polyprotic acid. The method produces nanostructures that have a uniform size distribution and uniform morphology. The nanostructures have diameters of less than 100 nm. The morphology includes nanoparticles, nanobelts, nanocubes, and nanoprisms. The second metal salt is dissolved in triethylene glycol. An INDEPENDENT CLAIM is included for an energy storing device.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of an experimental apparatus to make nanostructures.