The potential practical application of electric vehicles and large-scale energy storage system, have prompted extensive research in the development of electrode materials with high performance and high rate capability. Ultrafine TiO₂ and Nb₂O₅ nanocrystals/reduced graphene oxide (TiO₂/rGO and Nb₂O₅/rGO) were prepared by controllable hydrolysis and followed by thermal treatment. First, hydrolysis of titanium or niobium precursor formed amorphous hydroxide thin layer on graphene oxide (GO). After annealing at 450 °C under forming gas, amorphous hydroxide layer converted to TiO₂ or Nb₂O₅ nanocrystals with particle size of around 5 nm or 3 nm, respectively, and GO reduced to rGO with enhanced conductivity. TiO₂/rGO and Nb₂O₅/rGO were demonstrated as promising anode materials for high performance lithium ion batteries and sodium ion batteries. The architecture of ultrafine TiO₂ or Nb₂O₅ nanocrystals anchored on highly conductive rGO network and can not only enhance charge transfer and buffer the volume change during lithiation/delithiation or sodiation/desodiation processes, but also provide more active surface area for lithium or sodium ion storage, resulting in superior rate and cycle performance. Ex situ XPS analysis revealed that the sodium ion storage mechanism in Nb₂O₅ could be accompanied with Nb⁵⁺/Nb⁴⁺ redox reaction and the ultrafine Nb₂O₅ NCs provide more surface area to accomplish the redox reaction.