Cellulose nanocrystals (CNCs) have emerged as a promising templating material due to unique features, such as high surface area, surface hydroxyl groups and rod-like shape, which allow for sustainable nanoscale control of advanced functional materials. Especially, such high surface functionality and specific morphology can be imparted on the resultant nanomaterials with beneficial properties during templating. Here, we present synthesis of one-dimensional (1D) nanostructured vanadium oxides, such as VO2(B) and V2O5·nH2O nanobelts, with single- crystalline structure by hydrothermal treatment using CNCs as a sacrificial template. Importantly, the single-crystal vanadium oxide nanobelts exhibit the enhanced electrochemical performance of Li ion batteries with high specific capacity (> 300 mAh/g) and long lifespan (> 244 mAh/g at 50 cycles) compared to the polycrystalline nanoflakes counterpart. Furthermore, we suggest that during hydrothermal treatment the sacrificial CNC template-derived carbon is beneficial for electron transfer in cathode materials. Thus, we demonstrate that the utilization of CNC templating to develop novel single-crystalline oxide cathode nanomaterials can provide a fruitful pathway for extraordinary electrochemical performance of next-generation alkaline batteries.