Department of Chemistry, Oregon State University , Corvallis, Oregon 97331-4003, United States.
Nano Lett. 2014 Jul 9;14(7):4119-24. doi: 10.1021/nl501692p. Epub 2014 Jun 23.
For the first time, we demonstrate that orthorhombic V2O5 can exhibit superior electrochemical performance in sodium ion batteries when uniformly coated inside nanoporous carbon. The encapsulated V2O5 shows a specific capacity as high as 276 mAh/g, while the whole nanocomposite exhibits a capacity of 170 mAh/g. The V2O5/C composite was fabricated by a novel ambient hydrolysis deposition that features sequential water vapor adsorption in nanoporous carbon, followed by a hydrolysis reaction, exclusively inside the nanopores. The unique structure of the nanocomposite significantly enhances the capacity as well as the rate performance of orthorhombic V2O5 where the composite retains a capacity of over 90 mAh/g at a current rate of 640 mA/g. Furthermore, by calculating, we also revealed that a large portion of the sodium-ion storage, particularly at high current rates, is due to the V2O5 pseudocapacitance.
我们首次证明，在纳米多孔碳内均匀包覆的正交相 V2O5 在钠离子电池中具有优异的电化学性能。封装的 V2O5 表现出高达 276 mAh/g 的比容量，而整个纳米复合材料的容量为 170 mAh/g。V2O5/C 复合材料是通过一种新颖的环境水解沉积法制备的，该方法的特点是在纳米多孔碳中依次吸附水蒸气，然后在纳米孔内进行水解反应。纳米复合材料的独特结构显著提高了正交相 V2O5 的容量和倍率性能，复合材料在 640 mA/g 的电流速率下仍保持超过 90 mAh/g 的容量。此外，通过计算，我们还揭示了钠离子存储的很大一部分，特别是在高电流速率下，归因于 V2O5 的赝电容。
