Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, USA.
ACS Nano. 2012 May 22;6(5):4319-27. doi: 10.1021/nn300920e. Epub 2012 Apr 19.
Electrical energy storage plays an increasingly important role in modern society. Current energy storage methods are highly dependent on lithium-ion energy storage devices, and the expanded use of these technologies is likely to affect existing lithium reserves. The abundance of sodium makes Na-ion-based devices very attractive as an alternative, sustainable energy storage system. However, electrodes based on transition-metal oxides often show slow kinetics and poor cycling stability, limiting their use as Na-ion-based energy storage devices. The present paper details a new direction for electrode architectures for Na-ion storage. Using a simple hydrothermal process, we synthesized interpenetrating porous networks consisting of layer-structured V(2)O(5) nanowires and carbon nanotubes (CNTs). This type of architecture provides facile sodium insertion/extraction and fast electron transfer, enabling the fabrication of high-performance Na-ion pseudocapacitors with an organic electrolyte. Hybrid asymmetric capacitors incorporating the V(2)O(5)/CNT nanowire composites as the anode operated at a maximum voltage of 2.8 V and delivered a maximum energy of ∼40 Wh kg(-1), which is comparable to Li-ion-based asymmetric capacitors. The availability of capacitive storage based on Na-ion systems is an attractive, cost-effective alternative to Li-ion systems.
电能存储在现代社会中发挥着越来越重要的作用。当前的储能方法高度依赖锂离子储能装置，而这些技术的广泛应用可能会影响现有的锂储量。钠的丰富度使得基于钠离子的设备作为一种替代的、可持续的储能系统非常有吸引力。然而，基于过渡金属氧化物的电极通常表现出缓慢的动力学和较差的循环稳定性，限制了它们作为基于钠离子的储能设备的应用。本文详细介绍了一种用于钠离子存储的电极结构的新方向。我们使用简单的水热法合成了由层状 V(2)O(5)纳米线和碳纳米管（CNTs）组成的互穿多孔网络。这种结构提供了简便的钠离子插入/提取和快速的电子转移，使得可以使用有机电解质制造高性能的钠离子赝电容器。包含 V(2)O(5)/CNT 纳米线复合材料的混合不对称电容器作为阳极，在最大电压为 2.8 V 时运行，并提供了最大能量约 40 Wh kg(-1)，与锂离子基不对称电容器相当。基于钠离子系统的电容存储的可用性是对锂离子系统的一种有吸引力的、具有成本效益的替代方案。
