title: High-performance sodium-ion pseudocapacitors based on hierarchically porous nanowire composites.
abstract: 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.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, USA.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Chen
authors.forename: Veronica
authors.initials: V
authors.lastname: Augustyn
authors.forename: Xilai
authors.initials: X
authors.lastname: Jia
authors.forename: Qiangfeng
authors.initials: Q
authors.lastname: Xiao
authors.forename: Bruce
authors.initials: B
authors.lastname: Dunn
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Lu
mesh_terms: D004566:Electrodes; D008855:Microscopy, Electron, Scanning; D053770:Nanowires; D012964:Sodium / Q000737:chemistry*
chemical_list: D012964:Sodium