Synthesis and Charge Storage Properties of Hierarchical Niobium Pentoxide/Carbon/Niobium Carbide (MXene) Hybrid Materials
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- 作者：Chuanfang Zhang ; Majid Beidaghi ; Michael Naguib ; Maria R. Lukatskaya ; Meng-Qiang Zhao ; Boris Dyatkin ; Kevin M. Cook ; Seon Joon Kim ; Brandon Eng ; Xu Xiao ; Donghui Long ; Wenming Qiao ; Bruce Dunn ; Yury Gogotsi
- 刊名：Chemistry of Materials
- 出版年：2016
- 出版时间：June 14, 2016
- 年：2016
- 卷：28
- 期：11
- 页码：3937-3943
- 全文大小：459K
- 年卷期：0
- ISSN：1520-5002
文摘
Orthorhombic niobium pentoxide (T-Nb<sub>2sub>O<sub>5sub>) offers high capacitance and fast charging–discharging rate capabilities when used as an electrode material for Li-ion capacitors. A homogeneous distribution of T-Nb<sub>2sub>O<sub>5sub> nanoparticles in a highly conductive matrix represents a promising approach to maximize its energy and power densities. Here we report a one-step CO<sub>2sub> oxidation of two-dimensional (2D) Nb<sub>2sub>CT<sub>xsub>, a member of the MXenes family of 2D transition metal carbides, which leads to a hierarchical hybrid material with T-Nb<sub>2sub>O<sub>5sub> nanoparticles uniformly supported on the surface of Nb<sub>2sub>CT<sub>xsub> sheets with disordered carbon. The oxidation temperature, duration, and CO<sub>2sub> flow rate determine the T-Nb<sub>2sub>O<sub>5sub> crystallite size as well as the structure, composition, and the charge storage properties of the hybrid material. Fifty micrometer thick electrodes of the hybrid material exhibit high capacitance (330 C g<sup>–1sup> and 660 mF cm<sup>–2sup> at a charge–discharge time of 4 min) and good cycling performance in a nonaqueous lithium electrolyte. The charge storage kinetics are dominated by a surface-controlled process. The observed electrochemical performance is attributed to the intrinsic pseudocapacitive response and excellent energy storage capability of T-Nb<sub>2sub>O<sub>5sub> coupled with the fast charge transfer pathways provided by the conductive 2D Nb<sub>2sub>CT<sub>xsub> sheets and the as-formed disordered carbon.