Synthesis and Charge Storage Properties of Hierarchical Niobium Pentoxide/Carbon/Niobium Carbide (MXene) Hybrid Materials
2016; American Chemical Society; Volume: 28; Issue: 11 Linguagem: Inglês
10.1021/acs.chemmater.6b01244
ISSN1520-5002
AutoresChuanfang Zhang, Majid Beidaghi, Michael Naguib, Maria R. Lukatskaya, Meng‐Qiang Zhao, Boris Dyatkin, Kevin M. Cook, Seon Joon Kim, Eng Brandon, Xu Xiao, Donghui Long, Wenming Qiao, Bruce Dunn, Yury Gogotsi,
Tópico(s)Advancements in Battery Materials
ResumoOrthorhombic niobium pentoxide (T-Nb2O5) offers high capacitance and fast charging–discharging rate capabilities when used as an electrode material for Li-ion capacitors. A homogeneous distribution of T-Nb2O5 nanoparticles in a highly conductive matrix represents a promising approach to maximize its energy and power densities. Here we report a one-step CO2 oxidation of two-dimensional (2D) Nb2CTx, a member of the MXenes family of 2D transition metal carbides, which leads to a hierarchical hybrid material with T-Nb2O5 nanoparticles uniformly supported on the surface of Nb2CTx sheets with disordered carbon. The oxidation temperature, duration, and CO2 flow rate determine the T-Nb2O5 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–1 and 660 mF cm–2 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-Nb2O5 coupled with the fast charge transfer pathways provided by the conductive 2D Nb2CTx sheets and the as-formed disordered carbon.
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