2D Titanium and Vanadium Carbide MXene Heterostructures for Electrochemical Energy Storage
2D Titanium and Vanadium Carbide MXene Heterostructures for Electrochemical Energy Storage
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DOI：
10.1016/j.ensm.2021.06.014
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发表时间：
2021-06
影响因子：
20.4
通讯作者：
Armin VahidMohammadi;Wentao Liang;Mehrnaz Mojtabavi;M. Wanunu;M. Beidaghi
中科院分区：
文献类型：
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作者：
Armin VahidMohammadi;Wentao Liang;Mehrnaz Mojtabavi;M. Wanunu;M. Beidaghi
由不同2D材料的垂直堆叠构建的二维（2D）异质结构电极是用于电化学能量存储装置的最有前途的电极架构之一。这些材料为储能应用提供了有趣的机会，例如电极结构设计的多功能性，以及将具有不同特性的单个2D构建块集成到异质结构中的可能性。这些特征可以潜在地使新材料具有改进的或新的电化学特征。在这里，我们报告了由两种不同的2D过渡金属碳化物（MXene），Ti3C2Tx和V2CTx构建的2D异质结构的大规模液相自组装。阳离子驱动的自组装过程用于将两种MXene的带负电荷的薄片组装成异质层薄片。独立式和无粘合剂的MXene异质结构膜可以提供约1473 F cm− 3的高体积电容，并且在3 M H2SO4电解质中进行50，000次充放电循环后没有显示出电容损失。由于Ti3C2Tx和V2CTx的氧化还原反应的耦合，异质结构电极在其整个电位窗口上显示出几乎恒定的电流，这让人想起传统的赝电容材料。这种电化学行为不同于单个MXene电极或大多数其他新兴的赝电容材料，其最大性能通常在窄的电位范围内实现。
Two-dimensional (2D) heterostructured electrodes built from vertical stacking of different 2D materials are among the most promising electrode architectures for electrochemical energy storage devices. These materials offer interesting opportunities for energy storage applications such as versatility in the structural design of electrode, and the possibility to integrate individual 2D building blocks with different properties into heterostructures. These features can potentially enable new materials with improved or new electrochemical features. Here, we report on large-scale liquid phase self-assembly of 2D heterostructures built from two different 2D transition metal carbides (MXenes), Ti3C2Txand V2CTx. A cation-driven self-assembly process was used to assemble the negatively-charged flakes of the two MXenes into heterolayered flakes. The freestanding and binder-free MXene heterostructure films could deliver a high volumetric capacitance of ~1473 F cm−3and showed no capacitance loss after 50,000 charge-discharge cycles in 3 M H2SO4electrolyte. Due to coupling of redox reactions of Ti3C2Txand V2CTx, the heterostructure electrodes showed a nearly constant current over their entire potential window, which is reminiscent of traditional pseudocapacitive materials. This electrochemical behavior differs from individual MXene electrodes or most other emerging pseudocapacitive materials whose maximum performance is usually achieved in a narrow potential range.