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Size-Dependent Physical and Electrochemical Properties of Two-Dimensional MXene Flakes
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2018-06-29 00:00:00 , DOI: 10.1021/acsami.8b04662
Kathleen Maleski 1 , Chang E. Ren 1 , Meng-Qiang Zhao 1, 2 , Babak Anasori 1 , Yury Gogotsi 1
Affiliation  

Two-dimensional (2D) particles, including transition metal carbides (MXenes), often exhibit large lateral-size polydispersity in delaminated colloidal solutions. This heterogeneity results in challenges when conducting fundamental studies, such as investigating correlations between properties and the 2D flake size. To resolve this challenge, we have developed solution-processable techniques to control and sort 2D titanium carbide (Ti3C2Tx) MXene flakes after synthesis based on sonication and density gradient centrifugation, respectively. By tuning the sonication conditions, Ti3C2Tx flakes with varied lateral sizes, ranging from 0.1 to ∼5 μm, can be obtained. Furthermore, density gradient centrifugation was used to sort Ti3C2Tx flakes with different lateral sizes into more monodisperse fractions. These processing techniques allow for the characterization of size-dependent optical and electronic properties by measuring the absorption spectra and film conductivity, respectively. Additionally, by testing the material as electrochemical capacitor electrodes, we show the Ti3C2Tx flake-size dependence of electrochemical performance. Ti3C2Tx films made of flakes with lateral sizes of ∼1 μm showed the best capacitance of 290 F/g at 2 mV/s and rate performance with 200 F/g at 1000 mV/s. The work provides a general methodology which can be followed to control the size of MXenes and other 2D materials for a variety of applications and fundamental size-dependent studies.

中文翻译:

二维MXene薄片的尺寸依赖性物理和电化学性质

二维(2D)颗粒,包括过渡金属碳化物(MXenes),在分层的胶体溶液中通常表现出较大的横向多分散性。这种异质性在进行基础研究(例如研究性能与2D薄片尺寸之间的相关性)时会带来挑战。为解决这一挑战,我们开发了可溶液处理的技术,分别用于在超声处理和密度梯度离心法合成后控制和分选2D碳化钛(Ti 3 C 2 T x)MXene薄片。通过调节超声条件,Ti 3 C 2 T x可以得到横向尺寸范围从0.1到〜5μm的薄片。此外,使用密度梯度离心将具有不同横向尺寸的Ti 3 C 2 T x薄片分类为更多的单分散级分。这些处理技术可以通过分别测量吸收光谱和薄膜电导率来表征与尺寸有关的光学和电子特性。此外,通过测试该材料作为电化学电容器电极,我们显示了Ti 3 C 2 T x薄片尺寸对电化学性能的依赖性。钛3 C 2 T x由横向尺寸约为1μm的薄片制成的薄膜在2 mV / s时表现出290 F / g的最佳电容,在1000 mV / s时表现出200 F / g的速率性能。这项工作提供了一种通用方法,可用于控制MXene和其他2D材料的尺寸,以用于各种应用程序和与尺寸有关的基本研究。
更新日期:2018-06-29
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