Metallic molybdenum disulfide nanosheet-based electrochemical actuators
Metallic molybdenum disulfide nanosheet-based electrochemical actuators
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DOI：
10.1038/nature23668
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发表时间：
2017-09-21
期刊：
影响因子：
64.8
通讯作者：
Chhowalla, Manish
中科院分区：
文献类型：
--
作者：
Acerce, Muharrem;Akdogan, E. Koray;Chhowalla, Manish
将电能转换为机械能的致动器在各种机电系统和机器人技术（1-6）中是有用的，具有诸如可操纵导管（7）、用于飞行器的自适应机翼和减阻风力涡轮机（8）的应用。致动系统可以基于各种刺激，例如热、溶剂吸附/解吸（4，9）或电化学作用（在例如碳纳米管电极（1，10）、石墨电极（11）、聚合物电极（6，12 -14）和金属（15）的系统中）。在这里，我们证明了通过在薄塑料基底上重新堆叠二维金属二硫化钼（MoS 2）的化学剥离纳米片形成的电极膜的动态膨胀和收缩可以产生大量的机械力。这些薄膜能够在几毫米范围内提升超过电极150倍的质量，并进行数百次循环。具体而言，二硫化钼薄膜能够产生约17兆帕斯卡的机械应力-高于哺乳动物肌肉（约0.3兆帕斯卡）3，与陶瓷压电致动器（约40兆帕斯卡）相当-以及约0.6%的应变，工作频率高达1赫兹。致动性能归因于MoS 2纳米片的金属1 T相的高电导率、重新堆叠的MoS 2层的弹性模量（2至4吉帕斯卡）以及纳米片之间的快速质子扩散。这些结果可能会导致新的电化学执行器的高应变和高频应用。
Actuators that convert electrical energy to mechanical energy are useful in a wide variety of electromechanical systems and in robotics(1-6), with applications such as steerable catheters(7), adaptive wings for aircraft and drag-reducing wind turbines(8). Actuation systems can be based on various stimuli, such as heat, solvent adsorption/desorption(4,9), or electrochemical action (in systems such as carbon nanotube electrodes(1,10), graphite electrodes(11), polymer electrodes(6,12-14) and metals(15)). Here we demonstrate that the dynamic expansion and contraction of electrode films formed by restacking chemically exfoliated nanosheets of two-dimensional metallic molybdenum disulfide (MoS2) on thin plastic substrates can generate substantial mechanical forces. These films are capable of lifting masses that are more than 150 times that of the electrode over several millimetres and for hundreds of cycles. Specifically, the MoS2 films are able to generate mechanical stresses of about 17 megapascals-higher than mammalian muscle (about 0.3 megapascals) 3 and comparable to ceramic piezoelectric actuators (about 40 megapascals)-and strains of about 0.6 per cent, operating at frequencies up to 1 hertz. The actuation performance is attributed to the high electrical conductivity of the metallic 1T phase of MoS2 nanosheets, the elastic modulus of restacked MoS2 layers (2 to 4 gigapascals) and fast proton diffusion between the nanosheets. These results could lead to new electrochemical actuators for high-strain and high-frequency applications.