Electrochemically reconfigurable architected materials
Electrochemically reconfigurable architected materials
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DOI：
10.1038/s41586-019-1538-z
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发表时间：
2019-09-12
期刊：
影响因子：
64.8
通讯作者：
Greer, Julia R.
中科院分区：
文献类型：
--
作者：
Xia, Xiaoxing;Afshar, Arman;Greer, Julia R.
建筑材料可以通过改变其几何形状来积极响应外部刺激，如机械力，水合作用和磁场，从而实现新的功能。这样的转换通常是二进制的和易失的，因为它们在“开”和“关”状态之间切换，并且需要持续的外部刺激。在这里，我们开发的三维硅涂层的tetraxite微晶格，通过合作梁屈曲响应于电化学驱动的硅-锂合金化反应转化为正弦图案。原位显微镜揭示了一个可控的，非挥发性和可逆的结构转变，形成多个有序的屈曲域分离的扭曲域边界。我们调查的机械动力学的个别屈曲梁，相邻梁之间的合作耦合，和锂化率依赖的域尺寸分布，通过化学力学建模和统计力学分析。我们的研究结果强调了缺陷和能量波动在建筑材料动态响应中的关键作用。我们进一步证明，域边界可以编程，形成特定的模式，通过预先设计的人工缺陷，并通过微架构设计，可以实现各种重构自由度。该框架使电化学可重构结构材料的设计，制造，建模，行为预测和编程成为可能，并可能为超越嵌入电池电极，可调声子晶体和生物可植入设备开辟道路。
Architected materials can actively respond to external stimuli-such as mechanical forces, hydration and magnetic fields-by changing their geometries and thereby achieve novel functionalities. Such transformations are usually binary and volatile because they toggle between 'on' and 'off' states and require persistent external stimuli. Here we develop three-dimensional silicon-coated tetragonal microlattices that transform into sinusoidal patterns via cooperative beam buckling in response to an electrochemically driven silicon-lithium alloying reaction. In situ microscopy reveals a controllable, non-volatile and reversible structural transformation that forms multiple ordered buckling domains separated by distorted domain boundaries. We investigate the mechanical dynamics of individual buckling beams, cooperative coupling among neighbouring beams, and lithiation-rate-dependent distributions of domain sizes through chemo-mechanical modelling and statistical mechanics analysis. Our results highlight the critical role of defects and energy fluctuations in the dynamic response of architected materials. We further demonstrate that domain boundaries can be programmed to form particular patterns by pre-designing artificial defects, and that a variety of reconfigurational degrees of freedom can be achieved through micro-architecture design. This framework enables the design, fabrication, modelling, behaviour prediction and programming of electrochemically reconfigurable architected materials, and could open the way to beyond-intercalation battery electrodes, tunable phononic crystals and bio-implantable devices.