1成果简介 

智能手表、手机甚至部分无人机都依赖轻量、可充电储能器件，一旦报废，许多最终变成电子废弃物。本文，加州大学圣地亚哥分校 Tse Nga Ng、Nandu Koripally 等在《ACS Energy Letters》发表题为 “Recyclable Zinc Ion Structural Supercapacitor Enabled by Porous Vitrimer” 的论文，提出一种可快速拆解、多次循环利用的锌离子结构超级电容器。该器件采用锌金属?铜箔阳极、活性炭纤维阴极和多孔玻璃体聚合物基固态电解质（以 ZnCl? 水系溶液为离子源），结合可拆解的粘结与封装设计，实现了高性能与易回收的兼顾。

为概念验证，团队将四个超级电容器集成到一架模型滑翔机机翼中。在外接电源驱动螺旋桨条件下，滑翔机飞行距离约 3.7 米（12 英尺），而无外接电源时仅约 3.4 米（8 英尺），显示出器件的实际驱动能力。随后，器件在弱酸性水溶液中 30 分钟内实现层间分离，回收的碳纤维阴极在先后经历初始制备和两轮循环再利用后，累计完成超过 172,000 次充放电循环，且电性能保持稳定。该工作展示了兼具“结构承载 + 能量存储 + 易拆解回收”的一体化设计思路，为可持续电子器件设计提供了新范例。

2图文导读

Figure 1.Schematics of recyclable structural supercapacitors. The porous vitrimer composed of DGEBA, 2-AFD, and PEG contains reformable disulfide bonds, which bind the electrodes and separator layers together to form structural zinc ion supercapacitors. The cross-linking is reversible by chemical solvolysis at room temperature to recover and reuse electrode materials such as carbon fibers.

Figure 2.Characterization of structural electrolyte films. Films had been infused with 7.5 M ZnCl2 aqueous solution to incorporate salts for ionic transport. (a) Ionic conductivity as a function of vitrimer composition and material loading onto the separator substrate. The weight ratio of DGEBA:2-AFD blend was held constant at 2:3 in this dataset, while the same blend was adjusted with PEG by weight percentage. (b) Electrochemical impedance of a polypropylene separator as purchased (dark blue), following vitrimer coating before PEG dissolution (medium blue), and after PEG removal (light blue). Scale bar: 100 μm. (c) SEM images of the vitrimer-coated separator before (left) and after (right) dissolving PEG. (d) BET analysis to estimate surface area by the Rouquerol criteria and total pore volume obtained by Gurvich’s rule, explained in the Experimental Methods section. (e) Flexural stress versus deflection distance measured on separators coated with epoxy, vitrimer, or porous vitrimer. (f) Tensile stress versus applied strain on separators coated with epoxy, vitrimer, or porous vitrimer.

Figure 3.Characterization of structural supercapacitors. (a) Photographs showing the deflection of full cells with different binders. (b) Cross-sectional SEM image of the structural supercapacitor. (c) Cyclic voltammetry measured at a scan rate of 20 mV s?1, as the structural supercapacitor was subjected to increasing flexural deflection from 0 to 4 mm. (d) Specific capacitance and flexural stress as a function of deflection distance. The specific current and capacitance were calculated using the weight of active materials (AC & Zn = 4.56 mg). (e) A photograph and a circuit schematic of a model plane, in which four structural supercapacitors connected in parallel were integrated onto the top and bottom surfaces of the wing sections. (f) Charge?discharge voltage profiles versus time, at a constant current of 200 mA (equivalent to 4.67 mA cm?2 and 0.204 A g?1) for the integrated supercapacitors on the model plane.

Figure 4.Recycling process and characterization. (a) Structural supercapacitor placed in a TCEP-HCl solution to cleave disulfide bonds at room temperature and separate cell materials for recovery. (b) Electrochemical impedance of the structural supercapacitor in the as-fabricated condition and after refabrication using recycled cathodes. The same color legends apply to panels (b?f). (c) Cyclic voltammetry measured at a scan rate of 10 mV s?1 after 40 charge?discharge cycles. (d) Charge?discharge characteristics at a current density of 10 mA cm?2 at the 200th cycle (blue) and at the last cycle (gray: 12,600th; brown: 28,500th; orange: 65,500th). (e) Specific capacity, normalized by the AC and Zn active materials weight, versus charge?discharge cycles over 2 V, at a current density of 10 mA cm?2. Measurements on the original device were halted following a short circuit, while those on the recycled devices were stopped due to time constraints. (f) Specific energy versus specific power of structural supercapacitors, normalized to full device weight: (i) QxTh-rGO, (ii) LiCoO2-CF, (iii) CAG-CFRP,  (iv) FCF/E-IL-70-CF, and (v) CNT-MnO2-CF.

3小结 

总而言之，本文提出一种可回收锌离子结构超级电容器设计，以水系锌离子化学和多孔玻璃体聚合物固态电解质为基础，实现器件的快速拆解与多次循环再利用。碳纤维阴极在初始制备及两轮回收再利用过程中，累计完成超过 172,000 次充放电循环且性能稳定，兼顾了高循环寿命与可持续性。该工作为下一代兼具结构承载与易回收特性的储能器件设计提供了重要示范。

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