1 成果简介
具有优异柔韧性和压缩性的超级电容器在可穿戴电子设备领域具有广阔的发展前景。三维（3D）碳材料因其丰富的多孔结构和卓越的力学性能，在此类超级电容器中具有显著优势。然而，同时兼具优异力学性能和电化学性能的碳材料的制备仍面临挑战。 本文，四川大学赵江琦副研究员、张伟副研究员等在《Ind. Eng. Chem. Res》期刊 发表名为“Bioinspired “Enoki Mushroom-like” Hollow Nanorods Architectured NiO@Carbon Hybrid Foam for High-Performance Compressible Supercapacitors”的论文， 研究 通过可扩展的浸渍涂覆和碳化策略，开发了一种仿生NiO@碳混合泡沫（NiO@CCF）。所得的NiO@CCF在热解过程中原位生长出独特的“金针菇状”中空纳米棒，使其具有超低密度、固有的超亲水性、完全的压缩回弹性以及卓越的机械稳定性。
作为一种无粘合剂电极，NiO@CCF 展现出 372.75 F/g 的惊人比电容，比原始碳泡沫（86.36 F/g）高出 330%。这归因于以下协同效应：
(i) 分级多孔结构（具有 1156 m2/g 的高比表面积）提供了丰富的活性位点；
(ii) 可逆的法拉第反应增强了伪电容；
(iii) 中空纳米棒结构加速了离子/电子传输。组装而成的固态非对称超级电容器实现了46.68 Wh/kg的高能量密度，同时在80%压缩下体积电容增加了386%（1.54 → 7.49 F/cm³）。
这项工作为高性能可压缩超级电容器提供了一种经济高效的范式，推动了其在可穿戴储能领域的应用。
2 图文导读
图 1. (a) Fabrication process: dip-coating and carbonization. SEM images of (b) pure MF foam, (c) dip-coated MF/cellulose/Ni(OH) 2 , and (d–e) NiO@CCF at varying magnifications (20 μm, 1 μm, 200 nm). (f1–4) Zoomed-in images of SEM b–e. The “Enoki mushroom-like” hollow nanorods (d, arrow) mimic natural Enoki mushrooms (f3). (g) Representative multiscale SEM images.
图2. (a) TEM and HR-TEM images of the “enokitake-like” nanorods. (b) The XPS spectra of CF and NiO@CCF. High-resolution of Ni 2p (c) and N 1s (d) XPS spectra of the NiO@CCF. (e) The Raman spectra of CF and NiO@CCF. (f) Representative N2 adsorption–desorption isotherms and (g) pore size distributions for CF and NiO@CCF. The stress–strain curves of CF (h) and NiO@CCF (i) at different compressive strains. (j) Photographs showing the dynamic measurements of hydrophilic properties of NiO@CCF.
图3. Electrochemical performance of the CF, CCF, NiO@CCF. (a, e, i) CV curves of the CF, CCF, NiO@CCF at various scan rates. (b, f, j) Galvanostatic charge/discharge curves of the CF, CCF, NiO@CCF at different current densities. (c, g, k) Plot of specific capacitance at various current densities. (d, h, l) Nyquist plots of the CF, CCF, NiO@CCF electrode.
图4. (a) XRD data of CF, CCF, and NiO@CCF. (b) b values analysis of NiO@CCF. (c) Capacitive vs diffusion contribution of NiO@CCF. (d) Fitting of relaxation time constant. (e) Nyquist plots fitting results of the CF, CCF, NiO@CCF electrode. (f) Capacitive vs diffusion contribution of NiO@CCF.
图5. (a) Schematic illustration of the ASC device. (b) CV curves of the CCF//NiO@CCF ASC measured at different potential windows (100 mV/s). (c) GCD curves of the ASC measured at different potential windows (0.5 A/g). (d) Gravimetric specific capacitance and (e) energy density of the ASC under different potential windows. (f) CV curves of the CCF//NiO@CCF ASC measured at different scan rates. (g) GCD curves of the ASC at different current densities. (h) Plot of gravimetric and volumetric specific capacitance at various current densities. (i) Ragone plots of the ASC based on the total mass of the cathode and anode, in comparison with early reported supercapacitors. (j) Self-discharge behavior at 1.6 V in 6 M KOH electrolyte. (k) Cycling stability performance of the ASC collected at 5 A/g.
图6. (a) Photos of ASC under different degrees of bending CV curves of the ASC under different degrees of bending (b) and compression (c) (at 100 mV/s). (d) GCD curves of the ASC under different degrees of compression (at 0.5 A/g). (e) Gravimetric and volumetric specific capacitance of the ASC at different degrees of compression. (f) GCD curves of a single device and two devices connected in series as well as in parallel. (g) Photographs of three ASCs in series that power 20 red LED bulbs. (h) In situ specific capacitance of ASC under repeated bending at the angle of 90°.
3 小结
本研究提出了一种制备高性能混合碳泡沫（NiO@CCF）的新型低成本高效方法。以MF树脂泡沫为模板，采用纤维素溶液浸渍涂覆结合碱性再生工艺，在骨架上构建了纤维素薄膜和Ni(OH)₂纳米颗粒。随后经碳化处理，获得了具有“金针菇状”中空纳米棒的独特多孔结构。所得材料具有超低密度（19 mg/cm³），同时兼具卓越的柔韧性、可压缩回弹性和超亲水性。电化学表征显示，在1 A/g电流密度下比电容达372.75 F/g，在10 A/g电流密度下电容保持率为41.96%。基于该材料制备的可压缩非对称固态超级电容器展现出高能量密度和循环稳定性，并并在各种变形条件下保持稳定的储能性能。这些特性表明该材料在可穿戴电子设备领域具有广阔的应用前景。
