1成果简介 

        超细非晶纳米颗粒因其巨大的比表面积、良好的分散性、短的离子扩散路径、丰富的缺陷位点以及优异的化学稳定性，已成为储能应用领域极具前景的候选材料。本文，韩国首尔大学Moon Jong Han、Yuanzhe Piao、Ju-Hyung Kim等研究人员在《International Journal of Energy Research》期刊发表名为“Ultrafast and Facile Synthesis of Three-Dimensional Graphene-Metal Oxide Aerogels Toward High-Performance Hybrid Supercapacitors”的论文，研究通过一种超快速且环保的微波辅助方法合成了高性能电极材料，该方法能够产生协同电化学效应。将氧化铁和镍-钴氧化物纳米颗粒分别嵌入石墨烯气凝胶（GA）中作为负极和正极，从而形成高性能混合超级电容器（HSC）。

        在传统合成中通常最为耗时的热烧结步骤，使用家用微波炉仅需1分钟即可完成。所得的三电极系统在1A/g电流密度下，阳极和阴极的比容量分别达到714.4 C/g和521.4 C/g。组装后的器件展现出0.36 C cm?2的面积容量，并在50 mA cm?2的电流密度下经过13,000次充放电循环后仍能保持90%的容量。这种超快速且简便的方法实现了嵌入超细非晶态颗粒的宏观多孔GAs的可扩展制备，为下一代高性能储能器件提供了巨大潜力。

        2图文导读  

        图1、(a) Schematic illustration of the preparation of 3D graphene-TMO composites using a household microwave. SEM images of microwave-treated samples: (b, c) GA/Fe and (d, e) GA/NC. All samples were subjected to 60?s of microwave irradiation.

        

        图2、(a) Schematic illustration of the preparation of 3D graphene-TMO composites using a household microwave. SEM images of microwave-treated samples: (b, c) GA/Fe and (d, e) GA/NC. All samples were subjected to 60?s of microwave irradiation.

        

        图3、(a, b) TEM image and enlarged view of GA/Fe. (c) EDS elemental mapping images of GA/Fe showing Fe (yellow), C (red), and O (orange); the red box indicates the EDS mapping area. (d, e) TEM image and enlarged view of GA/NC. (f) EDS elemental mapping images of GA/NC showing C (red), Ni (cyan), and Co (yellow); the red box indicates the EDS mapping area. All samples were subjected to 60?s of microwave irradiation. Scale bars in (c) and (f) are 50?nm.

  

        图4、(a) XRD patterns of GA, GA/Fe, and GA/NC. Black bar markers indicate the positions of weak diffraction features detected in the experimental patterns, while the overall broad background reflects the dominant contribution from the GA framework. Reference peak positions corresponding to reported spinel NiCo2O4 phases (indicated by yellow diamonds) and spinel-type iron oxides (indicated by green diamonds) are marked to guide phase identification. XPS spectra of (b) GA/Fe and (c, d) GA/NC composites: (b) Fe 2p, (c) Ni 2p, and (d) Co 2p. All samples were subjected to 60?s of microwave irradiation.

 

        图5. Electrochemical performance of GA/NC samples with varying microwave irradiation durations. (a) CV curves of GA/NC samples at a scan rate of 50?mV?s?1. (b) Specific capacities of GA/NC samples evaluated at 1?A?g?1. (c) CV curves of GA/NC-60 at various scan rates. (d) GCD curves of GA/NC-60 at different current densities. The number in each sample name indicates the microwave irradiation time in seconds.

        图6、(a) Schematic illustration of the fabricated HSC. (b) CV curves of the device measured in different potential windows at a scan rate of 50?mV?s?1. (c) CV curves at scan rates ranging from 10 to 200?mV?s?1. (d) GCD profiles of the hybrid supercapacitor at various current densities. (e) Cycling stability and Coulombic efficiency at a current density of 50?mA?cm?2, with the inset showing an LED powered by the fabricated device. (f) Nyquist plots recorded before and after 13,000 cycles over a frequency range of 10?2 to 105?Hz, with the inset showing the equivalent circuit used for fitting.

 

        图7、(a) Schematic illustration of the fabricated HSC. (b) CV curves of the device measured in different potential windows at a scan rate of 50?mV?s?1. (c) CV curves at scan rates ranging from 10 to 200?mV?s?1. (d) GCD profiles of the hybrid supercapacitor at various current densities. (e) Cycling stability and Coulombic efficiency at a current density of 50?mA?cm?2, with the inset showing an LED powered by the fabricated device. (f) Nyquist plots recorded before and after 13,000 cycles over a frequency range of 10?2 to 105?Hz, with the inset showing the equivalent circuit used for fitting.

        3小结 

        在本研究中，通过一种家用微波辅助方法成功制备了三维石墨烯-TMO复合材料。热烧结步骤通常是传统合成中最耗时的阶段，但在本研究中仅需1分钟即可完成。这种超快且环保的加热过程使得超细非晶态TMO纳米颗粒在宏观多孔的GA骨架内均匀分布。经优化的GA/Fe和GA/NC电极在三电极配置下表现出优异的电化学性能，在1 A/g电流密度下分别展现出714.4和521.4 C/g的比容量。组装而成的GA/Fe||GA/NC高比容量电池展现出0.36 C cm?2的高面容量、1.5 V的扩展工作电压以及卓越的长期稳定性，即在13,000次循环后仍保留约90%的初始容量，且库仑效率接近100%。这些卓越性能归因于以下协同效应：

        (1) 互联的GA网络实现了高效且均匀的热传导；

        (2) 超细纳米颗粒形态带来了大比表面积、高分散度及短离子扩散路径；

        (3) 非晶结构带来的丰富缺陷与高化学稳定性。

        总体而言，本研究凸显了一种简便且可扩展的3D微波辅助合成策略的有效性，该策略可用于制造基于石墨烯-TMO混合架构的高性能、可持续且低成本的储能器件。

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