石墨氮化碳包裹的氢氧化锌钒电极，用于提高混合超级电容器的效率

摘要：尽管取得了进步，但电化学储能装置仍受到功率和能量密度要求的限制，无法完全取代化石燃料。本文，韩国岭南大学Jaesool Shim、Jaesool Shim等研究人员《Journal of Power Sources》期刊发表名为“Graphitic carbo

1成果简介

尽管取得了进步，但电化学储能装置仍受到功率和能量密度要求的限制，无法完全取代化石燃料。本文，韩国岭南大学Jaesool Shim、Jaesool Shim等研究人员《Journal of Power Sources》期刊发表名为“Graphitic carbon nitride wrapped zinc vanadium hydroxide electrode for improved hybrid supercapacitor efficiency”的论文，研究提出了一种新颖的氮化石墨碳包裹氢氧化锌钒异质结电极设计。我们利用静电层组装原理，通过调节 pH 值实现溶液自组装，合成了带有夹层的中空球形异质结构。

表面形态和晶体结构分析表明，这些夹层提供了有效的电子传输和离子扩散通道。同时，这些夹层调整了整个材料的能带隙，降低了电子传输障碍，提高了电化学性能。电化学测试表明，异质结电极结合了电池扩散和电容性近表面电化学反应的双重优势，表现出令人印象深刻的响应动力学和储能特性。值得注意的是，在电流密度为1Ag-1 时，该电极的比电容为 1931.5Fg-1。组装好的异质结//活性炭纽扣电池具有出色的能量密度（70.4 Wh kg-1）和功率密度（749.6 W kg-1）。此外，它还能在 10,000 次循环后保持近 100 % 的电容保持率和库仑效率。这项研究为开发和应用下一代高效储能设备指明了一个前景广阔的新方向。

2图文导读

方案一、(a). Schematic diagram of the dual energy storage mechanism in a ZnVOH @g-C3N4 electrode, combining battery diffusion and rapid capacitance response.

图1、(b). Schematic flow diagram of the preparation of special spherical ZnVOH and its ZnVOH@g-C3N4 heterojunction.

图2. Characterization of microscopic properties. The SEM images of (a) g-C3N4 nano-sheet, (b) ZnVOH hollow sphere with special layered construction, and (c) ZnVOH@g-C3N4 heterojunction. (d) The TEM picture of ZnVOH@g-C3N4, (e) Specific HR-TEM image with the corresponding FFT results, (f) SAED graphic of the heterojunction materials, and (g) The STEM and its elemental distribution results.

图3. Characterization of crystal structure characteristics. (a) The XRD patterns, (b) The magnified view of localized XRD patterns, (c) The ZnVOH@ g-C3N4' survey spectra, the high-resolution XPS of (d) Zn 2p, (e) O 1s, (f) V 2p, (g) N 1s, (h) C 1s, and (i) N2 adsorption/desorption isothermal curves.

图4. Characterization of electrochemical energy storage performance for materials. (a) The comparison of CV curves for diversified materials at a specific scanning speed, (b) the CV profiles of ZnVOH@g-C3N4 under different scanning speeds, (c) the comparison of GCD curves of various materials, (d) ZnVOH@ g-C3N4 's GCD curves at different current densities, (e) the specific capacitance of all materials at diverse current densities calculated via GCD and (f) capacitance retention for each material.

图5. Electrochemical kinetic characterization. (a) The B-values for heterostructured electrodes are used to characterize the relationship between peak current and scanning speed, (b) contribution distribution of ZnVOH@g-C3N4 electrode at specific scanning speed, (c) quantitative results on the contribution of ZnVOH@g-C3N4 electrode under diversified scanning speeds and (d) comparison of EIS for different materials, Nyquist plots with the corresponding circuit.

图6. Electrochemical properties of ZnVOH@g-C3N4//AC HSC devices. (a) CV curves at different working voltage windows, (b) CV profiles under diverse scanning speed s, (c) GCD curves under different current densities, (d) the specific capacitance of HSC device calculated from GCD, (e) comparison of EIS before and after cycle, (f) the specific capacitance and coulombic efficiency with cycling experiment and (g) the capacitance retention during 10,000 cycles with its GCD.

图7. Applications of ZnVOH@g-C3N4//AC HSC devices. (a) The comparison in Ragone plot with other devices and load test: (b) 60s, (c) 200s, (d) 310s.

3小结

在这项工作中，通过调节溶液的 pH 值，采用基于静电层叠原理的溶液自组装方法，合成了具有层状中空球形 ZnVOH@g-C3N4 的异质结构材料，并将其用作 HSC 的电池型阴极。这种由夹层组成的独特异质结构增强了电解质颗粒的插层空间，从而提供了高效的电子传输和离子扩散通道。同时，它还调节了材料的整体能带结构，降低了电子传输障碍。从而展现出强大的电化学储能性能。此外，异质材料电极的储能机理综合了电池和超级电容器的双重特性，展现出卓越的电化学动力学性能。在 2M KOH 电解液中实现了 1931.5 F g-1 的超高比容量（电流密度为 1 A g-1）。在功率密度分别为 749.6 W kg-1 和 11,223.0 W kg-1 的情况下，所制造的 HSC 储能装置的超高能量密度分别为 70.4 Wh kg-1 和 50.8 Wh kg-1。即使在电流密度为 20 A g-1 的情况下循环 10,000 次，该装置仍能保持近 100% 的容量保持率和库仑效率。这项研究开发的 HSC 储能装置的整体性能优于之前报道的大多数氢氧基基复合电极（参见表 1），尤其是能量密度接近锂离子电池。这项工作为利用电池和电容器的双重优势优化电极策略提供了宝贵的见解。此外，这种自组装可调带隙异质结构在半导体材料、光催化制氢和污染物降解等领域的应用也具有巨大潜力。

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