更高效:突破性材料提高超级电容器性能

诸平

Supercapacitors, known for their rapid energy storage and release capabilities, play a crucial role in renewable energy and environmental conservation. Recent advancements, such as oxygen vacancies engineering, have significantly improved the electrochemical performance of metal oxides, making them more effective for supercapacitor electrodes. New research demonstrates this progress, highlighting the potential of these materials in enhancing supercapacitor technology. Credit: Higher Education Press

据《科技日报》（SciTechDaily）网站2024年3月15日报道，山东大学材料液固结构演变与加工教育部重点实验室{Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, China}毕见强 (Jianqiang Bi)教授团队的突破性材料提高了超级电容器性能（Far More Efficient: Breakthrough Material Advances Supercapacitor Performance）。

超级电容器（Supercapacitors / ultracapacitors）又称电双层电容器(electric double-layer capacitors简称EDLCs)，是一种具有独特特性的先进储能器件。与传统电池不同，超级电容器通过电解液和高表面积电极之间的界面电荷的静电分离来储存能量。这种机制允许快速的能量存储和释放，使超级电容器能够提供高功率突发并表现出优异的循环寿命。

超级电容器在可再生能源和环境保护领域发挥着举足轻重的作用。在可再生能源的背景下，超级电容器是能量存储和传输系统的关键部件。它们快速储存和释放能量的能力使它们非常适合于消除间歇性能源，如太阳能和风能，确保持续可靠的能源供应。

在环境保护领域，超级电容器是传统储能设备的可持续替代品。它们的循环寿命长，充电/放电能力快，对环境影响小，是环保的选择。此外，它们在电动汽车和混合动力系统中的应用促进了向更清洁交通的过渡，与全球减少碳排放和应对气候变化的努力保持一致。总的来说，超级电容器对可持续能源解决方案的进步和环保意识的实践做出了重大贡献。

超级电容器技术的进展(Advancements in Supercapacitor Technology)

目前，氧空位工程(oxygen vacancies engineering)被广泛认为是提高超级电容器领域金属氧化物电化学性能的有效策略。在最近的研究中，毕见强 (Jianqiang Bi)教授团队在水热法合成NiFe₂O₄的基础上，成功地在活性炭床上通过后续热处理工艺合成了具有丰富氧空位的NiFe₂O_4-δ。经过精心处理得到的NiFe₂O_4-δ具有优异的导电性，其电容比NiFe₂O₄提高了3.7倍。

这种观察到的电化学性能的增强强调了氧空位在优化金属氧化物性能方面所起的关键作用。他们的研究结果有力地支持了这样一种观点，即有意引入氧空位对提高金属氧化物的电化学性能有很大的希望，从而使它们成为超级电容器电极的有前途的材料。这一新发现为储能领域的潜在应用开辟了道路，展示了氧空位工程对高性能超级电容器发展的重要影响。相关研究结果于2023年8月25日已经在《化学科学与工程前沿》（Frontiers of Chemical Science and Engineering）杂志网站发表——Xicheng Gao, Jianqiang Bi, Linjie Meng, Lulin Xie, Chen Liu. Activated carbon induced oxygen vacancies-engineered nickel ferrite with enhanced conductivity for supercapacitor application. Frontiers of Chemical Science and Engineering, 2023, 17: 2088–2100. DOI: 10.1007/s11705-023-2352-6. Published: 25 August 2023

本研究得到了山东省自然科学基金重大基础研究项目(Major Basic Research Projects of Shandong Natural Science Foundation Grant No. ZR2018ZB0104)、山东省科技发展项目(Science and Technology Development Project of Shandong Province Grant Nos. 2016GGX102003 and 2017GGX20105)和山东省自然科学基金(Natural Science Foundation of Shandong Province Grant No. ZR2017BEM032)的支持。

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Abstract

NiFe₂O₄ is a kind of bimetallic oxide possessing excellent theoretical capacity and application prospect in the field of supercapacitors. Whereas, due to the inherent poor conductivity of metal oxides, the performance of NiFe₂O₄ is not ideal in practice. Oxygen vacancies can not only enhance the conductivities of NiFe₂O₄ but also provide better adsorption of OH, which is beneficial to the electrochemical performances. Hence, oxygen vacancies engineered NiFe₂O₄ NiFe₂O_4−δ) is obtained through a two-step method, including a hydrothermal reaction and a further heat treatment in activated carbon bed. Results of electron paramagnetic resonance spectra indicate that more oxygen vacancies exist in the treated NiFe₂O_4−δ than the original one. UV-Vis diffuse reflectance spectra prove that the treated NiFe₂O_4−δ owns better conductivity than the original NiFe₂O₄. As for the electrochemical performances, the treated NiFe₂O_4−δ performs a high specific capacitance of 808.02 F·g⁻¹ at 1 A·g⁻¹. Moreover, the asymmetric supercapacitor of NiFe₂O_4−δ//active carbon displays a high energy density of 17.7 Wh·kg⁻¹ at the power density of 375 W·kg⁻¹. This work gives an effective way to improve the conductivity of metal oxides, which is beneficial to the application of metal oxides in supercapacitors.