锌离子混合超级电容器电极材料研究进展

锌离子混合超级电容器兼具了锌离子电池的高能量密度与超级电容器的高功率密度和高循环稳定性的优点,在便携式电子设备和电动汽车领域具有极高的应用前景。本文介绍了锌离子混合超级电容器的工作原理,全面系统梳理了碳材料(活性炭、多孔碳、碳纳米管、石墨烯、生物质衍生碳和MOFs/COFs衍生碳)和赝电容材料(二氧化钌和MXene基材料)等电容型电极材料的储锌能力,归纳了金属锌、锰基氧化物和钒基氧化物等电池型电极材料的研究进展,指出高性能锌离子混合超级电容器电极材料目前所面临的挑战及未来的发展方向。

锂离子电容器电极材料研究进展

锂离子电容器兼具锂离子电池高能量密度和超级电容器高功率密度的优点,被认为是电动汽车和功率型移动电子设备的理想储能器件。锂离子电容器的性能与其选用的电极材料体系和电极材料的储能特性密切相关,而选用不同体系的电极材料对锂离子电容器的组装工艺也影响深远。按照电容型活性材料和氧化还原型活性材料进行分类,总结了锂离子电容器电极材料的最新进展,并对今后重点发展的方向进行了展望。

在外电极放电空间配置正交导电电极后的初始激励电场分布问题

图(一)是一种常见的平板电容型外电极放电结构示意图.这种结构的最大特点是它的放电空间和激励电极之间被一层电介质所隔离。由于这层电介质的存在,放电过程中向电极运动的带电粒子因无法到达激励电极便在介质表面积聚起来,形成壁电荷。又由于壁电荷产生的电场与激励电场反向,所以随着壁电荷的增加,激励电场将逐渐受到削弱,最后使放电终止。要使放电得以继续,只有改变激励电场方向使之引发反向放电才行,所以外电极放电器件必须使用交变电源。

The relationship between the high-frequency performance of supercapacitors and the type of doped nitrogen in the carbon electrode

Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors,particularly in terms of their high-frequency response.However,the charge storage and electrolyte ion response mechanisms of different nitrogen dopants at high frequencies are still unclear.In this study,melamine foam carbons with different configurations of surfacedoped N were formed by gradient carbonization,and the effects of the configurations on the high-frequency response behavior of the supercapacitors were analyzed.Using a combination of experiments and first-principle calculations,we found that pyrrolic N,characterized by a higher adsorption energy,increases the charge storage capacity of the electrode at high frequencies.On the other hand,graphitic N,with a lower adsorption energy,increases the speed of ion response.We propose the use of adsorption energy as a practical descriptor for electrode/electrolyte design in high-frequency applications,offering a more universal approach for improving the performance of N-doped carbon materials in supercapacitors.