Solvent granularity in the differential electrical capacitance of supercapacitor and mechanism analysis
Solvent granularity in the differential electrical capacitance of supercapacitor and mechanism analysis
复制标题
超级电容器微分电容中的溶剂粒度及机理分析
DOI：
10.1016/j.physa.2019.121905
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发表时间：
2019-11
期刊：
影响因子：
--
通讯作者：
S. Zhou
中科院分区：
文献类型：
--
作者：
S. Zhou
在这项工作中，我们研究了溶剂粒度如何影响使用水性电解质的超级电容器的微分电容（C d ）以及调节 C d 与表面电荷密度 σ 曲线形态的分子机制。主要新发现和结论概括为以下几点：(i)溶剂粒度有助于提高C d 值，且随着表面电荷强度σ的增大，该作用趋于减弱；特别是，阈值σ随着孔径的增大而明显上升，超过阈值σ，溶剂粒度效应开始变得在图形上不可观察到。较小的孔径和/或较高的体积浓度有助于促进骆驼形曲线向钟形曲线的转变，并且这两个因素是协同作用的。（iii）无论C d− σ曲线是骆驼形还是钟形，以及抗衡离子是单价还是多价，当后者足够大时，C d值总是倾向于随着σ值下降；特别是，在非常小的孔隙条件下，当σ大约超过0.7C/m 2 时，C d 值最终接近于零。(iv)高反离子价数导致C d 值和驼峰曲线情况下C d 峰对应的阈值σ上升。(iv)引入了一个新概念：整个离子吸附容量随表面电荷强度的变化率，结合拥挤效应、共离子排斥效应，揭示了其机理。所有考虑的因素通过改变 EDL 中的静电屏蔽环境来影响 C d 的作用。
In this work, we study how solvent granularity influences the differential electrical capacitance (C d) of supercapacitor using aqueous electrolyte and molecular mechanism modulating the curve morphology of C d versus surface charge density σ. Main new findings and conclusions are summarized into several points:(i) the solvent granularity helps to raise the C d value, and the effect tends to weaken as the surface charge strength σ increases; particularly, the threshold σ, beyond which the solvent granularity effect begins to become graphically unobservable, rises obviously with the pore size.(ii) The bulk electrolyte concentration and pore size evidently influence the transition between camel-shaped and bell-shaped C d− σ curves; a smaller pore and/or a higher bulk concentration help to facilitate the change from camel-shaped into bell-shaped curve, and the two factors are cooperative.(iii) Whether the C d− σ curve is camel-shaped or bell-shaped, and the counter-ion is univalent or multivalent, the C d value always tends to drop with the σ value as the latter one is sufficiently large; particularly, under conditions of very small pore the C d value eventually approaches zero as the σ is approximately over 0.7C/m 2.(iv) High counter-ion valence causes rising of the C d value and the threshold σ corresponding to the C d peak in the case of the camel-shaped curve.(iv) A new concept is introduced: change rate of the whole ion adsorption capacity with the surface charge strength, which, combined with the crowding effect, co-ion exclusion effect, discloses the mechanism of action by which all factors considered influence C d by changing the electrostatic screening environment in the EDL.
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DOI：
10.1021/acs.jpcb.8b03119
发表时间：
2018-05
期刊：
The journal of physical chemistry. B
影响因子：
--
作者：
Zijian Wang;H. Lu
通讯作者：
Zijian Wang;H. Lu
影响因子：
3.7
作者：
Lei Zhang;D. Wilkinson;Zhongwei Chen;Jiujun Zhang
通讯作者：
Lei Zhang;D. Wilkinson;Zhongwei Chen;Jiujun Zhang
影响因子：
1.7
作者：
W. Silvestre-Alcantara;L. B. Bhuiyan;Jian Jiang;Jianzhong Wu;D. Henderson
通讯作者：
W. Silvestre-Alcantara;L. B. Bhuiyan;Jian Jiang;Jianzhong Wu;D. Henderson
DOI：
10.1119/1.11184
发表时间：
1998-06
期刊：
--
影响因子：
--
作者：
J. Hansen;I. R. Mcdonald;D. Henderson
通讯作者：
J. Hansen;I. R. Mcdonald;D. Henderson
影响因子：
1.6
作者：
Y. Mamasakhlisov;A. Naji;R. Podgornik
通讯作者：
Y. Mamasakhlisov;A. Naji;R. Podgornik