Tuning interfacial ion distribution to improve energy density of supercapacitors. (November 2022)

• Record Type: Journal Article
• Authors: Chen, Yunyi; Qing, Leying; Liu, Tongtong; Zhao, Shuangliang; Han, Yongsheng
• Is Part Of: Nano energy. Volume 102(2022)
• Publication Date: 2022-11
• Subjects: Supercapacitor -- Capacitance -- Ions distribution -- Energy density -- Density functional theory; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2022.107660
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Supercapacitors as energy carriers have the advantages of high-power efficiency and long-term stability. An improvement of their energy density promises a solution to make up for the weakness of secondary batteries at a high rate of applications. Here we report an attempt to improve the energy density of supercapacitor by tuning ions arrangement at the electrode-electrolyte interface. Upon the theoretical analysis with classical density functional theory (CDFT), we find that the capacitance of the supercapacitor is maximized at a mediate concentration of electrolytes, i.e., 1.0 M, where ions accumulate near the electrode surface and display a few multilayered oscillatory distributions. Further, by adjusting the dielectric constant of electrolyte solution and the electrode surface voltage, the interfacial ion distribution is tuned to optimize the energy density of supercapacitors. The theoretical results are corroborated by designed experiments, confirming the role of interfacial ion distribution in specific capacitance. This study shows that an appropriate interfacial ion distribution is beneficial to obtaining high capacitance, highlighting an unusual solution to improve the energy density of supercapacitors. Graphical Abstract: ga1 Highlights: Improving the energy density of capacitor by tuning interfacial ion distribution. Ions distribution regulated by concentration, dielectric constant and voltages A few multilayered oscillatory ions distributions are beneficial to energy density. The simulation results was confirmed by designed experiments. Providing a different strategy to improve the energy density of supercapacitors.