Reduced Self-Discharge of Supercapacitors Using Piezoelectric Separators

Abstract

The application of supercapacitors for long-term energy storage is largely limited by their self-discharge behavior. Finding an effective approach to suppress self-discharge remains a great research challenge. Herein, a porous poly­(vinylidene fluoride) (PVDF) membrane with a piezoelectric effect is employed as supercapacitor separators for reduced self-discharge. The PVDF membrane is prepared via a phase-inversion method followed by polarization to induce piezoelectricity. Self-discharge tests indicate that both open-circuit voltage (OCV) decay rate and leakage current of the supercapacitors with piezoelectric PVDF separators are reduced by more than 30% compared to those with nonpiezoelectric separators. The much lower self-discharge rate can be attributed to the impeded diffusion of electrolyte ions across the polarized PVDF separators.

Wearable Near-Field Communication Sensors for Healthcare: Materials, Fabrication and Application

“…Nevertheless, as wearable electronics require continuous testing, energy devices are an urgent problem to be solved. Micro-battery delivery systems, flexible large-capacity batteries, supercapacitors, and self-powered systems are the current solutions [ 125 , 126 , 127 , 128 ]. Additionally, the selection of biodegradable and non-toxic materials for wearable sensors is also an issue to be considered for their commercialization.…”

Fluorinated Ether‐Based Electrolyte for Supercapacitors with Increased Working Voltage and Suppressed Self‐discharge

“…Supercapacitors as energy storage devices have attracted great attention due to their high power density and long cycle life [1–20] . In addition to improving the energy density of supercapacitors, reducing the self‐discharge is also an imperative research task for practical applications of supercapacitors [21–34] . Increasing the working voltages of supercapacitors can effectively improve their energy densities, while electrolytes play a critical role in setting the limit of working voltage.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] In addition to improving the energy density of supercapacitors, reducing the self-discharge is also an imperative research task for practical applications of supercapacitors. [21][22][23][24][25][26][27][28][29][30][31][32][33][34] Increasing the working voltages of supercapacitors can effectively improve their energy densities, while electrolytes play a critical role in setting the limit of working voltage. Traditional organic electrolytes for supercapacitors such as tetraethylammonium tetrafluoroborate (TEABF 4 ) in acetonitrile have a working voltage of about 2.7 V. Further increasing the working voltage may lead electrolyte decomposition and hence serious self-discharge due to impurities generated by the side reactions of the charging process at high voltage.…”

Investigation of Self‐Discharge Behavior on Electrical Double‐Layer Capacitors by Hybrid Mechanism Simulation

“…SD refers to the spontaneous voltage decay across the capacitor that occurs when the capacitor is left unconnected to either a charging circuit or an electrical load after being charged, which determines the energy storage time and has become one of the challenges of the applications of EDLCs. [14][15][16][17] It is the characteristic of EDLCs, which exists even after one charge process and is different from the long-time failure mode in the aging test.To date, most of the investigations are focused on the factors and the methods to suppress the SD process of EDLCs, including the research on the component, the type and the preparative technique of electrolyte, [18][19][20][21][22] separator, [23][24][25][26][27] and AC, [28][29][30][31][32] while the studies discussing the mechanism behind the SD process are limited. Conway et al [33] proposed three kinds of SD models originally: activation-controlled faradaic process, ohmic leakage process, and diffusion control process.…”

“…To date, most of the investigations are focused on the factors and the methods to suppress the SD process of EDLCs, including the research on the component, the type and the preparative technique of electrolyte, [18][19][20][21][22] separator, [23][24][25][26][27] and AC, [28][29][30][31][32] while the studies discussing the mechanism behind the SD process are limited. Conway et al [33] proposed three kinds of SD models originally: activation-controlled faradaic process, ohmic leakage process, and diffusion control process.…”