Electrochemical Behavior of Single-Walled Carbon Nanotube Supercapacitors under Compressive Stress

Abstract

The effect of compressive stress on the electrochemical behavior of flexible supercapacitors assembled with single-walled carbon nanotube (SWNT) film electrodes and 1 M aqueous electrolytes with different anions and cations were thoroughly investigated. The under-pressed capacitive and resistive features of the supercapacitors were studied by means of cyclic voltammetry measurements and electrochemical impedance analysis. The results demonstrated that the specific capacitance increased first and saturated in corresponding decreases of the series resistance, the charge-transfer resistance, and the Warburg diffusion resistance under an increased pressure from 0 to 1723.96 kPa. Wettability as well as ion-size effect of different aqueous electrolytes played important roles to determine the pressure dependence behavior of the suerpcapacitors under an applied pressure. An improved high-frequency capacitive response with 1172 Hz knee frequency, which is significantly higher compared to reported values, was observed under the compressive pressure of 1723.96 kPa, indicating an improving and excellent high-power capability of the supercapacitors under the pressure. The experimental results and the thorough analysis described in this work not only provide fundamental insight of pressure effects on supercapacitors but also give an important guideline for future design of next generation flexible/stretchable supercapacitors for industrial and consumer applications.

Polypyrrole coated nylon lycra fabric as stretchable electrode for supercapacitor applications

“…The specific capacitance of PPy coated Nylon Lycra was calculated using the following equation [39]:…”

A “skeleton/skin” strategy for preparing ultrathin free-standing single-walled carbon nanotube/polyaniline films for high performance supercapacitor electrodes

“…[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Pure SWCNT film-based supercapacitor electrodes are usually regarded as a competitive material for high-power electrodes because of their good electrical conductivity and readily accessible surface area. 11,14,15 However, the specific surface area of the pure SWCNT filmbased electrodes is generally low because SWCNTs exist in the form of bundles, leading to a low energy density.…”

Electromechanical Properties of Polymer Electrolyte‐Based Stretchable Supercapacitors

“…The initial mechanical deformation likely enhances the electrolyte pathways to access the high surface area of the electrode material. [ 19 ] Initially at zero strain, the electrolyte may have diffi culty accessing inner elements of porous surface as a result of imperfect electrode fi lling. [ 1 ] The variation in the mechanical stress and specifi c capacitance at the higher strains is likely the result of the time-dependent mechanical behavior of the polymer.…”

“…[19][20][21] This work explores the use of aligned CNTs in an all solid-state supercapacitor confi guration for structural electronic applications and attempts to characterize the in situ multifunctional behavior of the materials. The supercapacitor materials selected in this study (electrode, electrolyte, current collector) were all designed to carry mechanical loads while simultaneously serving their conventional role in the supercapacitor system.…”