Enhancing the capacitive performance of a textile-based CNT supercapacitor

Abstract

A metal layer, used as a current collector layer for a textile-based supercapacitor (SC), was prepared on polyethylene terephthalate (PET) fabrics using wet chemical methods. By integrating this additional current collector layer into the SC structure, the carbon-nanotube (CNT)-based SC showed an improved capacitive performance. The specific capacitances of the CNT/Cu/PET SC and CNT/Au/PET SC were 4.312 Â 10 À3 F cm À2 and 3.683 Â 10 À3 F cm À2 respectively, about 60 times larger than that obtained from the CNT/PET SC without the metal collector layer. On the other hand, the energy densities of these CNT-based SCs with metal layers were found to be $50 fold increased as compared to the CNT/ PET SC. Similarly, the power densities of these two SCs with current collector layers were two orders of magnitude larger than that of CNT/PET SC. High flexibility was also demonstrated in these two metallayered SCs. For the durability measurement, the CNT/Au/PET SC showed a stable performance, with its specific capacitance maintained at about 89% of its initial value after 2500 charge-discharge cycles.However, the CNT/Cu/PET SC only showed a relatively short-term stability, as its specific capacitance dropped to 12% of its initial value after 2500 charge-discharge cycles. In order to further improve its capacitive performance, polyaniline (PANI) was deposited on the CNT/Au/PET SC surface using a cyclic voltammetric deposition method. A specific capacitance of 0.103 F cm À2 , about 30 times larger than that of the CNT/Au/PET SC, was obtained in the PANI/CNT/Au/PET SC which also showed good flexibility as well as high stability performance, with only 11% drop after 2500 charge-discharge cycles.On the basis of our results, we believe that by integrating a thin current collector layer into the textilebased CNT SC, its specific capacitance is enhanced while its flexibility and durability can be maintained.This method allows us to make any non-conducting fabric into a SC and turn it into a portable and wearable energy storage device.

Fabrication of polyaniline/copper sulfide/poly(ethylene terephthalate) thread electrode for flexible fiber‐shaped supercapacitors

“…The capacitance can be calculated according to the equation: where C is the specific capacitance (mF cm −2 ), I is the discharge current (mA), Δ t is the discharge time (s), s is the electrode area (cm 2 ), and Δ V is the potential window (V) during discharge. The specific capacitance of the two‐electrode symmetrical supercapacitor cell can be calculated according to the equation: where C cell is the total cell specific capacitance (mF cm −2 ) and S is the total area (cm −2 ) of two electrodes. The energy density ( E , Wh cm −2 ) and power densities ( P , W cm −2 ) were calculated according to the equations: …”

“…However, the assembled supercapacitors were relatively bulky and costly as the metal wires were utilized. Considering that wearable electronics require excellent durability and fabric‐like wearable comfort, fabrics would be a normal choice for being used as substrates . Among all kinds of commercial fabrics, poly(ethylene terephthalate (PET) is commonly used in clothing because of its economic value, chemical resistance, shrinkage resistance, good strength, consistency in quality, and ready availability .…”

Hierarchical Ni–Co layered double hydroxide nanosheets entrapped on conductive textile fibers: a cost-effective and flexible electrode for high-performance pseudocapacitors

“…[25][26][27][28][29] However, they are somewhat expensive, and a relatively complicated fabrication process would be required to manufacture these substrates which may impede their practical applications in wearable energy storage devices. 35 On the other hand, it is well known that binary metal oxides/hydroxides possess superior electrochemical characteristics for pseudocapacitors than those of single transition metal oxides/hydroxides since they have multiple oxidation states and high electrical conductivity. [32][33][34] The fabrication technology of CTs has been considerably developed in textile fabric industries by means of simple and cost-effective methods.…”

Commercial Dacron cloth supported Cu(OH)2 nanobelt arrays for wearable supercapacitors

“…However, these substrates are generally not suitable for integration into clothing and hence cannot effectively meet the wearable requirements. 3,7 Therefore, it is rather imperative that commercial textiles can be directly employed as a substrate to fabricate exible and wearable supercapacitors. It is known that, apart from its thinness, exibility, light weight and stretchability, cloth possesses a 3D porous structure, which allows a high areal mass loading of active materials and therefore high areal power and energy densities of the devices can be expected.…”