Unity Convoluted Design of Solid Li‐Ion Battery and Triboelectric Nanogenerator for Self‐Powered Wearable Electronics

Choi

et al. 2017

Small

Wearable rechargeable batteries require electrode platforms that can withstand various physical motions, such as bending, folding, and twisting. To this end, conductive textiles and paper have been highlighted, as their porous structures can accommodate the stress built during various physical motions. However, fabrics with plain weaves or knit structures have been mostly adopted without exploration of nonwoven counterparts. Also, the integration of conductive materials, such as carbon or metal nanomaterials, to achieve sufficient conductivity as current collectors is not well-aligned with large-scale processing in terms of cost and quality control. Here, the superiority of nonwoven fabrics is reported in electrochemical performance and bending capability compared to currently dominant woven counterparts, due to smooth morphology near the fiber intersections and the homogeneous distribution of fibers. Moreover, solution-processed electroless deposition of aluminum and nickel-copper composite is adopted for cathodes and anodes, respectively, demonstrating the large-scale feasibility of conductive nonwoven platforms for wearable rechargeable batteries.

Section: Wearable Batteriesmentioning

confidence: 99%

Solution‐Processed Metal Coating to Nonwoven Fabrics for Wearable Rechargeable Batteries

Choi

et al. 2017

Small

“…[1][2][3][4][5][6][7] However, most of the existing mechanical energy-to-electricity conversion devices generate alternating current (AC) outputs, which have to be rectified into direct current (DC) power prior to storage or use. Conversion of these tiny kinetic energies into electricity offers novel applications in the fields of sensors and power supply.…”

Section: Introductionmentioning

confidence: 99%

Doping Effect on Conducting Polymer‐Metal Schottky DC Generators

Shao

Fang

Wang

et al. 2018

Adv Elect Materials

nitride (InN) nanowire energy harvesters [8][9][10][11][12][13][14] ; 2) triboelectric-based generators with multiple electrification pairs or a sliding Schottky nanocontact [15][16][17] ; 3) conducting polymer-metal Schottky diodes. [18,19] In our previous studies, we have demonstrated that a conducting polymer film when forming a Schottky contact with a metal (such as Al or Al alloy) can produce DC outputs under compressive deformations. [18,19] The devices showed a large energy density. They are easy to fabricate, offering great potential for applications in various self-powered electronic devices.Polyaniline (PANI) is a major conducting polymer possessing high conductivity and processing ability. [20] It has shown vast application potential in the fields of supercapacitors, batteries, sensors, EMI shielding, and gas separation. [21][22][23] PANI can be easily doped and de-doped. The dopant and doping state have a great effect on the electrical properties of PANI. [24] For example, PANI emeraldine base (PANI-EB), i.e., non-doped PANI, is almost nonconductive with an electrical resistivity as high as 10 10 Ω cm −1 . [25] The conductivity is largely enhanced when doped with a protonic acid. [26] The dopant effect was attributed to the change of PANI crystallinity, interchain distance, and energy bandgap, hence leading to change in chemical and physical properties (e.g., electrochemical, spectroscopic, and modulus). [24,27,28] However, how dopant affects the energy conversion property of PANI-metal Schottky diodes has not been reported in research literature.In this study, we have for the first time demonstrated the effect of dopants on the mechanical-to-electrical energy conversion behavior of a conducting polymer-metal Schottky power generator. PANI was used as a conducting polymer model, which was doped with four protonic acids; orthophosphoric acid (H 3 PO 4 ), sulfuric acid (H 2 SO 4 ), perchloric acid (HClO 4 ), and hydrochloric acid (HCl). The dopants showed a great effect on energy conversion property. The device made of nondoped PANI only produced up to 1.5 mV and 0.55 nA cm −2 electrical outputs. The one from HCl-doped PANI generated much higher outputs (0.9 V and 33.9 µA cm −2 ) than those from PANI doped with other protonic acids. The change in electrical outputs was attributed to the effect of dopant on barrier height and conductivity. For Al/PANI-HCl/Au, the barrier height decreased significantly from 0.87 to 0.78 eV when the Conducting polymer-metal Schottky diodes show an interesting mechanical energy-to-electricity conversion ability to generate direct current (DC) power without rectification. However, little is reported about how dopants in conducting polymer affect the energy conversion behavior of Schottky diodes. In this study, a novel effect of dopants on mechanical energy-to-DC electricity conversion of conducting polymer-metal Schottky devices is demonstrated. Using polyaniline (PANI) as a model, conducting polymers doped with a series of protonic acids is prepared. Without dopant, the dev...

“…[11][12][13][14] Crucial to the successful implementation of TENGs in practical applications is to generate sufficient output power, usually stored in a capacitor or a battery, to operate the devices. [15][16][17][18] Strategies to enhance the output performance of TENGs are generally based on increasing of the transferred charge density between two contacted surfaces, as the electric potential is critically dependent on it. [19][20][21][22] Although the principle of contact-electrification has long been studied, [23][24][25] but whose mechanisms are still unclear.…”

mentioning

confidence: 99%

High‐Output Triboelectric Nanogenerator Based on Dual Inductive and Resonance Effects‐Controlled Highly Transparent Polyimide for Self‐Powered Sensor Network Systems

Jung

Advanced Energy Materials

et al. 2019

Internet of things (IoT), has triggered considerable interest in triboelectric nanogenerators (TENGs) as renewable and sustainable power sources, [1][2][3][4] owing to their high output power, [5,6] cost-effectiveness, [7] and high energy conversion efficiency. [8][9][10] The wide-availability and high functionality of TENGs offers itself to several practical applications. [11][12][13][14] Crucial to the successful implementation of TENGs in practical applications is to generate sufficient output power, usually stored in a capacitor or a battery, to operate the devices. [15][16][17][18] Strategies to enhance the output performance of TENGs are generally based on increasing of the transferred charge density between two contacted surfaces, as the electric potential is critically dependent on it. [19][20][21][22] Although the principle of contact-electrification has long been studied, [23][24][25] but whose mechanisms are still unclear. Recently, surface-states and electron cloud/potential models have been employed to explain the contact electrification mechanism. However, these models are limited to metal-semiconductors and metal-insulators, i.e., they may be not currently compatible with metal-polymers. [26,27] Other strategies have relied on the choice of materials in the triboelectric series with electronic and structural modifications, [28] such as a large work-function difference, [29,30] high porosity, [31,32] large dielectric constant, [33][34][35] and large surface roughness. [36][37][38] The maximum charge density of these TENGs in practical environments, however, requires additional processes, such as charges injection and poling process under high electric field. [35,[39][40][41] In particular, the injection process was quite efficient in increasing the charge density because it was considered to be limited by air breakdown. [38] Actually, the dielectric strengths of the polymers are larger than that of the air. The charge density was reached to 260 and 283 µC m −2 in TENGs with single-layered film and multilayered film, respectively. [40,41] Recently, several modifications to amplify the current flowing through the external circuit have been successfully demonstrated. [6,20,42] Metal-dielectric-metal structures or metal-metal contacts have been introduced, proven to increase the charge density of the TENG by several times.Since TENGs are driven by vibrations in the environment and human kinetics, the frequencies of the mechanical forces High-output triboelectric nanogenerators (TENGs) are demonstrated based on polyimide (PI)-based polymers by introducing functionalities (e.g., electronwithdrawing and electron-donating groups) into the backbone. The TENG based on 6FDA-APS PI, possessing the most negative electrostatic potential and the low-lying lowest unoccupied molecular orbital level, produces the highest effective charge density of about 860 µC m −2 in practical working conditions with the ion injection process. This may be ascribed to the excellent charge-retention characteristics as well as the enh...