The rapid development of portable/wearable electronics proposes new demands for energy storage devices, which are flexibility, smart functions and long-time outdoor operation. Supercapacitors (SCs) ...show great potential in portable/wearable applications, and the recently developed flexible, smart and self-sustainable supercapacitors greatly meet the above demands. In these supercapacitors, conductive polymers (CPs) are widely applied due to their high flexibility, conductivity, pseudo-capacitance, smart characteristics and moderate preparation conditions. Herein, we'd like to introduce the CP-based flexible, smart and self-sustainable supercapacitors for portable/wearable electronics. This review first summarizes the flexible SCs based on CPs and their composites with carbon materials and metal compounds. The smart supercapacitors,
i.e.
, electrochromic, electrochemical actuated, stretchable, self-healing and stimuli-sensitive ones, are then presented. The self-sustainable SCs which integrate SC units with energy-harvesting units in one compact configuration are also introduced. The last section highlights some current challenges and future perspectives of this thriving field.
Progress of utilizing conductive polymers and their composites to prepare flexible, smart and self-sustainable supercapacitors for portable/wearable electronics is reviewed.
A disposable and ecofriendly starch paper was used to fabricate a triboelectric nanogenerator (TENG) for the sensing of human perspiration. Using cost-effective and commercially accessible materials, ...the starch paper-based TENG (S-TENG) can be achieved through a rapid and simple fabrication method. The output performance varies with the absorbed water content, which can be utilized for human perspiration sensing. The starch structure can be broken down in water within 4 min. The proposed S-TENGs have a considerable potential in the field of green wearable electronics.
Flexible electronics based on the paper have attracted significant attention. A paper-based triboelectric nanogenerator (TENG) consisting of commercial and low-cost materials, e.g., printer paper, ...polytetrafluoroethylene tape, and conductive ink, was proposed in this study. This TENG unit can directly illuminate 24 blue commercial LEDs. Furthermore, compound paper-based TENGs were developed and a considerable enhancement of the electrical output performance was thereby realized. These compound TENGs can also serve as a height sensor.
Energy and the environment are two of the main issues facing the world today. As a consequence abundant renewable green energy sources such as wave energy, have become hot topics. Here, a ...multiple‐frequency triboelectric nanogenerator based on the water balloon (WB‐TENG) is proposed for harvesting water wave energy in any direction. Owing to the high elasticity of the water balloon, the WB‐TENG can realize a multiple‐frequency response to low‐frequency external mechanical simulations to generate high‐frequency electrical output. In addition, the water balloon can achieve self‐support without any additional supporting structure because of its tension, to make WB‐TENG still produce electrical output under slight vibration, which can also bring high energy conversion efficiency. Moreover, the fabricated WB‐TENG generates a maximum instantaneous short‐circuit current and an open‐circuit voltage of 147 µA and 1221 V, respectively. Most noteworthy, under the same conditions, the total transferred charge of WB‐TENG is 28 times than that of traditional TENG based on double plate structure during one working cycle. Therefore, this design can provide an effective way to promote the development of TENGs in blue energy.
Here, a multiple‐frequency triboelectric nanogenerator based on the water balloon (WB‐TENG) is proposed for harvesting water wave energy in any direction. This device enables a multiple‐frequency response to low‐frequency external mechanical simulations to generate high‐frequency electrical output. The WB‐TENG generates maximum instantaneous short‐circuit current (Isc) and an open‐circuit voltage (Voc) of 147 µA and 1221 V, respectively.
Triboelectric nanogenerators (TENG), which convert mechanical energy (such as ocean waves) from the surrounding environment into electrical energy, have been identified as a green energy alternative ...for addressing the environmental issues resulting from the use of traditional energy resources. In this experimental design, we propose rolling spherical triboelectric nanogenerators (RS-TENG) for collecting energy from low-frequency ocean wave action. Copper and aluminum were used to create a spherical frame which functions as the electrode. In addition, different sizes of spherical dielectric (SD1, SD2, SD3, and SD4) were developed in order to compare the dielectric effect on output performance. This design places several electrodes on each side of the spherical structure such that the dielectric layers are able to move with the slightest oscillation and generate electrical energy. The performance of the RS-TENG was experimentally investigated, with the results indicating that the spherical dielectrics significantly impact energy harvesting performance. On the other hand, the triboelectric materials (i.e., copper and aluminum) play a less important role. The copper RS-TENG with the largest spherical dielectrics is the most efficient structure, with a maximum output of 12.75 V in open-circuit and a peak power of approximately 455 nW.
Azo dyes are the most widely used synthetic dyes in the printing and dyeing process. However, the discharge of untreated azo dyes poses a potential threat to aqueous ecosystems and human health. ...Herein, we fabricated a novel heterogeneous catalyst: activated-carbon-fiber-supported ferric alginate (FeAlg-ACF). Together with peroxymonosulfate (PMS) and visible light, this photocatalytic oxidation system was used to remove an azo dye—azophloxine. The results indicated that the proposed catalytic oxidation system can remove 100% of azophloxine within 24 min, while under the same system, the removal rates were only 92% and 84% when ferric alginate was replaced with ferric citrate and ferric oxalate, respectively, which showed the superiority of FeAlg-ACF. The degradation of azophloxine is achieved by the active radicals (SO4•− and •OH) released from PMS and persistent free radicals from activated carbon fiber. Moreover, due to ferric alginate’s highly intrinsic photosensitivity, visible radiation can further enhance the ligand-to-metal charge transfer (LMCT) processes. After 24 min of treatment, the total organic carbon of the azophloxine solution (50 μmol/L) decreased from 1.82 mg/L to 79.3 μg/L and the concentration of nitrate ions increased from 0.3 mg/L to 8.6 mg/L. That is, up to 93.5% of azophloxine molecules were completely degraded into inorganic compounds. Consequently, potential secondary contamination by intermediate organic products during catalytic degradation was prohibited. The azophloxine removal ratio was kept almost constant after seven cycles, indicating the recyclability and longevity of this system. Furthermore, the azophloxine removal was still promising at high concentrations of Cl−, HCO3−, and CO32−. Therefore, our proposed system is potentially effective at removing dye pollutants from seawater. It provides a feasible method for the development of efficient and environmentally friendly PMS activation technology combined with FeAlg-ACF, which has significant academic and application value.
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•Facial mask was firstly introduced to fabricate TENG, and possessed a strong ability to lose electrons during triboelectrification.•The FM-TENGs are completely prepared using cost ...efficient, commercially available household material, i.e. facial mask, PTFE film, aluminum tape.•The approximate values of open circuit voltage (Voc) can extend to 1037 V, the short-circuit current (Isc) can reach 37.48 μA, and the output power density can arrive at 727.78 μW/cm2.•The FM-TENG with a size of 3 cm × 3 cm was capable of directly lighting 150 high-power LEDs , an electronic calculator.•We foresee that an electronic skin system for touch sensing is expected as a great progress in reusing of common commercial materials.
With the development of artificial intelligence, research on the touch sensor has become a popular object. Here, we proposed a novel triboelectric nanogenerator based on the facial mask (FM-TENG) for harvesting mechanical energy, and it can also serve as a flexible touch sensor. A series of triboelectricity experiments show that facial mask has a strong ability to lose electrons. The FM-TENG can generate good performance, as evidenced by peak short-circuit current (Isc), open-circuit voltage (Voc), and power density values of 37.48 μA, 1037 V, and 727.78 μW/cm2, respectively. Commercial electronics, including an electronic calculator, and a total of 150 high-power light-emitting diodes (LEDs), were easily driven by the FM-TENG. Additionally, the facial mask is harmless material for human skin, and thus it is smeared on the skin to form a self-powered flexible touch sensor to distinguish the different states of fingers. As a new-efficient method for developing low-cost bio-mechanical energy harvesters and self-powered touch sensors, we also foresee that an alert touch sensing system represents tremendous progress in the smart wireless sensor networks.
Recent years, triboelectric nanogenerators (TENGs) have attracted increased attention from researchers worldwide. Owing to their conductivity and triboelectric characteristics, metal materials can be ...made as both triboelectric materials and conductive electrodes. However, the surface of typical metals (such as copper, aluminum, and iron) is likely to be corroded when the sweat generated by human-body movement drops on the surface of TENGs, as this corrosion is detrimental to the output performance of TENGs. In this work, we proposed a novel corrosion-resistant copper-nickel based TENG (CN-TENG). Copper-nickel alloy conductive tape and polytetrafluoroethylene (PTFE) tape played the role of the triboelectric materials, and polymethyl methacrylate (PMMA) was utilized as the supporting part. The conductive copper-nickel alloy tape also served as a conductive electrode. The open-circuit voltage (V
) and short-circuit current (I
) can arrive at 196.8 V and 6 μA, respectively. Furthermore, peak power density values of 45 μW/cm
were realized for the CN-TENG. A series of experiments confirmed its corrosion-resistant property. The approximate value of V
for the fabricated TENG integrated into the shoe reached 1500 V, which is capable of driving at least 172 high-power LEDs in series. The results of this research provide a workable method for supporting corrosion-resistant self-powered wearable electronics.
Recently, the vigorous development of flexible piezoelectric nanogenerator and triboelectric nanogenerator (TENG) has attracted more and more attention from researchers. In this paper, we reported a ...novel double-piezoelectric-layer-enhanced TENG (DP-TENG) to harvest mechanical energy. The DP-TENG can also serve as a self-powered deformation sensor to detect bending motion. To realize the large-scale production and wide application, a sample fabrication method was developed to prepare DP-TENG using low-cost commercial materials, such as PTFE film, Nylon film, and PVDF film. Besides, the DP-TENG can be used to monitor the flow of hot air to serve as a self-powered temperature sensor. This research has provided an effective structural design about piezoelectric-enhanced TENG for harvesting environment mechanical energy, which has bright potentials in the field of self-power deformation system and airflow temperature monitoring.
Triboelectric nanogenerators (TENGs) have been investigated as a promising methodology to harvest mechanical energy into electricity. The matching impedance and the transient property of TENGs are ...important for their practical application. In this work, we proposed novel paper-based methodology for investigation of TENGs. First, we propose a novel method for triggering transience of pencil-on-paper (POP)-TENGs using household microwave oven and commercial graphite pencil. Moreover, a fast, simple and cost-effective approach for measuring the matching impedance of TENG based on paper variable resistor is proposed. The results of this work are beneficial for simple, fast and cost-effective functionalization of TENGs.
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