Polymers

Research

13 pages, 5842 KiB

Open AccessArticle

Use of Hydrogel Electrolyte in Zn-MnO₂ Rechargeable Batteries: Characterization of Safety, Performance, and Cu²⁺ Ion Diffusion

by Jungsang Cho, Damon E. Turney, Gautam Ganapati Yadav, Michael Nyce, Bryan R. Wygant, Timothy N. Lambert and Sanjoy Banerjee

Polymers 2024, 16(5), 658; https://doi.org/10.3390/polym16050658 - 28 Feb 2024

Viewed by 775

Abstract

Achieving commercially acceptable Zn-MnO₂ rechargeable batteries depends on the reversibility of active zinc and manganese materials, and avoiding side reactions during the second electron reaction of MnO₂. Typically, liquid electrolytes such as potassium hydroxide (KOH) are used for Zn-MnO₂ [...] Read more.

Achieving commercially acceptable Zn-MnO₂ rechargeable batteries depends on the reversibility of active zinc and manganese materials, and avoiding side reactions during the second electron reaction of MnO₂. Typically, liquid electrolytes such as potassium hydroxide (KOH) are used for Zn-MnO₂ rechargeable batteries. However, it is known that using liquid electrolytes causes the formation of electrochemically inactive materials, such as precipitation Mn₃O₄ or ZnMn₂O₄ resulting from the uncontrollable reaction of Mn³⁺ dissolved species with zincate ions. In this paper, hydrogel electrolytes are tested for MnO₂ electrodes undergoing two-electron cycling. Improved cell safety is achieved because the hydrogel electrolyte is non-spillable, according to standards from the US Department of Transportation (DOT). The cycling of “half cells” with advanced-formulation MnO₂ cathodes paired with commercial NiOOH electrodes is tested with hydrogel and a normal electrolyte, to detect changes to the zincate crossover and reaction from anode to cathode. These half cells achieved ≥700 cycles with 99% coulombic efficiency and 63% energy efficiency at C/3 rates based on the second electron capacity of MnO₂. Other cycling tests with “full cells” of Zn anodes with the same MnO₂ cathodes achieved ~300 cycles until reaching 50% capacity fade, a comparable performance to cells using liquid electrolyte. Electrodes dissected after cycling showed that the liquid electrolyte allowed Cu ions to migrate more than the hydrogel electrolyte. However, measurements of the Cu diffusion coefficient showed no difference between liquid and gel electrolytes; thus, it was hypothesized that the gel electrolytes reduced the occurrence of Cu short circuits by either (a) reducing electrode physical contact to the separator or (b) reducing electro-convective electrolyte transport that may be as important as diffusive transport. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Graphical abstract

13 pages, 3269 KiB

Open AccessArticle

Charge Carrier Mobility in Poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine Composites with Electron Acceptor Molecules

by Alexey R. Tameev, Alexey E. Aleksandrov, Ildar R. Sayarov, Sergey I. Pozin, Dmitry A. Lypenko, Artem V. Dmitriev, Natalia V. Nekrasova, Andrey Yu. Chernyadyev and Aslan Yu. Tsivadze

Polymers 2024, 16(5), 570; https://doi.org/10.3390/polym16050570 - 20 Feb 2024

Viewed by 641

Abstract

Polymer composites based on poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine (poly-TPD) with PCBM and copper(II) pyropheophorbide derivative (Cu-PP) were developed. In thin films of the poly-TPD and Cu-PP composites, the charge carrier mobility was investigated for the first time. In the ternary poly-TPD:PCBM:Cu-PP composite, the electron and hole [...] Read more.

Polymer composites based on poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine (poly-TPD) with PCBM and copper(II) pyropheophorbide derivative (Cu-PP) were developed. In thin films of the poly-TPD and Cu-PP composites, the charge carrier mobility was investigated for the first time. In the ternary poly-TPD:PCBM:Cu-PP composite, the electron and hole mobilities are the most balanced compared to binary composites and the photoconductivity is enhanced due to the sensitization by Cu-PP in blue and red spectral ranges. The new composites are promising for use in the development of photodetectors. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

11 pages, 3323 KiB

Open AccessArticle

A Novel and Green Method for Preparing Highly Conductive PEDOT:PSS Films for Thermoelectric Energy Harvesting

by Fuwei Liu, Luyao Gao, Jiajia Duan, Fuqun Li, Jingxian Li, Hongbing Ge, Zhiwei Cai, Huiying Li, Mengke Wang, Ruotong Lv and Minrui Li

Polymers 2024, 16(2), 266; https://doi.org/10.3390/polym16020266 - 18 Jan 2024

Viewed by 948

Abstract

As a π-conjugated conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is recognized as a promising environmentally friendly thermoelectric material. However, its low conductivity has limited applications in the thermoelectric field. Although thermoelectric efficiency can be significantly enhanced through post-treatment doping, these processes often involve environmentally [...] Read more.

As a π-conjugated conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is recognized as a promising environmentally friendly thermoelectric material. However, its low conductivity has limited applications in the thermoelectric field. Although thermoelectric efficiency can be significantly enhanced through post-treatment doping, these processes often involve environmentally harmful organic solvents or reagents. In this study, a novel and environmentally benign method using purified water (including room temperature water and subsequent warm water) to treat PEDOT:PSS film has been developed, resulting in improved thermoelectric performance. The morphology data, chemical composition, molecular structure, and thermoelectric performance of the films before and after treatment were characterized and analyzed using a scanning electron microscope (SEM), Raman spectrum, XRD pattern, X-ray photoelectron spectroscopy (XPS), and a thin film thermoelectric measurement system. The results demonstrate that the water treatment effectively removes nonconductive PSS from PEDOT:PSS composites, significantly enhancing their conductivity. Treated films exhibit improved thermoelectric properties, particularly those treated only 15 times with room temperature water, achieving a high electrical conductivity of 62.91 S/cm, a Seebeck coefficient of 14.53 μV K⁻¹, and an optimal power factor of 1.3282 µW·m^–1·K^–2. In addition, the subsequent warm water treatment can further enhance the thermoelectric properties of the film sample. The underlying mechanism of these improvements is also discussed. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

19 pages, 5941 KiB

Open AccessArticle

Self-Rotation of Electrothermally Responsive Liquid Crystal Elastomer-Based Turntable in Steady-State Circuits

by Zongsong Yuan, Junxiu Liu, Guqian Qian, Yuntong Dai and Kai Li

Polymers 2023, 15(23), 4598; https://doi.org/10.3390/polym15234598 - 01 Dec 2023

Viewed by 765

Abstract

Self-excited motions, characterized by their ability to harness energy from a consistent environment and self-regulate, exhibit significant potential in micro-devices, autonomous robotics, sensor technology, and energy generation. This study introduces an innovative turntable system based on an electrothermally responsive liquid crystal elastomer (LCE). [...] Read more.

Self-excited motions, characterized by their ability to harness energy from a consistent environment and self-regulate, exhibit significant potential in micro-devices, autonomous robotics, sensor technology, and energy generation. This study introduces an innovative turntable system based on an electrothermally responsive liquid crystal elastomer (LCE). This system facilitates self-rotation within a steady-state circuit. Employing an electrothermal LCE model, we have modeled and numerically analyzed the nonlinear dynamics of an LCE-rope within steady-state circuits, utilizing the four-order Runge–Kutta method for calculations. The numerical results reveal the emergence of two distinct motion patterns in the turntable system under steady-state conditions: a self-rotation pattern and a static pattern. The self-rotation is initiated when the system’s absorbed energy surpasses the energy lost due to damping effects. Furthermore, this paper delves into the critical conditions necessary for initiating self-rotation and examines the influence of various key dimensionless parameters on the system’s rotation amplitude and frequency. These parameters include gravitational acceleration, the initial position of the mass ball, elastic stiffness of the LCE and spring, limiting temperature, heating zone angle, thermal shrinkage coefficient, and damping factor. Our computational findings establish that these parameters exert a modulatory impact on the rotation amplitude and period. This research enhances the understanding of self-excited motions and offers promising avenues for applications in energy harvesting, monitoring, soft robotics, medical devices, and micro- and nano-devices. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

14 pages, 2471 KiB

Open AccessArticle

Flexible Actuators Based on Conductive Polymer Ionogels and Their Electromechanical Modeling

by Jiawei Xu, Hongwei Hu, Shengtao Zhang, Guanggui Cheng and Jianning Ding

Polymers 2023, 15(23), 4482; https://doi.org/10.3390/polym15234482 - 22 Nov 2023

Viewed by 895

Abstract

High-performance flexible actuators, integral components of soft robotics, hold promise for advancing applications in safe human–robot interactions, healthcare, and various other fields. Notable among these actuators are flexible electrochemical systems, recognized for their merits in low-voltage manipulation, rapid response speed, and cost-effectiveness. However, [...] Read more.

High-performance flexible actuators, integral components of soft robotics, hold promise for advancing applications in safe human–robot interactions, healthcare, and various other fields. Notable among these actuators are flexible electrochemical systems, recognized for their merits in low-voltage manipulation, rapid response speed, and cost-effectiveness. However, the optimization of output strain, response speed, and stability presents a significant challenge in this domain. Despite the application of diverse electrochemically active materials to enhance actuation performance, a critical need persists for corresponding electrical-mechanical models to comprehensively grasp actuation mechanisms. In this study, we introduce a novel electrochemical actuator that utilizes conductive polymer ionogel as active electrodes. This ionogel exhibits exceptional properties, including high conductivity, flexibility, and electrochemical activity. Our electrochemical actuators exhibit noteworthy bending strain capabilities and rapid response rates, achieving frequencies up to 10 Hz at a modest voltage of 1 V. An analytical model integrating ion migration and dynamic processes has been established to elucidate actuator behavior. Simulation results highlight that electrodes characterized by low resistance and high capacitance are optimal for simultaneous enhancement of bending strain and blocking force. However, the augmentation of Young’s modulus, while increasing blocking force, compromises bending strain. Furthermore, a larger aspect ratio proves beneficial for unidirectional stress output, leading to increased bending strain, while actuator blocking force diminishes with greater length. These findings underscore the intricate interplay between material properties and dimensions in optimizing the performance of flexible electrochemical actuators. This work provides important practical and theoretical guidance for the manufacture of high-performance flexible actuators and the search for new smart materials. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

14 pages, 2195 KiB

Open AccessArticle

Investigating the Aging Behavior of High-Density Polyethylene and Polyketone in a Liquid Organic Hydrogen Carrier

by Jyothsna Surisetty, Mohammadhossein Sharifian, Thomas Lucyshyn and Clemens Holzer

Polymers 2023, 15(22), 4410; https://doi.org/10.3390/polym15224410 - 15 Nov 2023

Viewed by 1024

Abstract

Hydrogen is recognized as a significant potential energy source and energy carrier for the future. On the one hand, storing hydrogen is a challenging task due to its low volumetric density, on the other hand, a particular type of hydrogen in the form [...] Read more.

Hydrogen is recognized as a significant potential energy source and energy carrier for the future. On the one hand, storing hydrogen is a challenging task due to its low volumetric density, on the other hand, a particular type of hydrogen in the form of a liquid can be used to store large quantities of hydrogen at ambient conditions in thermoplastic tanks. But storing hydrogen in this form for a long time in polymer tanks affects the physical and chemical properties of the liner. In the current automotive industry, high-density polyethylene (HDPE) has already been used in existing fuel tank applications. However long-term exposure to fuels leads to the permeation of hydrocarbons into the polymers, resulting in a loss of mechanical properties and reducing the efficiency of fuel cells (FC) in automotive applications. Additionally, facing material shortages and a limited supply of resin leads to an increase in the cost of the material. Therefore, an alternative material is being searched for, especially for hydrogen fuel tank applications. In this study, two semi-crystalline thermoplastics, HDPE and polyketone (POK), were compared, which were exposed to a selected liquid organic hydrogen carrier (LOHC) at 25 °C and 60 °C for up to 500 h in an enclosed chamber, to measure their fuel up-take. A short analysis was carried out using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and mechanical testing to understand the influence of the LOHC on the polymer over time. Fuel sorption and tensile properties showed a plasticizing effect on HDPE. The material degradation was more pronounced for the aged samples of HDPE in comparison to POK. As expected, thermal aging was increased at 60 °C. The fuel absorption of POK was lower compared to HDPE. A slight increase in crystallinity was observed in POK due to the aging process that led to changes in mechanical properties. Both HDPE and POK samples did not show any chemical changes during the aging process in the oven at 25 °C and 60 °C. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

16 pages, 4242 KiB

Open AccessArticle

Effects of Nd₂O₃ Nanoparticles on the Structural Characteristics and Dielectric Properties of PVA Polymeric Films

by Khulaif Alshammari, Thamer Alashgai, Alhulw H. Alshammari, Mostufa M. Abdelhamied, Satam Alotibi and Ali Atta

Polymers 2023, 15(20), 4084; https://doi.org/10.3390/polym15204084 - 14 Oct 2023

Cited by 1 | Viewed by 961

Abstract

Polyvinyl alcohol (PVA) and Neodymium (III) oxide (Nd₂O₃) were combined to synthesized flexible innovative PVA/Nd₂O₃ polymer composite samples utilizing a solution casting approach for use in dielectric devices. The XRD, FTIR, and SEM methods are all [...] Read more.

Polyvinyl alcohol (PVA) and Neodymium (III) oxide (Nd₂O₃) were combined to synthesized flexible innovative PVA/Nd₂O₃ polymer composite samples utilizing a solution casting approach for use in dielectric devices. The XRD, FTIR, and SEM methods are all investigated to characterize the composite films. In a frequency of 50 Hz to 5 MHz, the effects of additive Nd₂O₃ on the dielectric behavior of PVA were recorded. The PVA/Nd₂O₃ composite films were successfully fabricated, as shown by XRD and infrared spectroscopy. The scanning microscopy pictures showed that the Nd₂O₃ was loaded and distributed uniformly throughout the PVA. After the incorporation of Nd₂O₃, the composite PVA/Nd₂O₃ has a conductivity of 6.82

\times

10⁻⁹ S·cm⁻¹, while the PVA has a conductivity of 0.82

\times

10⁻⁹ S·cm⁻¹. Another improvement is the decrease in the relaxation time from 14.2

\times

10⁻⁵ s for PVA to 6.35

\times

10⁻⁵ s for PVA/Nd₂O₃, and an increase in the dielectric constant of 0.237 for PVA to 0.484 at a frequency of 100 Hz. The results showed that the composite samples have considerable changes as flexible films in different applications, including batteries and electronic circuits. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

14 pages, 3262 KiB

Open AccessArticle

Electrochemical Comparison of 2D-Flexible Solid-State Supercapacitors Based on a Matrix of PVA/H₃PO₄

by Bianca K. Muñoz, Andrés González-Banciella, Daniel Ureña, María Sánchez and Alejandro Ureña

Polymers 2023, 15(20), 4036; https://doi.org/10.3390/polym15204036 - 10 Oct 2023

Cited by 2 | Viewed by 839

Abstract

Different modifications of woven carbon fiber (WCF) based on carbon aerogel (CAG), copper oxide nanoparticles (CuO-NPs), and lignin (LIG) has been tested and used to study their effect on the fabrication and performance of a flexible supercapacitor. New symmetric flexible supercapacitors (SFSCs) were [...] Read more.

Different modifications of woven carbon fiber (WCF) based on carbon aerogel (CAG), copper oxide nanoparticles (CuO-NPs), and lignin (LIG) has been tested and used to study their effect on the fabrication and performance of a flexible supercapacitor. New symmetric flexible supercapacitors (SFSCs) were fabricated using different separators. According to the electrochemical results, the device fabricated using CAG and woven glass fiber (WGF) in a sandwich type configuration CAG/WGF/CAG embedded in H₃PO₄/PVA exhibited the best performance (1.4 F/g, 0.961 W/kg, 0.161 Wh/kg). A proof of concept based on a LED powered on and a bending test was done, and the capacitor demonstrated excellent electrochemical values even during and after bending. The new device was able to recover 96.12% of its capacitance when returned to its original unbent position. The manufacturing process was critical, as the fibers or layers must be completely embedded in the gel electrolyte to function effectively. A double flexible supercapacitor connected in parallel was fabricated and it showed higher stability, in the same voltage window, yielding 311 mF/cm² of areal capacitance. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Graphical abstract

15 pages, 2235 KiB

Open AccessArticle

Silver Nanoparticle–PEDOT:PSS Composites as Water-Processable Anodes: Correlation between the Synthetic Parameters and the Optical/Morphological Properties

by Stefania Zappia, Marina Alloisio, Julio Cesar Valdivia, Eduardo Arias, Ivana Moggio, Guido Scavia and Silvia Destri

Polymers 2023, 15(18), 3675; https://doi.org/10.3390/polym15183675 - 06 Sep 2023

Cited by 1 | Viewed by 916

Abstract

The morphological, spectroscopic and rheological properties of silver nanoparticles (AgNPs) synthesized in situ within commercial PEDOT:PSS formulations, labeled PP@NPs, were systematically investigated by varying different synthetic parameters (NaBH₄/AgNO₃ molar ratio, PEDOT:PSS formulation and silver and PEDOT:PSS concentration in the reaction [...] Read more.

The morphological, spectroscopic and rheological properties of silver nanoparticles (AgNPs) synthesized in situ within commercial PEDOT:PSS formulations, labeled PP@NPs, were systematically investigated by varying different synthetic parameters (NaBH₄/AgNO₃ molar ratio, PEDOT:PSS formulation and silver and PEDOT:PSS concentration in the reaction medium), revealing that only the reagent ratio affected the properties of the resulting nanoparticles. Combining the results obtained from the field-emission scanning electron microscopy analysis and UV-Vis characterization, it could be assumed that PP@NPs’ stabilization occurs by means of PSS chains, preferably outside of the PEDOT:PSS domains with low silver content. Conversely, with high silver content, the particles also formed in PEDOT-rich domains with the consequent perturbation of the polaron absorption features of the conjugated polymer. Atomic force microscopy was used to characterize the films deposited on glass from the particle-containing PEDOT:PSS suspensions. The film with an optimized morphology, obtained from the suspension sample characterized by the lowest silver and NaBH₄ content, was used to fabricate a very initial prototype of a water-processable anode in a solar cell prepared with an active layer constituted by the benchmark blend poly(3-hexylthiophene) and [6,6]-Phenyl C61 butyric acid methyl ester (PC₆₀BM) and a low-temperature, not-evaporated cathode (Field’s metal). Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

19 pages, 4694 KiB

Open AccessArticle

Fabrication of High-Performance Natural Rubber Composites with Enhanced Filler–Rubber Interactions by Stearic Acid-Modified Diatomaceous Earth and Carbon Nanotubes for Mechanical and Energy Harvesting Applications

by Md Najib Alam, Vineet Kumar, Han-Saem Jung and Sang-Shin Park

Polymers 2023, 15(17), 3612; https://doi.org/10.3390/polym15173612 - 31 Aug 2023

Cited by 3 | Viewed by 1612

Abstract

Mechanical robustness and high energy efficiency of composite materials are immensely important in modern stretchable, self-powered electronic devices. However, the availability of these materials and their toxicities are challenging factors. This paper presents the mechanical and energy-harvesting performances of low-cost natural rubber composites [...] Read more.

Mechanical robustness and high energy efficiency of composite materials are immensely important in modern stretchable, self-powered electronic devices. However, the availability of these materials and their toxicities are challenging factors. This paper presents the mechanical and energy-harvesting performances of low-cost natural rubber composites made of stearic acid-modified diatomaceous earth (mDE) and carbon nanotubes (CNTs). The obtained mechanical properties were significantly better than those of unfilled rubber. Compared to pristine diatomaceous earth, mDE has higher reinforcing efficiencies in terms of mechanical properties because of the effective chemical surface modification by stearic acid and enhanced filler–rubber interactions. The addition of a small amount of CNT as a component in the hybrid filler systems not only improves the mechanical properties but also improves the electrical properties of the rubber composites and has electromechanical sensitivity. For example, the fracture toughness of unfilled rubber (9.74 MJ/m³) can be enhanced by approximately 484% in a composite (56.86 MJ/m³) with 40 phr (per hundred grams of rubber) hybrid filler, whereas the composite showed electrical conductivity. At a similar mechanical load, the energy-harvesting efficiency of the composite containing 57 phr mDE and 3 phr CNT hybrid filler was nearly double that of the only 3 phr CNT-containing composite. The higher energy-harvesting efficiency of the mDE-filled conductive composites may be due to their increased dielectric behaviour. Because of their bio-based materials, rubber composites made by mDE can be considered eco-friendly composites for mechanical and energy harvesting applications and suitable electronic health monitoring devices. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Graphical abstract

14 pages, 5845 KiB

Open AccessArticle

Isinglass as an Alternative Biopolymer Membrane for Green Electrochemical Devices: Initial Studies of Application in Electric Double-Layer Capacitors and Future Perspectives

by Paweł Jeżowski and Przemysław Łukasz Kowalczewski

Polymers 2023, 15(17), 3557; https://doi.org/10.3390/polym15173557 - 26 Aug 2023

Cited by 2 | Viewed by 799

Abstract

The presented work discusses in detail the preparation of a cheap and environmentally friendly biopolymer membrane from isinglass and its physicochemical characterisation. One of the possible uses of the obtained membrane can be as a separator between electrodes in novel green electrochemical devices [...] Read more.

The presented work discusses in detail the preparation of a cheap and environmentally friendly biopolymer membrane from isinglass and its physicochemical characterisation. One of the possible uses of the obtained membrane can be as a separator between electrodes in novel green electrochemical devices as in, for example, electric double-layer capacitors (EDLCs). The functionality of the mentioned membrane was investigated and demonstrated by classical electrochemical techniques such as cyclic voltammetry (CV), galvanostatic cycling with potential limitation (GCPL), and electrochemical impedance spectroscopy (EIS). The obtained values of capacitance (approximately 30 F g⁻¹) and resistance (approximately. 3 Ohms), as well as the longevity of the EDLC during electrochemical floating at a voltage of 1.6 V (more than 200 h), show that the proposed biopolymer membrane could be an interesting alternative among the more environmentally friendly energy storage devices, while additionally it could be more economically justified. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

8 pages, 2380 KiB

Open AccessCommunication

Redox-Active Ferrocene Polymer for Electrode-Active Materials: Step-by-Step Synthesis on Gold Electrode Using Automatic Sequential Polymerization Equipment

by Hao-Xuan Guo, Yuriko Takemura, Daisuke Tange, Junichi Kurata and Hiroyuki Aota

Polymers 2023, 15(17), 3517; https://doi.org/10.3390/polym15173517 - 23 Aug 2023

Viewed by 843

Abstract

Redox-active polymers have garnered significant attention as promising materials for redox capacitors, which are energy-storage devices that rely on reversible redox reactions to store and deliver electrical energy. Our focus was on optimizing the electrochemical performance in the design and synthesis of redox-active [...] Read more.

Redox-active polymers have garnered significant attention as promising materials for redox capacitors, which are energy-storage devices that rely on reversible redox reactions to store and deliver electrical energy. Our focus was on optimizing the electrochemical performance in the design and synthesis of redox-active polymer electrodes. In this study, a redox-active polymer was prepared through step-by-step synthesis on a gold electrode. To achieve this, we designed an automatic sequential polymerization equipment that minimizes human intervention and enables a stepwise polymerization reaction. The electrochemical properties of the polymer gold electrodes were investigated. The degree of polymerization of the polymer grown on the gold electrode can be controlled by adjusting the cycle of the sequential operation. As the number of cycles increases, the amount of accumulated charge increases proportionally, indicating the potential for enhanced electrochemical performance. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Figure 1

14 pages, 5566 KiB

Open AccessArticle

Nanocarbon Black and Molybdenum Disulfide Hybrid Filler System for the Enhancement of Fracture Toughness and Electromechanical Sensing Properties in the Silicone Rubber-Based Energy Harvester

by Md Najib Alam, Vineet Kumar, Taemin Jeong and Sang-Shin Park

Polymers 2023, 15(9), 2189; https://doi.org/10.3390/polym15092189 - 05 May 2023

Cited by 1 | Viewed by 1584

Abstract

Recently, hybrid fillers have been found to be more advantageous in energy-harvesting composites. This study investigated the mechanical and electromechanical performances of silicone rubber-based composites made from hybrid fillers containing conductive nanocarbon black (NCB) and molybdenum disulfide (MoS₂). A hybrid filler [...] Read more.

Recently, hybrid fillers have been found to be more advantageous in energy-harvesting composites. This study investigated the mechanical and electromechanical performances of silicone rubber-based composites made from hybrid fillers containing conductive nanocarbon black (NCB) and molybdenum disulfide (MoS₂). A hybrid filler system containing only 3 phr (per hundred grams of rubber) MoS₂ and 17 phr NCB provided higher fracture strain, better tensile strength, and excellent toughness values compared to the 20 phr NCB-only-filled and 5 phr MoS₂-only-filled rubber composites. The chemical cross-link densities suggest that NCB promoted the formation of cross-links, whereas MoS₂ slightly reduced the cross-link density. The higher mechanical properties in the hybrid filler systems suggest that the filler particles were more uniformly distributed, which was confirmed by the scanning electron microscope study. Uniformly distributed filler particles with moderate cross-link density in hybrid filler systems greatly improved the fracture strain and fracture toughness. For example, the hybrid filler with a 17:3 ratio of NCB to MoS₂ showed a 184% increment in fracture toughness, and a 93% increment in fracture strain, compared to the 20 phr NCB-only-filled composite. Regarding electromechanical sensing with 2 kPa of applied cyclic pressure, the hybrid filler (17:3 CB to MoS₂) performed significantly better (~100%) than the 20 phr NCB-only compound. This may have been due to the excellent distribution of conducting NCB networks and piezoelectric MoS₂ that caused symmetric charging–discharging in the toughened hybrid composite. Thus, hybrid composites with excellent fatigue resistance can find dynamic applications, such as in blood pressure measurement. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Polymeric Materials in Energy Conversion and Storage

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (13 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI