The Experts below are selected from a list of 3114 Experts worldwide ranked by ideXlab platform
Husam N Alshareef - One of the best experts on this subject based on the ideXlab platform.
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micro Pseudocapacitors with electroactive polymer electrodes toward ac line filtering applications
ACS Applied Materials & Interfaces, 2016Co-Authors: Narendra Kurra, Chuan Xia, Qiu Jiang, Ahad Syed, Husam N AlshareefAbstract:In this study, we investigate the frequency response of micro-Pseudocapacitors based on conducting polymer electrodes such as poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole, and polyaniline. It is shown that by proper choice of polymeric material and device structure, miniaturized micro-Pseudocapacitors can match the frequency response of commercial bulky electrolytic capacitors. Specifically, we show that PEDOT-based micro-Pseudocapacitors exhibit phase angle of −80.5° at 120 Hz, which is comparable to commercial bulky electrolytic capacitors, but with an order of magnitude higher capacitance density (3 FV/cm3). The tradeoff between the areal capacitance (CA) and frequency response in the two-dimensional architecture (CA = 0.15 mF/cm2, phase angle of −80.5° at 120 Hz) is improved by designing three-dimensional thin-film architecture (CA = 1.3 mF/cm2, phase angle of −60° at 120 Hz). Our work demonstrates that fast frequency response can be achieved using electroactive polymer electrodes.
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ternary chalcogenide micro Pseudocapacitors for on chip energy storage
Chemical Communications, 2015Co-Authors: Narendra Kurra, Chuan Xia, Mohamed N Hedhili, Husam N AlshareefAbstract:We report the successful fabrication of a micro-pseudocapacitor based on ternary nickel cobalt sulfide for the first time, with performance substantially exceeding that of previously reported micro-Pseudocapacitors based on binary sulfides. The CoNi2S4 micro-pseudocapacitor exhibits a maximum energy density of 18.7 mW h cm−3 at a power density of 1163 mW cm−3, and opens up an avenue for exploring a new family of ternary oxide/sulfide based micro-Pseudocapacitors.
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highly stable supercapacitors with conducting polymer core shell electrodes for energy storage applications
Advanced Energy Materials, 2015Co-Authors: Wei Chen, Mohamed N Hedhili, Xianbin Wang, Husam N AlshareefAbstract:Conducting polymers such as polyaniline (PAni) show a great potential as pseudocapacitor materials for electrochemical energy storage applications. Yet, the cycling instability of PAni resulting from structural alteration is a major hurdle to its commercial application. Here, the development of nanostructured PAni–RuO2 core–shell arrays as electrodes for highly stable Pseudocapacitors with excellent energy storage performance is reported. A thin layer of RuO2 grown by atomic layer deposition (ALD) on PAni nanofibers plays a crucial role in stabilizing the PAni Pseudocapacitors and improving their energy density. The Pseudocapacitors, which are based on optimized PAni–RuO2 core–shell nanostructured electrodes, exhibit very high specific capacitance (710 F g−1 at 5 mV s−1) and power density (42.2 kW kg−1) at an energy density of 10 Wh kg−1. Furthermore, they exhibit remarkable capacitance retention of ≈88% after 10 000 cycles at very high current density of 20 A g−1, superior to that of pristine PAni-based Pseudocapacitors. This prominently enhanced electrochemical stability successfully demonstrates the buffering effect of ALD coating on PAni, which provides a new approach for the preparation of metal-oxide/conducting polymer hybrid electrodes with excellent electrochemical performance.
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microfabricated Pseudocapacitors using ni oh 2 electrodes exhibit remarkable volumetric capacitance and energy density
Advanced Energy Materials, 2015Co-Authors: Narendra Kurra, Nuha A Alhebshi, Husam N AlshareefAbstract:Metal hydroxide based microfabricated Pseudocapacitors with impressive volumetric stack capacitance and energy density are demonstrated. A combination of top-down photolithographic process and bottom-up chemical synthesis is employed to fabricate the micro-Pseudocapacitors (μ-Pseudocapacitors). The resulting Ni(OH)2-based devices show several excellent characteristics including high-rate redox activity up to 500 V s–1 and an areal cell capacitance of 16 mF cm–2 corresponding to a volumetric stack capacitance of 325 F cm–3. This volumetric capacitance is two-fold higher than carbon and metal oxide based μ-supercapacitors with interdigitated electrode architecture. Furthermore, these μ-Pseudocapacitors show a maximum energy density of 21 mWh cm–3, which is superior to the Li-based thin film batteries. The heterogeneous growth of Ni(OH)2 over the Ni surface during the chemical bath deposition is found to be the key parameter in the formation of uniform monolithic Ni(OH)2 mesoporous nanosheets with vertical orientation, responsible for the remarkable properties of the fabricated devices. Additionally, functional tandem configurations of the μ-Pseudocapacitors are shown to be capable of powering a light-emitting diode.
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facile synthesis of polyaniline nanotubes using reactive oxide templates for high energy density Pseudocapacitors
Journal of Materials Chemistry, 2013Co-Authors: Wei Chen, R B Rakhi, Husam N AlshareefAbstract:A remarkable energy density of 84 W h kg(cell)−1 and a power density of 182 kW kg(cell)−1 have been achieved for full-cell Pseudocapacitors using conducting polymer nanotubes (polyaniline) as electrode materials and ionic liquid as electrolytes. The polyaniline nanotubes were synthesized by a one-step in situ chemical polymerization process utilizing MnO2 nanotubes as sacrificial templates. The polyaniline-nanotube Pseudocapacitors exhibit much better electrochemical performance than the polyaniline-nanofiber Pseudocapacitors in both acidic aqueous and ionic liquid electrolytes. Importantly, the incorporation of ionic liquid with polyaniline-nanotubes has drastically improved the energy storage capacity of the PAni-nanotube Pseudocapacitors by a factor of ∼5 times compared to that of the PAni-nanotube Pseudocapacitors in the acidic aqueous electrolyte. Furthermore, even after 10 000 cycles, the PAni-nanotube Pseudocapacitors in the ionic liquid electrolyte maintain sufficient high energy density and can light LEDs for several minutes, with only 30 s quick charge.
Yi Cui - One of the best experts on this subject based on the ideXlab platform.
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Symmetrical MnO2–Carbon Nanotube–Textile Nanostructures for Wearable Pseudocapacitors with High Mass Loading
ACS Nano, 2011Co-Authors: Wei Chen, Mauro Pasta, Husam N Alshareef, Yuan Yang, Nian Liu, Yan Yao, Xing Xie, Yi CuiAbstract:While MnO2 is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO2 electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO2 nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO2 on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm2, which leads to a high areal capacitance of 2.8 F/cm2 at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO2–CNT–textile was used as a positive electrode, reduced MnO2–CNT–textile as a negative electrode, and 0.5 M Na2SO4 in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storag...
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symmetrical mno2 carbon nanotube textile nanostructures for wearable Pseudocapacitors with high mass loading
ACS Nano, 2011Co-Authors: Wei Chen, Mauro Pasta, Husam N Alshareef, Yuan Yang, Nian Liu, Yan Yao, Xing Xie, Yi CuiAbstract:While MnO2 is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO2 electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO2 nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO2 on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm2, which leads to a high areal capacitance of 2.8 F/cm2 at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO2–CNT–textile was used as a positive electrode, reduced MnO2–CNT–textile as a negative electrode, and 0.5 M Na2SO4 in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storag...
Wei Chen - One of the best experts on this subject based on the ideXlab platform.
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highly stable supercapacitors with conducting polymer core shell electrodes for energy storage applications
Advanced Energy Materials, 2015Co-Authors: Wei Chen, Mohamed N Hedhili, Xianbin Wang, Husam N AlshareefAbstract:Conducting polymers such as polyaniline (PAni) show a great potential as pseudocapacitor materials for electrochemical energy storage applications. Yet, the cycling instability of PAni resulting from structural alteration is a major hurdle to its commercial application. Here, the development of nanostructured PAni–RuO2 core–shell arrays as electrodes for highly stable Pseudocapacitors with excellent energy storage performance is reported. A thin layer of RuO2 grown by atomic layer deposition (ALD) on PAni nanofibers plays a crucial role in stabilizing the PAni Pseudocapacitors and improving their energy density. The Pseudocapacitors, which are based on optimized PAni–RuO2 core–shell nanostructured electrodes, exhibit very high specific capacitance (710 F g−1 at 5 mV s−1) and power density (42.2 kW kg−1) at an energy density of 10 Wh kg−1. Furthermore, they exhibit remarkable capacitance retention of ≈88% after 10 000 cycles at very high current density of 20 A g−1, superior to that of pristine PAni-based Pseudocapacitors. This prominently enhanced electrochemical stability successfully demonstrates the buffering effect of ALD coating on PAni, which provides a new approach for the preparation of metal-oxide/conducting polymer hybrid electrodes with excellent electrochemical performance.
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facile synthesis of polyaniline nanotubes using reactive oxide templates for high energy density Pseudocapacitors
Journal of Materials Chemistry, 2013Co-Authors: Wei Chen, R B Rakhi, Husam N AlshareefAbstract:A remarkable energy density of 84 W h kg(cell)−1 and a power density of 182 kW kg(cell)−1 have been achieved for full-cell Pseudocapacitors using conducting polymer nanotubes (polyaniline) as electrode materials and ionic liquid as electrolytes. The polyaniline nanotubes were synthesized by a one-step in situ chemical polymerization process utilizing MnO2 nanotubes as sacrificial templates. The polyaniline-nanotube Pseudocapacitors exhibit much better electrochemical performance than the polyaniline-nanofiber Pseudocapacitors in both acidic aqueous and ionic liquid electrolytes. Importantly, the incorporation of ionic liquid with polyaniline-nanotubes has drastically improved the energy storage capacity of the PAni-nanotube Pseudocapacitors by a factor of ∼5 times compared to that of the PAni-nanotube Pseudocapacitors in the acidic aqueous electrolyte. Furthermore, even after 10 000 cycles, the PAni-nanotube Pseudocapacitors in the ionic liquid electrolyte maintain sufficient high energy density and can light LEDs for several minutes, with only 30 s quick charge.
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Symmetrical MnO2–Carbon Nanotube–Textile Nanostructures for Wearable Pseudocapacitors with High Mass Loading
ACS Nano, 2011Co-Authors: Wei Chen, Mauro Pasta, Husam N Alshareef, Yuan Yang, Nian Liu, Yan Yao, Xing Xie, Yi CuiAbstract:While MnO2 is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO2 electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO2 nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO2 on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm2, which leads to a high areal capacitance of 2.8 F/cm2 at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO2–CNT–textile was used as a positive electrode, reduced MnO2–CNT–textile as a negative electrode, and 0.5 M Na2SO4 in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storag...
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symmetrical mno2 carbon nanotube textile nanostructures for wearable Pseudocapacitors with high mass loading
ACS Nano, 2011Co-Authors: Wei Chen, Mauro Pasta, Husam N Alshareef, Yuan Yang, Nian Liu, Yan Yao, Xing Xie, Yi CuiAbstract:While MnO2 is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO2 electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO2 nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO2 on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm2, which leads to a high areal capacitance of 2.8 F/cm2 at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO2–CNT–textile was used as a positive electrode, reduced MnO2–CNT–textile as a negative electrode, and 0.5 M Na2SO4 in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storag...
Bingqing Wei - One of the best experts on this subject based on the ideXlab platform.
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all solid state stretchable Pseudocapacitors enabled by carbon nanotube film capped sandwich like electrodes
ACS Applied Materials & Interfaces, 2016Co-Authors: Bingqing WeiAbstract:Stretchable Pseudocapacitors have demonstrated perspective potential as the power sources for stretchable/flexible electronics. However, one of the main limitations is to increase the mass loading of pseudocapacitive materials while maintaining high electrochemical performance. Therefore, the architectural design of stable and stretchable electrodes with a high mass loading of pseudocapacitive materials becomes critical and desirable. Here we report an all-solid-state sandwich-like stretchable pseudocapacitor, which overcomes the limitation of maximum loading of active pseudocapacitive materials and exhibits excellent structural and electrochemical stabilities, giving rise to outstanding cycling stability and rate capability. The enhanced pseudocapacitive performances result from the synergistic effect in the all-solid-state and binder-free structure: (1) faster ion diffusion rates and charge transport at electrode/electrolyte interfaces and (2) improved mechanical property to mitigate the electrode degra...
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fast and stable redox reactions of mno2 cnt hybrid electrodes for dynamically stretchable Pseudocapacitors
Nanoscale, 2015Co-Authors: Bingqing WeiAbstract:Pseudocapacitors, which are energy storage devices that take advantage of redox reactions to store electricity, have a different charge storage mechanism compared to lithium-ion batteries (LIBs) and electric double-layer capacitors (EDLCs), and they could realize further gains if they were used as stretchable power sources. The realization of dynamically stretchable Pseudocapacitors and understanding of the underlying fundamentals of their mechanical–electrochemical relationship have become indispensable. We report herein the electrochemical performance of dynamically stretchable Pseudocapacitors using buckled MnO2/CNT hybrid electrodes. The extremely small relaxation time constant of less than 0.15 s indicates a fast redox reaction at the MnO2/CNT hybrid electrodes, securing a stable electrochemical performance for the dynamically stretchable Pseudocapacitors. This finding and the fundamental understanding gained from the pseudo-capacitive behavior coupled with mechanical deformation under a dynamic stretching mode would provide guidance to further improve their overall performance including a higher power density than LIBs, a higher energy density than EDLCs, and a long-life cycling stability. Most importantly, these results will potentially accelerate the applications of stretchable Pseudocapacitors for flexible and biomedical electronics.
Yuan Yang - One of the best experts on this subject based on the ideXlab platform.
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designing three dimensional architectures for high performance electron accepting Pseudocapacitors
Journal of the American Chemical Society, 2018Co-Authors: Samuel R Peurifoy, Yuan Yang, Jake C Russell, Thomas J Sisto, Xavier Roy, Colin NuckollsAbstract:By storing energy from electrochemical processes at the electrode surface, Pseudocapacitors bridge the performance gap between electrostatic double-layer capacitors and batteries. In this context, molecular design offers the exciting possibility to create tunable and inexpensive organic electroactive materials. Here we describe a porous structure composed of perylene diimide and triptycene subunits and demonstrate its remarkable performance as a pseudocapacitor electrode material. The material exhibits capacitance values as high as 350 F/g at 0.2 A/g as well as excellent stability over 10 000 cycles. Moreover, we can alter the performance of the material, from battery-like (storing more charge at low rates) to capacitor-like (faster charge cycling), by modifying the structure of the pores via flow photocyclization. Organic materials capable of stable electron accepting pseudocapacitor behavior are rare and the capacitance values presented here are among the highest reported. More broadly, this work establ...
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Designing Three-Dimensional Architectures for High-Performance Electron Accepting Pseudocapacitors
2018Co-Authors: Samuel R Peurifoy, Yuan Yang, Jake C Russell, Thomas J Sisto, Xavier Roy, Colin NuckollsAbstract:By storing energy from electrochemical processes at the electrode surface, Pseudocapacitors bridge the performance gap between electrostatic double-layer capacitors and batteries. In this context, molecular design offers the exciting possibility to create tunable and inexpensive organic electroactive materials. Here we describe a porous structure composed of perylene diimide and triptycene subunits and demonstrate its remarkable performance as a pseudocapacitor electrode material. The material exhibits capacitance values as high as 350 F/g at 0.2 A/g as well as excellent stability over 10 000 cycles. Moreover, we can alter the performance of the material, from battery-like (storing more charge at low rates) to capacitor-like (faster charge cycling), by modifying the structure of the pores via flow photocyclization. Organic materials capable of stable electron accepting pseudocapacitor behavior are rare and the capacitance values presented here are among the highest reported. More broadly, this work establishes molecular design and synthesis as a powerful approach for creating tunable energy storage materials
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Symmetrical MnO2–Carbon Nanotube–Textile Nanostructures for Wearable Pseudocapacitors with High Mass Loading
ACS Nano, 2011Co-Authors: Wei Chen, Mauro Pasta, Husam N Alshareef, Yuan Yang, Nian Liu, Yan Yao, Xing Xie, Yi CuiAbstract:While MnO2 is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO2 electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO2 nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO2 on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm2, which leads to a high areal capacitance of 2.8 F/cm2 at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO2–CNT–textile was used as a positive electrode, reduced MnO2–CNT–textile as a negative electrode, and 0.5 M Na2SO4 in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storag...
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symmetrical mno2 carbon nanotube textile nanostructures for wearable Pseudocapacitors with high mass loading
ACS Nano, 2011Co-Authors: Wei Chen, Mauro Pasta, Husam N Alshareef, Yuan Yang, Nian Liu, Yan Yao, Xing Xie, Yi CuiAbstract:While MnO2 is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO2 electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO2 nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO2 on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm2, which leads to a high areal capacitance of 2.8 F/cm2 at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO2–CNT–textile was used as a positive electrode, reduced MnO2–CNT–textile as a negative electrode, and 0.5 M Na2SO4 in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storag...
