Papers by Chuizhou Meng
We present wafer-scale integrated microsupercapacitors
on an ultrathin and highly flexible paryl... more We present wafer-scale integrated microsupercapacitors
on an ultrathin and highly flexible parylene
platform, as progress toward sustainably powering biomedical
microsystems suitable for implantable and wearable applications.
All-solid-state, low-profile (<30 μm), and high-density
(up to ~500 μF/mm2) micro-supercapacitors are formed on an
ultrathin (~20 μm) freestanding parylene film by a wafer-scale
parylene packaging process in combination with a polyaniline
(PANI) nanowire growth technique assisted by surface plasma
treatment. These micro-supercapacitors are highly flexible and
shown to be resilient toward flexural stress. Further, direct integration
of micro-supercapacitors into a radio frequency (RF)
rectifying circuit is achieved on a single parylene platform,
yielding a complete RF energy harvesting microsystem. The
system discharging rate is shown to improve by ~17 times in
the presence of the integrated micro-supercapacitors. This result
suggests that the integrated micro-supercapacitor technology
described herein is a promising strategy for sustainably
powering biomedical microsystems dedicated to implantable
and wearable applications.
Keywords Energy storage .
Advanced Energy Materials, Dec 12, 2013
A novel integrated 3D micro-supercapacitor is reported. A through-via bottom electrode technique ... more A novel integrated 3D micro-supercapacitor is reported. A through-via bottom electrode technique is utilized for the first time for supercapacitor fabrication, and a highly miniaturized, flexible, and all-solid-state micro-supercapacitor with 3D integration capability is achieved. Module-wise compact integration of supercapacitors and their versatile powering applications are demonstrated. This device enables high-power energy storage in small-scale electronics.
Biomedical Microdevices, Jul 2013
We present a high-energy local power supply based on a flexible and solid-state supercapacitor fo... more We present a high-energy local power supply based on a flexible and solid-state supercapacitor for miniature wireless implantable medical devices. Wireless radio-frequency (RF) powering recharges the supercapacitor through an antenna with an RF rectifier. A power management circuit for the super-capacitive system includes a boost converter to increase the breakdown voltage required for powering device circuits, and a parallel conventional capacitor as an intermediate power source to deliver current spikes during high current transients (e.g., wireless data transmission). The supercapacitor has an extremely high area capacitance of ~1.3 mF/mm2, and is in the novel form of a 100 μm-thick thin film with the merit of mechanical flexibility and a tailorable size down to 1 mm2 to meet various clinical dimension requirements. We experimentally demonstrate that after fully recharging the capacitor with an external RF powering source, the supercapacitor-based local power supply runs a full system for electromyogram (EMG) recording that consumes ~670 μW with wireless-data-transmission functionality for a period of ~1 s in the absence of additional RF powering. Since the quality of wireless powering for implantable devices is sensitive to the position of those devices within the RF electromagnetic field, this high-energy local power supply plays a crucial role in providing continuous and reliable power for medical device operations.
Energy Technology, Oct 22, 2014
High-power micro-supercapacitors based on graphitic petal electrodes are designed and fabricated,... more High-power micro-supercapacitors based on graphitic petal electrodes are designed and fabricated, and charge/discharge rates up to 100 000 mV s−1 (1000 times faster than conventional supercapacitors) are achieved in 1 M H2SO4 aqueous electrolyte. The resulting devices exhibit excellent energy and power densities as well as good cyclic stability.
Advanced Energy Materials, Sep 23, 2013
The charge storage characteristics of a composite nanoarchitecture with a highly functional 3D mo... more The charge storage characteristics of a composite nanoarchitecture with a highly functional 3D morphology are reported. The electrodes are formed by the electropolymerization of aniline monomers into a nanometer-thick polyaniline (PANI) film that conformally coats graphitic petals (GPs) grown by microwave plasma chemical vapor deposition (MPCVD) on conductive carbon cloth (CC). The hybrid CC/GPs/PANI electrodes yield results near the theoretical maximum capacitance for PANI of 2000 F g−1 (based on PANI mass) and a large area-normalized specific capacitance of ≈2.6 F cm−2 (equivalent to a volumetric capacitance of ≈230 F cm−3) at a low current density of 1 A g−1 (based on PANI mass). The specific capacitances remain above 1200 F g−1 (based on PANI mass) for currents up to 100 A g−1 with correspondingly high area-normalized values. The hybrid electrodes also exhibit a high rate capability with an energy density of 110 Wh kg−1 and a maximum power density of 265 kW kg−1 at a current density of 100 A g−1. Long-term cyclic stability is good (≈7% loss of initial capacitance after 2000 cycles), with coulombic efficiencies >99%. Moreover, prototype all-solid-state flexible supercapacitors fabricated from these hybrid electrodes exhibit excellent energy storage performance.
Electroanalysis, Nov 15, 2013
The rapid development of miniaturized electronic devices has led to a growing need for rechargeab... more The rapid development of miniaturized electronic devices has led to a growing need for rechargeable micropower
sources with high performance. Among different sources, electrochemical microcapacitors or microsupercapacitors
provide higher power density than their counterparts and are gaining increased interest from the research and engineering
communities. To date, little work has appeared on the integration of microsupercapacitors onto a chip or
flexible substrates. This review provides an overview of research on microsupercapacitors, with particular emphasis
on state-of-the-art graphene-based electrodes and solid-state devices on both flexible and rigid substrates. The advantages,
disadvantages, and performance of graphene-based microsupercapacitors are summarized and new trends
in materials, fabrication and packaging are identified.
Journal of Postdoctoral Research, Dec 20, 2013
The rapid development of small, thin, lightweight, and even flexible wearable electronic devices ... more The rapid development of small, thin, lightweight, and even flexible wearable electronic devices has led to a growing need for matchable textile energy storage devices with high performance. Among different sources, supercapacitors are capable of providing higher power density than their counterparts and are drawing tremendous interest from both research and engineering communities. Just in the past two years, flexible and weaveable fiber-like supercapacitors have emerged and attracted increasing research attention. In this up-to-date review, after a brief introduction of supercapacitor principle, performance, and electrode/electrolyte materials, we summarize the current development of two types of fiber-like supercapacitors, as well as various advanced fiber electrode materials that have been utilized. Finally, we discuss integrated fiber-like power systems incorporated with fiber-like supercapacitors and fiber-like energy harvesting and conversion devices, and identify new research trends in materials, fabrication, and future applications.
Nano letters
In recent years, much effort have been dedicated to achieve thin, lightweight and even flexible e... more In recent years, much effort have been dedicated to achieve thin, lightweight and even flexible energy-storage devices for wearable electronics. Here we demonstrate a novel kind of ultrathin all-solid-state supercapacitor configuration with an extremely simple process using two slightly separated polyaniline-based electrodes well solidified in the H2SO4-polyvinyl alcohol gel electrolyte. The thickness of the entire device is much comparable to that of a piece of commercial standard A4 print paper. Under its highly flexible (twisting) state, the integrate device shows a high specific capacitance of 350 F/g for the electrode materials, well cycle stability after 1000 cycles and a leakage current of as small as 17.2 μA. Furthermore, due to its polymer-based component structure, it has a specific capacitance of as high as 31.4 F/g for the entire device, which is more than 6 times that of current high-level commercial supercapacitor products. These highly flexible and all-solid-state paperlike polymer supercapacitors may bring new design opportunities of device configuration for energy-storage devices in the future wearable electronic area.
Electrochemistry Communications
The carbon nanotube/polyaniline (CNT/PANI) composites have important potential applications as th... more The carbon nanotube/polyaniline (CNT/PANI) composites have important potential applications as the electrodes in energy storage devices for their attractive electrochemical properties. In this work, we report a novel method to prepare the interesting paper-like CNT/PANI composites by using the CNT network as the template. Compared with the conventional brittle CNT/PANI composites, these paper-like composites were much thin and flexible. This work demonstrates a new approach, which may transform a brittle polymer into flexible films. Meanwhile, these film electrodes showed much superior electrochemical performance such as higher specific capacitance, lower internal resistivity, and more stability under different current loads. These paper-like composite electrodes have promising applications in new kinds of energy storage devices.
Advanced Materials
Enhanced Seebeck coefficients and power factors – important for the conversion of heat to electri... more Enhanced Seebeck coefficients and power factors – important for the conversion of heat to electrical energy – are obtained in polyaniline/carbon nanotube (PANI/CNT) composites in which PANI coats CNT networks (see figure). The values are several times larger than those of either of the individual components. This new approach has potential for synthesizing high-performance thermoelectric materials.
Nanotechnology
Nanoporous current collectors for supercapacitors have been fabricated by cross-stacking super-al... more Nanoporous current collectors for supercapacitors have been fabricated by cross-stacking super-aligned carbon nanotube (SACNT) films as a replacement for heavy conventional metallic current collectors. The CNT-film current collectors have good conductivity, extremely low density (27 µg cm − 2), high specific surface area, excellent flexibility and good electrochemical stability. Nanosized active materials such as NiO, Co3O4 or Mn2O3 nanoparticles can be directly synthesized on the SACNT films by a straightforward one-step, in situ decomposition strategy that is both efficient and environmentally friendly. These composite films can be integrated into a pseudo-capacitor that does not use metallic current collectors, but nevertheless shows very good performance, including high specific capacitance (~500 F g − 1, including the current collector mass), reliable electrochemical stability (<4.5% degradation in 2500 cycles) and a very high rate capability (245 F g − 1 at 155 A g − 1).
ACS nano
In this work, we show that embedding super-aligned carbon nanotube sheets into a polymer matrix (... more In this work, we show that embedding super-aligned carbon nanotube sheets into a polymer matrix (polydimethylsiloxane) can remarkably reduce the coefficient of thermal expansion of the polymer matrix by two orders of magnitude. Based on this unique phenomenon, we fabricated a new kind of bending actuator through a two-step method. The actuator is easily operable and can generate an exceptionally large bending actuation with controllable motion at very low driving DC voltages (<700 V/m). Furthermore, the actuator can be operated without electrolytes in the air, which is superior to conventional carbon nanotube actuators. Proposed electrothermal mechanism was discussed and confirmed by our experimental results. The exceptional bending actuation performance together with easy fabrication, low-voltage, and controllable motion demonstrates the potential ability of using this kind of actuator in various applicable areas, such as artificial muscles, microrobotics, microsensors, microtransducers, micromanipulation, microcantilever for medical applications, and so on.
ACS nano
It is known that single-walled carbon nanotubes (SWNTs) strongly absorb light, especially in the ... more It is known that single-walled carbon nanotubes (SWNTs) strongly absorb light, especially in the near-infrared (NIR) region, and convert it into heat. In fact, SWNTs also have considerable ability to convert heat into electricity. In this work, we show that SWNT sheets made from as-grown SWNT arrays display a large positive thermoelectric coefficient (p-type). We designed a simple SWNT device to convert illuminating NIR light directly into a notable voltage output, which was verified by experimental tests. Furthermore, by a simple functionalization step, the p- to n-type transition was conveniently achieved for the SWNT sheets. By integrating p- and n-type elements in series, we constructed a novel NIR opto-electronic power source, which outputs a large voltage that sums over the output of every single element. Additionally, the output of the demo device has shown a good linear relationship with NIR light power density, favorable for IR sensors.
US Patents by Chuizhou Meng
An energy storage device includes first and second electrodes and a solid state electrolyte. The ... more An energy storage device includes first and second electrodes and a solid state electrolyte. The first electrode includes carbon nanotubes, a conductive polymer, and a metallization on said carbon nanotubes. The second electrode similarly includes carbon nanotubes, a conductive polymer, and a metallization on said carbon nanotubes. The solid state electrolyte is disposed at least in part between the first electrode and the second electrode. In at least some embodiments, the conductive polymer of the first electrode includes polyaniline, and the metallization of the first electrode is a gold metallization.
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Papers by Chuizhou Meng
on an ultrathin and highly flexible parylene
platform, as progress toward sustainably powering biomedical
microsystems suitable for implantable and wearable applications.
All-solid-state, low-profile (<30 μm), and high-density
(up to ~500 μF/mm2) micro-supercapacitors are formed on an
ultrathin (~20 μm) freestanding parylene film by a wafer-scale
parylene packaging process in combination with a polyaniline
(PANI) nanowire growth technique assisted by surface plasma
treatment. These micro-supercapacitors are highly flexible and
shown to be resilient toward flexural stress. Further, direct integration
of micro-supercapacitors into a radio frequency (RF)
rectifying circuit is achieved on a single parylene platform,
yielding a complete RF energy harvesting microsystem. The
system discharging rate is shown to improve by ~17 times in
the presence of the integrated micro-supercapacitors. This result
suggests that the integrated micro-supercapacitor technology
described herein is a promising strategy for sustainably
powering biomedical microsystems dedicated to implantable
and wearable applications.
Keywords Energy storage .
sources with high performance. Among different sources, electrochemical microcapacitors or microsupercapacitors
provide higher power density than their counterparts and are gaining increased interest from the research and engineering
communities. To date, little work has appeared on the integration of microsupercapacitors onto a chip or
flexible substrates. This review provides an overview of research on microsupercapacitors, with particular emphasis
on state-of-the-art graphene-based electrodes and solid-state devices on both flexible and rigid substrates. The advantages,
disadvantages, and performance of graphene-based microsupercapacitors are summarized and new trends
in materials, fabrication and packaging are identified.
US Patents by Chuizhou Meng
on an ultrathin and highly flexible parylene
platform, as progress toward sustainably powering biomedical
microsystems suitable for implantable and wearable applications.
All-solid-state, low-profile (<30 μm), and high-density
(up to ~500 μF/mm2) micro-supercapacitors are formed on an
ultrathin (~20 μm) freestanding parylene film by a wafer-scale
parylene packaging process in combination with a polyaniline
(PANI) nanowire growth technique assisted by surface plasma
treatment. These micro-supercapacitors are highly flexible and
shown to be resilient toward flexural stress. Further, direct integration
of micro-supercapacitors into a radio frequency (RF)
rectifying circuit is achieved on a single parylene platform,
yielding a complete RF energy harvesting microsystem. The
system discharging rate is shown to improve by ~17 times in
the presence of the integrated micro-supercapacitors. This result
suggests that the integrated micro-supercapacitor technology
described herein is a promising strategy for sustainably
powering biomedical microsystems dedicated to implantable
and wearable applications.
Keywords Energy storage .
sources with high performance. Among different sources, electrochemical microcapacitors or microsupercapacitors
provide higher power density than their counterparts and are gaining increased interest from the research and engineering
communities. To date, little work has appeared on the integration of microsupercapacitors onto a chip or
flexible substrates. This review provides an overview of research on microsupercapacitors, with particular emphasis
on state-of-the-art graphene-based electrodes and solid-state devices on both flexible and rigid substrates. The advantages,
disadvantages, and performance of graphene-based microsupercapacitors are summarized and new trends
in materials, fabrication and packaging are identified.