Fabrication Of Micro-supercapacitors Research Articles

Deformable moisture-activated all-solid-state planar microsupercapacitors

Recent advances in developing soft electronic devices have increased the demand for deformable storage devices. However, the fabrication of microsupercapacitors (MSCs) with satisfactory electrochemical performance and mechanical robustness remains a crucial challenge. In this work, deformable moisture-activated all-solid-state planar MSCs were designed and fabricated by an in situ laser reduction technology. The planar MSC shows a high areal-specific capacitance (∼4.7 mF cm−2 at 5 mV s−1) under high moisture (RH = 100%). Moreover, the tensile strength of the deformable planar MSC increased to 21 MPa. Moreover, the mechanical robustness of the planar MSC allows them to be folded into origami. The deformable moisture-activated all-solid-state planar MSC holds promises for soft storage devices.

Advances on Microsupercapacitors: Real Fast Miniaturized Devices toward Technological Dreams for Powering Embedded Electronics?

Microsupercapacitors (MSCs) have emerged as the next generation of electrochemical energy storage sources for powering miniaturized embedded electronic and Internet of Things devices. Despite many advantages such as high-power density, long cycle life, fast charge/discharge rate, and moderate energy density, MSCs are not at the industrial level in 2022, while the first MSC was published more than 20 years ago. MSC performance is strongly correlated to electrode material, device configuration, and the used electrolyte. There are therefore many questions and scientific/technological locks to be overcome in order to raise the technological readiness level of this technology to an industrial stage: the type of electrode material, device topology/configuration, and use of a solid electrolyte with high ionic conductivity and photopatternable capabilities are key parameters that we have to optimize in order to fulfill the requirements. Carbon-based, pseudocapacitive materials such as transition metal oxide, transition metal nitride, and MXene used in symmetric or asymmetric configurations are extensively investigated. In this Review, the current progress toward the fabrication of MSCs is summarized. Challenges and prospectives to improve the performance of MSCs are discussed.

Three dimensional high-performance micro-supercapacitors with switchable high power density and high energy density.

In the field of microscale energy storage, the fabrication of micro-supercapacitors (MSCs) with high power density and high energy density has always been a focus of research. In this work, laser-induced porous graphene and chemically deposited manganese dioxide nanoparticles are used as electrode materials, and a switchable MSC with two energy storage principles is obtained by designing symmetric interdigitated and square electrode structures. The aim is to overcome the preparation challenge of supercapacitors with high energy density and high power density by switching between two modes. In this MSC, the energy density of the high energy density mode (5.89 μW h cm-2) is 3.36 times that of the high power density mode (1.75 μW h cm-2), while the power density of the high power density mode (43.06 μW cm-2) is 1.44 times that of the high energy density mode (29.96 μW cm-2). In addition, under the drive of five serially connected MSCs, 27 LED lights can be continuously lit for 5 minutes. Therefore, this work provides a facile and novel method for the development of MSCs with high power density and high energy density, suggesting a great practical application value in the development of MSCs.

Laser-Induced Interdigital Structured Graphene Electrodes Based Flexible Micro-Supercapacitor for Efficient Peak Energy Storage.

The rapidly developing demand for lightweight portable electronics has accelerated advanced research on self-powered microsystems (SPMs) for peak power energy storage (ESs). In recent years, there has been, in this regard, a huge research interest in micro-supercapacitors for microelectronics application over micro-batteries due to their advantages of fast charge–discharge rate, high power density and long cycle-life. In this work, the optimization and fabrication of micro-supercapacitors (MSCs) by means of laser-induced interdigital structured graphene electrodes (LIG) has been reported. The flexible and scalable MSCs are fabricated by CO2-laser structuring of polyimide-based Kapton ® HN foils at ambient temperature yielding interdigital LIG-electrodes and using polymer gel electrolyte (PGE) produced by polypropylene carbonate (PPC) embedded ionic liquid of 1-ethyl-3-methyl-imidazolium-trifluoromethansulphonate [EMIM][OTf]. This MSC exhibits a wide stable potential window up to 2.0 V, offering an areal capacitance of 1.75 mF/cm2 at a scan rate of 5.0 mV/s resulting in an energy density (Ea) of 0.256 µWh/cm2 @ 0.03 mA/cm2 and power density (Pa) of 0.11 mW/cm2 @0.1 mA/cm2. Overall electrochemical performance of this LIG/PGE-MSC is rounded with a good cyclic stability up to 10,000 cycles demonstrating its potential in terms of peak energy storage ability compared to the current thin film micro-supercapacitors.

3D printing of high-performance micro-supercapacitors with patterned exfoliated graphene/carbon nanotube/silver nanowire electrodes

Micro-supercapacitors (MSCs) show great potential as on-chip energy storage devices for portable electronics. The major flaw of thin-film MSCs is their low energy density. To improve the energy density, thicker electrodes are required. However, the fabrication of MSCs with thick electrodes remains a challenge. In this work, a novel 3D printing method is employed to fabricate high-performance MSCs with interdigitated exfoliated graphene (EG)/carbon nanotube (CNT)/silver nanowire (AgNW) electrodes. The nanowelding of AgNW junction plays a critical role in the realization of 3D printing. To enhance the electrochemical performances of EG, phosphorus atoms are incorporated into the carbon framework with 1.7 at%. The areal capacitance of the 3D printed MSC is 21.6 mF cm−2 at a scan rate of 0.01 V s−1. The areal energy density of the MSC ranges from 0.5 to 2 μWh cm−2 with a maximum power density of 2.5 mW cm−2.

Photolithographic fabrication of planar on-chip micro-supercapacitors based on reduced graphene oxide films by modified liquid-air interface self-assembly

In this article, we demonstrated the fabrication of micro-supercapacitors by photolithography technology and liquid-air interface self-assembly method. A large-area uniform film with a thickness of 18 nm was fabricated by the modified liquid-air interface self-assembly, and a narrow finger gap, which was 30 μm, was manufactured by photolithography. In addition, the electrode width and the interdigital gap ratio were 3:1. The power density and energy density of the fabricated device were 1.21 W cm−3 and 2.93 mWh cm−3. There was an extremely short time constant of the fabricated device, which is 0.38 ms. All of these leaded to higher conductivity, shorter ion transmission distance and faster charge and discharge rates. In addition, 87.2% of the capacitance was retained after 10000 cycles.

Alternately Dipping Method to Prepare Graphene Fiber Electrodes for Ultra-high-Capacitance Fiber Supercapacitors.

SummaryFlexible fiber supercapacitors are promising candidate for power supply of wearable electronics. Fabrication of high-performance fibers is in progress yet challenging. The currently available graphene fibers made from wet-spinning or electro-deposition technologies are far away from practical applications due to their unsatisfactory capacitance. Here we report a facile alternately dipping (AD) method to coat graphene on wire-like substrates. The excellent mechanical properties of the substrate with greatly diverse choices can be carried over to the fiber supercapacitors. Under such guideline, the graphene fiber with a titanium core made by our AD method (AD:Ti@RGO) shows an ultra-high specific capacitance of up to 1,722.1 mF cm−2, which is ∼1,000 times that of wet-spinning- and electro-deposition-fabricated neat graphene fibers and presents the highest specific capacitance to date. With excellent mechanical properties and striking electrochemical performances, the AD:Ti@RGO-based supercapacitors light the path to the next-generation technologies for wearable devices.

Fabrication of Microsupercapacitors Based on Horizontally Aligned Carbon Nanotube Arrays

Fabrication of Microsupercapacitors Based on Horizontally Aligned Carbon Nanotube Arrays

Addressing Fundamental Problems in Capacitive Energy Storage

The rapidly growing demand for capacitive energy storage systems for applications such as self-powered micro and nanosystems, portable electronic devices, and large-scale stationary applications has inspired much research in an effort to develop devices that can provide high power and energy densities. The important factors affecting the performance of electrochemical capacitors (ECs) are the intrinsic properties of electrode materials and electrolytes, as well as the properties of their interfaces. There is no perfect electrode material and no ideal electrolyte that can meet the performance goal for every application. Therefore, a rational design of these materials is crucial for rapid advancement and widespread implementation of ECs. A large variety of nanostructured carbon materials are available nowadays that can be used as electrode materials.1 Zero- and one-dimensional nanoparticles, such as onion-like carbon and nanotubes, can provide a high power due to fast ion sorption/desorption on their outer surfaces.2 Two-dimensional graphene has been receiving an increasing attention due to its higher charge-discharge rates compared to porous carbons and high volumetric energy density. Three-dimensional porous activated, carbide-derived and templated carbon networks, having a high surface area and porosity in the subnanometer or a few-nanometers range, can provide high energy density if the pore size is matched with the electrolyte ion size.3 While aqueous electrolytes, such as sodium sulfate, are the safest and least expensive, they have a limited voltage window. Organic electrolytes are the most commonly used ones in commercial devices. Non-flammable ionic liquids are attracting an increasing attention due to their low vapor pressure leading to a safe operation in the range from -50°C to at least 100°C and a larger voltage window resulting in a higher energy density compared to other electrolytes.4 Further advances in development of materials and understanding charged solid-electrolyte interfaces are expected to lead to a wider use of capacitive energy storage at the scales ranging from microelectronics to automobiles and electrical grid.5,6 This talk will summarize some of the research efforts at Fluid Interface Reactions, Structure and Transport (FIRST) center towards understanding the effects of the structure of the electrode materials and properties of the electrode/electrolyte interfaces on the capacitive energy storage in ECs. References (1) Simon, P.; Gogotsi, Y. Capacitive Energy Storage in Nanostructured Carbon Electrolyte Systems. Acc. Chem. Res. 2012, 46, 1094–1103. (2) McDonough, J.; Gogotsi, Y. Carbon Onions: Synthesis and Electrochemical Applications. Electrochem. Soc. Interface 2013, 12, 61–66. (3) Presser, V.; Heon, M.; Gogotsi, Y. Carbide-Derived Carbons - From Porous Networks to Nanotubes and Graphene. Adv. Funct. Mater. 2011, 21, 810–833. (4) Van Aken, K. L.; Beidaghi, M.; Gogotsi, Y. Formulation of Ionic-Liquid Electrolyte to Expand the Voltage Window of Supercapacitors. Angew. Chemie 2015, 127, 4888–4891. (5) Presser, V.; Dennison, C. R.; Campos, J.; Knehr, K. W.; Kumbur, E. C.; Gogotsi, Y. The Electrochemical Flow Capacitor: A New Concept for Rapid Energy Storage and Recovery. Adv. Energy Mater. 2012, 2, 895–902. (6) Beidaghi, M.; Gogotsi, Y. Capacitive Energy Storage in Micro-Scale Devices: Recent Advances in Design and Fabrication of Micro-Supercapacitors. Energy Environ. Sci. 2014, 7, 867.

Capacitive energy storage in micro-scale devices: recent advances in design and fabrication of micro-supercapacitors

Miniaturized energy storage is essential for the continuous development and further miniaturization of electronic devices. Electrochemical capacitors (ECs), also called supercapacitors, are energy storage devices with a high power density, fast charge and discharge rates, and long service life. Small-scale supercapacitors, or micro-supercapacitors, can be integrated with microelectronic devices to work as stand-alone power sources or as efficient energy storage units complementing batteries and energy harvesters, leading to wider use of these devices in many industries. In recent years, the research in this field has rapidly advanced and micro-supercapacitors with improved storage capacity and power density have been developed. The important factors affecting the performance of micro-supercapacitors are the intrinsic properties of electrode materials and electrolyte, architectural design of the device and the fabrication methods. This paper reviews the recent advances in fabrication of materials and devices and provides a critical analysis of reported performances of micro-supercapacitors.