The advances in micro-size and in-plane supercapacitors lead to produce the miniaturizing energy storage devices in portable and bendable electronics. Micro-supercapacitors have unique electrochemical performance, such as high power density, fast charging, long cycle life, and high safety. The reduction time and cost in the fabrication processes of micro-supercapacitors are important factors in micro-fabrication technology. In this work, a simple, scalable and cost-effective fabrication of interdigitated reduced graphene oxide@polyaniline flexible micro-supercapacitors is presented. We found that in fabricating the interdigitated microelectrode patterns on PET substrate; the reduction of graphene oxide and growth of conducting polymer are rapidly performed simultaneously in one step by laser irradiation. The capacitance was 72 mF/cm2 at 0.035mA/cm2 current density. These high capacitance micro-supercapacitors demonstrate good stability and more than 93.5% of the capacitance retain after 1000 cycles at 0.7 mA/cm2 current density.
The study shows the importance of moving towards hollow nanostructures for obtaining next-generation supercapacitors and batteries. Amongst various sodium-based electrode materials, NaFePO4 is one of the most promising cathodic material because of its high electrochemical potential, structural, and thermal stability. To use this material in high performance Na-ion based energy storage device, it is imperative to combine it with a suitably optimized carbon structures and a redox additive modified electrolyte. This strategy is unequivocally established in the paper. On addition of redox additive…
Additive manufacturing and 3D printing in particular have the potential to revolutionize existing fabrication processes where objects with complex structures and shapes can be built with multifunctional material systems. For electrochemical energy storage devices such as batteries and supercapacitors, 3D printing methods allows alternative form factors to be conceived based on the end use application need in mind at the design stage. Additively manufactured energy storage devices require active materials and composites that are printable and this is influenced by performance requirements and t…
In this article we shall discuss the development of electrical storage system. Since the early days of electricity people have tried various methods to store electricity. One of the earliest device was a simple electrostatic capacitor that could store less than a micro Joule of energy. The battery has been the most popular in storing electricity as it has a higher energy density. We will discuss the development of batteries and their working principle. Although capacitors has never been thought of as a practical device for electricity storage, in the recent years there has been tremendous prog…
We have developed a flexible, interdigitated supercapacitor with high energy storing capacity for wearable, flexible electronic application. Locally obtained low cost biomass (banana peel) was impregnated with KOH under high temperature under an inert atmosphere to synthesize activated carbon with significant Brunauer Emmett Teller surface area of 62.03m2/g. The supercapacitor was fabricated by screen printing interdigitated current collector of conducting silver ink on a thin flexible PET substrate and subsequent deposition of activated carbon and drop casting of gel electrolyte. Fabricated s…
As renewable energy is becoming a critical energy source to meet the global demand, electrochemical energy storage devices become indispensable for the efficient energy storage and reliable supply. The electrode material is the key factor determining the energy storage capacity and the power delivery of the devices. Carbon-based materials are emerging as a viable candidate for electrodes, yet their low energy densities impede the development of advanced energy storage materials. Nanoparticle decoration of the carbon structures is one of the most promising and easy-to-implement a strategy to en…
A natural embodiment for multifunctional materials combining energy-storing capabilities and structural mechanical properties are layered structures, similar to both laminate structural composites and electrochemical energy storage devices. A structural composite with integrated electric double layer capacitive storage is produced by resin infusion of a lay up including woven glass fabric used as mechanical reinforcement, carbon nanotube non-woven fabrics as electrodes/current collectors and a polymer electrolyte. The energy-storing layer is patterned with holes, which after integration form r…
The development of green and biodegradable electrical components is one of the main fronts of research to overcome the growing ecological problem related to the issue of electronic waste. At the same time, such devices are highly desirable in biomedical applications such as integrated bio-electronics, for which biocompatibility is also required. Supercapacitors for storage of electrochemical energy, designed only with bio-degradable organic matter would contemplate both aspects, that is, they would be ecologically harmless after their service lifetime and would be an important component for ap…
Additive manufacturing has revolutionized the building of materials direct from design, allowing high resolution rapid prototyping in complex 3D designs with many materials. 3D printing hasenabled high strength damage-tolerant structures, bioprinted artificial organs and tissues, ultralight metals, medicine, education, prosthetics, architecture, consumer electronics,and as a prototyping tool for engineers and hobbyists alike. 3D printing has emerged as a useful tool for complex electrode and material assembly method for batteries and supercapacitors in recent years. The field initially grew fr…
Portable miniaturized energy storage micro-supercapacitor has engrossed significant attention due to its power source and energy storage capacity, replacing batteries in ultra-small electronic devices. Fabrication with porous and 2D graphitic nanomaterials with high conductivity and surface area signify high performance of micro-supercapacitor. In order to satisfy the fast-growing energy demands for the next-generation, we report performance and design of a 2D heterostructure of EDLC (g-C$_3$N$_4$) & pseudocapacitive (FeNi$_3$) resulting low ionic diffusion path and prominent charge storage ba…
With a large-scale usage of portable electric appliances, a high demand for increasingly high density energy storage devices has emerged. MoO3 has, in principle, a large potential as negative electrode material in supercapacitive devices, due to high charge densities that can be obtained from its reversible redox reactions. Nevertheless, the extremely poor electrochemical stability of MoO3 in aqueous electrolytes prevents a practical use in high capacitance devices. In this work, we describe how to overcome this severe stability issue by forming amorphous molybdenum oxide/tantalum oxide nanotu…
The advances in the mass scale manufacturing of microscale energy storage devices via inkjet printing rely on the development of high-quality printable ink. The earth-abundant, non-toxic carbon materials such as graphene, carbon nanotube (CNT), reduced graphene oxide (r-GO) have shown excellent electrochemical performance and thus garnered significant interest as suitable electrode material. Here we report the formulation of printable graphene aerogel ink and the fabrication of the micro-supercapacitors (μ-SCs) on flexible polyimide substrates via inkjet printing method. The advantage of using…
The miniaturization of energy storage units is pivotal for the development of next-generation portable electronic devices. Micro-supercapacitors (MSCs) hold a great potential to work as on-chip micro-power sources and energy storage units complementing batteries and energy harvester systems. The scalable production of supercapacitor materials with cost-effective and high-throughput processing methods is crucial for the widespread application of MSCs. Here, we report wet-jet milling exfoliation of graphite to scale-up the production of graphene as supercapacitor material. The formulation of aqu…
To achieve the further development of supercapacitors (SCs), which have intensively received attention as a next-generation energy storage system, the rational design of active electrode materials with electrochemically more favorable structure is one of the most important factors to improve the SC performance with high specific energy and power density. We propose and successfully grow copper sulfide (CuS) nanowires (NWs) as a chalcogenide-based electrode material directly on a Cu mesh current collector using the combination of a facile liquid-solid chemical oxidation process and an anion exc…
We report three different synthesis routes while maintaining similar reaction conditions to choose an effective way to precisely control the growth of ultrafine one dimensional LiMn2O4 in the form of nanorods. We developed a novel method of mixing the precursors through hydrothermal, yielding low dimensional precursors for effective solid state reaction to synthesize the nanorods. However, to achieve these, highly uniform beta-MnO2 nanorods were initially grown as one of the main precursors. The uniformity observed in as grown beta-MnO2 nanorods using hydrothermal technique help to attract min…
Heterostructures constructed from two-dimensional building blocks have shown promise for field-effect transistors, memory devices, photosensors and other electronic applications1,2. 2D nanosheet crystals can be constructed into multilayer heterostructures using layer-by-layer methods3, but that method cannot be used to fabricate large-scale and thick heterostructures, due to the time-consuming nature and low efficiency of the process. An alternative approach to deposit different two-dimensional materials is by inkjet printing4-7. Here we show the fabrication of a nanosheet supercapacitor by in…
Due to the shorter channel length allowing faster ion/charge movement, nanoscale molecular thin films can be attractive electronic components for next-generation high-performing energy storage devices. However, controlling chemical functionalization and achieving stable electrode-molecule interfaces at the nanoscale via covalent functionalization for low-voltage operational, ultrafast charging/discharging remains a challenge. Herein, we present a simple, controllable, scalable, low-cost, and versatile electrochemical grafting approach to modulate chemical and electronic properties of graphite …
Transition metal dichalcogenides like MoS2 can exist many phases like the semiconducting 2H and the metallic 1T phases which have shown intriguing properties for energy and electrocatalytic applications. However, the 2H and 1T phases normally distribute coherently in a single-layered MoS2 sheet which is accompanied with ubiquitous hetero-phase boundaries. In this work, by using density functional theory and electrochemical measurement, we report strong charge transfer ability between 2H/1T phase boundary of MoS2 and graphene which accounts for a superb coexistence of gravimetric and volumetric…
In past decades, the application of fractals to electrode design for enhanced signaling and electrochemical performance was a popular subject and enabled the growth of consumer micro-electronics. Supercapacitors, which are energy storage devices with many promising characteristics, have largely grown alongside of such developments in electronics, but little work has been done to use fractal electrodes in supercapacitors. In this work, plane-filling and fractal patterns were used in designing laser scribed graphene supercapacitor electrodes, allowing the scaling laws of capacitance with respect…
Graphene is well known to grow as flat sheets aligned with the growth substrate. Oriented graphene structures typically normal to the substrate have recently gained major attention. Most often, normal orientation is achieved in plasma-assisted growth and is believed to be due to plasma induced in-built electric field, which is usually oriented normal to the substrate. This work focuses on the effect of in-built electric field on growth direction, morphology, interconnectedness, and physical properties of various configurations of graphene structures and reveals the unique dependence of these f…
Porous metallic structures are regularly used in electrochemical energy storage devices as supports, current collectors or active electrode materials. Bulk metal porosification, dealloying, welding or chemical synthesis routes involving crystal growth or self-assembly for example, can sometimes provide limited control of porous length scale, ordering, periodicity, reproducibility, porosity and surface area. Additive manufacturing and 3D printing has shown the potential to revolutionize the fabrication of architected metals many forms, allowing complex geometries not usually possible by traditi…
In situ growth of hydrophilic nickel-cobalt layered double hydroxides nanosheets on biomass waste-derived porous carbon for high-performance hybrid supercapacitors
Here we report the extraordinary electrochemical energy storage capability of NiMoO4@NiMoO4 homogeneous hierarchical nanosheet-on-nanowire-arrays (SOWAs) synthesized on nickel substrate by a two-stage hydrothermal process. Comparatively speaking, the SOWAs electrode displays improved electrochemical performances than the bare NiMoO4 nanowire arrays. Such improvements can be ascribed to the characteristic homogeneous hierarchical structure which not only effectively increases the active surface areas for fast charge transfer, but also reduces the electrode resistance significantly by eliminatin…
This work presents a method to produce structural composites capable of energy storage. They are produced by integrating thin sandwich structures of CNT fiber veils and an ionic liquid-based polymer electrolyte between carbon fiber plies, followed by infusion and curing of an epoxy resin. The resulting structure behaves simultaneously as an electric double-layer capacitor and a structural composite, with flexural modulus of 60 GPa and flexural strength of 153 MPa, combined with 88 mF/g of specific capacitance and the highest power (30 W/kg) and energy (37.5 mWh/kg) densities reported so far fo…
Nanosized energy storage, energy-harvesting, and functional devices are the three key components for integrated self-power systems. Here, we report on nanoscale electrochemical devices with a nearly three-fold enhanced stored charge under the field effect. We demonstrated the field-effect transistor can not only work as a functional component in nanodevices but also serve as an amplifier for the nanosized energy storage blocks. This unusual increase in energy storage is attributed to having a wide range of accessible electronic density of states (EDOS), hence redox reactions are occurring with…
This review summarizes progress on structural composites with carbon nanotube fibres. It starts by analyzing their development towards a macroscopic ensemble of elongated and aligned crystalline domains, alongside the evolution of the structure of traditional high-performance fibres. Literature on tensile properties suggests that there are two emerging grades: highly aligned fibres spun from liquid crystalline solutions, with high modulus and strength, and spun from aerogels of ultra long-nanotubes, combining high strength and fracture energy. The fabrication of large unidirectional fabrics wi…
The fabrication method of diamond nanostructures can be divided into two categories: top-down etching and bottom-growth. The early work on 3D micro-structured diamond dates back to mid-1990s, using chemical vapor infiltration (CVI) techniques. In this technology, carbon or carbide fibers were typically used as the growth template. Almost in parallel, reactive ion etching (RIE) was applied to achieve diamond surface nanostructuring. After that the diamond surface nanostructures, typically vertically aligned diamond nanowires (or nanorods) has been mainly fabricated using top-down plasma etching…
Diffraction drastically limits the bit density in optical data storage. To increase the storage density, alternative strategies involving supplementary recording dimensions and robust read-out schemes must be explored. Here, we propose to encode multiple bits of information in the geometry of subwavelength dielectric nanostructures. A crucial problem in high-density information storage concepts is the robustness of the information readout with respect to fabrication errors and experimental noise. Using a machine-learning based approach in which the scattering spectra are analyzed by an artific…
Low-loss photonic integrated circuits (PIC) and microresonators have enabled novel applications ranging from narrow-linewidth lasers, microwave photonics, to chip-scale optical frequency combs and quantum frequency conversion. To translate these results into a widespread technology, attaining ultralow optical losses with established foundry manufacturing is critical. Recent advances in fabrication of integrated Si3N4 photonics have shown that ultralow-loss, dispersion-engineered microresonators can be attained at die-level throughput. For emerging nonlinear applications such as integrated trav…
Thermophotovoltaics are promising solid-state energy converters for a variety of applications such as grid-scale energy storage, concentrating solar-thermal power, and waste heat recovery. Here, we report the design, fabrication, and testing of large area (0.8 cm$^2$), scalable, single junction 0.74-eV GaInAs thermophotovoltaic devices reaching an efficiency of 38.8$\pm$2.0% and an electrical power density of 3.78 W/cm$^2$ at an emitter temperature of 1850°C. Reaching such a high emitter temperature and power density without sacrificing efficiency is a direct result of combining good spectral …
As a derivative of graphene, graphene oxide (GO) was initially developed by chemists to emulate some of the key properties of graphene, but it was soon recognized as a unique material in its own right, addressing an application space that is not accessible to chemical vapor deposition based materials. Over the past decade, GO has emerged as a new frontier material with tremendous advances in its material fabrication and quality control over its properties. These in turn have led to rapid progress in GO based photonics, electronics, and optoelectronics concepts and devices, evoking new science …
