Wearable Self-powered Systems Research Articles

A Self-Sensing and Self-Powered Wearable System Based on Multi-Source Human Motion Energy Harvesting.

Wearable devices play an indispensable role in modern life, and the human body contains multiple wasted energies available for wearable devices. This study proposes a self-sensing and self-powered wearable system (SS-WS) based on scavenging waist motion energy and knee negative energy. The proposed SS-WS consists of a three-degree-of-freedom triboelectric nanogenerator (TDF-TENG) and a negative energy harvester (NEH). The TDF-TENG is driven by waist motion energy and the generated triboelectric signals are processed by deep learning for recognizing the human motion. The triboelectric signals generated by TDF-TENG can accurately recognize the motion state after processing based on Gate Recurrent Unit deep learning model. With double frequency up-conversion, the NEH recovers knee negative energy generation for powering wearable devices. A model wearing the single energy harvester can generate the power of 27.01mW when the movement speed is 8km h-1, and the power density of NEH reaches 0.3W kg-1 at an external excitation condition of 3Hz. Experiments and analysis prove that the proposed SS-WS can realize self-sensing and effectively power wearable devices.

A Fully Self-Powered Wearable Leg Movement Sensing System for Human Health Monitoring.

Energy-autonomous wearable human activity monitoring is imperative for daily healthcare, benefiting from long-term sustainable uses. Herein, a fully self-powered wearable system, enabling real-time monitoring and assessments of human multimodal health parameters including knee joint movement, metabolic energy, locomotion speed, and skin temperature, which are fully self-powered by highly-efficient flexible thermoelectric generators (f-TEGs) is proposed and developed. The wearable system is composed of f-TEGs, fabric strain sensors, ultra-low-power edge computing, and Bluetooth. The f-TEGs worn on the leg not only harvest energy from body heat and supply power sustainably for the whole monitoring system, but also serve as zero-power motion sensors to detect limb movement and skin temperature. The fabric strain sensor made by printing PEDOT: PSS on pre-stretched nylon fiber-wrapped rubber band enables high-fidelity and ultralow-power measurements on highly-dynamic knee movements. Edge computing is elaborately designed to estimate multimodal health parameters including time-varying metabolic energy in real-time, which are wirelessly transmitted via Bluetooth. The whole monitoring system is operated automatically and intelligently, works sustainably in both static and dynamic states, and is fully self-powered by the f-TEGs.

MOF-derived porous Ni/C material for high-performance hybrid nanogenerator and self-powered wearable sensor

This study proposed a self-powered bio-sensing positioning system driven by MOF-derived porous Ni/C material-based hybrid nanogenerator. The porous structure of Ni/C nanoparticles provides a high specific surface area, increases the capacitance of the nano-composite, and traps more charges due to the formation of micro-capacitors, which boost the performance of TENGs. The as-fabricated enhanced TENG achieved a peak voltage of 820 V and a power density of 10.1 W/m2. An optimal bilayer structure was determined through experiments and simulations to obtain the maximum output performance. Flexible TENGs are placed on various parts of the body to achieve biomechanical energy harvesting and motion monitoring, and provide power sources for small electronics. By combining with electromagnetic generator (EMG), a wearable self-powered positioning system is constructed. This work provides a new idea to enhance the output of TENG, and broadens the application of TENG in self-powered wearable systems.

The Applications of Nano-Piezoelectric Composite in Flexible Wearable Self-Powered System

Nanomaterials have permeated every sphere of life, industry, and research. Due to the unique piezoelectric properties of nanometer materials and piezoelectric types, it is possible to convert mechanical energy into electricity by certain mathematical relationships, equivalent to the energy supply for equipment. This capability allows for the creation of sensitive sensor elements that can perceive the external environment on various levels, including thermal, mechanical, electrical, and optical. The generation of piezoelectric nanogenerators indicates that nanomaterials devices can be expected to achieve a natural self-powered system without external power or only provide a small amount of energy, and play an irreplaceable role in the fields of microelectronics, artificial intelligence, and human-computer interaction. In this review, examples of nano-piezoelectric ceramic materials and nano-piezoelectric polymers that can be applied to flexible self-powered systems are listed, and the advantages and problems of these two kinds of materials in flexible self-powered systems are comprehensively analyzed. This paper focuses on the performance improvement of 0-3 nano-composites on the original piezoelectric ceramics and polymer materials and their application in the flexible wearable self-powered system. In addition, it summarizes the difficulties and challenges in their practical applications and provides future research directions for researchers.

Manipulating Hierarchical Orientation of Wet-Spun Hybrid Fibers via Rheological Engineering for Zn-Ion Fiber Batteries.

Wet-spinning is a promising strategy to fabricate fiber electrodes for real commercial fiber battery applications, according to its great compatibility with large-scale fiber production. However, engineering the rheological properties of the electrochemical active materials to accommodate the viscoelasticity or liquid crystalline requirements for continuous wet-spinning remains a daunting challenge. Here, with entropy-driven volume-exclusion effects, the rheological behavior of vanadium pentoxide (V2 O5 ) nanowire dispersions is regulated through introducing 2D graphene oxide (GO) flakes in an optimal ratio. By optimizing the viscoelasticity and liquid-crystalline behavior of the spinning dope, the wet-spun hybrid fibers display controlled hierarchical orientation. The wet-spun V2 O5 /rGO hybrid fiber with the optimal 10:1 mass fraction (V2 O5 /rGO10:1 ) exhibits a highly oriented nanoblock arrangement, enabling efficient Zn-ion migration and an excellent Zn-ion storage capacity of 486.03 mAh g-1 at 0.1 A g-1 . A half-meter long quasi-solid-state fiber Zn-ion battery is assembled with a polyacrylamide gel electrolyte and biocompatible Ecoflex encapsulation. The thus-derived fiber Zn-ion battery is integrated into a wearable self-powered system, incorporating a highly efficient GaAs solar cell, which delivers a record-high overall efficiency (9.80%) for flexible solar charging systems.

Smart multi-responsive aramid aerogel fiber enabled self-powered fabrics

Wearable electronics and systems with self-powered real-time responses to various stimuli, such as mechanical, electrical, thermal and optical signals，are eagerly desired, however still remain great challenges. Herein, smart fibers with multi-response to external stimuli are developed via wet spinning porous aramid aerogel nanofibers while utilized as a three-dimensional hierarchical percolating skeleton for silver nanowires (AgNWs) interwoven MXene conductive network. The coaxial AgNWs/MXene@ aramid aerogel nanofibers with entangled heterostructures effectively avoid “trade-off” effect between high electrical conductivity and mechanical flexibility of smart fibers. Meanwhile, the hierarchical porous structure of aerogel conductive fibers induced strong capillary force and confinement to polyethylene glycol, which has a wide range of phase transition temperature and huge enthalpy to store tremendous thermal energy. After further encapsulated with transparent fluorosilicone resin, the stabilized smart fiber exhibits excellent self-cleaning properties with water and oil repellent. Furthermore, the woven aerogel fabrics coupled with thermoelectric generator realized efficient reversible energy conversion and storage as well as solar-thermal-electrical power generation for all-weather electricity power supply, which could drive the operation of wearable electronics and car models without batteries, providing an efficient strategy for outdoor travel and lunar rover continuous operating. The smart aramid aerogel fibers and fabrics hold great promise for next generation of self-powered wearable systems.

Reverse Electrowetting-on-Dielectric Energy Harvesting Using 3-D Printed Flexible Electrodes for Self-Powered Wearable Sensors

Reverse electrowetting-on-dielectric (REWOD) presents a unique low-frequency motion energy harvesting method to self-power wearable sensors for human health monitoring in real-time. However, previous studies in REWOD energy harvesting have mainly focused on enhancing power density using rigid electrodes, which due to their rigidity, are not ideal to be implemented as wearable energy harvesting or motion sensing applications from human motion activities. To be considered as the next generation self-powered wearable sensors, self-powered wearable sensors should operate continuously and sustainably in any kind of electrode bending motion and without an external power source. Herein, we demonstrate ac current generation by repeatedly modulating a liquid droplet of microliter volume on an elastomer-based three-dimensional printed flexible electrode without any external bias source. Flexible electrodes were fabricated by deposition of ∼200 nm of titanium (Ti) and an additional ∼200 nm of aluminum oxide (Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) along with ∼50 nm of chromium (Cr) as an interlayer between the metal and the dielectric layers, and all of these on a flexible polydimethylsiloxane substrate. Using a 50 μL electrolyte droplet and 2.5 mm of electrode displacement at a low-frequency motion of 1–2 Hz, a maximum peak-to-peak ac current of ∼340 nA was measured. Although significant progress has yet to be made toward implementing REWOD energy harvesting as a reliable source of power for wearable self-powered systems, this letter signifies the proof-of-concept in implementing flexible electrodes in REWOD energy harvesting.

A Non-Resonant Piezoelectric-Electromagnetic-Triboelectric Hybrid Energy Harvester for Low-Frequency Human Motions.

With the rapid development of wireless communication and micro-power technologies, smart wearable devices with various functionalities appear more and more in our daily lives. Nevertheless, they normally possess short battery life and need to be recharged with external power sources with a long charging time, which seriously affects the user experience. To help extend the battery life or even replace it, a non-resonant piezoelectric–electromagnetic–triboelectric hybrid energy harvester is presented to effectively harvest energy from low-frequency human motions. In the designed structure, a moving magnet is used to simultaneously excite the three integrated energy collection units (i.e., piezoelectric, electromagnetic, and triboelectric) with a synergistic effect, such that the overall output power and energy-harvesting efficiency of the hybrid device can be greatly improved under various excitations. The experimental results show that with a vibration frequency of 4 Hz and a displacement of 200 mm, the hybrid energy harvester obtains a maximum output power of 26.17 mW at 70 kΩ for one piezoelectric generator (PEG) unit, 87.1 mW at 500 Ω for one electromagnetic generator (EMG) unit, and 63 μW at 140 MΩ for one triboelectric nanogenerator (TENG) unit, respectively. Then, the generated outputs are adopted for capacitor charging, which reveals that the performance of the three-unit integration is remarkably stronger than that of individual units. Finally, the practical energy-harvesting experiments conducted on various body parts such as wrist, calf, hand, and waist indicate that the proposed hybrid energy harvester has promising application potential in constructing a self-powered wearable system as the sustainable power source.

3D‐Printed Wearable Electrochemical Energy Devices (Adv. Funct. Mater. 3/2022)

Wearable Electrochemical Energy Devices In article number 2103092, Gordon G. Wallace, Jun Chen, and co-workers summarize the recent developments in additive manufacturing of wearable thermocells, batteries, and supercapacitors. This unique prototype provides an alternative perspective with the potential to promote self-powered wearable systems for specific applications.

Wearable Thermoelectric Materials and Devices for Self-Powered Electronic Systems.

The emergence of artificial intelligence and the Internet of Things has led to a growing demand for wearable and maintenance-free power sources. The continual push toward lower operating voltages and power consumption in modern integrated circuits has made the development of devices powered by body heat finally feasible. In this context, thermoelectric (TE) materials have emerged as promising candidates for the effective conversion of body heat into electricity to power wearable devices without being limited by environmental conditions. Driven by rapid advances in processing technology and the performance of TE materials over the past two decades, wearable thermoelectric generators (WTEGs) have gradually become more flexible and stretchable so that they can be used on complex and dynamic surfaces. In this review, the functional materials, processing techniques, and strategies for the device design of different types of WTEGs are comprehensively covered. Wearable self-powered systems based on WTEGs are summarized, including multi-function TE modules, hybrid energy harvesting, and all-in-one energy devices. Challenges in organic TE materials, interfacial engineering, and assessments of device performance are discussed, and suggestions for future developments in the area are provided. This review will promote the rapid implementation of wearable TE materials and devices in self-powered electronic systems.

High power density of radiative-cooled compact thermoelectric generator based on body heat harvesting

Advancements in flexible and wearable electronics have led to the development of self-powered, wearable systems. Thermoelectric generators (TEGs) offer promising solutions toward self-powered energy harvesting from body heat. However, previously developed TEGs are large-sized owing to their heat sinks. Hence, high-quality heat sinks are required for flexible TEGs with a small size and high power for wearable devices. Herein, a TEG integrated with a flexible, micron-thin poly(vinylidene fluoride-co-hexafluoropropylene) radiative-cooled heat sink, with an emissivity of 97.47%, is proposed. The TEG with the radiative heat sink (TEG_rad) generates power by depositing heat into a cold space (temperature of 3 K) through passive radiative cooling. Thus, TEG_rad achieved a power density of 12.48 µW/cm 2 with a temperature difference (Δ T ) of 1.9 °C, higher than those of flexible TEGs that were previously reported, based on body heat harvesting under natural convection. Further, TEG_rad is not only more than two times compact, but also delivers high power output compared with a TEG with a bulky finned heat sink. Moreover, a flexible lithium–sulfur (Li-S) battery was coupled with TEG_rad to store the generated power for uninterrupted power supply to a self-powered wearable system. Integrated wearable radiative-cooled compact thermoelectric generator and Li-S battery system to offer high power density based on body heat harvesting. • Novel design of wearable thermoelectric generator with high emissivity of P(VdF-HFP) micron thin radiative heat sink. • Power output of TEG_rad outperformed TEG_fin during daytime and nighttime. • TEG_rad achieves highest power density of 12.48 µW/cm 2 based on body heat harvesting under natural convection condition. • Integration of flexible thermoelectric-Li-S system.

A passive perspiration biofuel cell: High energy return on investment

<h2>Summary</h2> Self-powered wearable systems that rely on bioenergy harvesters commonly require excessive energy inputs from the human body and are highly inefficient when accounting for the overall energy expenses. A harvester independent from the external environment for sedentary states has yet to be developed. Herein, we present a touch-based lactate biofuel cell that leverages the high passive perspiration rate of fingertips for bioenergy harvesting. Powered by finger contact, such a bioenergy-harvesting process can continuously collect hundreds of mJ of energy during sleep without movements, representing the most efficient approach compared to any reported on-body harvesters. To maximize the energy harvesting, complementary piezoelectric generators were integrated under the biofuel cell to further scavenge mechanical energy from the finger presses. The harvesters can rapidly and efficiently power sensors and electrochromic displays to enable independent self-powered sensing. The passive perspiration-based harvester establishes a practical example of remarkably high energy return on investment for future self-sustainable electronic systems.

Microfluidic-Architected Nanoarrays/Porous Core-Shell Fibers toward Robust Micro-Energy-Storage.

Methods enabling the controllable fabrication of orderly structural and active nanomaterials, along with high‐speed ionic pathways for charge migration and storage are highly fundamental in fiber‐shaped micro‐supercapacitors (MSCs). However, due to fiber‐electrodes with compact internal microstructure and less porosity, MSCs usually display a low energy density. Here, an innovative microfluidic strategy is proposed to design ordered porous and anisotropic core–shell fibers based on nickel oxide arrays/graphene nanomaterials. Owing to the homogeneous microchannels reaction, the graphene core maintains a uniformly anisotropic porous structure, and the nickel oxide shell keeps steadily vertically aligned nanosheets. The MSC presents an ultrahigh energy density (120.3 µWh cm−2) and large specific capacitance (605.9 mF cm−2). This higher performance originates from the microfluidic‐architected core–shell fiber with abundant ionic channels (plentiful micro‐/mesopores), large specific‐surface‐area (425.6 m2 g−1), higher electrical conductivity (176.6 S cm−1), and sufficient redox activity, facilitating ions with quicker diffusion and greater accumulation. Considering those outstanding properties, a wearable self‐powered system, converting and storing solar energy into electric energy, is designed to light up displays. This microfluidic strategy offers an effective way to design new structural materials, which will advance the development of next‐generation wearable/smart industries.

Flexible heatsink based on a phase-change material for a wearable thermoelectric generator

Thermoelectric generators (TEGs) represent a promising technology for self-powered wearable systems. Since the conventional TEGs have limitation to be used on the human body due to its structural rigidity, flexible TEGs have been studied and developed so that TEGs can be attached to an arbitrarily shaped surface on the human body. However, flexible TEGs require a good heatsink with good flexibility to allow them to produce enough power for wearable devices. In this study, a high-performance flexible heatsink based on a phase-change material (PCM) was proposed. PCM blocks were arranged in an array and good flexibility was realized with an elastomer that filled the space between the PCM blocks. Given that PCM can absorb a large amount of heat at the phase-change temperature, the heatsink can hold the temperature difference across the TEG constant for a relatively long period of time. Thus, the generated power from the flexible TEG was maintained at around 20 μW/cm2 for 33 min. The flexible heatsink can be reused because the PCM solidifies at room temperature. Furthermore, the PCM-based flexible heatsink is smaller and lighter than the conventional metal heatsink. The proposed heatsink is expected to contribute to the commercialization of self-powered wearable devices.

(Invited) Flexible Multifunctional III-N Semiconductor Materials and Devices for Energy Applications

We present recent development in flexible wide-bandgap semiconductor materials and devices. Especially, we focus on mechanically bendable group-III-nitride (III-N) thin-film heterostructures and their photonic, electronic, and energy-harvesting devices in energy applications. The presentation will cover various topics including (1) multi-functionality of flexible III-N devices, (2) direct growth of high-quality single-crystal-like GaN semiconductor thin films on low-cost flexible metal tapes, and (3) piezoelectric generators and sensors for self-powered wearable systems by harvesting and sensing ambient biomechanical energy. Flexible III-N thin-film heterostructures have an implication of more than just mechanically flexible materials. Bendable devices based on III-N heterostructures can be equipped with new functionalities and even further improved performance characteristics using a new concept of active polarization engineering by controlled external strains. We propose to develop multi-functional and/or further-improved-performance devices by utilizing the interactions between electronic and optical properties and mechanical forces in the flexible III-N heterostructures. The concept will enable new mechano-electro-photonic (MEP) devices. We will show by device modeling that new device concept in flexible transistors based on AlGaInN/GaN heterostructure is possible, including modulation of 2-dimensional electron gas (2DEG) density by bending, strain-effect transistors (Figure 1: I-V characteristics of strain-effect transistors), and high-hole-mobility transistors. Furthermore, photon emitters based on flexible III-N heterostructure can result in higher internal quantum efficiency (IQE), higher wall-plug efficiency (WPE), and color modulation by optimum bending conditions (Figure 2: Concept of color-tunable white light-emitting diodes). We study and develop nearly-single-crystalline GaN thin film on flexible metal tapes by a direct deposition technique for the demonstration of a new wide-bandgap semiconductor platform, targeting high-performance yet economical, flexible, and versatile device technology. Data and analysis are presented for the single-crystal-like film, as representatively shown in Figure 3 (Flexible hybrid tape substrate consisting of GaN thin film and Cu tape with crystallinity-transformational buffer layers). Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. We develop a flexible piezoelectric generator (F-PEG) with chemically stable and biocompatible III-N thin film. Data and analysis are presented for the flexible III-N F-PEG. We also demonstrate that the F-PEG can directly power electronics such as light-emitting diodes and electric watches, and charge commercial capacitors and batteries to operate an optical pulse sensor, as representatively shown in Figure 4 (Pulse sensor powered by F-PEG and heart rate measurement on a fingertip). Figure 1

Multilayered fiber-based triboelectric nanogenerator with high performance for biomechanical energy harvesting

With a rapid development of various wearable electronics, self-powered system and triboelectric nanogenerator (TENG) have attracted increasingly widespread attention. Tremendous efforts have been devoted to seeking effective approaches to increase the triboelectric charge density of friction surfaces and thus further boost the output performance of TENG. Here, we designed a multilayered fiber-based TENG to greatly enhance the charge density by creatively introducing a charge-transport layer and a charge-storage layer in the composite structure. The introduced conductive material and dielectric material could effectively increase the transfer rate and storage depth of triboelectric charges during the triboelectrification process. The short-circuit current and open-circuit voltage of the three-layer structured TENG were distinctively 3.07 times and 2.56 times larger respectively compared with the single-layer structured TENG. The power density of three-layer structured TENG with an effective area of 9 cm2 can reach as high as 0.13 W/m2 under a frequency of 3 Hz. The fabricated TENG can be integrated into a commercial kneepad to harvest versatile biomechanical energy from human motions. Besides, the composite TENG was demonstrated to sustainably drive some small wearable or portable electronics such as electronic watch, commercial thermometer and calculator. This presented work provides an innovative and effective approach to design novel mechanical energy-conversion devices with high performance for practical applications in the field of self-powered wearable system.

Laser direct writing of carbon-based micro-supercapacitors and electronic devices

Micro-supercapacitors (MSCs) are recognized as potential power supply units for on-chip micro-devices because they possess not only the advantages of supercapacitors but also the simplified packaging processes and compatibility with integrated circuits. Laser direct writing technique has been demonstrated as an effective tool for the fabrication of micro-supercapacitors and electronic devices using different materials. However, the high-performance micro-supercapacitors and the integration with electronic devices even the portable or wearable self-powered systems fabricated by the laser direct writing technique or in combination with other techniques still need to be demonstrated. In this paper, we will introduce our recent studies on the following several parts: the preparation of carbon-based micro-supercapacitors by laser direct writing on polyimide films in air, the improvement of the carbon MSC by laser direct writing in Ar, the carbon/TiO2 MSC with photo-rechargeable capability, the carbon/Au MSC with high-rate charge–discharge performance, and the in-plane integrated circuits with MSCs and sensors using the laser direct writing technique combining with other methods.

Concurrent Harvesting of Ambient Energy by Hybrid Nanogenerators for Wearable Self-Powered Systems and Active Remote Sensing.

Harvesting energy available from ambient environment is highly desirable for powering personal electronics and health applications. Due to natural process and human activities, steam can be produced by boilers, human perspiration, and the wind exists ubiquitously. In the outdoor environment, these two phenomena usually exist at the same place, which contain heat and mechanical energies simultaneously. However, previous studies have isolated them as separate sources of energy to harvest and hence failed to utilize them effectively. Herein, we present unique hybrid nanogenerators for individually/simultaneously harvesting thermal energy from water vapors and mechanical energy from intermittent wind blowing from the bottom side, which consist of a wind-driven triboelectric nanogenerator (TENG) and pyroelectric-piezoelectric nanogenerators (PPENGs). The output power of the PPENG and the TENG can be up to about 184.32 μW and 4.74 mW, respectively, indicating the TENG plays the dominant role. Our hybrid nanogenerators could provide different applications such as to power digital watch and enable self-powered sensing with wireless transmission. The device could also be further integrated into a face mask for potentially wearable applications. This work not only provides a promising approach for renewable energy harvesting but also enriches potential applications for self-powered systems and wireless sensors.

Printable Fabrication of Nanocoral‐Structured Electrodes for High‐Performance Flexible and Planar Supercapacitor with Artistic Design

Planar supercapacitors with high flexibility, desirable operation safety, and high performance are considered as attractive candidates to serve as energy-storage devices for portable and wearable electronics. Here, a scalable and printable technique is adopted to construct novel and unique hierarchical nanocoral structures as the interdigitated electrodes on flexible substrates. The as-fabricated flexible all-solid-state planar supercapacitors with nanocoral structures achieve areal capacitance up to 52.9 mF cm-2 , which is 2.5 times that of devices without nanocoral structures, and this figure-of-merit is among the highest in the literature for the same category of devices. More interestingly, due to utilization of the inkjet-printing technique, excellent versatility on electrode-pattern artistic design is achieved. Particularly, working supercapacitors with artistically designed patterns are demonstrated. Meanwhile, the high scalability of such a printable method is also demonstrated by fabrication of large-sized artistic supercapacitors serving as energy-storage devices in a wearable self-powered system as a proof of concept.

(Invited) Cost-Effective Fabrication of Nanostructured Electrodes for High-Performance Flexible Supercapacitors

The blooming market of portable and wearable electronic devices has triggered research interest in energy storage devices that combine both high performance and attractive form factors. Planar supercapacitors are considered as favorable alternatives or complements to batteries, especially to serve as highly flexible, environmentally-friendly and high performance energy storage devices for portable and wearable electronics. In this work, a scalable and printable method was developed to fabricate flexible planar supercapacitors. By using a cost-effective inkjet printing technique, novel and unique hierarchical Nickel (Ni)@Manganese dioxide (MnO2) nanocoral structures were constructed as the interdigitated electrodes on flexible substrates. The as-fabricated flexible all-solid-state planar supercapcacitor achieved an areal capacitance of 52.9 mF cm-2 with enhanced specific power and energy, and such a performance parameter is among the highest in literature for the same category of devices. More interestingly, the inkjet printing technique realized pattern designs with excellent versatility and working supercapacitors with various artistically designed patterns are demonstrated here. Meanwhile, the high scalability of such printable method was also demonstrated by fabrication of large size “power papers”, which successfully served as energy storage devices in wearable self-powered system to power up light emitting and gas detection devices.