Power Sources For Electronics Research Articles

Lightweight energy harvesting backpack achieved with a slingshot-inspired flexible accelerator

The energy harvesting backpack (EHB) has been recognized as a sustainable power source for wearable electronics, but its daily applications have been hindered by the rigid and heavy frame and accelerator structure. Therefore, a flexible and lightweight design strategy for EHBs is proposed based on a slingshot-inspired flexible accelerator (FA). The proposed FA accomplishes the speed acceleration for harvester actuation by rapidly releasing accumulated elastic potential energy. Then, a 1.9 kg electromagnetic EHB with the FA (FA-EEHB) is modeled, tested, and applied to wearable electronics. Actuated by 3.0 Hz ultralow-frequency vibrations, the FA-EEHB with a 2.0 kg payload can generate 215.1 mW output power, which is over eight times the 26.6 mW output of an EHB without FA. With a small payload of 1.0 kg, the FA-EEHB can work well over a large traveling speed range from 4 km/h to 9 km/h. The application experiment of the FA-EEHB was conducted at 5 km/h traveling speed with a 2.0 kg payload to demonstrate the ability to continuously power a lamp, charge a smartphone, and sustain a tracking and positioning system. This study provides a distinctive strategy for the flexible and lightweight design of EHBs with small payloads.

Electrochemical transformation of 2D materials to their quantum dots

The term two-dimensional (2D) material refers to a single layer of monatomic units or molecules that reveals distinct electrical and optical properties and has received much attention recently due to its immense application potential. For example, graphene as a monolayer has captured intense efforts during the past decade, and other 2D materials like transition metal dichalcogenides, phosphorene, borophene, bismuthene, and stanene have also evolved for various applications such as nanoelectronics, hydrogen storage, supercapacitors, and solar cells. More recently, their heterostructures including Janus layers have also emerged with several exceptional electronic properties. Although there are several ways of synthesizing quantum dots of these exciting materials, electrochemical methods are especially relevant for preparing 2D materials (often in a size-controlled manner) from suitable precursors. More importantly, hetero-atom doping could also be carried out at room temperature when these materials are prepared by applying electric field without any major change in the morphology or size distribution after doping. With this disposition, we summarize the essential experimental methodology and a few mechanistic insights for the electrochemical synthesis of quantum dots from different 2D materials. This topic has not been discussed unambiguously in the past, lacking the proper motivation to emphasize the importance of controlling the electric field, substrate electrodes, precursors, and the role of counter ions during the synthesis. In this review, we concisely discuss the synthesis of such 0D materials by electrochemical methods, the mechanism, advantages, and limitations in comparison with other methods, along with the benefits ensued for a few selected applications. The genre of this category of work has always been intriguing despite the fact that only a few other groups are involved in the synthetic methodology, making the topic an everchanging field of exciting applications ranging from flexible power sources for wearable electronics to green electrocatalysts for sustainability and nano-sensors for biological applications.

Toward Flexible and Stretchable Organic Solar Cells: A Comprehensive Review of Transparent Conductive Electrodes, Photoactive Materials, and Device Performance

AbstractFlexible and stretchable organic solar cells (FOSCs and SOSCs) hold immense potential due to their versatility and applicability in emerging areas such as wearable electronics, foldable devices, and biointegrated systems. Despite these promising applications, several challenges remain, primarily related to the mechanical durability, material performance, and scalability required for commercialization. This review comprehensively highlights recent advancements in the design and fabrication of FOSCs and SOSCs, with a particular emphasis on key functional layers, including transparent conductive electrodes, interfacial layers, photoactive materials, and top electrodes. Innovations in material design, such as active layers and transparent conductive electrodes with improved flexibility, are discussed alongside developments in device processes to achieve power conversion efficiencies exceeding 19%. Furthermore, the review addresses remaining challenges, including the need for scalable manufacturing techniques and enhanced mechanical robustness under strain. Finally, the prospects of FOSCs and SOSCs are analyzed, providing insights into how these technologies can contribute to the development of sustainable, high‐performance power sources for wearable electronic devices and other flexible electronics. This review offers valuable insights, bringing the commercialization of wearable, high‐performance FOSCs and SOSCs closer to reality.

High‐performance triboelectric nanogenerators boosted by synergistically aligned piezoelectric/conductive composite nanofibers

AbstractTo address the need for efficient, flexible, and wearable power sources for portable electronics, a high performance triboelectric nanogenerator (TENG) was proposed by incorporating vertically‐aligned barium titanate (BaTiO3)/antimony tin oxide (ATO) nanofibers in polydimethylsiloxane (PDMS) negative triboelectric layer, where BaTiO3 served as piezoelectric material, and ATO served as conductive filler. Silver‐coated conductive fabric was used as electrode to ensure integrability and wearability. By strategically coupling the triboelectric effect of PDMS, the piezoelectric effect of BaTiO3 nanofibers, and the charge transfer effect of ATO nanofibers, the TENG exhibited the optimum output voltage and current of approximately 119 V and 28 μA, and power density of 11.74 μW/cm2, respectively. This device demonstrates its potential applications in energy supply by effectively illuminating 174 commercial green LEDs and charging capacitors for powering electronics. Additionally, the successful integration of the TENG into a smart fencing jacket highlights its utility in practical applications.Highlights TENGs with vertically‐aligned BaTiO3/ATO composite nanofibers was constructed. The output performance of TENGs were enhanced by coupling triboelectric and piezoelectric effects. Conductive ATO nanofibers were incorporated to enhance charge transfer for performance enhancement. A smart fencing jacket with scoring system was developed using the wearable TENG.

Carbon fiber with superhydrophilic interface as metal-free air electrode for all-solid-state Zn-air batteries

The burgeoning interest in all-solid-state Zn-air batteries as next-generation power sources for portable electronics is conspicuous. A pivotal aspect of their advancement lies in developing cost-effective, metal-free air electrodes with high-activity bifunctional oxygen electrocatalysts. This study introduces a superhydrophilic carbon fiber modified with oxygen functional groups (CF-O), achieved through a straightforward one-step activation treatment. Comparative analyses reveal that the CF-O electrode surpasses pristine CF in oxygen reduction and evolution reaction (OER and ORR) activity due to enhanced active sites and expedited ion transport. Notably, the OER/ORR performance depends on the type and quantity of oxygen functional groups. The optimal CF-O electrode displays an OER overpotential of 365.6 mV at 10 mA cm-2 and an ORR peak potential of 0.683 V. Utilizing the CF-O sample as the air electrode in all-solid-state Zn-air batteries yields an open-circuit voltage of 1.28 V and a peak volume power density of 82.8 mW cm-3. Furthermore, endurance testing reveals a charge/discharge voltage gap of 1.07 V at a current density of 1.0 mA cm-2 after 30 cycles. This facile and economical fabrication approach for metal-free air electrodes holds promise for advancing high-performance metal-air batteries compared to various existing techniques.

Review of recent trends of advancements in multilevel inverter topologies with reduced power switches and control techniques

AbstractCurrently, multilevel inverters (MLI) are comprehensively used to integrate renewable energy sources with the grid or high‐power applications. MLI has outstanding properties such as high‐level output voltage with tremendous power quality and negligible harmonics distortion. General MLI topologies have a more complex circuit, high overall cost and installation area. Due to a large number of power switches and isolation of control circuit, fewer power electronic switches and DC source along with its suitable control logic is the need of the hour. Therefore, a lot of research scope exists in this area. Here, some of the topologies with a fewer number of power switches are reviewed and scrutinized. An extensive analysis of the topologies, control strategy and applications are presented here, suggesting suitable multilevel inverter solutions to the known industrial application or new research.

Integrating dual heat sources to enhance thermoelectric generator power output

The escalating demand for sustainable power sources for wearable electronics necessitates innovative solutions. This study tackles the challenge of sustainably powering wearable electronics, addressing the limitations of traditional batteries. The approach utilizes a thermoelectric generator with a flexible and stretchable substrate that integrates the photothermal effect and human body temperature as a heat source. A unique strategy is employed to achieve this, involving the combination of 10 g of polydimethylsiloxane, 0.5 g of carbon nanotubes powder, 1 g of base curing agent, and 1.15 g of ethyl acetate mixture used as the novel substrate material. The proposed composite substrate is paired with p-type and n-type thermoelectric legs of bismuth antimony telluride (Bi0.4Sb1.6Te3) and bismuth selenium telluride (Bi1.7Te3.7Se0.3), respectively. This innovative design ensures high flexibility, stretchability, and conformability, facilitating seamless integration into wearable electronic devices. Experimental validation and simulation-based studies reveal a power density of 166.29 μW/cm2, sufficient for powering small-scale wearable electronics. The thermoelectric generator coupled with a novel composite substrate showed 65.6 % stretchability, further underscoring its durability and adaptability. The critical finding lies in the dual heat source integration, which collectively boosts power output and ensures year-round performance, pushing the boundaries of wearable energy harvesting technologies.

A Paper-Based Wearable Moist-Electric Generator for Sustained High-Efficiency Power Output and Enhanced Moisture Capture.

Disposable wearable electronics are valuable for diagnostic and healthcare purposes, reducing maintenance needs and enabling broad accessibility. However, integrating a reliable power supply is crucial for their advancement, but conventional power sources present significant challenges. To address that issue, a novel paper-based moist-electric generator is developed that harnesses ambient moisture for power generation. The device features gradients for functional groups and moisture adsorption and architecture of nanostructures within a disposable paper substrate. The nanoporous, gradient-formed spore-based biofilm and asymmetric electrode deposition enable sustained high-efficiency power output. AJanus hydrophobic-hydrophilic paper layer enhances moisture harvesting, ensuring effective operation even in low-humidity environments. This research reveals that the water adsorption gradient is crucial for performance under high humidity, whereas the functional group gradient is dominant under low humidity. The device delivers consistent performance across diverse conditions and flexibly conforms to various surfaces, making it ideal for wearable applications. Its eco-friendly, cost-effective, and disposable nature makes it a viable solution for widespread use with minimal environmental effects. This innovative approach overcomes the limitations of traditional power sources for wearable electronics, offering a sustainable solution for future disposable wearables. It significantly enhances personalized medicine through improved health monitoring and diagnostics.

Unveiling the energy-harnessing properties of free-standing Lithium Niobate/PVDF nanocomposite film toward biomechanical and wave energy harvesting

We demonstrated a facile fabrication of lithium niobate (LNO) nanostructures embedded in polyvinylidene fluoride (PVDF) using ultrasound irradiation followed by a solvent-casting method and assessed their use towards biomechanical and wave energy harvesting. The physicochemical characterizations of LNO/PVDF nanocomposite films, such as FE-SEM, FT-IR, laser-Raman, and mapping analyses, ensure the formation of uniformly dispersed LNO nanostructures in PVDF matrix with enhanced electroactive β-phase. A piezoelectric nanogenerator (PENG) was constructed using LNO/PVDF nanocomposite with different weight ratios of LNO, and their energy harvesting performances were investigated. The 5 wt.% LNO/PVDF PENG showed better energy harvesting properties, generating a high voltage of 44 V, short-circuit current of ∼0.45 µA, power density (2.2 µW cm−2), and excellent stability. The LNO/PVDF PENG, when placed in the human body, shows an output voltage of 2.6 V, even under minimal deformation applied to the device, suggesting better energy-conversion properties. To evaluate the wave energy harnessing property, the LNO/PVDF PENG was placed under water, which shows the difference in voltage output from 5.43 to 14.7 mV (low to high) with respect to the variation in wave energy. Our experimental findings ensure that LNO/PVDF PENG will act as a suitable power source for next-generation wearable and portable electronics.

The Voltage-Based Implementation of the Tunneling Mechanism in Aging Models for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have become one of the most crucial power sources for electronics and electric vehicles due to high energy density, long cycle life, environmental friendliness, etc. Precise explanation and prediction of the aging behavior of LIBs is quickly becoming a hotspot. A solid electrolyte interface (SEI) growth is regarded as the dominant factor of capacity losses in LIBs. However, the previous SEI growth and aging models were based on energy levels. That means the energy barrier related to the Fermi level of SEI and electrode was used as the input parameter. It is not straightforward to implement, especially for industrial applications. Furthermore, the state-of-charge (SoC) and the energy barrier were usually assumed to be constant during (dis)charging, contradicting common sense and affecting the calculations' accuracy.The present work proposes and experimentally validates an advanced voltage-based aging model. The voltage of the anode electrode is adopted as an input parameter in this model. It is easier to introduce dependence of aging on the voltage/SoC of the electrode with this model. It is found that deep delithiation of the anodes and lower SoC of LIBs will mitigate electron tunneling, lower SEI growth, and reduce calendar aging. Commonly used anode materials, such as graphite, Li4Ti5O12, and blended Si/C, are presented as interesting cases to investigate the effects of different electrode materials on the tunneling current profiles during (dis)charging for the first time. The model is instructive and can predict aging in LIBs with various electrode materials. This model and related analyses are beneficial for further optimizing LIB's electronic and electrode properties and as interesting limiting cases for testing battery modeling software.

Single-Anion Conductive Solid-State Electrolytes with Hierarchical Ionic Highways for Flexible Zinc-Air Battery.

Flexible zinc-air batteries are leading power sources for next-generation smart wearable electronics. However, flexible zinc-air batteries suffer from the highly-corrosive safety risk and limited lifespan due to the absence of reliable solid-state electrolytes (SSEs). Herein, a single-anion conductive SSE with high-safety is constructed by incorporating a highly amorphous dual-cation ionomer into a robust hybrid matrix of functional carbon nanotubes and polyacrylamide polymer. The as-fabricated SSE obtains dual-penetrating ionomer-polymer networks and hierarchical ionic highways, which contribute to mechanical robustness with 1200 % stretchability, decent water uptake and retention, and superhigh ion conductivity of 245 mS ⋅ cm-1 and good Zn anode reversibility. Remarkably, the flexible solid-state zinc-air batteries delivers a high specific capacity of 764 mAh ⋅ g-1 and peak power density of 152 mW ⋅ cm-2 as well as sustains excellent cycling stability for 1050 cycles (350 hours). This work offers a new paradigm of OH- conductors and broadens the definition and scope of OH- conductors.

Flexible Hybrid Supercapacitor Achieving 2.2V with NiCo2S4/Polyaniline/MnO2 and N, S-Co-Doped Carbon Nanofibers for Ultra-High Energy Density.

Flexible all-solid-state asymmetric supercapacitors (FAASC) represent a highly promising power sources for wearable electronics. However, their energy density is relatively less as compared to the conventional batteries. Herein, a novel ultra-high energy density FAASC is developed using nickel-cobalt sulfide (NiCo2S4)/polyaniline (PANI)/manganese dioxide (MnO2) ternary composite on carbon fiber felt (CF) as positive and N, S-co-doped carbon nanofibers (CNF)/CF as negative electrode, respectively. Initially, porous δ-MnO2 nanoworm-like network is decorated on CF using potentiodynamic method. Subsequently, interconnected PANI nanostructures is grown on the MnO2 via a facile in situ chemical polymerization, followed by the electrodeposition of highly porous NiCo2S4 nanowalls. Benefiting from 3D porous structure of conductive CF and redox active properties of NiCo2S4, PANI and MnO2, FAASC achieved a superior energy storage capacity. Later, high-performance N, S-co-doped CNF/CF negative electrode is synthesized using electropolymerization of PANI nanofibers on CF, followed by the carbonization process. The assembled FAASC exhibits a wide voltage window of 2.2V and remarkable specific capacitance of 143 F g-1 at a current density of 1 A g-1. The cell further delivers a superb energy density of 71.6Wh kg-1 at a power density of 492.7W kg-1, supreme cycle life and remarkable electrochemical stability under mechanical bending.

Exploring a New Class of PVDF/3‐Aminopropyltriethoxysilane (core) and 2,2‐Bis(hydroxymethyl)butyric Acid (monomer)‐Based Hyperbranched Polyester Hybrid Fibers by Electrospinning Technique for Enhancing Triboelectric Performance

AbstractWith the rapid advancement in sensor technologies, triboelectric nanogenerators (TENGs) have emerged as a promising sustainable power source for intelligent electronics. Herein, fabricated a novel 3‐aminopropyltriethoxysilane (core) and 2,2‐bis(hydroxymethyl)butyric acid (monomer)‐based hyperbranched polyester by facile single‐step polycondensation technique generation 2 (Si‐HBP‐G2). Further, a new class of polyvinylidene fluoride (PVDF) and different weight percentages (0, 5, 10, 15, and 20 wt%) of Si‐HBP‐G2 hybrid fiber blends are prepared by traditional electrospinning technique. The as‐prepared Si‐HBP‐G2 and its blends are well characterized using SEM/EDS, FTIR, NMR, and XRD studies. The influence of Si‐HBP‐G2 content on triboelectric performance in terms of the open circuit potential (VOC) and short circuit current (ISC) is evaluated using aluminum (Al) as a counter electrode. Among them, 15 wt% of Si‐HBP‐G2/PVDF hybrid fiber mat (PG2‐15) exhibits superior electrical performance. Which is almost increased 5.9 times (22–130 V) of VOC and 4.9 times (0.71–3.5 µA) of ISC than PVDF fiber mate. These results reveal the significance of Si‐HBP‐G2 in the triboelectric performance. The optimized TENG device (PG2‐15/Al‐TENG) exhibits a peak power density of 0.2 Wm−2 at 100 MΩ external load. Finally, the PG2‐15/Al‐TENG practically demonstrates real‐time application energy harvesting applications such as powering 100 LEDs and a stopwatch.

Synergistic energy harvesting and humidity sensing with single electrode triboelectric nanogenerator

Humidity sensors using triboelectric nanogenerators (TENGs) technology can provide continuous operation without the need for additional batteries. These sensors provide sustainable and self-powered humidity monitoring solutions, that can be utilized in various agriculture platforms and food processing industries. In this work, a sol-gel method is utilized to process the bismuth ferrite (abbreviated as BFO) materials and a simple mould pressing method to obtain freestanding Ethylene-vinyl acetate (abbreviated EVA)-BFO composites. These composites were characterized to shed light upon structural and microstructural properties. The single electrode mode operating TENG was fabricated having 2 cm × 2 cm active area at various wt.% of BFO onto EVA-based composites to compare the electrical response. The 5 wt.% BFO-EVA-based composites/FEP-based TENG generates a voltage and current of 45 V and 800 nA. Further, the TENG device was tested for long-term stability for 400 s, and charging of various capacitors having capacitance values such as 0.1 μF, 1 μF, 4.7 μF, and 10 μF along with 3 times charging/discharging cycles of 0.1 μF capacitor have been demonstrated. The humidity sensing mechanism elucidated which follows the conduction process based on the Grotthuss proton hopping mechanism. The TENG demonstrates a sensitivity of 0.53 V/RH% over the relative humidity range from 25 % to 85 %. The powering of the wristwatch confirms that fabricated TENG can be a reliable power source for future low-power electronics.

Three-dimensional high-aspect-ratio microarray thick electrodes for high-rate hybrid supercapacitors

Hybrid supercapacitors (HSCs) with facile integration and high process compatibility are considered ideal power sources for portable consumer electronics. However, as a crucial component for storing energy, traditional thin-film electrodes exhibit low energy density. Although increasing the thickness of thin films can enhance the energy density of the electrodes, it gives rise to issues such as poor mechanical stability and long electron/ion transport pathways. Constructing a stable three-dimensional (3D) ordered thick electrode is considered the key to addressing the aforementioned contradictions. In this work, a manufacturing process combining lithography and chemical deposition techniques is developed to produce large-area and high-aspect-ratio 3D nickel ordered cylindrical array (NiOCA) current collectors. Positive electrodes loaded with nickel–cobalt bimetallic hydroxide (NiOCA/NiCo-LDH) are constructed by electrodeposition, and HSCs are assembled with NiOCA/nitrogen-doped porous carbon (NiOCA/NPC) as negative electrodes. The HSCs exhibits 55% capacity retention with the current density ranging from 2 to 50 mA cm−2. Moreover, it maintains 98.2% of the initial capacity after long-term cycling of 15,000 cycles at a current density of 10 mA cm−2. The manufacturing process demonstrates customizability and favorable repeatability. It is anticipated to provide innovative concepts for the large-scale production of 3D microarray thick electrodes for high-performance energy storage system.

Wedge-shape Al and Mg co-doped zinc oxide thin films: A Facile Route to achieve high thermoelectric power factor

Thin film thermoelectric technology has immense potential to become a next-generation power source for small-scale electronics. However, the rapid development of thin film thermoelectric still lacks a controllable structural design to improve the performance of thermoelectric devices for required temperature applications. This work presented a controlled thermoelectric design of ZnO-based thin films by Al and Mg co-doping using ALD. Herein, the Mg-doped ZnO sample exhibits the highest Seebeck coefficient of −311.83 μVK−1 at 500oC, while the maximum thermoelectric power factor of 3.68 μWcm−1K−2 is obtained at 300oC, which drops for higher temperatures. This decrease in power factor resulted from the reduction in electrical conductivity above 300oC. Similarly, the Al and Mg co-doped ZnO sample (Mg/Al ≈2 at%) exhibits a high thermoelectric power factor of 3.85 μWcm−1K−2 for ZnO based material due to its moderate electrical conductivity and Seebeck coefficient value at 325oC and behave monotonically for elevated temperatures. Scanning electron microscope (SEM) images show the formation of wedge-shaped structures for Al-incorporated samples, which helps to boost the overall thermoelectric performance. Additionally, we performed XRD, UV–Vis, Hall, and AFM analysis to get a deep insight into structural, optical, electrical, and surface features of the grown thin films and their linkage with the thermoelectric properties.

High-Performance Bifunctional Electrocatalysts for Flexible and Rechargeable Zn-Air Batteries: Recent Advances.

Flexible rechargeable Zn-air batteries (FZABs) exhibit high energy density, ultra-thin, lightweight, green, and safe features, and are considered as one of the ideal power sources for flexible wearable electronics. However, the slow and high overpotential oxygen reaction at the air cathode has become one of the key factors restricting the development of FZABs. The improvement of activity and stability of bifunctional catalysts has become a top priority. At the same time, FZABs should maintain the battery performance under different bending and twisting conditions, and the design of the overall structure of FZABs is also important. Based on the understanding of the three typical configurations and working principles of FZABs, this work highlights two common strategies for applying bifunctional catalysts to FZABs: 1) powder-based flexible air cathode and 2) flexible self-supported air cathode. It summarizes the recent advances in bifunctional oxygen electrocatalysts and explores the various types of catalyst structures as well as the related mechanistic understanding. Based on the latest catalyst research advances, this paper introduces and discusses various structure modulation strategies and expects to guide the synthesis and preparation of efficient bifunctional catalysts. Finally, the current status and challenges of bifunctional catalyst research in FZABs are summarized.

A high-performance dual-mode energy harvesting with nonlinear pendulum and speed-amplified mechanisms for low-frequency applications

Vibrations induced by human motions and vehicle operations feature low-frequency, broadband, and time-varying. However, enhancing the power density of energy harvesting for various low-frequency applications presents a significant challenge. This paper proposes a high-performance dual-mode energy harvester (DM-EH) incorporating coupled nonlinear pendulum and speed-amplified mechanisms with gears for the simultaneous scavenging vibration and rotation energy. The pendulum serves as the energy capture unit for detecting vibration energy while ensuring the effective operation of the generation unit in rotational environments. The gears amplify the speed of the excitation and enable frequency up-conversion, thereby enhancing the energy conversion. Experimental results substantiate the DM-EH's ability to extract power from vehicle operations at speeds ranging from 60 to 540 rpm, as well as from human motions at frequencies of 0.7–1.5 Hz with 30° amplitudes. In rotation mode, the prototype achieves a maximum average direct current power of 3.79 W, while in vibration mode, it attains 244 mW. The prototype successfully powers portable electronics and supports battery-free triaxial acceleration and temperature multi-sensors during human motions and railway simulation tests. This prototype showcases immense potential as a sustainable power source for portable electronics and self-powered monitoring applications.

Highly adhesive hydrogel electrolytes driven by adenosine monophosphate and Fe3+ for high-voltage asymmetric flexible zinc-air batteries

Flexible zinc-air batteries (ZABs) are a promising power source for wearable electronics, owing to their high energy density and low cost. However, the limited operating voltage of about 1.4 V and the complex external packaging of conventional ZABs hinder their practical application. Herein, a hydrogel electrolyte (PAMA-ANa/Fe3+) is rapidly prepared for flexible ZABs using copolymers of acrylamide and acrylic acidic (PAMA), along with sodium adenosine-5′-monophosphate (AMPNa) and Fe3+. By leveraging the synergistic effects of exceptional mechanical properties, strong adhesion and the acidic-alkaline decoupling of the PAMA-ANa/Fe3+ hydrogel electrolyte, an asymmetric flexible ZAB (AF-ZAB) based on an acidic-alkaline double-layer PAMA-ANa/Fe3+ hydrogel electrolyte is assembled in a simple and rapid manner. This AF-ZAB achieves an excellent operating voltage of 2.15 V and a high power density of 75.86 mW cm−2. This study provides a new method and strategy for the development and assembly of novel high-voltage flexible quasi-solid-state batteries and other energy storage devices.

Asymmetric Zn-N4 atomic sites embedded hollow fibers as stable Zn anode for high-performance Zn-ion hybrid capacitor

Zn based electrochemical energy storage systems (EES) have attracted tremendous interests owing to their low cost and high intrinsic safety. Nevertheless, the uncontrolled growth of Zn dendrites and the side reactions of Zn metal anodes (ZMAs) severely restrict their applications. To address these issues, we design the asymmetric Zn-N4 atomic sites embedded hollow fibers (AS-IHF) as the flexible host for stable ZMAs. Through introducing different nitrogen resources in the synthesis, two kinds of coordination, i. e. Zn-N (pyridinic) and Zn-N (pyrrolic), are introduced in the Zn-N4 atomic module synchronously. The asymmetric Zn-N4 module with regulated micro-environment facilitates the superior zincophilic features and promotes the Zn adsorption. Meanwhile, the highly porous structure of the hollow fiber effectively reduces local current density, homogenize Zn ion flux, and alleviate structure stress. All the advantages endow the high efficiency and good stability for Zn plating/stripping. Both theoretical and experimental results demonstrate the high reversibility, low nucleation overpotential, and dendrite-free behavior of the AS-IHF@Zn anode, which afford the high stability in high-rate and long-term cycling. Moreover, the solid-state Zn-ion hybrid capacitor (ZIHC) based on AS-IHF@Zn anode shows the high flexibility, reliability, and superior long-term cycling capability in a wide-range of temperatures (−20–25 °C). Therefore, the present work not only gives a new strategy for modulating local environments of single atomic sites, but also propels the development of flexible power sources for diverse electronics.