Ideal Power Source Research Articles

Tri-objective and multi-parameter geometric optimization of two-stage radioisotope thermoelectric generator based on NSGA-II

Radioisotope thermoelectric generator (RTG) is one of ideal power sources for deep space exploration due to the long service life and high stability. To further extend service life and improve electrical output, this study is first to simultaneously optimize electrical output and mechanical stability induced by thermal stress of the two-stage RTG using non-dominated sorting genetic algorithm-II. Skutterudite and bismuth telluride are used as the thermoelectric materials in hot-stage and cold-stage thermoelectric generators, respectively. The maximum von Mises stress of the skutterudite-stage (VonSKD) and bismuth telluride-stage (VonBT) thermoelectric generator and the conversion efficiency of the two-stage RTG (ηtwo) are set to the three objectives, and twelve geometrical parameters of two-stage RTG are used as variables. Electrical output and mechanical stability are simulated with COMSOL 6.0 Multiphysics software based on the finite element method. Results show that the ranges of ηtwo, VonSKD, and VonBT in the Pareto front are 4.81–7.57 %, 112.2–228.46 and 19.24–87.33 MPa, respectively, when the temperature difference is 300 K. TOPSIS decision-making method is used to select the specific optimal solution on the Pareto front according to the weight of the different objectives. Comparisons between tri- and bi-objective as well as single-stage optimization are also carried. Results show that there are strong influences among these three objectives. The performance of one objective would improve at the expense of the performance of the remaining objectives decrease if a larger weight was given. The VonSKD has the greatest importance among the three objectives, followed by ηtwo, and the smallest is VonBT. Skutterudite-stage thermoelectric generator should be particularly considered in the design of two-stage RTGs. The two-stage RTGs with different weight factors exhibit different electrical performances due to different geometrical parameters. This research can provide references for two-stage thermoelectric generators in more scenarios to improve electrical performances and extend service life.

A novel Al/BiCl3/γ-Al2O3 composite for small-sized fuel cell: Fabrication, performance and mechanisms

Small-sized fuel cell is an ideal and promising power source for portable devices due to its long-term electricity supply and free of CO2 emission. However, its commercialization is obstructed by reliable hydrogen source, which should be non-corrosiveness, as compact as possible, stable and controllable high purity hydrogen supply. In this study, a novel in situ hydrogen production material Al/BiCl3/γ-Al2O3 composite is synthesized, which exhibits high hydrogen yield, fast hydrogen production rate and outstanding storage stability. The hydrogen production performance of Al/BiCl3/γ-Al2O3 can be adjusted by changing BiCl3:γ-Al2O3 weight ratio, additive content and milling time. XRD and SEM results indicate that surface cracks, active surface and metal Bi produced in fabrication process lead to the high hydrolysis activity of Al/BiCl3/γ-Al2O3. Mechanism analyses reveal that hydrogen production process is the results of pitting, microgalvanic effect and catalytic effect. Taking into account hydrogen production performance, capacity and cost, Al/5 wt%BiCl3/5 wt%γ-Al2O3 milled for 2 h is a potential hydrogen production material, which can in situ supply hydrogen for small-sized fuel cell.

Advanced Deep Learning Techniques for Battery Thermal Management in New Energy Vehicles

In the current era of energy conservation and emission reduction, the development of electric and other new energy vehicles is booming. With their various attributes, lithium batteries have become the ideal power source for new energy vehicles. However, lithium-ion batteries are highly sensitive to temperature changes. Excessive temperatures, either high or low, can lead to abnormal operation of the batteries, posing a threat to the safety of the entire vehicle. Therefore, developing a reliable and efficient Battery Thermal Management System (BTMS) that can monitor battery status and prevent thermal runaway is becoming increasingly important. In recent years, deep learning has gradually become widely applied in various fields as an efficient method, and it has also been applied to some extent in the development of BTMS. In this work, we discuss the basic principles of deep learning and related optimization principles and elaborate on the algorithmic principles, frameworks, and applications of various advanced deep learning methods in BTMS. We also discuss several emerging deep learning algorithms proposed in recent years, their principles, and their feasibility in BTMS applications. Finally, we discuss the obstacles faced by various deep learning algorithms in the development of BTMS and potential directions for development, proposing some ideas for progress. This paper aims to analyze the advanced deep learning technologies commonly used in BTMS and some emerging deep learning technologies and provide new insights into the current combination of deep learning technology in new energy trams to assist the development of BTMS.

β-ketoenamine-linked covalent organic frameworks ultrathin film for transparent supercapacitors with enhanced charge storage capability

With the development of electronic products toward optical transparency and intelligent portability, transparent supercapacitors (TSCs) have been considered as one of the ideal and efficient power sources. However, it is still a challenge to explore covalent organic frameworks (COFs) based transparent conductive electrodes (TCEs) with high photoelectric property and capacitive activity. Herein, β-ketoenamine DqTp (DAAQ-TFP, DAAQ = 2,6-diaminoanthraquinone, and TFP = 1,3,5-triformylphluroglucinol) COFs ultrathin films are synthesized for TCEs through the Schiff base reaction of DAAQ and TFP. The DqTp ultrathin films fully expose the redox-active anthraquinone moieties, shorten the ion/electron transport path, accelerate the transport and diffusion rate, and thus enhance charge storage capability. DqTp-1 TCEs possess the excellent optoelectronic property with optical transmittance (T550 nm) of 69.46%, sheet resistance (Rs) of 7.45 Ω sq−1, and remarkable areal capacitance (CA) of 355.67 μF cm−2. The corresponding asymmetric DqTp-1//PANI TSCs (T550 nm = 58.06%) yield a high CA of 64.55 μF cm−2 at 3 μA cm−2 and have a maximum areal energy density of 0.015 μWh cm−2 at 1.95 μW cm−2. After 5000 cycles, the capacitance retention is 96.9%. This work provides key insights into the design and synthesis of transparent redox-active COFs-based TSCs with excellent photoelectric property and enhanced charge storage capability.

Steady Output Triboelectric-Electromagnetic Hybrid Generator with Variable Drag Turbine Blades for Natural Wind Energy Harvesting.

In recent years, the triboelectric-electromagnetic hybrid generator (TEHG) has been widely studied. However, the problems of unsteady output and high starting wind speed of traditional TEHG in the wind energy environment have not been effectively solved. This work introduces an innovative solution in the form of a steady output triboelectric-electromagnetic hybrid generator (SO-TEHG) with variable drag turbine blades. The SO-TEHG integrates the energy management circuit to output steady electric energy under random wind conditions. In addition, the integration of variable drag turbine blades with the triboelectric nanogenerator (TENG) reduces the wind speed threshold required for SO-TEHG activation. In comparison to the traditional turbine blades, which necessitate a minimum wind speed of 3 m/s, the SO-TEHG's innovative design allows it to commence power generation at a lower 2 m/s wind speed, producing an additional output of 50 V. This enhanced starting capability in mild breezes positions the SO-TEHG as an ideal power source for applications. In practical farmland settings, experimental results conclusively demonstrate the SO-TEHG's ability to successfully activate soil hygrothermographs and hydrogen sensors. As a steady power source driven by gentle winds, the SO-TEHG holds tremendous promise for advancing smart agriculture.

Self-powered intelligent liquid crystal attenuator for metasurface real-time modulating

Triboelectric Nanogenerator (TENG) is capable of efficiently capturing mechanical energy and transforming it into electrical energy for self-powered systems, making it an ideal power source for Polymer Dispersed Liquid Crystal (PDLC). Herein, a Self-powered Intelligent Liquid Crystal Attenuator (SPILCA) is demonstrated for metasurface real-time modulating. The convergent beam-shaping metasurface consisting of holey meta-atoms with diameters ranging from 100 nm to 300 nm is fabricated by e-beam lithography (EBL). While the unique optical characteristics of the metasurface can be modulated within a certain frequency range, the E7 Liquid Crystal (E7-LC) has a large index of birefringence, and it can be powered by TENG to switch between two optical response states. Therefore, the combination of metasurface and SPILCA can achieve real-time control of metasurface by using the electricity regulatory of LC and the electromagnetic response of the metasurface. In order to build this SPILCA for metasurface modulating, a vertically contact-separated TENG based on Nylon electrospun film as triboelectric material is proposed. The maximum values of the open-circuit voltage, short-circuit current, transferred charge are 165 V, 25 µA, and 86 nC, respectively. By measuring the optical power and testing the modulation effect of SPILCA on the metasurface, it can be seen that the SPILCA has a good modulation effect on the optical signal, and even can reach 96 % intensity modulation when the laser source wavelength is 450 nm and the current is 0.09 A. This self-powered photoelectric response device does not require additional electrical power supply, and has great potential in future smart optical system design.

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.

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.

Preparation of LiLaZrMO (M= Ga/Al) solid electrolytes for thermal batteries

Thermal batteries (TBs) are ideal power sources for high temperature environment due to their high specific energy, long storage time, and quick activation. However, the common molten salt electrolytes (MSE) suffer from overflow under overload or high spin state, which could lead to short circuit of the batteries. To address this issue, LiLaZrMO (LLZMO, M = Ga/Al) doped with different elements are prepared. The doping elements result in the phase change of LiLaZrO (LLZO) from tetragonal to cubic, alters the distribution of Li atoms and increases the ion transport bottleneck sizes. In particular, LiLaZrGaO (LLZGO) has the lowest activation energy (0.3 eV) and the highest total conductivity (2.57 × 10−2 S cm−1 at 500 °C) owing to the larger bottleneck and unique Li+ transport channel. TB with LLZGO provides the highest discharge specific capacity of 368.5 mAh g−1 and lowest internal resistance (0.23 Ω cm−2). Compared with the ones using LiF–LiCl–LiBr MSE, TB with LLZGO solid electrolyte (SE) also shows superior performance in pulse discharge capabilities due to the stable internal resistance as well as the fluctuation free characteristics. Therefore, LLZGO SE holds great potential as viable alternative to MSEs in TBs.

Tough and elastic hydrogel thermocells for heat energy utilization

Hydrogel thermocells possess great potential in the energy conversion field as they directly absorb waste heat from the environment to drive redox reactions for continuous electricity generation. However, achieving high toughness and good elasticity simultaneously in hydrogel thermocells remains a challenge because of the inherent contradiction of energy dissipation mechanisms, severely limiting their practical applications and lifespan. To address this, a skin-like hydrogel network with a highly dense interwoven network is developed to construct hydrogel thermocells with good elasticity and high toughness. The dense network structure can effectively disperse the stress and hinder crack propagation, thus breaking the contradiction between high toughness and good elasticity. The thermocell realizes a toughness of 460 J m−2 while reaching an elastic limit strain of 350 %, far exceeding the elasticity of previous stretchable hydrogel thermocells. Meanwhile, it exhibits ultra-low hysteresis and excellent fatigue resistance under tensile and compressive cyclic loads. Moreover, the thermocell can work stably over long periods, enabling stable voltage output even under compression, bending, and stretching. In addition, the thermocell can power the LED lamp and calculator, and can also be connected in series to form large arrays, thus rendering it an ideal power source for wearable devices.

RETRACTED: Research on the kinetics characteristics and in-cylinder combustion of opposed rotary piston engine for different power output modes

As a new type of internal combustion engine, opposed rotary piston (ORP) engine has the advantages of simple structure and high working frequency, and can achieve high power density. Consequently, it stands as an ideal power source for hybrid power systems and unmanned aerial vehicles. The ORP engine has different power output modes, corresponding to different piston rotation and volume evolutions of combustion chamber. However, the effect of power output modes on kinetics characteristics and in-cylinder combustion of ORP engines are still uncovered. In this paper, the kinematic model of an ORP engine is established for scenarios involving power output by different shafts (Shaft 1 and Shaft 3). Meanwhile, the piston rotation patterns and cylinder volume variations are investigated correspondingly. Further, three-dimensional numerical model of the ORP engine is established, enabling analysis of in-cylinder combustion characteristics, engine performance, as well as nitrogen oxides (NOx) emissions. The results indicate that the volume variations of all cylinders follow a consistent pattern under the power output by Shaft 3. A pair of opposed cylinders features longer durations of intake and expansion strokes, and shorter durations of compression and exhaust strokes, the other pair of combustion chambers is the opposite under the power output by Shaft 1. The engine demonstrates a charging efficiency of 95.36 %, with corresponding indicated thermal efficiency and indicated power output of 38.08 % and 40.9 kW, respectively. The two adjacent cylinders present significantly different operation processes in the case of the power output by Shaft 1, achieving charging efficiencies of 94.29 % and 89.11 %, respectively, with the indicated thermal efficiency of 34.49 % and 31.60 %. The corresponding minimum indicated specific fuel consumption under the two power output modes are 211.7 g/kW∙h and 243.7 g/kW∙h, respectively, accompanied by NOx emission factors of 25.3 g/kW∙h and 17.6 g/kW∙h. With the given range of ignition timing, a trade-off relationship exists between the engine performance and NOx emissions. The power density of the case of power output by Shaft 3 is superior to that of Shaft 1.

Modelling and operation characteristics of air-cooled PEMFC with metallic bipolar plate used in unmanned aerial vehicle

The air-cooled proton exchange membrane fuel cell stack composed of the metallic bipolar plate with simple system and lightweight characteristics, is regarded as an ideal power source for unmanned aerial vehicles. A zero-dimensional model is developed to analyze the operation characteristics at heights in the range of 0–3000 m. The temperature should not exceed 60 °C to ensure safe and effective operation. The peak power decreases by 20 % and the stack has good adaptability to altitudes. The performance degradation can be largely attributed to the lower oxygen pressure at high altitudes through normalization analysis. It is more significant at higher current densities owing to increased air starvation. The increase of the air stoichiometry is conducive to heat dissipation and reduces mass transfer loss. The voltage initially increases and then decreases as the air stoichiometry increases, and the optimal air stoichiometry corresponding to the maximum voltage is determined. Appropriately increasing the air stoichiometry can improve the consistency of the temperature and voltage distributions.

Electrostatically anchored MXene-Thionine hybrid electrodes for a flexible supercapacitor to attain exceptional performance

Portable photorechargeable supercapacitors hold great promise as ideal power sources for future IoT applications. However, the widespread implementation of supercapacitors is hindered by their suboptimal energy density. Organic electrodes, with their high specific capacity, have become rising stars in the energy storage community. Herein, we pioneer an electrostatic-anchoring in situ polymerization reaction pathway to synthesize MXene-organic hybrid electrode materials. Theoretical calculations show that thionine (Th) is the optimal candidate for grafting onto the pseudocapacitive 2D MXene due to its low energy levels, narrow band gap, and multiple active sites. Multilevel interactions between Th and MXene are established to prevent Th from dissolution, to inhibit the MXene from restacking, and to facilitate electron accumulation in Th, thus enhancing the accessibility/absorption of ions in electrolytes and electrode stability. The hybrid electrodes exhibit a specific capacity as high as 4906.7 mF/cm2 at 1 mA cm−2; more importantly, an integrated asymmetric flexible supercapacitor displays high specific capacity (3183.1 mF/cm2) and large energy density (1432.4 mWh/cm2), all three values are the highest among their respective categories. Combining supercapacitors with all-inorganic perovskite solar cells to achieve rapid charge storage.

A high performance ion-solvating membrane-type direct ammonia fuel cell

Low-temperature direct ammonia fuel cells (DAFCs) are considered as an ideal power source for transportation due to their high energy density, easy storage and transportation, and reasonable cost. However, the alkaline electrolyte membranes suitable for DAFCs needs further research and development to achieve high power density output. Here, we conducted a pioneering study on the application of polybenzimidazole (PBI) based ion-solvating membrane (ISM) in DAFCs. The potential effect of ammonia crossover on the membrane properties during the operation of PBI ISMs based DAFCs was revealed through the treatment of poly(2,2'-(1,4-naphthylene)-5,5′-bibenzimidazole) (NPBI) and poly(2,2'-(meta-phenylene)-5,5′-bibenzimidazole) (m-PBI) ISMs with ammonia-alkali solution. More importantly, the performance of DAFCs based on PBI ISMs was reported for the first time, and the NPBI ISM based DAFC exhibited an exceptional peak power density (PPD) of 80 mW/cm2 at 80 °C, outperforming other alkaline ion membranes under identical testing conditions. Further optimization of operating conditions indicated that the performance of NPBI ISM-based DAFCs was highly dependent on concentration of KOH. This work provides a new direction and guidance for the development of alkaline polyelectrolyte membranes suitable for high performance low-temperature DAFCs.

Neutronic-thermalhydraulic coupling analysis of heat pipe failure accidents of a new type of megawatt heat pipe reactor

Heat pipe cooled reactors featured with high energy density, long lifecycle, modularity, and compact structure could be ideal power sources for large unmanned undersea vehicles (UUVs). In the early stage of reactor concept design, heat pipe failure accident is usually one of the design basis accidents that need to be considered. In this study, a set of transient analysis models for heat pipe failure accidents of a new type of megawatt heat pipe reactor is established. The models include the point kinetics model, Core Matrix module and Fuel-Heat Pipe module heat conduction models, and radiation heat transfer model for the inner core cavity. 2D-3D combined method is used to solve the heat conduction model in the Fuel-Heat Pipe module. Based on the models, a transient analysis code for heat pipe failure accidents is developed using FORTRAN. The models are separately validated based on the analytical solutions, the experimental data or the CFD results by FLUENT. Neutronic-thermalhydraulic coupling calculation is conducted in normal operation condition and heat pipe failure accidents. The peak temperatures of each region are below their melting points in all presumed heat pipe failure accidents which reflects the good inherent safety of the core. Meanwhile, the calculation results by the code are in good agreement with those of FLUENT, and the maximum relative error of the peak temperature does not exceed 1.5%. The code calculation time is 1/8 of FLUENT ensuring the accuracy of important parameters, effectively reducing the computation costs and improving the computation efficiency. The code also provides a basis for subsequent transient operation condition and typical accidents analysis of this reactor.

A Hundreds‐Milliampere‐Hour‐Scale Solid‐State Aluminum–Sulfur Pouch Cell

AbstractAluminum‐sulfur (Al–S) batteries are exploited as an ideal power source for grid‐scale energy storage due to the abundant Al and S resources and superior safety. However, the short lifespan and lack of appropriate current collectors for positive electrodes have restricted the large‐size manufacture and practicability of Al–S batteries. Here a solid‐state electrolyte and current collector‐free positive electrode are demonstrated to construct a large‐size solid‐state Al–S pouch cell. The ionic liquid‐impregnated metal–organic‐framework solid electrolytes are filled into the gel polymer electrolyte to achieve the large‐size production of composite solid‐state electrolyte (MSE@GPE). Meanwhile, the MSE@GPE electrolytes, serving as the binder and ionic conductor, are introduced into sulfur‐anchored cobalt/nitrogen co‐doped graphene to prepare an all‐in‐one composite sulfur‐positive electrode without a current collector. The as‐assembled Al–S pouch cell delivers a reversible capacity of 288 mAh and a cell‐level energy density of >90 Wh kg−1. Furthermore, the cycle life of this Al–S pouch cell can reach over 400 times with capacity retention of 80%, benefiting from the significant inhibiting effect of MSE@GPE electrolyte on the shuttle effect of polysulfide. The results provide a path for fabricating practical Al–S batteries, narrowing the gap between their high theoretical specific energy and the realization in practical operation.

Analysis of influences of injection parameters on combustion process based on 2-stroke rod-less opposed piston diesel engine

Global concerns about environmental pollution and fuel consumption are increasing, and as emissions regulations become more stringent, exploring new power and structural forms to optimise diesel engines is the way forward for future breakthroughs in diesel engines. The 2-Stroke Rod-less Opposed Piston (2S-ROPE) has been extensively studied for its vibration-free and simple construction. Compared to conventional four-stroke engines, it has a smaller bore, shorter cycle time, higher power and lower fuel consumption in the same time, making it an ideal power source for small engines. In this paper, the rod-less structure is applied to a two-stroke opposed-piston diesel engine for the first time. Based on experimental verification by spraying, a dynamic high-precision three-dimensional model of computational fluid dynamics (CFD) is established, using lateral injection, to clarify the various airflow patterns that occur in the cylinder during the intake and exhaust of the 2S-ROPE, and investigates the effects of injection timing and injection pressure on the oil–gas mixing and combustion processes in the 2S-ROPE cylinder. The results show that the in-cylinder turbulent kinetic energy is highest at an injection timing of 15° BTDC (Before Top Dead Center) and that fuel injection has the greatest effect on in-cylinder airflow disturbance at this time. At 17.5° BTDC, the duration of in-cylinder combustion was the longest. The effect of injection timing on the burst pressure is linear, for every 2.5° advance, the maximum pressure in the cylinder increases by about 2 MPa. 20 MPa of injection pressure increases, the stall period is shortened by less than 1°, the combustion duration CA10-90 is shortened with the increase in injection pressure, and for every 20 MPa increase in injection pressure, the burst pressure increases by 1 MPa, which is a significant increase.

Untethered Magnetic Soft Robot with Ultra-Flexible Wirelessly Rechargeable Micro-Supercapacitor as an Onboard Power Source.

Soft robotics has developed rapidly in recent years as an emergent research topic, offering new avenues for various industrial and biomedical settings. Despite these advancements, its applicability is limited to locomotion and actuation due to the lack of an adequate charge storage system that can support the robot's sensory system in challenging conditions. Herein, an ultra-flexible, lightweight (≈50 milligrams), and wirelessly rechargeable micro-supercapacitor as an onboard power source for miniaturized soft robots, capable of powering a range of sensory is proposed. The simple and scalable direct laser combustion technique is utilized to fabricate the robust graphene-like carbon micro-supercapacitor (GLC-MSC) electrode. The GLC-MSC demonstrates superior areal capacitance (8.76mFcm-2 ), and maintains its original capacitance even under extreme actuation frequency (1-30Hz). As proof of conceptthe authors fabricate a fully integrated magnetic-soft robotthat shows outstanding locomotion aptitude and charged wirelessly (up to 2.4V within 25s), making it an ideal onboard power source for soft robotics.

Flexible Thermoelectric Devices with Flexible Heatsinks of Phase-Change Materials and Stretchable Interconnectors of Semi-Liquid Metals.

Flexible thermoelectric (TE) devices offer great potential for wearable thermal management and self-powered systems, but heat dissipation and electrical interconnection remain key challenges. In this study, we address these issues by integrating flexible TE devices with phase-change material (PCM) heatsinks and stretchable semi-liquid metal (semi-LM) interconnectors. The effectiveness of PCMs with varying melting points for temperature regulation in different environmental conditions is demonstrated, delivering cooling effects exceeding 10 °C. Furthermore, the utilization of semi-LMs instead of LMs enables excellent stretchability and efficient heat dissipation. Moreover, the TE devices generate power with a density of 7.3 μW/cm2 at an ambient temperature of 22 °C, making it an ideal power source for a wearable self-powered sensing system. Successful integration into garments and armbands confirms the practicality and adaptability of these flexible thermoelectric devices, establishing them as critical components for future wearables with superior resilience to daily wear and tear.

Wide-Temperature Flexible Supercapacitor of Organohydrogel Electrolyte and Its Combined Electrode.

Hydrogel-based flexible supercapacitors possess the merits of highly ionic conductivity and superior power density, but the existence of water limits their application in the extreme temperature scenarios. Noticeably, it is a challenge for people to design more extremely temperature adaptable systems for flexible supercapacitor based on hydrogel with wide-temperature region. In this work, a wide-temperature flexible supercapacitor that can operate at -20-80 °C is fabricated by the organohydrogel electrolyte and its combined electrode (also known as electrode/electrolyte composite). By introducing highly hydratable LiCl into ethylene glycol (EG)/H2O binary solvent, owning to the ionic hydration effect of LiCl and hydrogen-bond interaction between EG and H2O molecules, the organohydrogel electrolyte exhibits satisfactory freezing resistance (-113.9 °C of freezing point), anti-drying capability (78.2% of weight retention after vacuum drying at 60 °C for 12 hours) and excellent ionic conductivity both at room temperature (13.9 mS/cm) and low temperature (6.5 mS/cm after 31 days at -20 °C). By using organohydrogel electrolyte as binder, the prepared electrode/electrolyte composite effectively reduces interface impedance and enhances specific capacitance due to the uninterrupted ion transport channels and extended interface contact area. The assembled supercapacitor delivers a specific capacitance of 149 F/g, power density of 160 W/kg and energy density of 13.24 Wh/kg at the current density of 0.2 A/g. The initial capacitance can maintain 100% after 2000 cycles at 1.0 A/g. More importantly, the specific capacitances can be well maintained even at -20 °C and 80 °C. With other advantages such as excellent mechanical property, the supercapacitor is an ideal power source suitable for various working conditions.