Coupling Enhancement of a Flexible BiFeO_(3) Film-Based Nanogenerator for Simultaneously Scavenging Light and Vibration Energies

Coupled nanogenerators have been a research hotspot due to their ability to harvest a variety of forms of energy such as light,mechanical and thermal energy and achieve a stable direct current output.Ferroelectric films are frequently investigated for photovoltaic applications due to their unique photovoltaic properties and bandgap-independent photovoltage,while the flexoelectric effect is an electromechanical property commonly found in solid dielectrics.Here,we effectively construct a new form of coupled nanogenerator based on a flexible BiFeO_(3) ferroelectric film that combines both flexoelectric and photovoltaic effects to successfully harvest both light and vibration energies.This device converts an alternating current into a direct current and achieves a 6.2% charge enhancement and a 19.3%energy enhancement to achieve a multi-dimensional"1+1>2"coupling enhancement in terms of current,charge and energy.This work proposes a new approach to the coupling of multiple energy harvesting mechanisms in ferroelectric nanogenerators and provides a new strategy to enhance the transduction efficiency of flexible functional devices.

Fully Fabric-Based Triboelectric Nanogenerators as Self-Powered Human-Machine Interactive Keyboards

Combination flexible and stretchable textiles with self-powered sensors bring a novel insight into wearable functional electronics and cyber security in the era of Internet of Things.This work presents a highly flexible and self-powered fully fabric-based triboelectric nanogenerator(F-TENG)with sandwiched structure for biomechanical energy harvesting and real-time biometric authentication.The prepared F-TENG can power a digital watch by low-frequency motion and respond to the pressure change by the fall of leaves.A self-powered wearable keyboard(SPWK)is also fabricated by integrating large-area F-TENG sensor arrays,which not only can trace and record electrophysiological signals,but also can identify individuals’typing characteristics by means of the Haar wavelet.Based on these merits,the SPWK has promising applications in the realm of wearable electronics,self-powered sensors,cyber security,and artificial intelligences.

Laser-Etched Stretchable Graphene-Polymer Composite Array for Sensitive Strain and Viscosity Sensors

The ability to control surface wettability and liquid spreading on textured surfaces is of interest for extensive applications.Soft materials have prominent advantages for producing the smart coatings with multiple functions for strain sensing.Here,we report a simple method to prepare flexible hydrophobic smart coatings using graphene-polymer films.Arrays of individual patterns in the films were created by laser engraving and controlled the contact angle of small drops by pinning the contact lines in a horizontal tensile range of 0-200%.By means of experiments and model,we demonstrate that the ductility of drops is relied on the height-to-spacing ratio of the individual pattern and the intrinsic contact angle.Moreover,the change of drop size was utilized to measure the applied strain and liquid viscosity,enabling a strain sensitivity as high as 1068μm2/%.The proposed laser-etched stretchable graphene-polymer composite has potential applications in DNA microarrays,biological assays,soft robots,and so on.

High-performance supercapacitors based on free-standing SiC@PEDOT nanowires with robust cycling stability

Conductive polymers as one of the candidate materials with pseudocapacitor behavior have inspired wide attentions,because of their high conductivity,fexibility,low cost and excellent processability.However,the intrinsically poor cycling stability induced by the volume change over the doping/dedoping redox process limits their practical applications.Herein,we report the exploration of electrodes with robust cycling capacity for supercapacitors(SCs),which are rationally designed by coating conductive poly(3,4-ethylenedioxythiophene)(PEDOT)around free-standing SiC nanowires using an all-dry oxidative chemical vaper deposition(oCVD)method.The as-constructed SiC@PEDOT nanowire architecture enables a specific capacitance of 26.53 m F/cm^(2)at 0.2 m A/cm^(2),which is~370%to that of SiC nanowire counterpart(7.04 m F/cm^(2)).Moreover,their aqueous-based SCs exhibit robust cycling stability with104%capacity retention after 10000 cycles,which is among the highest values achieved for PEDOTbased SCs.

High-Efficiency Wastewater Purification System Based on Coupled Photoelectric–Catalytic Action Provided by Triboelectric Nanogenerator

It is of great importance to explore a creative route to improve the degradation e ciency of organic pollutants in wastewater.Herein,we construct a unique hybrid system by combining self-powered triboelectric nanogenerator(TENG)with carbon dots-TiO_(2)sheets doped three-dimensional graphene oxide photocatalyst(3 DGA@CDs-TNs),which can significantly enhance the degradation e ciency of brilliant green(BG)and direct blue 5 B(DB)owing to the powerful interaction of TENG and 3 DGA@CDs-TNs photocatalyst.The power output of TENG can be applied for wastewater purification directly,which exhibits a selfpowered electrocatalytic technology.Furthermore,the results also verify that TENG can replace conventional electric catalyst to remove pollutants e ectively from wastewater without any consumption.Subsequently,the unstable fragments and the plausible removal pathways of the two pollutants are proposed.Our work sheds light on the development of e cient and sustainable TENG/photocatalyst system,opening up new opportunities and possibilities for comprehensive utilization of random energy.

In situ induced cation-vacancies in metal sulfides as dynamic electrocatalyst accelerating polysulfides conversion for Li-S battery

Cation vacancy engineering is considered to be one of the effective methods to solve the issues of shuttling and sluggish redox kinetics of Li PSs owing to the intrinsic tunability of electronic structure.However,cation vacancies are few studied in the Li-S realm due to their complex and rigid preparation methods.In this work,one-step pyrolysis is reported to in situ introduce Fe-vacancies into iron sulfide(Fe_(0.96)S)as a sulfur host.For this host structure,Fe_(0.96)S is first employed as an adsorbent and catalyst in Li-S system.During the carbonization process,a tight contact structure of Fe_(0.96)S crystal and carbon network(Fe_(0.96)S@C)is in situ constructed,and the carbon layer as a conductor provides smooth electrons transfer pathways for redox reactions.Meanwhile,due to the introduction of Fe-vacancies in Fe S crystal,the adsorption capability and catalytic effect for Li PSs have been substantially enhanced.Moreover,the presence of Fe_(0.96)S crystal favors the mobility of electron and diffusion of Li+,which is revealed by the experiments and theoretical calculations.Through synergy respective advantages effect of Fe_(0.96)S and carbon,the Fe_(0.96)S@C-S cathode delivers high-rate capability at 5.0 C and stable long-life performance.Even under a high sulfur loading of 3.5 mg/cm^(2),the durable cyclic stability is still exhibited with the capacity retention of 93%over 400 cycles at 1.0 C,and the coulombic efficiency is≥98%.Noting that this strategy greatly simplifies the synthetic process of currently known cation-vacancy materials and furnishes a universal mentality for designing both divinable and astonishing new cation-vacancy materials.

Nanogenerator-Based Self-Charging Energy Storage Devices

One significant challenge for electronic devices is that the energy storage devices are unable to provide su cient energy for continuous and long-time operation,leading to frequent recharging or inconvenient battery replacement.To satisfy the needs of next-generation electronic devices for sustainable working,conspicuous progress has been achieved regarding the development for nanogenerator-based self-charging energy storage devices.Herein,the development of the self-charging energy storage devices is summarized.Focus will be on preparation of nanomaterials for Li-ion batteries and supercapacitors,structural design of the nanogenerator-based self-charging energy storage devices,performance testing,and potential applications.Moreover,the challenges and perspectives regarding self-charging energy storage devices are also discussed.

Human Machine Interface with Wearable Electronics Using Biodegradable Triboelectric Films for Calligraphy Practice and Correction

Letter handwriting,especially stroke correction,is of great importance for recording languages and expressing and exchanging ideas for individual behavior and the public.In this study,a biodegradable and conductive carboxymethyl chitosan-silk fibroin(CSF)film is prepared to design wearable triboelectric nanogenerator(denoted as CSF-TENG),which outputs of V_(oc)≈165 V,I_(sc)≈1.4μA,and Q_(sc)≈72 mW cm^(−2).Further,in vitro biodegradation of CSF film is performed through trypsin and lysozyme.The results show that trypsin and lysozyme have stable and favorable biodegradation properties,removing 63.1%of CSF film after degrading for 11 days.Further,the CSF-TENG-based human-machine interface(HMI)is designed to promptly track writing steps and access the accuracy of letters,resulting in a straightforward communication media of human and machine.The CSF-TENG-based HMI can automatically recognize and correct three representative letters(F,H,and K),which is benefited by HMI system for data processing and analysis.The CSF-TENG-based HMI can make decisions for the next stroke,highlighting the stroke in advance by replacing it with red,which can be a candidate for calligraphy practice and correction.Finally,various demonstrations are done in real-time to achieve virtual and real-world controls including writing,vehicle movements,and healthcare.

Correction to:A Hybrid Biofuel and Triboelectric Nanogenerator for Bioenergy Harvesting

In the original publication,the authors’contribution is missing in the acknowledgment section.The correct acknowledgement is provided in this correction.Also,in Fig.4,the second(c)after figure(d)should be read as(e).In Fig.5(i),the Y-axis label“Current(μA)”should be read as“Voltage”.

Tribotronics: an emerging field by coupling triboelectricity and semiconductors

Tribotronics is an emerging research field that focuses on the coupling of triboelectricity and semiconductors.In this review,we summarise and explore three branches of tribotronics.Firstly,we introduce the tribovoltaic effect,which involves direct-current power generation through mechanical friction on semiconductor interfaces.This effect offers significant advantages in terms of high power density compared to traditional insulator-based triboelectric nanogenerators.Secondly,we elaborate on triboelectric modulation,which utilises the triboelectric potential on field-effect transistors.This approach enables active mechanosensation and nanoscale tactile perception.Additionally,we present triboelectric management,which aims to improve energy supply efficiency using semiconductor device technology.This strategy provides an effective microenergy solution for sensors and microsystems.For the interactions between triboelectricity and semiconductors,the research of tribotronics has exhibited the electronics of interfacial friction systems,and the triboelectric technology by electronics.This review demonstrates the promising prospects of tribotronics in the development of new functional devices and self-powered microsystems for intelligent manufacturing,robotic sensing,and the industrial Internet of Things.

Scalable rolling-structured triboelectric nanogenerator with high power density for water wave energy harvesting toward marine environmental monitoring

In the context of advocating a green and low-carbon era,ocean energy,as a renewable strategic resource,is an important part of planning and building a new energy system.Triboelectric nanogenerator(TENG)arrays provide feasible and efficient routes for large-scale harvesting of ocean energy.In previous work,a spherical rolling-structured TENG with three-dimensional(3D)electrodes based on rolling motion of dielectric pellets was designed and fabricated for effectively harvesting low-frequency water wave energy.In this work,the external shape of the scalable rolling-structured TENG(SR-TENG)and internal filling amount of pellets were mainly optimized,achieving an average power density of 10.08 W∙m^(−3)under regular triggering.In actual water waves,the SR-TENG can deliver a maximum peak power density of 80.29 W∙m^(−3)and an average power density of 6.02 W∙m^(−3),which are much greater than those of most water wave-driven TENGs.Finally,through a power management,an SR-TENG array with eight units was demonstrated to successfully power portable electronic devices for monitoring the marine environment.The SR-TENGs could promote the development and utilization of ocean blue energy,providing a new paradigm for realizing the carbon neutrality goal.

A multifunctional optical-thermal logic gate sensor array based on ferroelectric BiFeO_(3) thin films

The growing need to process a diverse range of data has ignited effort in developing new multifunctional logic gate devices.In this article,we report a new form of all-in-one logic gate system that exploits the photoresponsivity of a self-powered multifunctional BiFeO_(3)(BFO)sensor material.The BFO sensor can not only detect both light intensity and temperature,but it can also execute three common logic gates of“AND”,“OR”,and“NOT”by converting optical and thermal inputs into electrical output.The diverse functionality of the BFO logic gate sensor array utilizes the unique light-and temperaturecontrolled energy band structure and carrier behavior of the BFO material.To demonstrate the potential,a 3×3 logic gate sensor matrix is developed,which successfully detected light and temperature distributions,and accurately produced the three basic logic gate operations.This work provides a new route to construct highly integrated multifunctional electronic devices for the advancement of large sensing,communication,and computing operations.

Stretchable nanogenerators for scavenging mechanical energy

Using stretchable nanogenerators to obtain disordered mechanical energy from the environment is an ideal way to realize wearable power supply equipment and self-power electronic devices,and alleviate the energy crisis.It is of great significance to integrate the stretchability into the nanogenerator,which can fit the complex shape of the target object better and is well suitable for wearable electronics.When applied to the human body,it can directly harvest human body mechanical energy to power wearable electronic devices and get rid of the trouble of charging.This paper systematically reviewed nanogenerators in stretchability,focusing on stretchable triboelectric nanogenerators,stretchable piezoelectric nanogenerators,and stretchable hybrid nanogenerators.Their physical mechanism,material selection,structure design,and output performance are discussed in detail.It is concluded that the fabrication methods of various devices can be broadly categorized into the two most important device types,namely fiber-like and planar.A detailed analysis of representative work and the latest progress in the past decade is performed.It is most important that excellent stretchability and high-power output are the key point to realize application value of stretchable nanogenerators.In addition,we discuss opportunities and challenges,as well as future development direction of stretchable nanogenerators.

Prim-O-glucosylcimifugin ameliorates aging-impaired endogenous tendon regeneration by rejuvenating senescent tendon stem/progenitor cells

Adult tendon stem/progenitor cells(TSPCs)are essential for tendon maintenance,regeneration,and repair,yet they become susceptible to senescence with age,impairing the self-healing capacity of tendons.In this study,we employ a recently developed deep-learning-based efficacy prediction system to screen potential stemness-promoting and senescence-inhibiting drugs from natural products using the transcriptional signatures of stemness.The top-ranked candidate,prim-O-glucosylcimifugin(POG),a saposhnikovia root extract,could ameliorate TPSC senescent phenotypes caused by long-term passage and natural aging in rats and humans,as well as restore the self-renewal and proliferative capacities and tenogenic potential of aged TSPCs.In vivo,the systematic administration of POG or the local delivery of POG nanoparticles functionally rescued endogenous tendon regeneration and repair in aged rats to levels similar to those of normal animals.Mechanistically,POG protects TSPCs against functional impairment during both passage-induced and natural aging by simultaneously suppressing nuclear factor-κB and decreasing mTOR signaling with the induction of autophagy.Thus,the strategy of pharmacological intervention with the deep learning-predicted compound POG could rejuvenate aged TSPCs and improve the regenerative capacity of aged tendons.

Highly stretchable kirigami-patterned nanofiber-based nanogenerators for harvesting human motion energy to power wearable electronics

Wearable electronics are advancing towards miniaturization and flexibility.However,traditional energy supply methods have largely hindered their development.An effective solution to this problem is to convert human mechanical energy into electricity to power wearable electronic devices.Therefore,it is greatly attractive to design flexible,foldable and even stretchable energy harvesting devices.Herein,we use the electrospinning and kirigami approach to develop a type of highly stretchable kirigami-patterned nanofiber-based triboelectric nanogenerator(K-TENG).Due to its innovative structural design,the K-TENG can achieve a tensile strain of 220%,independent of the tensile properties of the material itself.When a person swings their arms,the K-TENG fixed to the clothing can convert mechanical energy from human movement into electrical energy.The produced electricity can directly drive 50 LED lights and a digital watch,or be stored in a lithium battery to charge the smartwatch and smartphone,respectively.This study employs a new method to fabricate a stretchable triboelectric nanogenerator and demonstrates its promising applications in wearable power technology.

The recent advances in self-powered medical information sensors

Monitoring various medical information distributed throughout the body is of great importance in early clinic diagnosis and treatment of disease.To discover abnormal medical signals and find their causes in good time,the human body should be monitored continuously and accurately.To meet the requirements,various battery-less and self-powered information acquisition techniques are invented.In this review,the recent advances in self-powered medical information sensors(SMIS)with different functions,structure design,and electric performance are summarized and discussed.The SMIS mainly involves triboelectric nanogenerator(TENG),piezoelectric nanogenerator(PENG),pyroelectric nanogenerator(PyNG)/thermoelectric generator(TEG)and solar cell.Additionally,this review also analyzed the remaining challenges and prospected the development direction of SMIS in future.

The first technology can compete with piezoelectricity to harvest ultrasound energy for powering medical implants

Sustainable operation of implanted medical devices is essential for clinic applications.However,limited battery capacity is a key challenge for most implantable medical electronics[1].Higher-capacity battery is not an ideal choice,because battery capacity is usually linearly dependent on battery volume[2].New energy harvesters have been developed as promising alternative solutions,which extracted energy from the ambient environment and biosystem for powering implantable devices[3],However,the energy reclaimed from body and ambient environment also have power lim让ation,such as thermal gradient and bioelectric potential.Delivery ultrasound or RF energy into the body and generate electrical power by a converter is a reliable solution.

Raindrop energy-powered autonomous wireless hyetometer based on liquid-solid contact electrification

Triboelectric nanogenerators(TENGs)can directly harvest energy via solid-liquid interface contact electrification,making them very suitable for harvesting raindrop energy and as active rainfall sensors.This technology is promising for realizing a fully self-powered system for autonomous rainfall monitoring combined with energy harvesting/sensing.Here,we report a raindrop energy-powered autonomous rainfall monitoring and wireless transmission system(R-RMS),in which a raindrop-TENG(R-TENG)array simultaneously serves as a raindrop energy harvester and rainfall sensor.At a rainfall intensity of 71 mm/min,the R-TENG array can generate an average short-circuit current,open-circuit voltage,and maximum output power of 15 pA,1800 V,and 325 pW,respectively.The collected energy can be adjusted to act as a stable 2.5 V direct-current source for the whole system by a power management circuit.Meanwhile,the R-TENG array acts as a rainfall sensor,in which the output signal can be monitored and the measured data are wirelessly transmitted.Linder a rainfall intensity of 71 mm/min,the R-RMS can be continuously powered and autonomously transmit rainfall data once every 4 min.This work has paved the way for raindrop energy-powered wireless hyetometers,which have exhibited broad prospects in unattended weather monitoring,field surveys,and the Internet of Things.

Self-powered electronic paper with energy supplies and information inputs solely from mechanical motions

The electronic paper(E-paper)displays features such as flexibility,sunlight visibility,and low power consumption,which makes it ideal for Internet of Things(IoT)applications where the goal is to eliminate bulky power modules.Here,we report a unique self-powered E-paper(SPEP),where information inputs and energy supplies are all converted from mechanical motion by a triboelectric nanogenerator(TENG).The operation of an electrophoretic E-paper is first investigated,identifying the current density as a determinative parameter for driving pigment particle motion and color change.Electrical and optical responses of the E-paper driven by a slidingmode TENG are then found to be consistent with that under a current source mode.All-in-one monochromic and chromatic SPEPs integrated with a flexible transparent TENG are finally demonstrated,and a pixelated SPEP is discussed for future research.The sliding-driven mechanism of SPEP allows for a potential handwriting function,is free of an extra power supply,and promises undoubtedly a wide range of future applications.

Mechanoluminescent hybrids from a natural resource for energy-related applications

Mechanoluminescent(ML)materials that directly convert mechanical energy into photon emission have emerged as promising candidates for various applications.Despite the recent advances in the development of both novel and conventional ML materials,the limited access to ML materials that simultaneously have the attributes of high brightness,low cost,self-recovery,and stability,and the lack of appropriate designs for constructing ML devices represent significant challenges that remain to be addressed to boost the practical application of ML materials.Herein,ML hybrids derived from a natural source,waste eggshell,with the aforementioned attributes are demonstrated.The introduction of the eggshell not only enables the preparation of the hybrid in a simple and cost-effective manner but also contributes to the homochromatism(red,green,or blue emission),high brightness,and robustness of the resultant ML hybrids.The significant properties of the ML hybrids,together with the proposed structural design,such as porosity or core–shell structure,could expedite a series of mechanic-optical applications,including the self-luminous shoes for the conversion of human motions into light and light generators that efficiently harvest water wave energy.The fascinating properties,versatile designs,and the efficient protocol of“turning waste into treasure”of the ML hybrids represent significant advances in ML materials,promising a leap to the practical applications of this flouring material family.