Effects of Rattling Behavior of K and Cd Atoms along Different Directions in Anisotropic KCdAs on Lattice Thermal Transport and Thermoelectric Properties

We employ advanced first principles methodology,merging self-consistent phonon theory and the Boltzmann transport equation,to comprehensively explore the thermal transport and thermoelectric properties of KCdAs.Notably,the study accounts for the impact of quartic anharmonicity on phonon group velocities in the pursuit of lattice thermal conductivity and investigates 3ph and 4ph scattering processes on phonon lifetimes.Through various methodologies,including examining atomic vibrational modes and analyzing 3ph and 4ph scattering processes,the article unveils microphysical mechanisms contributing to the lowκL within KCdAs.Key features include significant anisotropy in Cd atoms,pronounced anharmonicity in K atoms,and relative vibrations in non-equivalent As atomic layers.Cd atoms,situated between As layers,exhibit rattling modes and strong lattice anharmonicity,contributing to the observed lowκL.Remarkably flat bands near the valence band maximum translate into high PF,aligning with ultralowκL for exceptional thermoelectric performance.Under optimal temperature and carrier concentration doping,outstanding ZT values are achieved:4.25(a(b)-axis,p-type,3×10^(19)cm^(−3),500 K),0.90(c-axis,p-type,5×10^(20)cm^(−3),700 K),1.61(a(b)-axis,n-type,2×10^(18)cm^(−3),700 K),and 3.06(c-axis,n-type,9×10^(17)cm^(−3),700 K).

MXene-Based Quantum Dots Optimize Hydrogen Production via Spontaneous Evolution of Cl-to O-Terminated Surface Groups

MXene quantum dots(MQDs)offer wide applications owing to the abundant surface chemistry,tunable energy-level structure,and unique properties.However,the application of MQDs in electrochemical energy conversion,including hydrogen evolution reaction(HER),remains to be realized,as it remains a challenge to precisely control the types of surface groups and tune the structure of energy levels in MQDs,owing to the high surface energy-induced strong agglomeration in post-processing.Consequently,the determination of the exact catalytically active sites and processes involved in such an electrocatalysis is challenging because of the complexity of the synthetic process and reaction conditions.Herein,we demonstrated the spontaneous evolution of the surface groups of the Ti_(2)CT_(x)MQDs(x:the content of O atom),i.e.,replacement of the-Cl functional groups by O-terminated ones during the cathode reaction.This process resulted in a low Gibbs free energy(0.26 eV)in HER.Our steady Ti_(2)CO_(x)/Cu_(2)O/Cu foam systems exhibited a low overpotential of 175 mV at 10 mA cm^(-2)in 1 M aq.KOH,and excellent operational stability over 165 h at a constant current density of-10 mA cm^(-2).

Earth-Abundant CaCO_(3)-Based Photocatalyst for Enhanced ROS Production,Toxic By-Product Suppression,and Efficient NO Removal

Photoinduced reactive oxygen species(ROS)-based pollutant removal is one of the ideal solutions to achieve the conversion of solar energy into chemical energy and thus to address environmental pollution.Here,earthabundant CaCO_(3)-decorated g-C_(3)N_(4)(g-C_(3)N_(4)labeled as CN,CaCO_(3)-decorated g-C_(3)N_(4)sample labeled as CN-CCO)has been constructed by a facile thermal polymerization method for safe and efficient photocatalytic NO removal.The decorated CaCO_(3)as“transit hub”extends theπbonds of CN to deviate from the planes and steers the random charge carriers,which thus provides extra active sites and expedites spatial charge separation to facilitate adsorption/activation of reactants and promote formation of ROS participating in the removal of pollutant.Furthermore,boosted generation of ROS regulates the photocatalytic NO oxidation pathway and thus increases the selectivity of products.NO prefers to be directly oxidized into final product(nitrate)rather than toxic intermediates(NO_(2)),which is well demonstrated by theoretically simulated ROS-based reaction pathways and experimental characterization.The present work promotes the degradation of pollutant and simultaneously suppresses the formation of toxic by-product,which paves the way for ROS-based pollutant removal.

Effects of Heat Treatment and Additive LiF on the Properties of Solid-State Electrolyte of Li_(1.5)Al_(0.5)Ge_(1.5)(PO_(4))_(3)

A solid electrolyte of LAGP[Li_(1.5)Al_(0.5)Ge_(1.5)(PO_(4))_(3)]contained 0.5 wt%Li F was prepared by using low-volatile raw materials.The effects of different heat treatment conditions(750–900°C,4–10 h)and additive(Li F)on the ionic conductivity,structural morphology,and crystal transformation process were investigated in detail.EIS(electrochemical impedance spectroscopies)showed that the ionic conductivity of LAGP contained 0.5 wt%Li F had a highest value of 3.17×10^(-4)S cm^(-1)with low activation energy(0.31 e V)after treating 825°C for 6 h,more than LAGP of 2.45×10^(-4)S cm^(-1).DSC analysis and SEM images indicated that adding a small amount of Li F to LAGP not only can lower the glass transition temperature(from 513°C to507°C)and crystallization temperature(from 622°C to 605°C),but also can modify the grain boundary and increase the relative density of LAGP(from 95.8%to 97.7%).

Perspective on High-Energy Carbon-Based Supercapacitors

Supercapacitors based on carbon materials have advantages such as high power density,fast charging/discharging capability,and long lifetime stability,playing a vital role in the field of electrochemical energy storage technologies.To further expand the practical applications of carbon-based supercapacitors,their energy density,which is essentially determined by the specific capacitance and operating voltage,should be improved.This review provides fundamental knowledge on achieving high energy density of supercapacitors.We first address the relationship of the features of carbon materials,such as the surface area,pore size distribution,and surface functional groups,with their electrochemical performances,such as the gravimetric and volumetric capacitance,surface pseudocapacitance,and operating voltage.Then,we discuss the properties of electrolytes from nonaqueous and aqueous to hybrid one from the thermodynamic and kinetic aspects,and present their effects on capacitance and operating voltage.Finally,we illustrate different cell design strategies and their basic principles for increasing operating voltage.We also highlight the recent advances related to these fields and provide our insight into high-energy supercapacitors.

Ultra-Robust and High-Performance Rotational Triboelectric Nanogenerator by Bearing Charge Pumping

As an emerging technology to convert environmental high-entropy energy into electrical energy,triboelectric nanogenerator(TENG)has great demands for further enhancing the service lifetime and output performance in practical applications.Here,an ultra-robust and high-performance rotational triboelectric nanogenerator(R-TENG)by bearing charge pumping is proposed.The R-TENG composes of a pumping TENG(P-TENG),an output TENG(O-TENG),a voltage-multiplying circuit(VMC),and a buffer capacitor.The P-TENG is designed with freestanding mode based on a rolling ball bearing,which can also act as the rotating mechanical energy harvester.The output low charge from the P-TENG is accumulated and pumped to the non-contact O-TENG,which can simultaneously realize ultralow mechanical wear and high output performance.The matched instantaneous power of R-TENG is increased by 32 times under 300 r/min.Furthermore,the transferring charge of R-TENG can remain 95%during 15 days(6.4×10^(6)cycles)continuous operation.This work presents a realizable method to further enhance the durability of TENG,which would facilitate the practical applications of high-performance TENG in harvesting distributed ambient micro mechanical energy.

Robust Cross-Linked Na_(3)V_(2)(PO_(4))_(2)F_(3) Full Sodium-Ion Batteries

Sodium-ion batteries(SIBs)have rapidly risen to the forefront of energy storage systems as a promising supplementary for Lithium-ion batteries(LIBs).Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)as a common cathode of SIBs,features the merits of high operating voltage,small volume change and favorable specific energy density.However,it suffers from poor cycling stability and rate performance induced by its low intrinsic conductivity.Herein,we propose an ingenious strategy targeting superior SIBs through cross-linked NVPF with multi-dimensional nanocarbon frameworks composed of amorphous carbon and carbon nanotubes(NVPF@C@CNTs).This rational design ensures favorable particle size for shortened sodium ion transmission pathway as well as improved electronic transfer network,thus leading to enhanced charge transfer kinetics and superior cycling stability.Benefited from this unique structure,significantly improved electrochemical properties are obtained,including high specific capacity(126.9 mAh g^(-1)at 1 C,1 C=128 mA g^(-1))and remarkably improved long-term cycling stability with 93.9%capacity retention after 1000 cycles at 20 C.The energy density of 286.8 Wh kg^(-1)can be reached for full cells with hard carbon as anode(NVPF@C@CNTs//HC).Additionally,the electrochemical performance of the full cell at high temperature is also investigated(95.3 mAh g^(-1)after 100 cycles at 1 C at 50℃).Such nanoscale dual-carbon networks engineering and thorough discussion of ion diffusion kinetics might make contributions to accelerating the process of phosphate cathodes in SIBs for large-scale energy storages.

High-Resolution Mass Spectroscopy for Revealing the Charge Storage Mechanism in Batteries: Oxamide Materials as an Example

The pursuit of high-performance electrode materials is highly desired to meet the demand of batteries with high energy and power density.However,a deep understanding of the charge storage mechanism is always challenging,which limits the development of advanced electrode materials.Herein,high-resolution mass spectroscopy(HR-MS)is employed to detect the evolution of organic electrode materials during the redox process and reveal the charge storage mechanism,by using small molecular oxamides as an example,which have ortho-carbonyls and are therefore potential electrochemical active materials for batteries.The HR-MS results adequately proved that the oxamides could reversibly store lithium ions in the voltage window of 1.5–3.8 V.Upon deeper reduction,the oxamides would decompose due to the cleavage of the C–N bonds in oxamide structures,which could be proved by the fragments detected by HR-MS,^(1)H NMR,and the generation of NH_(3)after the reduction of oxamide by Li.This work provides a strategy to deeply understand the charge storage mechanism of organic electrode materials and will stimulate the further development of characterization techniques to reveal the charge storage mechanism for developing high-performance electrode materials.

A Hydrogen Iron Flow Battery with High Current Density and Long Cyclability Enabled Through Circular Water Management

The hydrogen-iron(HyFe)flow cell has great potential for long-duration energy storage by capitalizing on the advantages of both electrolyzers and flow batteries.However,its operation at high current density(high power)and over continuous cycling testing has yet to be demonstrated.In this paper,we discuss our design and demonstration of a water management strategy that supports high current and long cycling performance of a HyFe flow cell.Water molecules associated with the movement of protons from the iron electrode to the hydrogen electrode are sufficient to hydrate the membrane and electrode at a low current density of 100 mA cm^(-2)during the charge process.At higher charge current density,more aggressive measures must be taken to counter back-diffusion driven by the acid concentration gradient between the iron and hydrogen electrodes.Our water management approach is based on water vapor feeding in the hydrogen electrode,and water evaporation in the iron electrode,thus enabling the high current density operation of 300 mA cm^(-2).

Recent Advances in Carbon-Based Current Col lectors/Hosts for Alkali Metal Anodes

The urgent demand for high-energy-density storage systems evokes the research upsurge on the alkali metal batteries with high theoretical capacities.However,the utilization of alkali metal anodes,including Li,Na,and K,is significantly hindered by notorious dendrite growth,undesirable corrosion,and unstable solid electrolyte interface.In order to resolve these issues,the carbon materials for the rational design of current collector/host that can regulate the plating/stripping behavior of alkali metal have been exploited.These carbon-based current collectors/hosts are featured with many pivotal advantages,including mechanical integrity to accommodate the volume change,superior electronic/ionic conductivity,large available surface area,and rich functionalization chemistries to increase the affinity to alkali metal.In this review,the recent progress on various dimensional carbon-based current collectors/hosts with different chemical components in stabilizing the alkali metal anodes through the regulation of initial deposition and subsequent growth behavior during plating/stripping process is provided.The nanostructured carbon scaffolds with self-affinity to alkali metals,as well as the carbon frameworks with internal/external affinitive sites to alkali metals,catalogued by various dimensions,are discussed in this review.Therefore,these appealing strategies based on the carbon-based current collectors/hosts can provide a paradigm for the realization of high-energy-density alkali metal batteries.

High-Voltage Aqueous Zinc Batteries Achieved by Tri-functional Metallic Bipolar Electrodes

Aqueous rechargeable zinc batteries are very attractive for energy storage applications due to their low cost and high safety.However,low operating voltages limit their further development.For the first time,this work proposes a unique approach to increase the voltages of aqueous zinc batteries by using tri-functional metallic bipolar electrode with good electrochemical activity and ultrahigh electronic conductivity,which not only participates in redox reactions,but also functions as an electrical highway for charge transport.Furthermore,bipolar electrode can replace expensive ion selective membrane to separate electrolytes with different pH;thus,redox couples with higher potential in acid condition and Zn=Zn(OH)^(2-)_(4) couple with lower potential in alkaline condition can be employed together,leading to high voltages of aqueous zinc batteries.Herein,two types of metallic bipolar electrodes of Cu and Ag are utilized based on three kinds of aqueous zinc batteries:Zn–MnO_(2),Zn–I_(2),and Zn–Br_(2).The voltage of aqueous Zn–MnO_(2) battery is raised to 1.84 V by employing one Cu bipolar electrode,which shows no capacity attenuation after 3500 cycles.Moreover,the other Ag bipolar electrode can be adopted to successfully construct Zn–I_(2) and Zn–Br_(2) batteries exhibiting much higher voltages of 2.44 and 2.67 V,which also show no obvious capacity degradation for 1000 and 800 cycles,representing decent cycle stability.Since bipolar electrode can be applied in a large family of aqueous batteries,this work offers an elaborate high-voltage concept based on tri-functional metallic bipolar electrode as a model system to open a door to explore high-voltage aqueous batteries.

Unveiling the Underlying Mechanism of Transition Metal Atoms Anchored Square Tetracyanoquinodimethane Monolayers as Electrocatalysts for N_(2) Fixation

We for the first time systematically studied the structures and electrochemical nitrogen reduction reaction properties of two-dimensional single transition-metal anchored square tetracyanoquinodimethane monolayers(labeled as:TM-sTCNQ,TM=3d,4d,5d series transition metals)by employing density functional theory method.Through highthroughput screenings and full reaction path researches,two promising electrochemical nitrogen reduction reaction catalysts Nb-sTCNQ and MosTCNQ have been obtained.The nitrogen reduction reaction onset potential on Nb-sTCNQ is as low as−0.48 V.Furthermore,the Nb-sTCNQ catalyst can quickly desorb NH3 produced with a free energy of 0.65 eV,giving Nb-sTCNQ excellent catalytic cycle performance.The high catalytic activity of the two materials might be attributed to the effective charge transfer between the active center and adsorbed N_(2),which enables the active center to adsorb and activate inert N_(2) molecules well,and the reduction processes require small energy input(i.e.,the maximum free energy changes are small).This work provides insights for finding highly efficient,stable,and low-cost nitrogen reduction reaction electrocatalysts.We hope our results can promote further experimental and theoretical research of this field.

Understanding Bonding Nature ofα-Keggin Polyoxometalates[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S):A Generalized Superatomic Perspective

α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature.Here,first-principles calculations show that XW_(12)are core–shell structures composed of a shell and an XO_(4)^(n−)core,both are stabilized by covalent interactions.Interestingly,owing to the presence of a substantial number of electrons in W_(12)O_(36)shell,the frontier molecular orbitals of XW_(12)are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model.Detailed analysis indicates that energetically high lying filled molecular orbitals(MOs)have reached unusually high-angular momentum characterized by quantum number K or higher,allowing for the accommodation of numerous electrons.This attribute confers strong electron acceptor ability and redox activity to XW_(12).Moreover,electrons added to XW_(12)still occupy the K orbitals and will not cause rearrangement of the MOs,thereby maintaining the stability of these structures.Our findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.

Characteristic Study of Self-Powered Sensors Based on Native Protein Composite Film

Flexible electronic sensors composed of flexible film and conductive materials play an increasingly important role in wearable and internet information transmission.It has received more and more attention and made some progress over the decades.However,it is still a great challenge to prepare biocompatible and highly transparent conductive films.Egg white is a pure natural protein-rich material.Hydroxypropylmethyl cellulose has a good compatibility and high transparency,which is an ideal material for flexible sensors.Here,we overcome the problem of poor mechanical flexibility and electrical conductivity of protein,and develop a high transparency and good flexibility hydroxypropylmethyl cellulose/egg white protein composite membrane-based triboelectric nanogenerator('X'-TENG).The experimental results show that the flexible pressure sensor based on'X'-TENG has a high sensitivity,fast response speed,and low detection limit.It can even be used as a touch/pressure sensing artificial electronic skin.It can also be made into an intelligent waffle keyboard for recording and tracking users of the keyboard.Our strategy may provide a new way to easily build flexible electronic sensors and move toward practical applications.

High-Efficiency Photo-Induced Charge Transfer for SERS Sensing in N-Doped 3D-Graphene on Si Heterojunction

Nitrogen-doped three-dimensional graphene(N-doped 3D-graphene)is a graphene derivative with excellent adsorption capacity,large specific surface area,high porosity,and optoelectronic properties.Herein,N-doped 3D-graphene/Si heterojunctions were grown in situ directly on silicon(Si)substrates via plasma-assisted chemical vapor deposition(PACVD),which is promising for surface-enhanced Raman scattering(SERS)substrates candidates.Combined analyses of theoretical simulation,incorporating N atoms in 3D-graphene are beneficial to increase the electronic state density of the system and enhance the charge transfer between the substrate and the target molecules.The enhancement of the optical and electric fields benefits from the stronger light-matter interaction improved by the natural nano-resonator structure of N-doped 3D-graphene.The as-prepared SERS substrates based on N-doped 3D-graphene/Si heterojunctions achieve ultra-low detection for various molecules:10^(-8)M for methylene blue(MB)and 10^(-9)M for crystal violet(CRV)with rhodamine(R6G)of 10^(10)M.In practical detected,10^(-8)M thiram was precisely detected in apple peel extract.The results indicate that N-doped 3D-graphene/Si heterojunctions based-SERS substrates have promising applications in low-concentration molecular detection and food safety.

Enhanced Electrochemical Properties and Optimized Li^(+)Transmission Pathways of PEO/LLZTO-Based Composite Electrolytes Modified by Supramolecular Combination

Poly(ethylene oxide)(PEO)and Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(LLZTO)-based composite polymer electrolytes(CPEs)are considered one of the most promising solid electrolyte systems.However,agglomeration of LLZTO within PEO and lack of Li^(+)channels result in poor electrochemical properties.Herein,a functional supramolecular combination(CD-TFSI)consisting of activeβ-cyclodextrin(CD)supramolecular with self-assembled LiTFSI salt is selected as an interface modifier to coat LLZTO fillers.Benefiting from vast H-bonds formed betweenβ-CD and PEO matrix and/or LLZTO,homogeneous dispersion and tight interface contact are obtained.Moreover,^(6)Li NMR spectra confirm a new Li^(+)transmission pathway from PEO matrix to LLZTO ceramic then to PEO matrix in the as-prepared PEO/LLZTO@CD-TFSI CPEs due to the typical cavity structure ofβ-CD.As a proof,the conductivity is increased from 5.3×10^(-4)S cm^(-1)to 8.7×10^(-4)S cm^(-1)at 60℃,the Li^(+)transference number is enhanced from 0.38 to 0.48,and the electrochemical stability window is extended to 5.1 V versus Li/Li^(+).Li‖LiFePO_(4)CR2032 coin full cells and pouch cells prove the practical application of the as-prepared PEO/LLZTO@CD-TFSI CPEs.This work offers a new strategy of interface modifying LLZTO fillers with functional supramolecular combination to optimize PEO/LLZTO CPEs for solid lithium batteries.

Extraordinary Ultrahigh-Capacity and Long Cycle Life Lithium-Ion Batteries Enabled by Graphitic Carbon Nitride-Perylene Polyimide Composites

Graphitic carbon nitride(g-C_(3)N_(4))is widely used in organic metal-ion batteries owing to its high porosity,facile synthesis,stability,and high-rate performance.However,pristine g-C_(3)N_(4)nanosheets exhibit poor electrical conductivity,irreversible metal-ion storage capacity,and short-term cycling owing to their high concentration of graphitic-N species.Herein,a series of 3,4:9,10-perylenetetracarboxylic diimide-coupled g-C_(3)N_(4)composite anode materials,CN-PI_(x)(x=0.2,0.5,0.75,and 1),was investigated,which exhibited an unusually high surface nitrogen content(23.19-39.92 at.%)and the highest pyridinic-N,pyrrolic-N,and graphitic-N contents reported to date.The CN-PI_(1)anode delivers an unprecedented and continuously increasing ultrahigh discharging capacity of exceeding 8400 mAh g^(-1)(1.96 mWh cm^(-2))at 100 mA g^(-1)with high specific energy density(E_(sp))of~7700 Wh kg^(-1)and the volumetric energy density(E_(v))of~14956 Wh L-1 and an excellent long-term stability(414 mAh g^(-1)or 0.579 mWh cm^(-2)at 1 A g^(-1)).Furthermore,the activation of the CN-PI_(x)electrodes contributes to their superior electrochemical performance,resulting from the fact that the Li+is not only stored in the CN-PI_(x)composites but also CN-PI_(x)activated the Li^(0)adlayer on the CN-PI_(1)-Cu heterojunction as an SEI layer to avoid the direct contact of Li^(0)phase and the electrolyte.The CN-PI_(1)full cell with LiCoO_(2)as the cathode delivers a discharge capacity of~587 mAh g^(-1)at a 1 A g^(-1)after 250 cycles with a Coulombic efficiency nearly 99%.This study provides a strategy to develop N-doped g-C_(3)N_(4)-based anode materials for realizing long-lasting energy storage devices.

High-Con cent rat ion Electrosynthesis of Formic Acid/Formate from CO_(2):Reactor and Electrode Design Strategies

The electrochemical CO_(2)reduction reaction(CO_(2)RR),driven by renewable energy,provides a potential carbon-neutral avenue to convert CO_(2)into valuable fuels and feedstocks.Conversion of CO_(2)into formic acid/formate is considered one of the economical and feasible methods,owing to their high energy densities,and ease of distribution and storage.The separation of formic acid/formate from the reaction mixtures accounts for the majority of the overall CO_(2)RR process cost,while the increment of product concentration can lead to the reduction of separation cost,remarkably.In this paper,we give an overview of recent strategies for highly concentrated formic acid/formate products in CO_(2)RR.CO_(2)RR is a complex process with several different products,as it has different intermediates and reaction pathways.Therefore,this review focuses on recent study strategies that can enhance targeted formic acid/formate yield,such as the all-solid-state reactor design to deliver a high concentration of products during the reduction of CO_(2)in the electrolyzer.Firstly,some novel electrolyzers are introduced as an engineering strategy to improve the concentration of the formic acid/formate and reduce the cost of downstream separations.Also,the design of planar and gas diffusion electrodes(GDEs)with the potential to deliver high-concentration formic acid/formate in CO_(2)RR is summarized.Finally,the existing technological challenges are highlighted,and further research recommendations to achieve high-concentration products in CO_(2)RR.This review can provide some inspiration for future research to further improve the product concentration and economic benefits of CO_(2)RR.

Toward the Design of High-performance Supercapacitors by Prussian Blue, its Analogues and their Derivatives

Supercapacitors(SCs)with high power output have attracted increasing attention as efficient and environmentally friendly energy storage devices.Prussian blue and its analogues(PB/PBAs)are simple coordination polymers with tunable chemical compositions and open framework.Prussian blue can act as electrode materials in its pristine form and has also been utilized to derive various metallic nanostructures for electrochemical applications due to their simple fabrication process,non-toxic characteristics,and low price.Here,we firstly describe the charge storage mechanisms of SCs briefly followed by an introduction of the fabrication methods of PB/PBAs and their derivatives.Then,a comprehensive review on recent studies of the use of PB/PBAs and their derivatives as the electrode materials for SCs are given with a focus on strategies to improve their electrochemical performances.Finally,we discuss critical challenges in this research area and propose some general ideas for future research.

Advances in Porous Perovskites:Synthesis and Electrocatalytic Performance in Fuel Cells and Metal-Air Batteries

With a rising energy demand and anabatic environmental crisis arising from the fast growth in human population and society economics,numerous efforts have been devoted to explore and design plentiful multifunctional materials for meeting highefficiency energy transfer processes,which happen in various developed energy conversion and storage systems.As a special kind of multi-metal oxides,perovskite with attractive physical and chemical properties,is becoming a rapidly rising star on the horizon of high-performance catalytic materials with substantial research behaviors worldwide.The porous nanostructure in targeted catalysts is favorable to the catalytic activity and thus improves the overall efficiency of these energy-related installations.In this review paper,recent advances made in the porous perovskite nanostructures for catalyzing several anodic or cathodic reactions in fuel cells and metal-air batteries are comprehensively summarized.Plenty of general preparation methods employed to attain porous perovskite-type oxides are provided,followed by a further discussion about the influence of various strategies on structures and catalytic properties of the porous perovskites.Furthermore,deep insights gathered in the future development of porous perovskite-based materials for energy conversion and storage technologies are also provided.