Prussian Blue Analogue‑Templated Nanocomposites for Alkali‑Ion Batteries:Progress and Perspective

Lithium-ion batteries(LIBs)have dominated the portable electronic and electrochemical energy markets since their commercialisation,whose high cost and lithium scarcity have prompted the development of other alkali-ion batteries(AIBs)including sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).Owing to larger ion sizes of Na^(+)and K^(+)compared with Li^(+),nanocomposites with excellent crystallinity orientation and well-developed porosity show unprecedented potential for advanced lithium/sodium/potassium storage.With enticing open rigid framework structures,Prussian blue analogues(PBAs)remain promising self-sacrificial templates for the preparation of various nanocomposites,whose appeal originates from the well-retained porous structures and exceptional electrochemical activities after thermal decomposition.This review focuses on the recent progress of PBA-derived nanocomposites from their fabrication,lithium/sodium/potassium storage mechanism,and applications in AIBs(LIBs,SIBs,and PIBs).To distinguish various PBA derivatives,the working mechanism and applications of PBA-templated metal oxides,metal chalcogenides,metal phosphides,and other nanocomposites are systematically evaluated,facilitating the establishment of a structure–activity correlation for these materials.Based on the fruitful achievements of PBA-derived nanocomposites,perspectives for their future development are envisioned,aiming to narrow down the gap between laboratory study and industrial reality.

Cesium-doped manganese-based Prussian blue analogue as a high-efficiency cathode material for potassium-ion batteries

Prussian blue analogues (PBAs) are regarded as promising cathode materials for potassium-ion batteries(PIBs) owing to their low cost and high reversible capacity.Compared to other PBAs,potassium manganese hexacyanoferrate (KMnHCF) stands out for its superior capacity and operating voltage.However,Jahn-Teller effect of Mn^(3+)and the structural collapse caused by potassium ion insertion/extraction still affect the structural stability and electrochemical performance of this material.Herein,a green and efficient synthesis method is adopted to substitute potassium ions in KMnHCF with an appropriate amount of cesium ions to form a column effect.Cesium-doped KMnHCF (Cs-KMnHCF) mitigates the irreversible structural damage caused by potassiation/depotassiation and the Jahn-Teller effect,thereby improving the cycling stability.In addition,it widens the lattice channels,reduces the diffusion barrier of potassium ions,and optimizes the diffusion kinetics.By rationally controlling the doping amount of Cs^(+),the obtained K_(1.71)Cs_(0.05)Mn[Fe(CN)_(6)]_(0.95·0.05)·0.88H_(2)O exhibits remarkable electrochemical performance,with an initial discharge capacity of 137.6 mA h g^(-1)at a current density of 20 mA g^(-1)and a capacity retention of 89.6%after 600 cycles at 200 mA g^(-1).More importantly,when assembled with a pitch-derived soft carbon anode,the full cell manifests excellent cycle stability and rate performance.This work is expected to provide a highly efficient cathode material for the practical application of PIBs.

Prussian Blue Analogues in Aqueous Batteries and Desalination Batteries

In the applications of large-scale energy storage,aqueous batteries are considered as rivals for organic batteries due to their environmentally friendly and low-cost nature.However,carrier ions always exhibit huge hydrated radius in aqueous electrolyte,which brings difficulty to find suitable host materials that can achieve highly reversible insertion and extraction of cations.Owing to open threedimensional rigid framework and facile synthesis,Prussian blue analogues(PBAs)receive the most extensive attention among various host candidates in aqueous system.Herein,a comprehensive review on recent progresses of PBAs in aqueous batteries is presented.Based on the application in different aqueous systems,the relationship between electrochemical behaviors(redox potential,capacity,cycling stability and rate performance)and structural characteristics(preparation method,structure type,particle size,morphology,crystallinity,defect,metal atom in highspin state and chemical composition)is analyzed and summarized thoroughly.It can be concluded that the required type of PBAs is different for various carrier ions.In particular,the desalination batteries worked with the same mechanism as aqueous batteries are also discussed in detail to introduce the application of PBAs in aqueous systems comprehensively.This report can help the readers to understand the relationship between physical/chemical characteristics and electrochemical properties for PBAs and find a way to fabricate high-performance PBAs in aqueous batteries and desalination batteries.

Ternary Ni-based Prussian blue analogue with superior sodium storage performance induced by synergistic effect of Co and Fe

Prussian blue analogue Na2Ni[Fe(CN)6](Ni-PB)has been widely studied as a cathode material for sodium-ion battery due to its excellent cycling performance.However,Ni-PB has a low theoretical capacity of 85 mAh g^(−1) because of the electrochemical inertness of Ni.Herein,ternary Ni-PB is successfully synthesized by double doping with Co and Fe at Ni-site,and the effect of doping with Co and Fe on the electrochemical performance of Ni-PB is systematically investigated through theoretical calculations and electrochemical tests.The first principles calculations confirm that double doping with Co and Fe can significantly reduce the energy barrier and bandgap of Ni-PB.X-ray diffraction and composition analysis results indicate that ternary NiCoFe-PB composite not only has good crystallinity and high Na content but also has low defects and crystal water.Electrochemical tests reveal that,besides the capacity contribution of high-spin Co/Fe and low-spin Fe,Co-doping enhances the electrochemical activity of low-spin Fe and Fe-doping improves the activity of high-spin Co;moreover,double doping can decrease the diffusion resistance of Na+ions through solid electrolyte interface film,accelerate the kinetics for both ion diffusion process and Faradic reaction,and increase active sites.Under the synergistic effect of Co and Fe,this ternary NiCoFe-PB exhibits outstanding electrochemical performance with a high initial discharge capacity of 120.4 mAh g^(−1) at 20mA g^(−1) and an extremely low capacity fading rate of 0.0044%per cycle at a high current density of 2 A g^(−1) even after 10,000 cycles,showing great application potential of ternary NiCoFe-PB in the field of large-scale energy storage.

Construction of hierarchical photocatalysts by growing ZnIn_(2)S_(4) nanosheets on Prussian blue analogue-derived bimetallic sulfides for solar co-production of H_(2) and organic chemicals

Exploring highly efficient bifunctional photocatalysts for simultaneous H2 evolution and organic chemical production in pure water represents a green route for sustainable solar energy storage and conversion.Herein,a facile strategy was explored for preparing a hierarchical porous heterostructure of Fe_(4)Ni_(5)S_(8)@ZnIn_(2)S_(4)(FNS@ZIS)by the in situ growth of ZIS nanosheets on Prussian blue analogue(PBA)-derived bimetallic FNS sulfides.A series of FNS@ZIS hierarchical structures were facilely prepared by adjusting the loading amount(n%)of FNS(n=19,26,and 32 for FNS@ZIS-1-3).These structures can efficiently drive the solar co-production of H_(2) and organic chemicals.The optimal co-production was achieved with FNS@ZIS-2,affording a H_(2) evolution rate of 10465μmol·g^(-1)·h^(-1),along with high selectivity for the oxidation of benzyl alcohol to benzaldehyde(>99.9%).The performance was 22 and 31 times higher than that of FNS and ZIS,respectively,and even superior to the state-of-the-art results achieved using various sacrificial agents.Further mechanistic study indicated that the unique hierarchical core/shell architecture can facilitate interfacial charge separation,afford bimetallic synergy,abundant active sites and excellent photostability.This work highlights a simple and efficient method for preparing porous multimetallic hierarchical structures for the solar co-production of organic chemicals and H_(2) fuel.

Unveiling anomalous lattice shrinkage induced by Pi-backbonding in Prussian blue analogues

Transition-metal(TM)-based Prussian blue and its analogues(TM-PBAs) have attracted considerable attention as cathode materials owing to their versatile ion storage capability with tunable working voltages. TM-PBAs with different crystal structures, morphologies, and TM combinations can exhibit excellent electrochemical properties because of their unique and robust host frameworks with well-defined<100> ionic diffusion channels. Nonetheless, there is still a lack of understanding regarding the performance dependence of TM-PBAs on structural changes during charging/discharging processes. In this study, in situ X-ray diffraction and X-ray absorption fine structure analyses elucidate the TMdependent structural changes in a series of TM-PBAs during the charging and discharging processes.During the discharging process, the lattice volume of Fe-PBA increased while those of Ni-and Cu-PBAs decreased. This discrepancy is attributed to the extent of size reduction of the cyanometallate complex([Fe(CN)_(6)]) via pi-backbonding from Fe to C due to redox flips of the low-spin Fe^(3+/2+) ion. This study presents a comprehensive understanding of how TM selection affects capacity acquisition and phase transition in TM-PBAs, a promising class of cathode materials.

Moderate heat treatment of CoFe Prussian blue analogues for enhanced oxygen evolution reaction performance

Prussian blue analogues(PBAs) with inherent ordered structures and abundant metal ion sites are widely explored as precursors for various electrochemical applications,including oxygen evolution reaction(OER).Using a range of characterization techniques including Fourier-transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and energy dispersive spectroscopy(EDS),this work discloses the process of replacement of K^(+)by NH4^(+)in the interstitial spaces of the CoFe PBA by a hot aqueous urea solution,which influences the transformation of PBAs under further heat treatment and the OER performance of the deriva tives.After heat treatment at 400℃ under Ar flow,high-resolution transmission electron microscopy(HRTEM) images reveal that CoFe alloy nanoparticles grew on the crystalline cubes of CoFe PBA with K^(+),while CoFe PBA cubes with NH4^(+)become amorphous.Besides,the derivative of CoFe PBA with NH4^(+)(Ar-U-CoFe PBA) performs better than the derivative of CoFe PBA with K^(+)(Ar-CoFe PBA) in OER,registering a lower overpotential of 305 mV at 10 mA cm^(-2),a smaller Tafel slope of 36.1 mV dec^(-1),and better stability over a testing course of 20 h in 1.0 M KOH.A single-cell alkaline electrolyzer,using Ar-U-CoFe PBA and Pt/C for the anodic and cathodic catalyst,respectively,requires an initial cell voltage of 1.66 V to achieve 100 mA cm^(-2)at 80℃,with negligible degradation after100 h.

Ultralow-Energy-Barrier H_(2)O_(2)Dissociation on Coordinatively Unsaturated Metal Centers in Binary Ce-Fe Prussian Blue Analogue for Efficient and Stable Photo-Fenton Catalysis

The low intrinsic activity of Fenton catalytic site and high demand for light-energy input inhibit the organic-pollution control efficiency of photo-Fenton process.Here,through structural design with density functional theory(DFT)calculations,Ce is predicted to enable the construction of coordinatively unsaturated metal centers(CUCs)in Prussian blue analogue(PBA),which can strongly adsorb H_(2)O_(2)and donate sufficient electrons for directly splitting the O-O bond to produceOH.Using a substitution-co-assembly strategy,binary Ce-Fe PBA is then prepared,which rapidly degrades sulfamethoxazole with the pseudo-first-order kinetic rate constant exceeding reported values by 1-2 orders of magnitude.Meanwhile,the photogenerated electrons reduce Fe(Ⅲ)and Ce(Ⅳ)to promote the metal valence cycle in CUCs and make sulfamethoxazole degradation efficiency only lose 6.04%in 5 runs.Overall,by introducing rare earth metals into transition metal-organic frameworks,this work guides the whole process for highly active CUCs from design and construction to mechanism exploration with DFT calculations,enabling ultrafast and stable photo-Fenton catalysis.

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.

基于MWCNTs和Co-Fe双金属普鲁士蓝类似物的电化学传感检测牛奶中的H_(2)O_(2)

该研究构建了钴铁普鲁士蓝类似物(Co-FePBA)和多壁碳纳米管(MWCNTs)修饰的无酶电化学传感器(NF/Co-FePBA/MWCNTs/GCE),Co-FePBA模拟过氧化氢酶对H_(2)O_(2)进行电催化还原,产生较强的电流响应,用于牛奶中H_(2)O_(2)的快速、灵敏电化学检测。在最优条件下,该传感器对H_(2)O_(2)的电流响应有较宽的线性范围(0.01~5.0 mmol/L),检出限(LOD,S/N=3)为0.52μmol/L。此外,该传感器具有较强的抗干扰能力和良好的重复性、重现性和稳定性,用于实际牛奶样品检测中回收率为91.3%~103%,相对标准偏差(RSD)≤2.7%(n=3)。该电化学检测方法可以实现牛奶中H_(2)O_(2)的低成本、简单、快速、高灵敏检测。

Co-Fe普鲁士蓝类配合物纳米颗粒的微乳液法制备与表征(英文)

Highly oriented cubic, hollow cubic and spherical nanoparticles of cobalt-iron Prussian blue analogues were synthesized in poly oxyethylene tertoctylphenyl ether (TritonX-100)/n-hexanol/cyclohexane microemulsion. The effects of the water-to-surfactant molar ratio (w), the reactant concentration and the reaction temperature on the morphology of cobalt-iron Prussian blue analogues were studied. The samples were characterized by transmission electron microscopy (TEM), field emission scan electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and infrared spectroscopy (IR).

Co-Fe普鲁士蓝/多壁碳纳米管复合材料的超电容性能

Co-Fe普鲁士蓝(CoPBA)是目前被广泛研究的超级电容器正极材料,其比电容高循环性能好,但低导电性和较差的倍率性能限制了其在超级电容器中的应用。为了提高CoPBA的导电性和电化学性能,本文以Co-glycerate为前驱体,采用牺牲模板法制备了Co-Fe普鲁士蓝/多壁碳纳米管(CoPBA/MWCNT)复合材料,利用XRD、SEM和FTIR等对复合材料的结构和形貌进行表征,使用电化学工作站在三电极体系和非对称超级电容器中测定了复合材料的电化学性能。实验结果表明:采用牺牲模板法成功合成出形貌较好的球状复合材料,以中性溶液Na_(2)SO_(4)为电解液,测得在1 A/g的电流密度下复合材料的质量比电容达到391.5 F/g。在10 A/g的高电流密度下比电容达到312.6 F/g,为1 A/g时的79.8%。利用软件模拟得出电荷转移电阻由3.9Ω降低到1.1Ω。以CoPBA/MWCNT为正极,以活性炭为负极制成非对称电容器,在功率密度为1092 W/kg时能量密度可达39.5 Wh/kg,5000次循环后容量保持率为85.2%。采用牺牲模板法制备的CoPBA/MWCNT,其电容、导电性和倍率性能均有提高,并具有较高的实际应用价值。

Hollow and substrate-supported Prussian blue,its analogs,and their derivatives for green water splitting

To meet the current energy needs of society,the highly efficient and continuous production of clean energy is required.One of the key issues facing the green hydrogen evolution is the construction of efficient,low-cost electrocatalysts.Prussian blue(PB),Prussian blue analogs(PBAs),and their derivatives have tunable metal centers and have attracted significant interest as novel photo-and electrochemical catalysts.In this review,recent research progress into PB/PBA-based hollow structures,substrate-supported nanostructures,and their derivatives for green water splitting is discussed and summarized.First,several remarkable examples of nanostructured PB/PBAs supported on substrates(copper foil,carbon cloth,and nickel foam)and hollow structures(such as single-shelled hollow boxes,open hollow cages,and intricate hollow structures(multi-shell and yolk-shell))are discussed in detail,including their synthesis and formation mechanisms.Subsequently,the applications of PB/PBA derivatives((hydr)oxides,phosphides,chalcogenides,and carbides)for water splitting are discussed.Finally,the limitations in this research area and the most urgent challenges are summarized.We hope that this review will stimulate more researchers to develop technologies based on these intricate PB/PBA structures and their derivatives for highly efficient,green water splitting.

Abnormal magnetic behavior of prussian blue analogs modified with multi-walled carbon nanotubes

This work examines the origin of the abnormal magnetism exhibited by Cu Mn Fe-PBAs modified with multi-walled carbon nanotubes(MWCNTs).The system of Cu Mn Fe-PBAs@MWCNTs coexists with both large and small clusters.Cu Mn Fe-PBAs clusters have an average particle size of 28 nm,and some of the smaller particles are adsorbed on the surface of MWCNTs.Surprisingly,the magnitude of magnetization increases linearly with decreasing temperature.When above the Curie temperature,the magnitude of magnetization is significantly greater than that of PBAs without being modified.This phenomenon can be attributed to magnetostatic interactions between ultra-fine magnetic nanoparticles adsorbed on the surface of MWCNTs.Using the Monte Carlo method,we simulated the magnetostatic interaction of cylindrical adsorbed particles,and the simulation results are almost identical to those observed experimentally.The results indicate that 0.089Cu Mn Fe-PBAs clusters per 1 nm^(2)can be adsorbed onto the surface area of MWCNTs.We demonstrate that MWCNTs adsorbing magnetic particles exhibit magnetic behavior,and suggest a method for producing ultrafine materials.It also introduces a new method of calculating the adsorption efficiency of carbon nanotubes,offering theoretical guidance for future research on nanomaterials with enhanced adsorption efficiency.

FeNi Prussian blue analogues on highly graphitized carbon nanosheets as efficient glucose sensors

Meeting the continuous glucose monitoring requirements of individuals necessitates the research and development of sensors with high sensitivity and stability.In this study,a straightforward strategy was proposed for synthesizing ultra-thin oxygen-rich graphitized carbon nanosheets(denoted as GCS-O).These nanosheets are obtained by calcining a topologically two-dimensional indium-based coordination polymer.Subsequently,the growth of FeNi Prussian blue analogue(PBA)on GCS-O effectively introduces active sites and increases the nitrogen content within the carbonaceous matrix.The resulting FeNi-PBA/GCS-O composite exhibits excellent glucose sensing performance with a broad linear range of 1 to 1300μmol·L^(-1).Meanwhile,it also achieves a high sensitivity of 2496μA·mmol^(-1)·L·cm^(-2),a limit of detection of 100nmol·L^(-1)(S/N=3),and commendable long-term durability.The relatively simple synthesis process,exceptional sensitivity,and satisfactory electrochemical sensing performance of FeNi-PBA/GCS-O open up new directions for biosensor applications.

Prussian Blue Analogue Derived N-Doped Graphitic Carbon Wrapped Iron-Cobalt Nanoparticles as Recyclable Heterogeneous Catalysts for Friedel-Crafts Acylation

The rational design of efficient heterogeneous catalysts for Friedel-Crafts acylation reactions is highly desirable for meeting the need for the industrial production of various aromatic ketone compounds and biomass-derived chemicals.Herein,we reported that graphitic carbon wrapped FeCo bimetallic nanoparticles confined in nitrogen-doped carbon nanotubes,which were prepared by pyrolysis of FeCo-based Prussian blue analogue and melamine via a two-stage programmed heating procedure,exhibited excellent catalytic activity and recyclability for the acylation of aromatic compounds with acyl chlorides.The oxidized bimetallic species embedded in the external graphitic carbon shell should be the main active sites for the acylation reaction.The graphitic carbon shell and the carbon nanotube could provide effective protection on the active metal species against leaching through multiple interactions,leading to the formation of a highly active and durable heterogeneous catalyst for the acylation reaction.

In Situ Electron Paramagnetic Resonance Reveals Fading Mechanism of Mn-Based Prussian Blue Analogue:Accelerated Mn Dissolution Due to Charge Delocalization

Contrasting with Fe-based Prussian blue analogues(PBAs),Mn-based PBAs with higher energy density are more promising cathode materials for Na-ion batteries.However,fast capacity fading has severely impeded its practical use,which is still not well understood.To elucidate the fading mechanism,in situ and ex situ electron paramagnetic resonance are employed here.The results first demonstrate the charge delocalization of Mn2+and Mn dissolution during cycles,which are further proved to be highly related.Our work reveals the inherent shortcoming of Mn-based PBA cathodes in liquid electrolyte.

Energy storage materials derived from Prussian blue analogues

Prussian blue analogues(PBAs) with open frameworks have drawn much attention in energy storage fields due to their tridimensional ionic diffusion path, easy preparation, and low cost. This review summarizes the recent progress of using PBAs and their derivatives as energy storage materials in alkali ions,multi-valent ions, and metal-air batteries. The key factors to improve the electrochemical performance of PBAs as cathode materials in rechargeable batteries were firstly discussed. Several approaches for performance enhancement such as controlling the amounts of vacancies and coordinated water, optimizing morphologies, and depositing carbon coating are described in details. Then, we highlighted the significance of their diverse architectures and morphologies in anode materials for lithium/sodium ion batteries. Finally, the applications of Prussian blue derivatives as catalysts in metal-air batteries are also reviewed, providing insights into the origin of favorable morphologies and structures of catalyst for the optimal performance.

Rapid and Scalable Synthesis of Prussian Blue Analogue Nanocubes for Electrocatalytic Water Oxidation

Design and fabrication of earth-abundant electrocatalysts for oxygen evolution reaction(OER)is essential in improving the overall ef-ficiency of water electrolysis.In this work,we proposed a rapid and scalable synthesis route for fabricating Prussian blue analogue(PBA)nano cubes with tun able compositi ons and uniform particle size.With the structural ben efits of abu ndant surface sites,facile charge transfer behavior and favorable Co^(2+)-to-Co^(3+)pre-oxidation reaction,fast generation and accumulation of the catalytically active Co3+sites can be achieved for the CoCo PBA nano cubes,leadi ng to remarkable OER activity with simulta neously achieved low overpotential,large anodic current density,small Tafel slope as well as outstanding intrinsic activity.Of note,by performing Iong-term OER operati on,the CoCo PBA nano cubes exhibit a remarkable 5.5-folds performs nee enhan ceme nt,and obvious surface rec on struc-tion and the accumulation of high-valence Co species can be identified,proving the crucial role of pre-oxidation process in boosting the OER catalysis.This work proposed a un iversal approach for the rapid,scalable and con trollable fabricati on of the PBA-based materials,and the elucidation of the pre-oxidation process in facilitating the OER catalysis may provide useful guidanee for designing and optimizing advanced catalysts for energy-related electro-oxidation reactions in the future.

Hierarchical flower-like cobalt phosphosulfide derived from Prussian blue analogue as an efficient polysulfides adsorbent for long-life lithium-sulfur batteries

Lithium-sulfur (Li-S) battery as one of the most attractive candidates for energy storage systems has attracted extensive interests.Herein,for the first time,hierarchical flower-like cobalt phosphosulfide architectures (defined as "CoSP") derived from Prussian blue analogue (PBA) was fabricated through the conversion of Co-based PBA in PxSy atmosphere.The as-prepared polar CoSP could effectively trap polysulfides through the formation of strong chemical bonds.In addition,after the combination of CoSP with high conductive rGO,the obtained CoSP/rGO as sulfur host material exhibits ultralow capacity decay rate of 0.046% per cycle over 900 cycles at a current density of 1 C.The excellent performance could be attributed to the shortened lithium diffusion pathways,fastened electron transport ability during polysulfide conversion,and increased much more anchor active sites to polysulfides,which is expected to be a promising material for Li-S batteries.It is believed that the as-prepared CoSP/rGO architectures will shed light on the development of novel promising materials for Li-S batteries with high cycle stability.