Progress on Transition Metal Ions Dissolution Suppression Strategies in Prussian Blue Analogs for Aqueous Sodium-/Potassium-Ion Batteries

Aqueous sodium-ion batteries(ASIBs)and aqueous potassium-ion batteries(APIBs)present significant potential for large-scale energy storage due to their cost-effectiveness,safety,and environmental compatibility.Nonetheless,the intricate energy storage mechanisms in aqueous electrolytes place stringent require-ments on the host materials.Prussian blue analogs(PBAs),with their open three-dimensional framework and facile synthesis,stand out as leading candidates for aqueous energy storage.However,PBAs possess a swift capacity fade and limited cycle longevity,for their structural integrity is compromised by the pronounced dis-solution of transition metal(TM)ions in the aqueous milieu.This manuscript provides an exhaustive review of the recent advancements concerning PBAs in ASIBs and APIBs.The dissolution mechanisms of TM ions in PBAs,informed by their structural attributes and redox processes,are thoroughly examined.Moreover,this study delves into innovative design tactics to alleviate the dissolution issue of TM ions.In conclusion,the paper consolidates various strategies for suppressing the dissolution of TM ions in PBAs and posits avenues for prospective exploration of high-safety aqueous sodium-/potassium-ion batteries.

Magnetization of mixed ferri-ferrimagnets composed of Prussian blue analogs A1_xA2_(1-x)B

The magnetization of ternary metal Prussian blue analogues AlxA21-xB, formed by three different sublattices A1, A2 and B, is studied by using the effective-field theory with self-spin correlations. Effects of the mole fraction x, the anisotropy and the transverse magnetic field on the magnetization are discussed.

Fully fluorinated hybrid zeolite imidazole/Prussian blue analogs with combined advantages for efficient oxygen evolution reaction

Hybrid metal-organic framework(MOF)derivatives play a significant role in the novel catalyst development in energy conversion reactions.Here,we demonstrated the low-temperature fully fluorinated zeolitic imidazole framework(ZIF)coupled with a three-dimensional open framework Prussian blue analog(PBA)with combined advantages for electrocatalytic oxygen evolution reaction(OER)in water splitting reaction.The spectroscopic analysis and the electrochemical studies revealed the combined advantages of efficient electronic effect and active site synergism.Because of good conductivity improvement by Ndoped carbon derived from ZIF and the high electrochemical surface area and active site exposure from PBA derivatives,good catalytic performance was obtained on the optimal catalyst of Co Ni ZIF/Co Fe-PBAF-300,which required a low overpotential of 250 m V to reach 10 m A/cm^(2)loaded on the glassy carbon electrode,with Tafel slope of 47.4 m V/dec,and very high dynamic and steady stability.In addition,the multi-component with the mixed structure from highly polar metal fluorides promoted the easy formation of the active phase as revealed by the post-sample analysis.The current results showed a novel composite catalyst materials development from the hybrid MOF derivatives,which would be promising in the electrolysis of water oxidation reactions and energy-relevant catalysis reactions.

Experimental and computational optimization of Prussian blue analogues as high-performance cathodes for sodium-ion batteries:A review

In this review,we discuss the electrochemical properties of Prussian blue(PB)for Na^(+)storage by combining structural engineering and electrolyte modifications.We integrated experimental data and density functional theory(DFT)in sodium-ion battery(SIB)research to refine the atomic arrangements and crystal lattices and introduce substitutions and dopants.These changes affect the lattice stability,intercalation,electronic and ionic conductivities,and electrochemical performance.We unraveled the intricate structure-electrochemical behavior relationship by combining experimental data with computational models,including first-principles calculations.This holistic approach identified techniques for optimizing PB and Prussian blue analog(PBA)structu ral properties for SIBs.We also discuss the tuning of electrolytes by systematically adjusting their composition,concentration,and additives using a combination of molecular dynamics(MD)simulations and DFT computations.Our review offers a comprehensive assessment of strategies for enhancing the electrochemical properties of PB and PBAs through structural engineering and electrolyte modifications,combining experimental insights with advanced computational simulations,and paving the way for next-generation energy storage systems.

The design and synthesis of Prussian blue analogs as a sustainable cathode for sodium-ion batteries

Sodium-ion batteries(SIBs)present great appeal in various energy storage systems,especifically for stationary grid storage,on account of the abundance of sources and low cost.Unfortunately,the commercialization of SIBs is mainly limited by available electrode materials,especially for the cathodes.Prussian blue analogs(PBAs),emerge as a promising alternative for their structural feasibility in the application of SIBs.Decreasing the defects(vacancies and coordinated water)is an effective strategy to achieve superior electrochemical performance during the synthetic processes.Herein,we summarize crystal structures,synthetic methods,electrochemical mechanisms,and the influences of synthesis conditions of PBAs in detail.This comprehensive overview on the current research progresses of PBAs will give guides and directions to solve the existing problems for their application in SIBs.

Enhanced conductivity and stability of Prussian blue cathodes in sodium-ion batteries by surface vapor-phase molecular selfassembly

With many merits such as facile synthesis,economy,and relatively high theoretical capacity,Prussian blue analogs(PBAs)are considered promising cathode materials for sodium-ion batteries(SIBs).However,their practical applications still suffer from a low actual specific capacity and inferior stability owing to the imperfect crystallinity,irreversible phase transition,and low intrinsic conductivity.Herein,a surface-modification technique for vapor-phase molecular self-assembly was developed to prepare Fe-based PBAs,specifically sodium iron hexacyanoferrate(NaFeHCF),with a uniform conductive polymer protective layer of polypyrrole(PPy)on the surface,resulting in NaFeHCF@PPy.The incorporation of a PPy protective layer not only improves the electronic conductivity of NaFeHCF@PPy,but also effectively mitigates the dissolution of Fe-ions during cycling.Specifically,this advanced vapor-phase technique avoids Fe^(2+)oxidation and Na^(+)loss during liquid-phase surface modification.The NaFeHCF@PPy exhibited a remarkably enhanced cycling performance,with capacity retentions of 85.6%and 69.1%over 500 and 1000 cycles,respectively,at 200 mA/g,along with a superior rate performance up to 5 A/g(fast kinetics).Additionally,by adopting this strategy for Mn-based PBAs(NaMnHCF@PPy),we further demonstrated the universality of this method for PBA cathodes in SIBs.

Polymorphic cerium-based Prussian blue derivatives with in situ growing CNT/Co heterojunctions for enhanced microwave absorption via polarization and magnetization

In this paper,the structure evolution of cerium cobaltohexanoate(Ce[Co(CN)6],Ce-Co Prussian blue analog(PBA))has been realized by solvent catalysis at room temperature.The hexagonal bipyramidal microcrystals of Ce-Co PBA can be gradually transformed into dendrites by different proportions of ethanol(EtOH)and water.At the same time,the porous dendrites CeO_(2)/Co@carbon nanotub(CNT)with oxygen-rich vacancies(OVs)can be obtained by annealing Ce-Co PBA at 700℃.The microstructure study shows that carbon nanotubes will be catalyzed after annealing at high temperature,and the cobalt metal particles encapsulated in carbon nanotubes will be anchored in the matrix,regulating the impedance matching and multi-polarization suppression of the material,and its unique structure,vacancies,and strong interface effect make the material exhibit excellent electromagnetic wave(EMW)absorption performance.When the matching thickness is 2.5 mm,the minimum reflection loss(RLmin)of the composite is-51.68 dB,and the effective absorption bandwidth(RL<-10 dB)is 7.76 GHz.These results show that the prepared CeO_(2)/Co@CNT composite has excellent EMW absorption properties.It is expected to be a candidate material for EMW absorption.

Trifunctional robust electrocatalysts based on 3D Fe/N-doped carbon nanocubes encapsulating Co4N nanoparticles for efficient battery-powered water electrolyzers

Herein,we have designed a highly active and robust trifunctional electrocatalyst derived from Prussian blue analogs,where Co_(4)N nanoparticles are encapsulated by Fe embedded in N-doped carbon nanocubes to synthesize hierarchically structured Co_(4)N@Fe/N-C for rechargeable zinc-air batteries and overall water-splitting electrolyzers.As confirmed by theoretical and experimental results,the high intrinsic oxygen reduction reaction,oxygen evolution reaction,and hydrogen evolution reaction activities of Co_(4)N@Fe/N-C were attributed to the formation of the heterointerface and the modulated local electronic structure.Moreover,Co_(4)N@Fe/N-C induced improvement in these trifunctional electrocatalytic activities owing to the hierarchical hollow nanocube structure,uniform distribution of Co_(4)N,and conductive encapsulation by Fe/N-C.Thus,the rechargeable zinc-air battery with Co_(4)N@Fe/N-C delivers a high specific capacity of 789.9 mAh g^(-1) and stable voltage profiles over 500 cycles.Furthermore,the overall water electrolyzer with Co_(4)N@Fe/N-C achieved better durability and rate performance than that with the Pt/C and IrO2 catalysts,delivering a high Faradaic efficiency of 96.4%.Along with the great potential of the integrated water electrolyzer powered by a zinc-air battery for practical applications,therefore,the mechanistic understanding and active site identification provide valuable insights into the rational design of advanced multifunctional electrocatalysts for energy storage and conversion.

Prussian blue with intrinsic heme-like structure as peroxidase mimic

Despite the intrinsic peroxidase-like activity of Prussian blue nanopartides （PBNPs）, their enzyme-mimic mechanism has been scarcely investigated to date. Herein, we probed the catalytic site of PBNPs for the first time, by comparing their peroxidase-like activity with that of a series of Prussian blue analogs （PBAs） in which Fe atoms were replaced by Co, Ni, and Cu. The PBNPs exhibited the highest maximal reaction velocity （1.941 μM·s^-1）, which was at least 13 times higher than that of the PBAs, demonstrating that the peroxidase-like properties of PBNPs could be ascribed to the FeNx （x=4-6） instead of the FeC6 units. Notably, the PBNPs/H2O2 couple also showed much higher oxidizability than .OH radicals produced from the Fenton reaction, implying that a high active Fe（W）=O intermediate might be formed in the FeNx units. This study can thus pave the way for the wider application of PBNPs in biomimetic reactions.

Magnetic Behavior of Ferri-ferromagnetic Alloy in Presence of External Magnetic Field

The magnetic behavior of the mixed ferro-ferrimagnetie alloy with （Aa Bb Cc）y D structure composed of Ising spins SA=1, SB = 5/2, SC= 2, and SD = 3/2 in the presence of the external magnetic field is investigated by the use of the effective field theory. The role of concentration b is discussed in this system in detail. Results show that for a =0.4, only when the concentration b is in the region 0.60 ≥b 〉 0.34 can the ferrimagnetic behavior be seen. Otherwise, the alloy shows ferromagnetic behavior.

Copper Nitroprusside-Based Electrochemical Sensor for Detection of Tryptophan

This work presents a novel electrochemical approach for detecting tryptophan through its interaction with copper nitroprusside,which is synthesized using a simple chemical co-precipitation method.The utilization of the reduction reaction inherent to copper nitroprusside effectively exhibits high selectivity against common interferences present in urine,such as melatonin,lactate,cytosine,cytidine,urea,ascorbic acid,creatine,creatinine,tyrosine,glycine,alanine,arginine,and lysine.The method demonstrates two linear ranges:0.0-0.15 mmol/L and 0.15-2.0 mmol/L with the sensitivities of 119.7±0.2μA/(mmol/L)and 9.9±0.4μA/(mmol/L),respectively.The limit of detection(3S_(B)/m)was determined to be 5.5μmol/L.Application of the sensor in synthetic urine yielded the recovery of 103%±5%.

Accessory ligand strategies for hexacyanometallate networks deriving perovskite polycrystalline electromagnetic absorbents

The controllable adjustment of electromagnetic(EM)properties for high-efficiency EM absorbents are indispensable,nonetheless,rare in crystals engineering regulation.Herein,for the first time,regulated amount of sodium citrate was employed as accessory ligand of cobalt cation in aqueous solution to kinetically assist the controllable fabrication of Prussian blue analogs(PBAs)and corresponding lanthanide perovskite hybrid Co Fe alloy polycrystals.Especially,the multi-phase features were analyzed based on Rietveld refinement of XRD patterns,illustrating the existence of distortions,defects and heterogeneous interfaces in resultant polycrystals.Benefited to the dielectric and magnetic adjustment,polycrystalline absorbents achieved excellent impedance matching and EM attenuation,as the minimum reflection loss of Co Fe/La FeO_(3)and Co Fe/La FeO_(3)/La_(2)O_(3)reached-44.13 and-33.95 d B,ranking broadest effective bands up to 4.88 and 3.36 GHz.The validity of the strategy provided a novel sight into the controllable fabrication of high-performance magnetic semiconductor polycrystalline devices.

MOF-derived multi-interface carbon-based composites with enhanced polarization loss and efficient microwave absorption

Metal-organic framework materials(MOFs)have been widely stu-died because of their adjustable composition and controllable structure in the field of microwave absorption(MA).Therein,Prussian blue analogs(PBA)have attracted the attention of researchers with ultra-high metal content.However,the attenua-tion ability of microwave for PBA-based composites is still unsatis-factory up to now.Therefore,the NiFe/CoFe@C composites were prepared by carbonizing polymetallic PBA(NiCoFe PBA)materials in this work,and the influence of different metal alloy components on MA was explored by adjusting the ratio of metal ions(Ni^(2+)/Co^(2+)).Moreover,the NiFe/CoFe@C composites have rich interfaces and enhance the polarization loss due to the introduction of Ni and it has an optimal performance at 2.7 mm that is the reflection loss(RL)is−41.49 dB and an effective absorption bandwidth(EAB)is 7.12 GHz with 1/1(Ni^(2+)/Co^(2+)).The above data provides a research idea for obtaining light and efficient absorbers.

Thermally Induced Reversible Metal-to-Metal Charge Transfer in Mixed-Valence{Fe^(Ⅲ)_(4)Fe^(Ⅱ)_(4)}Cubes

The engineering of switchable moleculeswith dramatic magnetic change is currently among themost active areas in chemical research.Here,two cyanide-bridged mixed-valence{Fe^(Ⅲ)_(4)Fe^(Ⅱ)_(4)}cubes were prepared,both of which,interestingly,exhibited reversible thermally inducedmetal-to-metal charge transfer(MMCT)behavior between{Fe^(Ⅲ,LS)_(4)Fe^(Ⅱ,HS)_(4)}and{Fe^(Ⅱ,LS)_(4)Fe^(Ⅲ,HS)_(4)}configurations with the transition temperature(T_(1/2))of 274 and 230 K,respectively.These cubes provided a rare example of discrete homometallic complexes exhibiting the reversible MMCT rather than spin crossover behavior.In stark contrast to the heterometallic Fe/Co system,in which the charge transfer(CT)and spin transition(ST)processes occur simultaneously,the detailed structural and Mössbauer spectroscopy analyses confirmed the CT property without involving ST.In addition,both of these cubes showed excellent redox flexibility in solutionwith seven quasi accessible electronic states.

Preventing surface passivation of transition metal nanoparticles in oxygen electrocatalyst to extend the lifespan of Zn-air battery

Prolonging the lifespan of oxygen catalysts in Zn-air batteries was urgently required for the potential commercialization.Herein,two interactional active species were integrated into porous N-doped carbon microspheres(Co-Fe-Ru/PNCS)to act as bifunctional oxygen electrocatalysts.Due to the electron transfer from Ru to Co/Fe element,the high value state of Ru could promote OER performance and reduce the charge voltage of the battery.An extended cycle stability of 200 h was achieved in Co-Fe-Ru/PNCS-based battery.Moreover,the quasi in-situ potentiodynamic sweep of air-electrode in battery cell confirmed it was the incorporation of Ru that avoided the passivation of Co/Fe-based nanoparticles.Accordingly,this novel electrocatalyst may provide a new strategy of designing durable bifunctional oxygen electrocatalyst for Zn-air batteries.