Prussian Blue Cathode Research Articles

Mesoporous hollow Fe4[Fe(CN)6)]3 hierarchical nanocrystal architecture for advanced sodium-ion batteries

Prussian blue (PB) has been broadly recognized as promising cathode materials for sodium-ion batteries (SIBs) due to its large interstitial space and robust frame structure, whereas their applications are impeded by unsatisfied long-term cyclability and poor rate capability due to its inherent lattice defects. Herein, we report to fabricate the mesoporous hollow Fe4(Fe(CN)6)3 (one kind of PB) hierarchical nanocrystal architecture by the hydrothermal crystallization and HCl etching of the mesoporous precursor Fe4[Fe(CN)6]3 cubic particles, leading to high crystallinity and large specific surface area. The resultant Fe4[Fe(CN)6]3 cathode for SIBs exhibits a good reversibility and cycling stability with a capacity retention of 75.6 % at 0.5 C after 200 cycles as well as superb rate capability featuring a stable discharge specific capacity of 30.2 mAh g−1 at as high as 10 C, demonstrating the fast kinetics and low polarization of electrochemical reaction, which might be ascribed to the unique architecture and high crystallinity. This offers a new route to designing PB cathode of for SIBs with high rate capabilities.

Advanced Prussian Blue Cathodes for Rechargeable Li-Ion Batteries

Taking advantage of fact that the surface electrons of metallic nanoparticles (NPs) can be effectively released even at a low voltage bias, we demonstrate an improvement in the electrochemical performance of nanosized Prussian Blue (PB)-based secondary batteries through the incorporation of bare Ag or Ni NPs in the vicinity of the working PB NPs. It is found that the capacity for electrochemical energy storage of the 17 nm PB-based battery is significantly higher than the capacity of 10 nm PB-based, 35 nm PB-based or 46 nm PB-based batteries. There is a critical PB size for the highest electrochemical energy storage efficiency. The full specific capacity CF of the 17 nm PB-based battery stabilized to 62 mAh/g after 130 charge–discharge cycles at a working current of IW = 0.03 mA. The addition of 14 mass percent of Ag NPs in the vicinity of the PB NPs gave rise to a 32% increase in the stabilized CF. A 42% increase in the stabilized CF could be obtained with the addition of 14 mass percent of Ag NPs on the working electrode of the 35 nm PB-based battery. An enhancement in CF was also found for electrodes incorporating bare Ni NPs but the effect was smaller.

Enhancing cyclic stability of Mn-based Prussian blue cathode for Potassium Ion storage by High-spin Fe substitution strategy

Aqueous K-ion batteries (AKIBs) are being considered as promising candidates, although they still confront numerous problems. Here we propose a high-spin Fe substitution method to enhance the long-term cyclic stability of Mn-based Prussian blue analogue (Mn-PBA) cathode. The prepared K1.86Mn[Fe(CN)6]0.96·0·19H2O (KMF) are electrochemically activated for 20-cycle CV scan in the hybrid electrolyte containing KNO3+Fe(NO3)3. The modified cathode (KMF-100) achieves a high capacity of 185.8 mAh g−1 and high-capacity retention of 89.8 % at 2 A g−1 after 1500 cycles (based on maximum capacity). The high-spin Fe substitution strategy not only activates the transition metal at high spin sites to contribute extra capacity, but also promotes the partial dissolved Mn2+ to return to the PBA in the hybrid electrolyte with Fe3+, relieving the Jahn-Teller effect of Mn(Ⅲ). In contrast, the KMF in the pure KNO3 electrolyte does not exhibit this behavior. The DFT calculation further demonstrate the reconstituted Prussian blue structure can increase the electrical conductivity and improve ion diffusion kinetics of the cathode material. Notably, it suppresses the change in C-Fe bond lengths during K-ion extraction, maintaining outstanding structural stability throughout cycle. This work provides a novel way to prepare high-stability manganese-based PBA cathode.

Aging Mechanism of Mn-Based Prussian Blue Cathode Material by Synchrotron 2D X-ray Fluorescence

The aging mechanism of 10% and 30% nickel-substituted manganese hexacyanoferrate cathode material in aqueous zinc-ion batteries has been explored through the advanced synchrotron-based two-dimensional X-ray fluorescence technique. Thanks to the two-dimension modality, not only were the metal concentration dynamics throughout the entire electrodes followed during the aging process, but their spatial distribution was also revealed, suggesting the route of the material transformation. The dissolution of Mn and Ni, as well as the penetration of Zn inside the framework were detected, while the Mn aggregations were found outside the hexacyanoferrate framework. Additionally, the possibility of conducting X-ray absorption spectroscopy measurements on the regions of interest made it possible to explore the chemical state of each metal, and furthermore, synchrotron-based powder X-ray diffraction demonstrated the gradual structural modification in 30% Ni-containing sample series in terms of the different phase formation.

Sequentially epitaxial multi-shelled Mn-based Prussian blue cathode for highly stable sodium-ions batteries

The sodium manganese hexacyanoferrate (MnPB) has drawn widely attention as a remarkable cathode material for sodium-ions batteries owing to its high theoretical capacity (∼170 mAh g–1), environmental-friendly and low cost. However, it suffers from serious capacity fading and inferior cycling stability caused by the inevitable Jahn-Teller distortion and significant volume change during Na+insertion/extraction process. Herein, we propose a simple one-pot method for constructing a multi-shelled Mn-based Prussian blue through sequentially epitaxial growth CoPB and NiPB on the surface of MnPB (NiCoMnPB). The density functional theory calculations demonstrate the unequal affinities of different metal ions with various chelating agents (citrate and ferrocyanide), leading to the dissociation and recombination of metal ions and chelating agents in a certain order. Effectively inheriting merits of CoPB and NiPB, the NiCoMnPB reveals enhanced charge transfer kinetics, suppressed volume change and alleviative Jahn-Teller distortion during cycling, thereby exhibiting superior rate capacity (∼54.2 mAh g–1 at 3200 mA/g), long-term cyclic stability and capacity retention (∼76 % over 1000 cycles at 800 mA/g). This work provides a simple method to construct multi-shelled PBAs, which can integrate the virtues of different materials to ameliorate the electrochemical properties of initial materials.

Hollow Layered Iron-Based Prussian Blue Cathode with Reduced Defects for High-Performance Sodium-Ion Batteries.

Fe-based Prussian blue (Fe-PB) analogues have emerged as promising cathode materials for sodium-ion batteries, owing to their cost-effectiveness, high theoretical capacity, and environmental friendliness. However, their practical application is hindered by [Fe(CN)6] defects, negatively impacting capacity and cycle stability. This work reports a hollow layered Fe-PB composite material using 1,3,5-benzenetricarboxylic acid (BTA) as a chelating and etching agent by the hydrothermal method. Compared to benzoic acid, our approach significantly reduces defects and enhances the yield of Fe-PB. Notably, the hollow layered structure shortens the diffusion path of sodium ions, enhances the activity of low-spin Fe in the Fe-PB lattice, and mitigates volume changes during Na-ion insertion/extraction into/from Fe-PB. As a sodium-ion battery cathode, this hollow layered Fe-PB exhibits an impressive initial capacity of 95.9 mAh g-1 at a high current density of 1 A g-1. Even after 500 cycles, it still maintains a considerable discharge capacity of 73.1 mAh g-1, showing a significantly lower capacity decay rate (0.048%) compared to the control sample (0.089%). Moreover, the full cell with BTA-PB-1.6 as the cathode and HC as the anode provides a considerable energy density of 312.2 Wh kg-1 at a power density of 291.0 W kg-1. This research not only enhances the Na storage performance of Fe-PB but also increases the yield of products obtained by hydrothermal methods, providing some technical reference for the production of PB materials using the low-yield hydrothermal method.

In Situ Defect Engineering in Carbon by Atomic Self-Activation to Boost the Accessible Low-Voltage Insertion for Advanced Potassium-Ion Full-Cells.

Enhancing the low-potential capacity of anode materials is significant in boosting the operating voltage of full-cells and constructing high energy-density energy storage devices. Graphitic carbons exhibit outstanding low-potential potassium storage performance, but show a low K+ diffusion kinetics. Herein, in situ defect engineering in graphitic nanocarbon is achieved by an atomic self-activation strategy to boost the accessible low-voltage insertion. Graphitic carbon layers grow on nanoscale-nickel to form the graphitic nanosphere with short-range ordered microcrystalline due to nickel graphitization catalyst. Meanwhile, the widely distributed K+ in the precursor induces the activation of surrounding carbon atoms to in situ generate carbon vacancies as channels. The graphite microcrystals with defect channels realize reversible K+ intercalation at low-potential and accessible ion diffusion kinetics, contributing to high reversible capacity (209mAhg-1 at 0.05Ag-1 under 0.8V) and rate capacity (103.2mAhg-1 at 1Ag-1). The full-cell with Prussian blue cathode and graphitic nanocarbon anode maintains an obvious working platform at ca. 3.0V. This work provides a strategy for the in situ design of carbon anode materials and gives insights into the potassium storage mechanism at low-potential for high-performance full-cells.

Building Stable Solid-State Potassium Metal Batteries.

Solid-state potassium metal batteries (SPMBs) are promising candidates for the next generation of energy storage systems for their low cost, safety, and high energy density. However, full SPMBs are not yet reported due to the K dendrites, interfacial incompatibility, and limited availability of suitable solid-state electrolytes. Here, stable SPMBs using a new iodinated solid polymer electrolyte (ISPE) are presented. The functional ions reconstruct ion transport channels, providing efficient potassium ion transport. ISPE shows a combination of high ionic conductivity, superior interfacial compatibility, and electrochemical stability. In situ alloying and iodinated interlayer increase K metal compatibility for prolonged cycling with low polarization. Moreover, the ISPE enables SPMBs with Prussian blue cathode stable operation at a high voltage of 4.5V, a superior rate capability, and long-term cycling over 3000 cycles (4.2V vs K+/K) with an ultra-high coulombic efficiency of 99.94%. More importantly, a classic solid-state potassium metal pouch cell achieves 4.2V stable cycling over 800 cycles with a high retention of 93.6%, presenting a new development strategy for secure and high-performance rechargeable solid-state potassium metal batteries.

Portable self-powered electrochemical aptasensing platform for ratiometric detection of mycotoxins based on multichannel photofuel cell

Self-powered electrochemical sensors based on photofuel cells have attracted considerable research interest because their unique advantage of not requiring an external electric source, but their application in portable and multiplexed targets assay is limited by the inherent mechanism. In this work, a portable self-powered sensor constructed with multichannel photofuel cells was developed for the ratiometric detection of mycotoxins, namely ochratoxin A (OTA) and patulin (PAT). The spatially resolved CdS/Bi2S3-modified photoanodes and a shared Prussian Blue cathode were integrated on an etched indium-tin oxide slide to fabricate the multichannel photofuel cell. The aptamers of OTA and PAT were covalently bonded to individual photoanode regions to build sensitive interfaces, and the specific recognition of analytes impaired the output performance of constructed PFC. Accordingly, ratiometric sensing of OTA and PAT was achieved by utilizing the output performance of a control PFC as a reference signal. This approach effectively eliminates the impact of light intensity on the accuracy of the detection. Under the optimal conditions, the proposed sensing chip exhibited linear ranges of 2.0–1000 nM and 5.0–500 nM for OTA and PAT, respectively. The detection limits (3 S/N) were determined to be 0.25 nM for OTA and 0.27 nM for PAT. The developed ratiometric sensing method demonstrated good selectivity and stability in the simultaneous detection of OTA and PAT. It was successfully utilized for the analysis of OTA and PAT real samples. This work provides a new perspective for construction of portable and ratiometric self-powered sensing platform.

A ZIF-8 modified Prussian blue cathode material for sodium-ion batteries with long cycling life and excellent storage stability

Prussian blue analogues have been intensely investigated as promising cathode materials for sodium-ion batteries owing to their high capacities, easy synthesis and low cost. However, the poor cycling performance due to the presence of lattice defects and the structural deterioration when exposed to humid air hinder their practical application. Herein we report an effective surface modification method to tackle these issues. A Zinc-zeolitic imidazolate framework (ZIF-8) modified PB sample is prepared by in-situ growth via simple wet chemical reaction. The obtained PB@ZIF-8 composite with a ZIF-8 coating layer of ∼70 nm thickness on the 2–5 μm PB particle surface shows excellent cycling stability with reversible capacity of 106.5 mAh g−1 at 1C charge-discharge rate and a remarkable capacity retention of 96.7 % after 500 cycles. Furthermore, the PB@ZIF-8 composite shows excellent storage stability owing to its moisture-proof property. After exposure to high humidity air (RH=70 %) for 24 h or storage for 180 days in a bottle filled with air of relative humidity RH=40 %, the PB@ZIF-8 sample still maintains excellent cycling performance. ZIF-8 coating layer not only acts as a shield for PB particles against the electrolyte corrosion, but also resists the H2O attacking in humid environment.

Achieving a superior Na storage performance of Fe‐based Prussian blue cathode by coating perylene tetracarboxylic dianhydride amine

AbstractFe‐based Prussian blue (Fe‐PB) cathode material shows great application potential in sodium (Na)‐ion batteries due to its high theoretical capacity, long cycle life, low cost, and simple preparation process. However, the crystalline water and vacancies of Fe‐PB lattice, the low electrical conductivity, and the dissolution of metal ions lead to limited capacity and poor cycling stability. In this work, a perylene tetracarboxylic dianhydride amine (PTCDA) coating layer is successfully fabricated on the surface of Fe‐PB by a liquid‐phase method. The aminated PTCDA (PTCA) coating not only increases the specific surface area and electronic conductivity but also effectively reduces the crystalline water and vacancies, which avoids the erosion of Fe‐PB by electrolyte. Consequently, the PTCA layer reduces the charge transfer resistance, enhances the Na‐ion diffusion coefficient, and improves the structure stability. The PTCA‐coated Fe‐PB exhibits superior Na storage performance with a first discharge capacity of 145.2 mAh g−1 at 100 mA g−1. Long cycling tests exhibit minimal capacity decay of 0.027% per cycle over 1000 cycles at 1 A g−1. Therefore, this PTCA coating strategy has shown promising competence in enhancing the electrochemical performance of Fe‐PB, which can potentially serve as a universal electrode coating strategy for Na‐ion batteries.

Enabling High‐Performance Potassium‐Ion Batteries by Manipulating Interfacial Chemistry

AbstractAs a promising candidate for the flame‐retardant electrolyte, triethyl phosphate (TEP)/potassium bis(fluorosulfonyl)amide (KFSI)‐based electrolyte has drawn much attention in the K‐ion battery community. Although the TEP/KFSI formula at a moderate main salt concentration (normally, <3 m) enables the compatibility of the reactive K metal anode, the long‐standing oxidative instability of KFSI salt remains unsolved. Here, an additive strategy is reported to address the high‐voltage issue in the TEP/KFSI electrolyte, and generalize it to the other KFSI‐based electrolytes. The addition of potassium nitrate changes the surface charge distribution and effectively suppresses the decomposition of KFSI toward the high‐voltage cathode. The nitrate‐containing electrolyte enables superior stability of a 4.3 V‐class K‐ion battery, as evidenced by its 80% capacity retention over 2000 cycles (≈6 months) at the 1 C rate. Moreover, the long‐cycling stability of the graphite‐based full cell with Prussian Blue cathode is demonstrated.

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

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

Simultaneous derivatization and exfoliation of a multilayered Ti3C2Tx MXene into amorphous TiO2 nanosheets for stable K-ion storage.

Two-dimensional transition metal compounds (2D TMCs) have been widely reported in the fields of energy storage and conversion, especially in metal-ion storage. However, most of them are crystalline and lack active sites, and this brings about sluggish ion storage kinetics. In addition, TMCs are generally nonconductors or semiconductors, impeding fast electron transfer at high rates. Herein, we propose a facile one-step route to synthesize amorphous 2D TiO2 with a carbon coating (a-2D-TiO2@C) by simultaneous derivatization and exfoliation of a multilayered Ti3C2Tx MXene. The amorphous structure endows 2D TiO2 with abundant active sites for fast ion adsorption and diffusion, while the carbon coating can facilitate electron transport in an electrode. Owing to these intriguing structural and compositional synergies, a-2D-TiO2@C delivers good cycling stability with a long-term capacity retention of 86% after 2000 cycles at 1.0 A g-1 in K-ion storage. When paired with Prussian blue (KPB) cathodes, it exhibits a high full-cell capacity of 50.8 mA h g-1 at 100 mA g-1 after 140 cycles, which demonstrates its great potential in practical applications. This contribution exploits a new approach for the facile synthesis of a-2D-TMCs and their broad applications in energy storage and conversion.

Low temperature colloidal synthesis of carbon coated Prussian blue cathode for high-rate and long-life sodium-ion batteries

Low temperature colloidal synthesis of carbon coated Prussian blue cathode for high-rate and long-life sodium-ion batteries

Development of Quasi-solid-state Na-ion Battery Based on Water-minimal Prussian Blue Cathode

Development of Quasi-solid-state Na-ion Battery Based on Water-minimal Prussian Blue Cathode

Nanoarchitectonics for a long-life and robust Na-ion battery at low temperature with Prussian blue cathode and low-concentration electrolyte

Na-ion batteries are considered as promising battery systems for large-scale energy storage. Although Na-ion batteries exhibit enhanced low-temperature cycling performance compared with lithium-ion batteries, there is still a great challenge to overcome for practical low-temperature applications. In this work, we propose a low-performance Na-ion battery composed of FeNi co-doped Mn-based Prussian cathode (FeNi-MnHCF) and a low-concentration electrolyte (0.5 mol L−1) containing a small amount of 2,2,2-trifluoroethyl acetate (ETFA, 1 wt%). The introduction of ETFA could decrease the viscosity, increase ionic conductivity and change the solvation structure of the electrolyte at low temperature. ETFA could also participate in constructing a uniform, stable, and Na-ion conductive CEI layer, enabling rapid Na-ion transport and effective protection of FeNi-MnHCF. The cells with the ETFA-contained electrolyte and FeNi-MnHCF cathode exhibit excellent rate capability and long cycle life at low temperature. When being cycled at −20 °C, the cell with ETFA could retain 92.1 % of the capacity after 1120 cycles at 1 C. The cell could also show stable cycling after overcharge to 4.8 V or overdischarge to 1.2 V at −20 °C. This work sheds light on the design of long-life and robust Na-ion batteries for sustainable energy storage at low temperature.

Enabling High-Capacity Electrochemical Magnesium Intercalation in Prussian Blue Cathode Via Synthesis Route Optimization

Magnesium-ion batteries (MIBs) have emerged as a promising candidate for post-lithium-ion batteries. However, their widespread adoption is hindered by the limited number of host materials that can intercalate magnesium ions reversibly in a nonaqueous electrolyte with a high operating voltage, such as Prussian Blue analogues. Unfortunately, the capacity of Prussian Blue is by far limited (<100 mAh g−1), resulting in low energy density, despite their high operating voltage. In this study, we present a systematic synthesis route optimization that allows for high-capacity magnesium ion insertion into Prussian Blue. Our defect-free and water-free Prussian Blue demonstrates reversible magnesium intercalation with a first discharge capacity of 127 mAh g−1 at 25 °C and 156 mAh g−1 at 60 °C, with an average discharge voltage of ~2.1 V (vs. Mg/Mg2+) in a nonaqueous, chloride-free electrolyte. The high-capacity magnesium ion insertion into our optimized Prussian Blue offers insights into the importance of material preparation for high-energy cathode materials in MIBs.

Research Progress of Prussian Blue and Its Analogs as High-Performance Cathode Nanomaterials for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) are investigated as promising alternatives to lithium-ion batteries (LIBs) on account of the economical abundance and reliable availability of sodium, as well as its analogous chemical properties compared to lithium. Nevertheless, the performance of SIBs is severely restricted by the availability of satisfactory cathode nanomaterials with stable frameworks to accommodate the transportation of large-sized Na+ ions. These challenges can be effectively resolved when exploiting Prussian blue (PB) and its analogs (PBAs) as SIB cathodes. This is mainly because PB and PBAs have 3D open frameworks with large interstitial space, which are more favorable for fast insertion/extraction of Na+ ions during the charging/discharging process, thus enabling the improvement of integrated performance in SIB systems. This overview offers a comprehensive summarization of recent advancements in the electrochemical performance of PB and PBAs when employing them as cathodes in SIBs. For better understanding, the fabrication strategy, structural characterization, and electrochemical performance exposition are systematically organized and explained according to tuning PB and metal-based PBAs. Additionally, the current trajectories and prospective future directions pertaining to the utilization of PB and PBA cathodes in the SIB system are thoroughly examined and deliberated upon.

A Pyrazine‐Pyridinamine Covalent Organic Framework as a Low Potential Anode for Highly Durable Aqueous Calcium‐Ion Batteries

AbstractRechargeable aqueous calcium‐ion batteries (CIBs) are promising for reliable large‐scale energy storage. However, they face significant challenges, primarily stemming from suboptimal anodes, resulting in unfavorable voltage profiles, limited capacity, and diminished durability, all of which hinder the development of CIBs. Here, a covalent organic framework (PTHAT‐COF) featuring repeated pyrazine and pyridinamine units, employed as the anode material for aqueous CIBs, is introduced. This innovative approach results in a remarkably flat ultralow potential plateau ranging from −0.6 to −1.05 V (vs Ag/AgCl), attributed to the high level of the lowest unoccupied molecular orbital. Furthermore, the PTHAT‐COF anode exhibits outstanding rate performance (152.3 mAh g−1 @ 1 A g−1), exceptional long‐term cycling stability, and remarkable capacity retention (10 000 cycles with 89.9% retention). Mechanistic studies, including experimental and theoretical calculations, reveal that C═N active sites reversibly trap Ca2+ ions via chemisorption during the discharging/charging process. The PTHAT‐COF demonstrates exceptional structural stability throughout cycling. Finally, by pairing PTHAT‐COF with a high‐voltage manganese‐based Prussian blue cathode, a complete aqueous CIB with a voltage interval of 2.2 V is achieved, exhibiting extraordinary durability (10 000 cycles with 83.6% retention). This research illuminates the potential of organic anode materials in aqueous batteries to achieve higher battery voltages.