Metaphosphate Research Articles

Origin of over-cycling tolerance achieved by metal phosphate coating for transition metal oxide lithium-ion batteries

Surface coating methods with metal phosphates (e.g., AlPO4, NiPO4, CoPO4, Co3(PO4)2, FePO4) have been widely employed to improve the electrochemical performance of the layered LiNi1-x-yCoxMnyO2 (NMC, where x < 1 and y < 1) battery system. However, the key mechanism that underpins the performance/stability improvement is not fully understood. Herein, an amorphous FePO4 coating method is chosen to investigate the effects of the coating on the electrochemical property and the surface environment of the cathode. A particular attention has been devoted to the origin of the over-charge tolerance achieved by the metal phosphate coating. To gain further insight into the improvement process by the FePO4, a density functional theory (DFT) simulation has been conducted. The enhanced stability during the high voltage cycling can be ascribed to the increased Fe(3d)-O(2p) covalency. Consequently, the TM(3d)-O(2p) character become less covalent, which in turn minimizes the electron extractions from the O(2p) band during the charge compensation process. This study offers a crucial aspect of the optimized materials design for metal phosphate coatings to enhance the battery stability and performance.

Improving the rate capacity and cycle stability of FeP anodes for lithium-ion batteries via in situ carbon encapsulation and copper doping

FeP has emerged as an appealing anode material for lithium-ion batteries (LIBs) thanks to its high theoretical capacity, safe voltage platform and rich resources. Nevertheless, sluggish charge transfer kinetics, inevitable volume expansion and easy agglomeration of active materials limit its practical applications. Here, novel Cu-doped FeP@C was synthesized by a synergistic strategy of metal doping and in situ carbon encapsulation. The optimized Cu-doped FeP@C anode demonstrates a highly reversible specific capacity (920 mAh g−1 at 0.05 A g−1), superb rate performance (345 mAh g−1 at 5 A g−1) and long-term cycle stability (340 mAh g−1 at 2 A g−1 after 600 cycles). The electrochemical mechanism was investigated by cyclic voltammetry, kinetic analysis and DFT calculations. The results reveal that carbon frameworks can improve the conductivity and slow down the volume expansion, with highly dispersed FeP facilitating Li-ion migration during the charge and discharge processes. Additionally, Cu doping leads to rearrangement of the charge density and an additional lattice distortion in FeP, which boosts the electron mobility and enriches the surface-active sites, promoting electrochemical reaction and charge storage. This study presents a feasible and effective design for developing transition metal phosphate (TMP) anodes for high-performance LIBs.

Effect of Fe dopant concentration on electrochemical properties of Ni2P2O7 thin films

Transition metal phosphates have attracted great attention in energy storage applications because of their good ionic conductivity, enriched redox action and high specific capacitance. Fe doped Ni2P2O7 thin films (FNP) successfully prepared by following chemical bath deposition technique which is facile and reproducible one. The thin film characterization such as structural, morphological, compositional and electrochemical studies of Fe doped FNP with dopant concentration 0.5 M, 0.10 M and 0.15 M express effects in respective properties leading to selection of promising electrode material for supercapacitor applications. Impurity free Fe doped FNP films, all belonging to monoclinic system with agglomerated microspheres in morphology exhibit noticeable specific capacitance. 0.15 M Fe doped Ni2P2O7 thin film (FNP3) shows profound effect on electrochemical properties delivering a specific capacitance of 492 F/g at low current density with 13.12 Wh/kg energy density (ED) at 0.17 kW/kg power density (PD) in the present work. Stability tests on FNP3 shows excellent capacitance retention of 96% after 2000 cycles which is a prerequisite for supercapacitors.

Nutrient recovery from biogas slurry via hydrothermal carbonization with different agricultural and forestry residue

Hydrothermal carbonization (HTC) of various agricultural and forestry waste (yellow bamboo, green bamboo, peanut shell, wood meal, peanut straw, wheat straw, rice husk, corn straw) with biogas slurry (BS) was studied, with the goal of recovering nutrients from BS. The ideal biomass material for nitrogen recovery was green bamboo, where 46.64 % of N was recovered after HTC at 250 °C for 3 h. The best one for phosphorus recovery was peanut straw, where P in liquid residue was not detectable post HTC. However, with all types of biomass tested, HTC failed recovering potassium from BS. Nitrogen recovery performance was positively correlated to the total cellulosic content of biomass as C-N active binding site for the formation of aliphatic amine were mainly provided by cellulose and hemicellulose. Increased metal salt concentration in biomass feedstock promoted phosphorus recovery as the mechanism was formation of metal phosphate precipitates. The hydrochars obtained from different biomass samples resulted in a wide range of pore sizes, which was critical for nutrient slow-release characteristics and plant growth promoting microorganism immobilization. Pot experiment further confirmed corn straw hydrochar had significant advantages over chemical fertilizer in water and nutrient retaining, which was critical for the enhancement of long-term soil fertility.

Novel transition metal modified layered phosphate for reducing the fire hazards of PA6

To date polyamide 6 (PA6) have been widely applied in many different fields such as mechanical parts, electronic and electrical products. Nevertheless, the inherent flammability of PA6 threaten the safety of life and properties, restricting its comprehensive applications. In this work, three types of metal phosphate modified layered melamine phytate hybrids are designed and prepared by supramolecular self-assembly technology, and the hybrids are incorporated into glass fiber reinforced PA6. The flame retardancy as well as smoke suppression properties of the composites with different transition metal modified flame retardants are compared and investigated. The results of cone calorimeter test indicate that the metal phosphate modified layered melamine phytate based composites can reduce both the peak heat release (pHRR, <32%) and total heat release (THR, <28%) compared to those of pure glass fiber reinforced PA6; the smoke and toxic volatiles productions are also reduced significantly, and Cu phosphate modified layered melamine phytate hybrids (PA-MEL-Cu) perform better than other flame retardants on suppressing the heat release and smoke releasing of PA6. The mechanism investigations demonstrate that the improved fire safety properties of PA6 composites are attributed to the physical barrier effect and the selective catalysis effect of transition metal during the combustion. This strategy not only prepares metal phosphate modified layered melamine phosphate by in-situ precipitation, but also promotes the promising potentials of melamine phosphate in the flame retardant application of polymer composites.

A review on system and materials for aqueous flexible metal–air batteries

AbstractThe exploration of aqueous flexible metal–air batteries with high energy density and durability has attracted many research efforts with the demand for portable and wearable electronic devices. Aqueous flexible metal–air batteries feature Earth‐abundant materials, environmental friendliness, and operational safety. Each part of one metal–air battery can significantly affect the overall performance. This review starts with the fundamental working principles and the basic battery configurations and then highlights on the common issues and the recent advances in designing high‐performance metal electrodes, solid‐state electrolytes, and air electrodes. Bifunctional oxygen electrocatalysts with high activity and long‐term stability for constructing efficient air electrodes in flexible metal–air batteries are summarized including metal‐free carbon‐based materials and nonprecious Co/Fe‐based materials (alloys, metal oxides, metal sulfites, metal phosphates, metal nitrates, single‐site metal–nitrogen–carbon materials, and composites). Finally, a perspective is provided on the existing challenges and possible future research directions in optimizing the performance and lifetime of the flexible aqueous solid‐state metal–air batteries.

Water Splitting: Recent Scientific and Technological Advances

Hydrogen is a green fuel and has great potential as a sustainable and renewable energy carrier. It can be produced by electrocatalytic, photocatalytic, photoelectrochemical water splitting. It is essential to develop highly effective catalysts for economic and large-scale hydrogen production. Currently, phosphorus-containing catalysts have gained a lot of attention because of their unique properties such as different oxidation states, tunable structure, and exceptional physiochemical properties. In this review paper, the topics discussed are part of numerous research carried out to date in water splitting by phosphorus-containing photocatalysts and electrocatalysts that include phosphorus in elemental form, metal phosphonates, metal phosphates, transition metal phosphides, metal phosphorus trichalcogenides, and phosphorus-doped materials. A detailed mechanism of water splitting and the activity origin of phosphorus-containing catalysts are presented. Lastly, there are some challenges in water splitting listed below that we need to overcome shortly.

In Situ Reconstruction NiO Octahedral Active Sites for Promoting Electrocatalytic Oxygen Evolution of Nickel Phosphate.

Electrochemical activation strategy is very effective to improve the intrinsic catalytic activity of metal phosphate toward the sluggish oxygen evolution reaction (OER) for water electrolysis. However, it is still challenging to operando trace the activated reconstruction and corresponding electrocatalytic dynamic mechanisms. Herein, a constant voltage activation strategy is adopted to in situ activate Ni2 P4 O12 , in which the break of NiONi bond and dissolution of PO4 3- groups could optimize the lattice oxygen, thus reconstructing an irreversible amorphous Ni(OH)2 layer with a thickness of 1.5-3.5nm on the surface of Ni2 P4 O12 . The heterostructure electrocatalyst can afford an excellent OER activity in alkaline media with an overpotential of 216.5 mV at 27.0 mA cm-2 . Operando X-ray absorption fine structure spectroscopy analysis and density functional theory simulations indicate that the heterostructure follows a nonconcerted proton-electron transfer mechanism for OER. This activation strategy demonstrates universality and can be used to the surface reconstruction of other metal phosphates.

Redox flow desalination for tetramethylammonium hydroxide removal and recovery from semiconductor wastewater

As part of humankind’s path towards more sustainable water technologies, redox flow desalination (RFD) has emerged as a promising technology due to its high energy efficiency and easy operation. So far, RFD research has focused on removing and recovering inorganic salts such as lithium-ions, heavy metal ions, or phosphate and nitrate ions. Thus, the potential of RFD in water desalination and resource recovery processes has not been fully demonstrated. Therefore, this study aimed to assess RFD for the valorization of tetramethylammonium hydroxide (TMAH) as value-added organic compounds from wastewater beyond inorganic elements, which is widely being used as an etching solvent, photoresist developer, and surfactant in semiconductor and display industries. By applying a low cell voltage (<1.2 V), a reversible redox reaction allowed a continuous removal of TMAH from the wastewater stream and a simultaneous recovery for reuse as a form of tetramethylammonium cation. The TMAH removal rate was approximately 4.3 mM/g/h with a 40% recovery ratio. With various operational conditions (i.e., TMAH concentration, cell voltage, and flow rate), our system exhibited a high potential for the valorization of TMAH with 60% reduction in capital cost compared to conventional desalination processes.

Improved Proton Adsorption and Charge Separation on Cadmium Sulfides for Photocatalytic Hydrogen Production

Cadmium sulfide has attracted wide attention in photocatalytic hydrogen production, due to its appropriate bandgap and band positions. However, high‐rate photogenerated electron–hole recombination and few active sites on CdS lead to its low photocatalytic activity. Herein, a PANI/NCPP/CdS (PANI/NiCoP/NiCoPi/CdS) hybrid as a noble metal‐free visible light‐driven photocatalyst is reported, with metal phosphides, metal phosphates, and polyaniline (PANI) as reduction and oxidation cocatalysts, respectively. This hybrid not only facilitates the charge separation and transfer owing to the formation of heterojunction, but also improves the local concentration of H+ on the surface of catalysts due to the formation of the protonated amine groups on PANI, beneficial to hydrogen evolution reaction. As a result, the as‐prepared photocatalyst could show a high hydrogen evolution rate of 170.3 mmol g−1 h−1 and an apparent quantum efficiency of 41.37% at 420 nm, representing one of the best performances of all‐CdS‐based photocatalysts.

The Global Biogeochemical Cycle of Arsenic

AbstractDirect exploitation and use of arsenic resources has diminished in recent years, but inadvertent mobilizations of As from mineral extractions (metal ores, coal, and phosphate rock) are now as much as ten‐fold greater (1,500–5,600 × 109 g/yr) than the As released by the natural rate of rock weathering at the Earth's surface (60–544 × 109 g/yr). Although some As from mining activities enters global cycling through leaching and spills, the amount of dissolved As in rivers (23 × 109 g/yr) is similar to the theoretical mobilization of As from chemical weathering. Anthropogenic emissions to the atmosphere (17–38 × 109 g As/yr) are double the natural background sources (10–25 × 109 g As/yr), largely as a result of the smelting of Cu and other non‐ferrous ores. This results in increased atmospheric deposition near regions with high mining and industrial activities, with potential consequences to human health, natural ecosystems and agriculture. Using median values for As, the ratio of anthropogenic to natural emissions to the atmosphere (1.57) suggests a human impact on the global As cycle that rivals those for V, Hg and Pb.

Efficient liquefaction of Kraft lignin over N-doped carbon supported size-controlled MoC nanoparticles in supercritical ethanol

It is a great challenge to cleave CO bonds in lignin during liquefaction of Kraft lignin into fuels as the bond is characterized by high energy, and the complex composition of lignin oil makes it difficult to separate and purify monomers. Hence, there is an urgent need for highly selective catalysts that can help in the cleavage of these high-energy bonds. We aimed to develop effective and inexpensive catalysts for the synthesis of guaiacol compounds. Liquefaction of Kraft lignin was achieved by using a novel N-doped carbon-supported MoC nanoparticle catalyst (MoC-x@NC, x = 0.5, 1, and 1.5). 77.58 wt% of guaiacol compounds was present in 41.5 wt% of lignin oil after liquefaction of lignin. 2-phenoxy-1-phenylethanol was used as model compound to confirm the efficient CO bond-breaking properties of MoC-x@NC. Additionally, it was observed that high-valence molybdenum and metal phosphate on the surface of catalysts promoted the conversion of benzene alcohols to phenols which further enhanced the content of the guaiacol compounds. N-doped graphitic carbon substrate helps in the alkylation of guaiacol into 4-alkyl guaiacol in the presence of alkyl fragments in ethanol.

On phosphorus chemical shift anisotropy in metal (IV) phosphates and phosphonates: A 31 P NMR experimental study.

The phosphorus chemical shift anisotropies, 31 PΔcs, and asymmetry parameters η were measured by the 31 P{1 H} NMR experiments in static and low-frequency spinning samples of the zirconium phosphates and phosphonates and also in the mixed Zr (IV)/Sn (IV) phosphate/phosphonate material. The data obtained have shown a 111 connectivity in the HPO4 and PO3 groups, which does not change at modification and intercalation of the materials. The 31 PΔcs values of the phosphonate groups (43-49 ppm) significantly surpass the values characterizing the HPO4 groups (23-37 ppm). The 31 P Δcs values obtained for the metal (IV) phosphates were discussed in terms of P-O distances. The 31 P chemical shift anisotropy parameters can help at elucidation of local structures in phosphate and phosphonate materials.

Interface regulation of Pt quantum dots doped nickel phosphide and cobalt hydroxide to promote electrocatalytic overall water splitting

The transition metal phosphates are earth-abundant minerals that have been shown to perform well in electrocatalytic water splitting, whereas these catalysts still tend to have excessively high overpotentials and slow kinetics in HER and OER processes. In the present work, hybrid catalysts consisting of Pt quantum dots doped NiP (NiP-Pt) nano-embroidery spheres and Co(OH)2 nanosheets were successfully prepared by two-step electrodeposition method. The excellent catalytic performance of the catalyst relies principally on the synergistic interaction between NiP and Pt quantum dots. Additionally, the NiP-Pt exhibits strong electronic interactions at the interface with Co(OH)2. Consequently, the catalyst has a strong catalytic performance in terms of HER and OER catalytic performance. In terms of HER, an overpotential of only 40 mV is required when the current density reaches 10 mA cm−2, corresponding to a Tafel slope of 49.85 mV·dec−1. At the same time, the catalyst also performs well at OER, with a current density of 10 mA cm−2 at an overpotential of 186 mV and a Tafel slope of 53.049 mV·dec−1 much less than most electrocatalysts. This study involving electrodeposition and doping of quantum dots provides a new idea for the efficient synthesis of fundamental HER and OER bifunctional catalysts.

Atomic Layer Deposition of Metal Phosphates

Since the introduction of lithium iron phosphate (LFP) as an electrode material for Li-ion batteries (LIB’s), metal phosphates in general have become increasingly important. The strong covalency of the P-O bonds typically results in a very good thermal and structural stability, which is one of the main reasons for the success of LFP as a LIB electrode. However, the applications of these metal phosphates are multi-fold. Apart from LIB’s, they have been proven to be promising towards e.g. electrocatalytic water splitting, biocompatible coatings or even as protective coatings for luminescent materials.With these applications in mind, the research towards the deposition of these materials also becomes increasingly important. Atomic Layer Deposition (ALD) has emerged as a deposition technique with unique nanotailoring capabilities compared to conventional methods, particularly owing to its high thickness and compositional control. Down-scaling micro-electronic devices according to Moore’s law has already increased interest in the unique capabilities ALD can offer. However, in addition to using ALD for the fabrication of such devices, it can also offer a unique way to create model systems to gain a fundamental insight for a broad range of applications.From this it can be seen why the combination of both research fields, i.e. ALD of metal phosphates, is gaining a lot of interest over the past years. Since the first metal phosphate has been deposited in 1969, a big challenge has been to find a suitable phosphate precursor. Today, the most popular choice proves to be trimethyl phosphate, i.e. TMP. It has allowed for the deposition of a variety of phosphates (e.g. aluminium phosphate, lithium phosphate, iron phosphate, etc.), but more research is required to further extent this research field. To stimulate this research, a comprehensive study on the currently (un)available literature is needed. It would e.g. allow to get a better understanding on the effect of different phosphate precursors and/or various reaction mechanisms during ALD can be better understood, as well as the potential applications of these materials (such as lithium ion battery applications). As such a study on ALD of metal phosphates was so far not yet available, we hope that this work can create a view that is of interest towards various scientific fields, and help to guide future thin film researchers.

A Study on the Cathode Materials Recovery Process Using Various Wet Chemistry

Demand for lithium-ion batteries (LIBs) has increased dramatically over the years due to the rapid market expansion of electric vehicles. Current commercial lithium ion batteries mainly contain nickel, cobalt, manganese metal oxides, lithium, phosphates, aluminum, copper, graphite, organic electrolytes and other chemicals. Therefore, the recycling and reuse of used lithium-ion batteries at the end of their useful life are of great interest by many researchers. However, due to the high energy density, high safety and low price of lithium-ion batteries, the difference and variety are large, which poses great difficulties in recycling waste lithium-ion batteries. Lithium ion batteries recycling typically involves both physical and chemical processes. Physical processes typically include pretreatment and direct recovery of electrode materials. These processes typically include decomposition, crushing, screening, magnetic separation, washing, heat treatment, etc. As shown in Figure 1, chemical processes can generally be divided into pyrometallurgical and hydrometallurgical processes which include leaching, separation, extraction and chemical/electrochemical precipitation. Recently, recycling technologies for lithium secondary batteries through a direct regeneration process have been attracting attention. Directly regeneration technique has the advantages of short recovery route, low energy consumption, eco-friendly compared to pyrometallurgical and hydrometallurgical processes. In order to recover the cathode active material from the separated electrode plate, a process for separating the PVDF binder and the cathode active material is required. In general, N-methyl-2-pyrrolidone (NMP) is the most common solvent for the manufacture of cathode electrodes in the battery industry. Although ~99% of the solvent used in electrode manufacturing is recovered, it is however limited in several countries due to negative environmental impacts.In this study, the cathode materials were separated electrode from used lithium ion cell using various wet-chemistry. Chemical, structural, and electrochemical characteristics of the cathode materials and substrate were investigated. Figure 1

The immobilization protocol greatly alters the effects of metal phosphate modification on the activity/stability of immobilized lipases

Mineralization of immobilized enzymes has showed to couple the advantages of both processes. Here, the influence of the immobilization protocol on the effects of mineralization has been investigated. The lipases from Thermomyces lanuginosus and Candida rugosa were immobilized on octyl-, vinyl sulfone (VS) octyl (blocked with different nucleophiles) and glutaraldehyde- (at different pH values) agarose beads. The stability, activity and specificity of the biocatalysts were very different, both the differently blocked VS-biocatalysts and the glutaraldehyde biocatalysts prepared at different pH. All biocatalysts were submitted to mineralization using different metals. The activity, specificity and stability effects of the mineralization strongly depended on the enzyme and on the immobilization protocol. For the same enzyme, a mineralization protocol could be negative, positive or present no effect depending on the enzyme immobilization procedure and substrate. In the best cases, activity could be increased by a two-fold factor, while stability was significantly improved in many instances. These results highlight the great potential of mineralization of immobilized enzymes to improve their properties, as well as the great interactions that immobilization protocol and mineralization can exhibit. The combination of both methodologies greatly increases the possibilities to find a biocatalyst that can be suitable for a specific process.

Application of smart responsive materials in phosphopeptide and glycopeptide enrichment

蛋白质的磷酸化和糖基化作为研究最广泛的两种翻译后修饰(PTMs),在疾病的早期无创诊断、预后和治疗评估中表现出越来越大的潜力。蛋白质的异常磷酸化和糖基化经常被用于临床蛋白质组学研究和疾病相关生物标志物的发现。目前已有多种材料被开发用于磷酸化肽和糖肽的富集研究,其中,智能响应材料由于具有独特的响应特性,已被陆续报道用于磷酸化肽和糖肽的富集。智能响应材料可对外界刺激做出响应,发生结构和性质上的变化,将光、电、热、机械等信号转化为生物化学信号。响应分子是决定智能响应材料响应特性的先决条件,它们在不同刺激条件下(如温度、pH、光、机械应力、电磁场等)的可逆异构化将导致材料的宏观物理和化学性质的动态变化。与传统材料相比,智能响应材料可以可逆地“打开”和“关闭”,具有更好的可调控性。由于引起智能材料响应的刺激信号对其性能具有重要的影响,综述根据施加的刺激种类对智能响应材料进行分类,具体分为外源性响应材料和内源性响应材料,且分别总结了外源性响应材料、内源性响应材料以及内外源共同响应材料在磷酸化肽和糖肽富集方面的工作。此外,综述对智能响应材料在磷酸化肽和糖肽富集方面的发展前景进行了展望,并且提出了智能响应材料在其他蛋白质翻译后修饰方面的应用中存在的挑战。

Electrochemistry Isolates Elemental Phosphorus from Mg3(PO4)2

Phosphorus (P) is an essential raw material for many value-added chemicals in modern industry, yet the natural minerals to extract P are depleting. As an alternative, municipal wastewater is a promising secondary source of P. Recovery of P from wastewater by chemically induced precipitation as insoluble metal phosphates is a typical practice. Mg3(PO4)2 is a commonly found phosphate in sewage sludge or incinerated sewage sludge ash. Here we try to extract elemental P from Mg3(PO4)2 by electrochemistry. By using molten CaCl2 as the solvent, PO4 3− in the Mg3(PO4)2 crystal can be quickly leached into the melt as free ions. The presence of Mg2+ in the melt boosts the solubility and dissolution rate of PO4 3− significantly. High-purity elemental P can be isolated from free PO4 3− in the melt by electrolysis. This work demonstrates that Mg3(PO4)2 is a possible precursor to prepare elemental P by electrochemistry, though the negative influence of Mg2+ of forming solid MgO on the electrode surface during electrolysis needs to be addressed.

Rare-earth-free Mn4+ ions activated Ba2YSbO6 phosphors for solid-state lighting, flexible display, and anti-counterfeiting applications

Recenlty, rare-earth (RE)-free ions (Mn4+) activated phosphor materials are becoming an alternative source while replacing Eu2+ ions activated metal oxide, phosphate, and nitride phosphors for multi-functional applications. In this report, we prepared novel RE-free Mn4+ (mol%) ions activated double perovskite-type Ba2YSbO6 (BYSO:Mn4+) phosphor materials by a solid-state reaction method in an ambient condition. The physicochemical properties such as phase purity, elemental composition, and morphology of the materials were systematically investigated. The temperature-dependent photoluminescence (PL) properties of the BYSO:8 mol% Mn4+ (i.e., BYSO:8Mn4+) phosphor samples were studied. The PL excitation of the phosphors showed a broadband spectrum in the near-ultraviolet region from 300 to 450 nm with a maximum intensity at 353 nm. Under 353 nm excitation, the Mn4+ ions activated phosphors showed a broadband far-red emission in the region of 650–750 nm with a maximum intensity at 694 nm due to the 2Eg→4A2g electronic configuration. The BYSO:8Mn4+ phosphors also showed a lower intensity band at 667 nm and the corresponding Commission Internationale de l’Eclairage chromaticity coordinate for the optimized phosphor was (0.653, 0.274) which is more beneficial, especially for the growth process in plants. Additionally, the optimized BYSO:8Mn4+ phosphor maintained good thermal PL behavior and its related binding energy value was 0.29 eV. Considering these good benefits from the BYSO:8Mn4+ phosphor, we further fabricated a red light-emitting device to demonstrate its potential applicability in solid-state lighting. Also, the as-prepared polydimethylsiloxane composite films demonstrated their suitability for flexible display and anti-counterfeiting applications in harsh environmental conditions.