Addition Of Phosphoric Acid Research Articles

(Battery Division Student Research Award Sponsored by Mercedes-Benz Research & Development) Sustainable High-Performance Lithium-Ion Batteries: Aqueous Processing of Cobalt-Free High-Energy Cathodes

Increasing the environmental benignity of the lithium-ion battery (LIB) technology is one of the greatest challenges associated with their continuously increasing demand. At the same time, the performance metrics in terms of energy density, power capability and reliability have to be at least maintained to meet the requirements of the rapidly growing electric vehicle market.[1] Besides introducing cobalt-free high-performance active materials, such as the high-voltage spinel LiNi0.5Mn1.5O4 (LNMO),[2] the implementation of aqueous electrode processing strategies for lithium-ion cathodes, is a key step to realize environmentally benign battery production. To achieve this ambitious goal, the deployment of nature-derived, inexpensive polymers in combination with the use of water as dispersion agent provides the great possibility to spare energy-intensive drying procedures and costly dry-room conditions, and thus, will turn the whole battery fabrication more eco-efficient and abolish the need of harmful and rather costly N-methyl-2-pyrrolidone (NMP) as processing solvent for mutagenic and teratogenic fluorine-containing binders.[3,4] What could easily be established for graphite anodes, appears more complicated for transition metal oxide-based and imperatively cobalt-free cathode materials, which suffer from lithium leaching and transition metal dissolution when getting in contact with water, which has, so far, rendered the use of aqueous binders very challenging.[5,6] The strategies developed in our group enable the achievement of this desirable goal: The first one, i.e., the addition of phosphoric acid during electrode preparation, targets the prevention of the aluminum current collector corrosion and simultaneously stabilizes the LNMO particle surface, hence, avoiding the active material degradation in contact with water. The second one, i.e., the crosslinking of the binder by means of citric acid, provides an enhanced cycling stability of the aqueous processed electrodes.[ 6,7] Remarkably, these two complementary approaches can be easily adapted in the electrode preparation process without requiring any additional processing step. To achieve positive electrode tapes, readily available for large-scale high-energy lithium-ion batteries, a carbon-coated current collector is used. It provides functional groups to crosslink the positive electrode coating layer to the underlying aluminum foil. The resulting electrodes demonstrate significant improvements concerning the electrode to current collector adhesion and their capacity retention.[ 8] Through the further optimization of the initial formation cycles, these electrodes offer an electrochemical performance exceeding that of LNMO-based reference electrodes, comprising state-of-the-art poly(vinylidene difluoride) (PVdF) as binder. Transferring this knowledge to other modified biopolymers, such as chitosan and guar gum in combination with relations derived between structure and performance of electrodes made from these cheap, abundant and naturally available binders finally leads to the realization of entirely water-processed high-performance LIBs employing sustainable cobalt-free high-voltage LNMO cathodes and graphite anodes.[ 9,10] References D. Larcher and J. M. Tarascon, Nat. Chem., 7, 19–29 (2015).M. Kuenzel et al., Mater. Today, In Press (2020) https://doi.org/10.1016/j.mattod.2020.04.003.D. Bresser, D. Buchholz, A. Moretti, A. Varzi, and S. Passerini, Energy Environ. Sci., 11, 3096–3127 (2018).A. Kwade et al., Nat. Energy, 3, 290–300 (2018).Michael M. Thackeray, J. Am. Ceram. Soc., 82, 3347–3354 (1993).N. Loeffler et al., ChemSusChem, 9, 1112–1117 (2016).M. Kuenzel et al., ChemSusChem, 11, 562–573 (2018).M. Kuenzel et al., ACS Appl. Energy Mater., 3, 218–230 (2020).M. Kuenzel et al., Batter. Supercaps, 3, 155–164 (2020).M. Kuenzel et al., ChemSusChem, 13 (2020) https://doi.org/10.1002/cssc.201903483.

Performance and ageing behavior of water-processed LiNi0.5Mn0.3Co0.2O2/Graphite lithium-ion cells

In this study, water-processed LiNi0.5Mn0.3Co0.2O2 cathodes (NMC532) are investigated. Notably, corrosion of aluminum current collector occurring in aqueous processing owing to alkalinity of NMC slurry is avoided through addition of phosphoric acid which buffers the slurry pH, or by using a carbon-coated collector. The impact of small amounts of phosphoric acid on the electrochemical performance is evaluated in half-cells, and the best formulations are selected to perform further ageing tests in pouch cells. In particular, post mortem analyses such as electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy are conducted on the cathodes after long-term cycling in Li-ion cells to fully understand the enhanced cycling stability observed with H3PO4-containing water-based cathode. These analyses allow to conclude on the influence of the binder, the current collector, and the aqueous immersion of the NMC532 powder.

Visible-Light Sensitive Photocatalytic Activity of FeO<i><sub>x</sub></i>- and P-Modified TiO<sub>2</sub> with Rutile Structure

Nanocrystalline rutile TiO2 particles were prepared via hydrothermal treatment of Ti-containing precursors obtained by low-temperature aging for a transparent diluted HCl solution of amorphous TiO2. The products were modified with FeOx and phosphoric acid, and the photocatalytic activities of the obtained catalysts under visible-light irradiation were examined. By the addition of FeOx or phosphoric acid, the photocatalytic activity of the rutile TiO2 was slightly increased. On the contrary, by the FeOx loading and subsequent addition of phosphoric acid, significant increases in the photocatalytic activity were attained. Results of UV-vis suggest that the iron oxides formed on the surface of rutile TiO2 were changed into highly dispersed iron phosphate species by the addition of phosphoric acid. It was presumed that these species effectively suppress the recombination reaction between the photogenerated electrons and holes and contribute to the high photocatalytic activity of the rutile TiO2 photocatalysts modified with FeOx and phosphoric acid.

Semivolatile organic compounds in the products from hydrothermal carbonisation of sugar cane bagasse and vinasse by gas chromatography-mass spectrometry

In this paper, sugar cane bagasse and vinasse were subjected to a hydrothermal carbonisation process (HTC), under different reaction conditions (temperature, time and percentage of phosphoric acid addition). Semivolatile organic compounds (SVOC) were extracted from both the products obtained by the HTC: hydrochar (HC) and process water (PW), and identified by gas chromatography together with mass spectrometry (GC–MS). The main SVOC in HC and PW are phenols, carboxylic acids, ketones, and particularly to products obtained using vinasse, they contain nitrogen compounds, sterols and fatty acids. Higher temperature and acid percentage addition respectively brought greater aromatisation and functionalisation in HC. Furthermore, the addition of phosphoric acid within the HTC led to the decrease of phenolic compounds and furans, and an increase in the formation of carboxylic acids and ketones in the PW. In the PW were found important compounds such as 4-methyl-3-pentenoic acid and 4-hydroxy-butanoic acid to industry.

Aqueous Ni-rich-cathode dispersions processed with phosphoric acid for lithium-ion batteries with ultra-thick electrodes

Lithium-ion battery (LIB) production can benefit both economically and environmentally from aqueous processing. Although these electrodes have the potential to surpass electrodes conventionally processed with N-methyl-2-pyrrolidone (NMP) in terms of performance, significant issues still exist with respect to ultra-thick cathodes (≫4 mAh/cm2 areal capacities). A major concern for these types of electrodes with high-nickel active material stems from lithium leaching from active material, which drives the pH of the dispersion in excess of 12 and subsequently corrodes the current collector interface. As this corrosion reaction proceeds, hydrogen generation at the interface creates bubbles which cause severe cracking in the dried electrode surface. When areal loadings are increased, this effect becomes more pronounced and is detrimental to both mechanical and electrochemical properties of these electrodes. Herein, a technique for mitigating corrosion at the current collector by adjusting the pH of the dispersion with the addition of phosphoric acid is investigated. Phosphoric acid was added in 0.5 wt% increments between 0.0 and 1.5 wt%, and effects on rheology, adhesion, corrosion, and electrochemical performance were investigated. A technique is reported for producing aqueous processed cathodes with areal loadings of 6–8 mAh/cm2 with reduced surface cracking and superior high-rate discharge capacity (i.e. high-power performance) for this class of cathode loadings.

Thick Aqueous Processed Cathodes Enabled By Phosphoric Acid Addition

Aqueous processed cathodes for lithium-ion batteries are favorable for both cost and environmental reasons; however, these electrodes still face significant problems with increasing areal capacities (i.e. thickness). Transition metal leaching from high nickel content active materials creates a very basic slurry, pH in excess of 12. This slurry composition subsequently corrodes the aluminum current collector, which leads to hydrogen gas generation. As a consequence, bubbling at the electrode interface causes substantial damage to the dried electrode. As the loading of these electrodes is increased, this mechanism becomes more severe and results in lack of adhesion and cohesion. In this work we investigate the introduction of varying amounts of phosphoric acid to combat the rise in pH and suppress the corrosion at the current collector surface. Phosphoric acid was added in increments of 0.5, 1, and 1.5 wt% and the subsequent effects on slurry rheology, particle size, adhesion, and electrochemical cycling were investigated. In this work we report a technique for obtaining thick (6-8 mAh/cm2) cathodes that exhibit reduced surface cracking and display improved rate performance as compared to control samples.

Study of levoglucosenone obtained in analytical pyrolysis and screw-type reactor, separation and distillation

This research is dedicated to the study on the formation of levoglucosenone and other main volatiles from the catalytic pyrolysis with the addition of phosphoric acid of birch wood and lignocelluloses obtained by birch wood hydrothermal treatment. Py-GC/MS/FID method was used to evaluate the contents of the main products. Lignocelluloses were found to be a more promising precursor to obtain levoglucosenone with lesser content of furfural: For birch wood and lignocelluloses hydrothermally treated at 150 and 180 °C, Py-GC/MS/FID revealed levoglucosenone yields of 12.83, 16.94 and 21.08%, correspondingly (at 5% phosphoric acid addition). When birch wood impregnated with 5% H3PO4 was pyrolized in the laboratory screw-type reactor, the levoglucosenone yield was 6.5%. The composition and content of volatiles formed in analytical pyrolysis, bio-oil and its chloroform extract were compared. Extraction of bio-oil with chloroform and consequent distillation resulted in fractions containing 79.14% of levoglucosenone.

Plasma Electrolytic Oxidation of Titanium in H2SO4–H3PO4 Mixtures

Oxide layers on titanium foils were produced by galvanostatically controlled plasma electrolytic oxidation in 12.9 M sulfuric acid with small amounts of phosphoric acid added up to a 3% mole fraction. In pure sulfuric acid, the oxide layer is distinctly modified by plasma discharges. As the time of the process increases, rough surfaces with typical circular pores evolve. The predominant crystal phase of the titanium dioxide material is rutile. With the addition of phosphoric acid, discharge effects become less pronounced, and the predominant crystal phase changes to anatase. Furthermore, the oxide layer thickness and mass gain both increase. Already small amounts of phosphoric acid induce these effects. Our findings suggest that anions of phosphoric acid preferentially adsorb to the anodic area and suppress plasma discharges, and conventional anodization is promoted. The process was systematically investigated at different stages, and voltage and oxide formation efficiency were determined. Oxide surfaces and their cross-sections were studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phase composition was determined by X-ray diffraction and confocal Raman microscopy.

Preparation of phosphorus-doped porous carbon for high performance supercapacitors by one-step carbonization.

Biomass-derived porous carbon has received increasing attention as an energy storage device due to its cost-effectiveness, ease of manufacture, environmental friendliness, and sustainability. In this work, phosphorus-doped porous carbon was prepared from biomass sawdust (carbon source) and a small amount of phosphoric acid (P-doping source and gas expanding agent) by one-step carbonization. For comparison, parallel studies without phosphate treatment were performed under the same conditions. Benefiting from the addition of phosphoric acid, the prepared carbon material has higher carbon yield, higher specific area and micropore volume. Due to the heteroatom doping of P in the carbon material, the optimized PC-900 sample not only exhibits high specific capacitances of 292 F g−1 and 169.4 F g−1 at current densities of 0.1 A g−1 and 0.5 A g−1, respectively, but also excellent cycle longevity (98.3% capacitance retention after 5000 cycles) in 1 M H2SO4. In addition, the supercapacitor exhibits a high energy density of 10.6 W h kg−1 when the power density is 224.8 W kg−1 at a discharge current density of 0.5 A g−1. This work proposes a sustainable strategy to reuse waste biomass in high-performance and green supercapacitors for advanced energy storage equipment.

Effect of palm shell ash and phosphoric acid chemical solution on subgrade material towards CBR value

Soil stabilization is a process of mixing soil with particular materials to restore engineering properties of soil which is an attempt to change or fix the engineering properties of soil in fulfilling particular technical requirement. The examination result of soil as a subgrade coating conducted in this study is classified as expansive soil. Unfixed subgrade condition may cause various damages on road pavement. Thus, in this study, subgrade repairment was administered by utilizing stabilization method of a mixture palm shell ash (PSA) and phosphoric acid chemical solution. The experiment aims to decrease dependency of cement as stabilization material in regular usage, in order to save cost in economic aspect of infrastructure. This study intends to analyze the effect of palm shell ash and phosphoric acid addition towards CBR value as subgrade construction layer of road pavement. The study outcomes shows several conclusions: (1) the decreasing value of optimal water content, plastic index, and swelling; (2) the increasing value of unsoaked CBR, soaked CBR, and isolated CBR. (3) the stabilization material mixture has been achieved, therefore it can be used as subgrade repairmen on expansive soils for minimum standard of subgrade coating for road pavement.

Preparation and characterization of floating porous graphite carbon monoliths produced from biomass and its application

Herein, a new floating porous graphite carbon monolith (FCM) was prepared using the graphite powder and peanut shells as the carbon skeleton and using FAC and sepiolite as the swelling agent. The multi-hierarchical porous FCMs were obtained by two-step acid activation method. The effects of the addition of biomass and phosphoric acid on the physical properties and pore structure of the prepared material were investigated. The FCM was combined with codoped titania to develop a new floating photocatalysts. The results showed an increase in the amount of biomass materials during FCM preparation increased the ratio of mesoporous structure in the products. In addition, a high micropore volume ratio and the strongest adsorption effect were achieved by optimizing the phosphoric acid impregnation ratio. After process optimization, the densities of the prepared FCMs ranged between 0.75 and 0.89 g/cm3, and the specific surface area and diameter range of the large pores of the material were 104.5 m2/g and 3-50 μm, respectively. Moreover, the new floating catalysts displayed the excellent photocatalytic properties and recyclability performance.

Nanocrystalline Powder Cores for High-Power High-Frequency Applications

Soft magnetic composites (SMCs) based magnetic cores are attractive in high-frequency inductor design. The desired overall core permeability of SMC core can be achieved by adjusting the powder size, addition of insulation material and phosphoric acid, and pressure during the preparation process to reduce the air gap loss and ease the inductor design. The nanocrystalline alloy (Fe-Cu–Nb–Si–B) is an emerging SMC with high saturation flux density and low hysteresis loss, showing potential suitability for SMC-based magnetic cores. To date, nanocrystalline alloys are mostly used in form of laminated ribbon for magnetic cores, and nanocrystalline powder SMCs have been seldom used in practice. Also, neither experimental validation nor comparison with other commercialized and commonly used SMC cores has been reported. In this article, the structure and manufacturing process of nanocrystalline powder cores are introduced. The calculation of core loss is defined for the nanocrystalline powder core. The characteristics and performance of the nanocrystalline powder toroidal core are compared with those of existing commercial SMC cores, such as Fe–Si powder (X flux), Fe–Ni powder (High flux), Fe–Si–Al powder (Kool Mμ), and Fe-Ni–Mo powder (MPP). Experimental results are conducted at frequencies from 100 to 600 kHz to verify the loss calculation and feasibility of this new nanocrystalline powder core.

Cellulose hydrolysis using ionic liquids and inorganic acids under dilute conditions: morphological comparison of nanocellulose.

The preparation of cellulose nanocrystals (CNCs) from cellulose extracted from cotton gin motes (CGM) using an ionic liquid (1-butyl-3-methylimidazolium chloride, [BMIm]Cl) under dilute conditions is reported. The concurrent process involves minimal swelling of cellulose with an ionic liquid and hydrolysis of the cellulose initiated by the addition of either phosphoric (H3PO4), hydrochloric (HCl), or sulfuric (H2SO4) acid. The obtained nanocrystals had similar physical properties (e.g. crystallinity) to the counterparts prepared under conventional conditions and exhibited superior thermal properties for sulfate CNCs. Additionally, the obtained CNCs had low surface functionalization, yet were colloidally stable for >90 days, which is a desirable trait for post-functionalization of CNCs. This process represents a general strategy utilizing dilute ionic liquids in the preparation of nanocellulose under mildly acidic conditions.

Development of a Phosphoric Acid-Mediated Hyaluronic Acid Gel Sheet for Efficient Transdermal Delivery of Alendronate for Anti-Osteoporotic Therapy.

For efficient transdermal delivery of alendronate (ALN) for anti-osteoporotic therapy, we developed a hyaluronic acid (HA) gel sheet that was prepared simply by enhancing HA noncovalent interactions using phosphoric acid and polyhydric alcohol (propanediol and glycerin). HA solution viscosity increased after addition of phosphoric acid, and the HA gel sheet formed after heated drying. The HA gel sheet could be converted to high viscosity state by addition of water. These results indicate that phosphoric acid enhances the noncovalent interactions of HA molecules. The HA gel sheet elicited no skin irritation over 7 days after a 24-h application. The permeation of ALN across rat and human skin was 109 and 7.17 µg/cm2, respectively, up to 24 h after application of the ALN-loaded HA gel sheet, which is sufficient for clinical treatment of osteoporosis. The bioavailability of ALN in rats was ~20% after application of the ALN-loaded HA gel sheet, and plasma calcium levels were effectively reduced 3 days after sheet application. Furthermore, in a rat osteoporosis model, the reduction in tibial bone density was suppressed by treatment with the ALN-loaded HA gel sheet. These results indicate that our phosphoric acid-mediated HA gel sheet is a promising transdermal formulation for efficient ALN delivery.

Development of composition formulations, based on natural bischofite, to protect wood from fire

We have studied the chemical composition of natural bischofite extracted from well No. 1 at Zaturin deposit and revealed that the sufficient saturation of МgСl 2 allows its use as an environmentally-oriented base for composition formulations in order to protect wood from fire. Our experimental research has confirmed the efficiency of applying organic synthetic dyes (methyl orange, bromothymol blue) as coloring additives for the reported composition formulations. Technological features have been defined for using the pigment concentrates of trade marks «Amber» and «Sniezko», which form two-phase systems with a solution of natural bischofite. It has been proven that the proposed coloring additives ensure the stable wood coloration and saturated color of its surface. The efficiency of using coloring additives (bromothymol blue and methyl orange; the pigment concentrates of ТМ «Amber» and TM «Sniezko») for the developed composition formulations aimed at fire-protective treatment of wood has been confirmed under laboratory conditions. Our experimental study has established that flammability time of the timber treated with a composition formulation without coloring additives increases by 4 times compared to untreated wood. The fire-retardant mechanism of the developed composition formulations is predetermined by the successive processes of bischofite salt conversion under a temperature influence and by the addition of orthophosphoric acid, which is a strong fire retardant. Introducing the coloring additive (colorant) methyl orange to the composition formulation increases its flammability time by more than 4 times, compared to untreated wood. Thus, there is reason to argue that the developed composition formulations that contain coloring additives (colorants) are environmentally-oriented and economically feasible. At the same time, the results obtained resolve an integrated task, namely ensuring fire- and bio-protection, as well as visualizing the applied treatment of wood-based construction structures at residential buildings and non-residential facilities

The Synthesis of α-Hydroxy- and α-Chlorophosphonic Acid Derivatives Starting from Benzaldehydes and Phosphorous Acid or Dimethyl Phosphite

The addition of phosphorous acid on the C=O group of substituted benzaldehydes in the presence of hydrochloric acid in water affords a mixture of the corresponding α - chlorophosphonic acid and α-hydroxyphosphonic acid. The selectivity towards the α-chloro derivatives may be increased to 92% by the excess of HCl applying forcing conditions. α- Hydroxyphosphonic acids may be synthesized better in yields of 83-92% by the hydrolysis of the corresponding dimethyl α-hydroxyphosphonates. α-Chlorophosphonic acids may also be obtained in yields of 66-79% from α -hydroxyphosphonic esters by reaction with thionyl chloride followed by hydrolysis. The α -chlorophosphonic acids and esters are useful intermediates for other phosphonic derivatives.

Effect of phosphoric acid in the pre-hydrolysis process of dissolving pulp production from bamboo-willow

Bamboo-willow is a type of fast-growing wood with a high hemicellulose content. In the present study, the effects of phosphoric acid addition on the main components of bamboo-willow and pre-hydrolysis liquor (PHL) were explored, and subsequently the pre-hydrolyzed bamboo-willow chips were cooked, O–H–P bleached, and acid post-treated to produce dissolving pulp. The results showed that adding phosphoric acid to the pre-hydrolysis stage effectively removed hemicellulose and increased the cellulose content of the pre-hydrolyzed bamboo-willow. The major component of the hemicelluloses was xylan/xylose, which represented approximately 62% to 78% of the total sugars in the PHL. Glucose was the most abundant sugar that was produced, apart from xylose, and represented approximately 12% to 25% of the total sugars in the PHL. Additionally, 73% to 83% of the total sugars in the PHL were in an oligomeric form. The obtained bamboo-willow dissolving pulp could be used to produce viscose rayon with a 92.1% α-cellulose content, 4.77% hemicellulose content, and 675 degree of polymerization.

Improvement of corrosion resistance of magnesium alloy by high-temperature high-pressure cavitation treatment

In this study, basic research on the formation of a film for improving the corrosion resistance of a Mg alloy (AZ31) surface was carried out by the addition of dilute phosphoric acid during water jet peening (WJP) and multifunction cavitation (MFC). These mechanochemical (MC) processes are referred to as MC-WJP and MC-MFC, respectively. MC-WJP and MC-MFC processing formed a film on the AZ31 alloy surface that contained phosphate compounds, including oxides, hydroxides, and carbides. Because MFC or WJP processing forms fine cracks on the alloy surface, we concluded that a thick film was formed on the “MC” surfaces because phosphoric acid adhered to these cracks. The film formed on the surface processed by MC-MFC was thicker than that formed on the MC-WJP processed surface because the former process produces higher-temperature cavitation bubbles.

Effective control of water-interactive states on mesoporous silica films by phosphoric acid addition

The effect of the phosphoric acid addition into the mesoporous silica (MPS) films on the water molecular states was investigated using the infrared spectral separation techniques. When the larger amount of the phosphoric acid was introduced into the MPS films, the surface wettability was changed to hydrophilicity. The interactions between the PO43− and silicate ions would occur to form the phosphoric acid-interacted MPS films, and the surface silanol groups were effectively interacted with the water molecules, indicating the importance of the incorporated phosphoric ions.

Phosphoric acid‐modified magnesium oxychloride: Study of water stability, kinetics, and pair distribution function

AbstractMagnesium oxychloride (MOC) excels in performance applications due to inherent structural strength, fire retardant properties, and numerous other attributes. To avoid the slow degradation of MOC when exposed to water, phosphoric acid is usually added, effectively increasing retention of structural properties (water stability). While this is an effective method, it is poorly understood. Additions of 2.5 wt.% and above had positive impacts on the water stability, preserving ~50 wt.% crystalline MOC after water stability tests. Phosphoric acid addition also impacted the reaction kinetics, increasing the activation energy of curing from 72.2 to 87.6‐95.2 kJ/mol. Using synchrotron X‐ray scattering and pair distribution function analysis, we identified an unreported amorphous phase formed when phosphoric acid is added; this phase contains structural motifs related to MgHPO4·3H2O (newberyte), Mg2P2O7·3.5H2O (magnesium pyrophosphate), and amorphous MOC phase. The short‐range order of the samples show a prominent peak at ~3.2 Å that grows with increasing acid addition, believed to be a combination of newberyte (~3.4 Å Mg–P), pyrophosphate (~3.25 Å Mg–P), and MOC (~3.15 Å Mg–Mg). We propose that the increased water stability observed is due to this combined amorphous phase, which retains the low water solubility properties of MgHPO4·3H2O and Mg2P2O7·3.5H2O, effectively protecting the MOC crystalline phase.