Lithium-Ion Battery Power Performance Assessment for the Climb Step of an Electric Vertical Takeoff and Landing (eVTOL) Application.

High power is a critical requirement of lithium-ion batteries designed to satisfy the load profiles of advanced air mobility. Here, we simulate the initial takeoff step of electric vertical takeoff and landing (eVTOL) vehicles powered by a lithium-ion battery that is subjected to an intense 15C discharge pulse at the beginning of the discharge cycle followed by a subsequent low-rate discharge. We conducted extensive electrochemical testing to assess the long-term stability of a lithium-ion battery under these high-strain conditions. The main finding is that despite the performance recovery observed at low rates, the reapplication of high rates leads to drastic cell failure. While the results highlight the eVTOL battery longevity challenge, the findings also emphasize the need for tailored battery chemistry designs for eVTOL applications to address both anode plating and cathode instability. In addition, innovative second-use strategies would be paramount upon completion of the eVTOL services.

Sodium Rich Vanadium Oxy-Fluorophosphate - Na3.2 Ni0.2 V1.8 (PO4 )2 F2 O - as Advanced Cathode for Sodium Ion Batteries.

Conventional sodium-based layered oxide cathodes are extremely air sensitive and possess poor electrochemical performance along with safety concerns when operating at high voltage. The polyanion phosphate, Na3 V2 (PO4 )3 stands out as an excellent candidate due to its high nominal voltage, ambient air stability, and long cycle life. The caveat is that Na3 V2 (PO4 )3 can only exhibit reversible capacities in the range of 100 mAh g-1 , 20% below its theoretical capacity. Here, the synthesis and characterizations are reported for the first time of the sodium-rich vanadium oxyfluorophosphate, Na3.2 Ni0.2 V1.8 (PO4 )2 F2 O, a tailored derivative compound of Na3 V2 (PO4 )3 , with extensive electrochemical and structural analyses. Na3.2 Ni0.2 V1.8 (PO4 )2 F2 O delivers an initial reversible capacity of 117 mAh g-1 between 2.5 and 4.5 V under the 1C rate at room temperature, with 85% capacity retention after 900 cycles. The cycling stability is further improved when the material is cycled at 50 °C within 2.8-4.3 V for 100 cycles. When paired with a presodiated hard carbon, Na3.2 Ni0.2 V1.8 (PO4 )2 F2 O cycled with a capacity retention of 85% after 500 cycles. Cosubstitution of the transition metal and fluorine in Na3.2 Ni0.2 V1.8 (PO4 )2 F2 O as well as the sodium-rich structure are the major factors behind the improvement of specific capacity and cycling stability, which paves the way for this cathode in sodium-ion batteries.

Na3 Zr2 Si2 PO12 Solid Electrolyte Membrane for High-Performance Seawater Battery.

Seawater batteries (SWBs) have gained tremendous interest in the electrochemical energy storage research field because of their low cost, natural abundance, and potential use for long-duration energy storage. Advancing a SWB to demonstration projects is plagued by the poor electrochemical performance stemming from the poor interfaces of the solid electrolyte (SE), as well as the structural and chemical instabilities and sluggish ionic transport properties. In this study, the anode compartment of a surrogate SWB is constructed with a Na | SE | hard carbon configuration, and tailored dopants are introduced into the Nasicon-type Na3 Zr2 Si2 PO12 (NZSP) SE membrane. After doping with TiO2 , a much more densely packed pellet with uniformly distributed porous structure is obtained. Changes in surface chemistry and local structure in the bulk are observed, which are believed to contribute to the improved ionic conductivity and higher critical current density of the TiO2 -doped NZSP. Stable cycling performance with reversible capacities based on different Na storage mechanisms are also demonstrated.

Differences in the Interfacial Mechanical Properties of Thiophosphate and Argyrodite Solid Electrolytes and Their Composites.

Interfacial mechanics are a significant contributor to the performance and degradation of solid-state batteries. Spatially resolved measurements of interfacial properties are extremely important to effectively model and understand the electrochemical behavior. Herein, we report the interfacial properties of thiophosphate (Li3PS4)- and argyrodite (Li6PS5Cl)-type solid electrolytes. Using atomic force microscopy, we showcase the differences in the surface morphology as well as adhesion of these materials. We also investigate solvent-less processing of hybrid electrolytes using UV-assisted curing. Physical, chemical, and structural characterizations of the materials highlight the differences in the surface morphology, chemical makeup, and distribution of the inorganic phases between the argyrodite and thiophosphate solid electrolytes.

Design new epoxy nanocomposite coatings based on metal vanadium oxy-phosphate M0.5VOPO4 for anti-corrosion applications.

Epoxy nanocomposite coatings are an essential way to protect petroleum storage tanks from corrosion. For this purpose, the new nanocomposite epoxy coatings (P-M/epoxy composites) have been successfully designed. The P-M/epoxy composites are based on the metal vanadium oxy-phosphate M0.5VOPO4 (where M = Mg, Ni, and Zn). The function of P-M/epoxy composites as anti-corrosion coatings was explored using electrochemical and mechanical tests. Using electrochemical impedance spectroscopy (EIS), it has been noticed that the pore resistance and polarization resistance of the P-M/epoxy composites remain higher as compared to the neat epoxy. The P-M/epoxy composites have the greatest impact on the cathodic dis-bonded area and water absorption. Besides, P-M/epoxy composites exhibit a very high order of mechanical properties. Further, Mg0.5VOPO4 has the greatest effect on the anti-corrosion properties of epoxy coating followed by Zn0.5VOPO4 and Ni0.5VOPO4. All these properties lead to developing effective anti-corrosion coatings. Thus, the net result from this research work is highly promising and provides a potential for future works on the anti-corrosion coating.

Layered zinc hydroxide as an adsorbent for phosphate removal and recovery from wastewater.

At present, phosphate removal and recovery from wastewater is gaining wide attention due to the dual issues of eutrophication, caused by the increased production of algae, and universal phosphorus scarcity. In this study, a layered zinc hydroxide (LZH) was synthesized by a simple precipitation method and characterized via various techniques. Experiments investigating the effect of contact time, pH, LZH dose, initial phosphate concentration, and co-existing ions on phosphate adsorption were conducted. LZH exhibited a high phosphate adsorption capacity (135.4 mg g-1) at a neutral pH. More than 50% of phosphate was removed within the first 60 s of contact time at an initial phosphate concentration of 5 mg L-1. Phosphate removal using the as-prepared LZH adsorbent was also tested in real treated sewage effluent reducing the residual phosphate amount to levels inhibiting to the growth of algae. Furthermore, phosphate desorption from LZH was investigated using acetic acid and sodium hydroxide regenerants which showed to be very effective for phosphate recovery.

Crystal Growth, Single Crystal Structure, and Biological Activity of Thiazolo-Pyridine Dicarboxylic Acid Derivatives.

Four novel TPDCA derivatives were prepared via a supersaturation method combining TPDCA with water, N-methyl-2-pyrrolidone (NMP), Na(PO2H2), and ammonia solution: 2(C9H7NO5S)H2O (1), (C9H7NO5S)C5H9NO (2), (C9H7NO5S)Na(PO2H2) (3), and (C9H5NO5S)(NH4)2(H2O) (4). Their crystal structures were determined by single-crystal X-ray diffraction. Compounds (1) and (2) crystallize in the monoclinic space groups P21 and P21/c, respectively, whereas compounds (3) and (4) crystallize in the triclinic space group P1̅. Weak and moderate hydrogen bonds were detected in the four compounds. In the biological tests, (1) and (3) exhibited significant antibacterial activity against Escherichia coli and Staphylococcus aureus; in addition, (1) was cytotoxic against leukemia HL-60 cells with the IC50 value of 158.5 ± 12.5 µM.

Lithium Iron Aluminum Nickelate, LiNix Fey Alz O2 -New Sustainable Cathodes for Next-Generation Cobalt-Free Li-Ion Batteries.

In recent years, cobalt has become a critical constraint on the supply chain of the Li-ion battery industry. With the ever-increasing projections for electric vehicles, the dependency of current Li-ion batteries on the ever-fluctuating cobalt prices poses serious environmental and sustainability issues. To address these challenges, a new class of cobalt-free materials with general formula of LiNix Fey Alz O2 (x + y + z = 1), termed as the lithium iron aluminum nickelate (NFA) class of cathodes, is introduced. These cobalt-free materials are synthesized using the sol-gel process to explore their compositional landscape by varying aluminum and iron. These NFA variants are characterized using electron microscopy, neutron and X-ray diffraction, and Mössbauer and X-ray photoelectron spectroscopy to investigate their morphological, physical, and crystal-structure properties. Operando experiments by X-ray diffraction, Mössbauer spectroscopy, and galvanostatic intermittent titration have been also used to study the crystallographic transitions, electrochemical activity, and Li-ion diffusivity upon lithium removal and uptake in the NFA cathodes. NFA compositions yield specific capacities of ≈200 mAh g-1 , demonstrating reasonable rate capability and cycling stability with ≈80% capacity retention after 100 charge/discharge cycles. While this is an early stage of research, the potential that these cathodes could have as viable candidates in next-generation cobalt-free lithium-ion batteries is highlighted here.

Temperature-dependent Battery Performance of a Na3 V2 (PO4 )2 F3 @MWCNT Cathode and In-situ Heat Generation on Cycling.

Excellent structural stability, high operating voltage, and high capacity have made Na3 V2 (PO4 )2 F3 a promising cathode material for sodium-ion batteries. However, high-temperature battery performances and heat generation measurements have not been systematically reported yet. Carbon-coated Na3 V2 (PO4 )2 F3 @MWCNT (multi-walled carbon nanotube) samples are fabricated by a hydrothermal-assisted sol-gel method and the electrochemical performances are evaluated at three different temperatures (25, 45, and 55 °C). The well-crystallized Na3 V2 (PO4 )2 F3 @MWCNT samples exhibit good cycling stability at both low and high temperatures; they deliver an initial discharge capacity of 120-125 mAhg-1 at a 1 C rate with a retention of 53 % capacity after 1,400 cycles with 99 % columbic efficiency. The half-cell delivers a capacity of 100 mAhg-1 even at a high rate of 10 C at room temperature. Furthermore, the Na3 V2 (PO4 )2 F3 @MWCNT samples show good long-term durability; the capacity loss is an average of 0.05 % per cycle at a 1 C rate at 55 °C. Furthermore, ionic diffusivity and charge transfer resistance are evaluated as functions of state of charge, and they explain the high electrochemical performance of the Na3 V2 (PO4 )2 F3 @MWCNT samples. In-situ heat generation measurements reveal reversible results upon cycling owing to the high structural stability of the material. Excellent electrochemical performances are also demonstrated in the full-cell configuration with hard carbon as well as antimony Sb/C anodes.

Single crystal structure, vibrational spectroscopy, gas sorption and antimicrobial properties of a new inorganic acidic diphosphates material (NH4)2Mg(H2P2O7)2•2H2O.

We report on the successful synthesis of diammonium magnesium dihydrogendiphosphate (V) dihydrate compound (NH4)2Mg(H2P2O7)2•2H2O using a wet chemical route. Single crystal X-ray diffraction analysis and micro Raman spectroscopy are employed to characterize the compound. We demonstrate, using a multidisciplinary approach, that this compound is ideal for carbon dioxide (CO2) capture in addition to other anthropogenic gasses. We show here -from both an experimental as well as from a density functional theory (DFT) calculations routes- the potential for adopting this compound into domestic air-conditioning units (ACUs). From these experiments, the resistance to bacterial growth is also investigated, which is critical for the adoption of this compound in ACUs. Our  compound exhibits a higher methane (CH4) sorptivity as compared to CO2 at 25 °C and 45 °C under pressures up to 50 bars. Furthermore, DFT electronic structure calculations are used to compute the main structural and electronic properties of the compound, taking into consideration the characteristics of the identified pores as a function of the progressive CO2 vs. CH4 loadings. Finally, the antibacterial assay reveals a strong antibacterial activity against the tested Gram-positive and Gram-negative bacteria, with a large zone of inhibition against the tested E. Coli, S. Aureus and K. Pneumonia.

Eutectic Synthesis of the P2-Type NaxFe1/2Mn1/2O2 Cathode with Improved Cell Design for Sodium-Ion Batteries.

An engaging area of research in sodium-ion batteries (SIBs) has been focusing on discovery, design, and synthesis of high-capacity cathode materials in order to boost energy density to levels close enough to that of state-of-the-art lithium-ion batteries. Of particular interest, P2-type layered oxide, Na2/3Fe1/2Mn1/2O2, has been researched as a potential cathode in SIBs based on its high theoretical capacity of 260 mA h/g and use of noncritical materials. However, the reported synthesis methods are not only complex and energy-demanding but also often yield inhomogeneous and impure materials with capacities less than 200 mA h/g under impractical test conditions. Here, we report a novel synthesis route using low-temperature eutectic reaction to produce highly homogeneous, crystalline, and impurity-free P2-NaxFe1/2Mn1/2O2 with enhanced Na-ion diffusivity and kinetics. The overall electrochemical performances of the Na-ion cells have been improved by pairing the P2-cathode with presodiated hard carbon anodes, leading to reversible capacities in the range of 180 mA h/g. This new approach is a contribution toward the simplification of synthesis and scalability of sodium-based cathodes with high crystallinity and fine-tuned morphology and the realization of a sodium-ion battery system with lower cost and improved electrochemical performance.

Probing the Li4 Ti5 O12 Interface Upon Lithium Uptake by Operando Small Angle Neutron Scattering.

The formation of a solid-electrolyte interphase (SEI) on the surface of Li4 Ti5 O12 (LTO) has become a highly controversial topic, with arguments for it and against it. However, prior studies supporting the formation of an SEI layer have typically suggested that a layer forms upon cycling of a cell, although the layer is probed after disassembling. In this study, cubic mesostructured LTO is synthesized with crystallite domain sizes between 3 and 4 nm and uniform pores with diameters ≤8 nm. The mean pore size is controlled between 4-8 nm through the use of a triblock amphipathic copolymer with a tunable hydrophobic block as template and by thermal treatment. The LTO morphology obtained is spherical and evolves upon heat treatment. These materials show excellent electrochemical performance, including high rate capability and capacity retention. The LTO material is subjected to operando small-angle neutron scattering and X-ray photoelectron spectroscopy experiments, which reveal that the highly debated SEI forms at potentials as high as 2.2 V, first as a LiF-rich layer and subsequently by the growth of a carbonaceous layer. These SEI products form first on the smaller pores before forming on the mesopores.

Structural and thermal properties of Na2Mn(SO4)2·4H2O and Na2Ni(SO4)2·10H2O.

The title compounds were prepared via a wet chemistry route and their crystal structures were determined from single crystal X-ray diffraction data. Na2Mn(SO4)2·4H2O crystallizes with a monoclinic symmetry, space group P21/c, with a = 5.5415(2), b = 8.3447(3), c = 11.2281(3) Å, ß = 100.172(1)°, V = 511.05(3) Å3 and Z = 2. Na2Ni(SO4)2·10H2O also crystallizes with a monoclinic symmetry, space group P21/c, with a = 12.5050(8), b = 6.4812(4), c = 10.0210(6) Å, ß = 106.138(2)°, V = 780.17(8) Å3 and Z = 2. Na2Mn(SO4)2·4H2O is a new member of the blödite family of compounds, whereas Na2Ni(SO4)2·10H2O is isostructural with Na2Mg(SO4)2·10H2O. The structure of Na2Mn(SO4)2·4H2O is built up of [Mn(SO4)2(H2O)4]2- building blocks connected through moderate O-H⋯O hydrogen bonds with the sodium atoms occupying the large tunnels along the a axis and the manganese atom lying on an inversion center, whereas the structure of Na2Ni(SO4)2·10H2O is built up of [Ni(H2O)6]2+ and [Na2(SO4)2(H2O)4]2- layers. These layers which are parallel to the (100) plane are interconnected through moderate O-H⋯O hydrogen bonds. The thermal gravimetric- and the powder X-ray diffraction-analyzes showed that only the nickel phase was almost pure. At a temperature above 300 °C, all the water molecules evaporated and a structural phase transition from P21/c-Na2Ni(SO4)2·10H2O to C2/c-Na2Ni(SO4)2 was observed. C2/c-Na2Ni(SO4)2 is thermally more stable than Na2Fe(SO4)2 and therefore it would be suitable as the positive electrode for sodium ion batteries if a stable electrolyte at high voltage is developed.

Impact of surface coating on electrochemical and thermal behaviors of a Li-rich Li1.2Ni0.16Mn0.56Co0.08O2 cathode.

Lithium-rich layered oxide materials are considered as potential cathode materials for future high-performance lithium-ion batteries (LIBs) owing to their high operating voltage and relatively high specific capacity. However, perceptible issues such as poor rate performance, poor capacity retention, and voltage degradation during cycling need to be improved before the successful commercialization of the material. In this report, zirconia coated Li1.2Ni0.16Mn0.56Co0.08O2 (NMC) (where ZrO2 = 1.0, 1.5 and 2.0 wt%) materials are synthesized using a sol-gel assisted ball milling approach. A comparison of structural, morphological and electrochemical properties is examined to elucidate the promising role of ZrO2 coating on the performance of the NMC cathode. A uniform and homogeneous ZrO2 coating is observed on the surface of NMC particles as evident by TEM elemental mapping images. The ZrO2 coated NMCs exhibit significantly improved electrochemical performance at a higher C-rate as compared to pristine material. 1.5% ZrO2 coated NMC demonstrates better cycling stability (95% capacity retention) than pristine NMC (77% capacity retention) after 50 cycles. All ZrO2 coated NMC materials demonstrated improved thermal stability compared to pristine material. The difference in onset temperature of 2 wt% ZrO2 coated and pristine NMC is 20 °C. The improved electrochemical performance of ZrO2 coated NMC can be attributed to the stabilization of its surface structure due to the presence of ZrO2.

Graphene nanoplatelet doping of P3HT:PCBM photoactive layer of bulk heterojunction organic solar cells for enhancing performance.

Hybrid organic photovoltaic (OPV) cells based on conjugated polymer photoactive materials are promising candidates for flexible, high-performance and low-cost energy sources owing to their inexpensive materials, cost-effective processing and ease of fabrication by simple solution processes. However, the modest PV performance obtained to date-in particular the low power conversion efficiency (PCE)-has impeded the large scale deployment of OPV cells. The low PCE in OPV solar cells is mainly attributed to the low carrier mobility, which is closely correlated to the transport diffusion length of the charge carriers within the photoactive layers. The 2D graphene material could be an excellent candidate for assisting charge transport improvement in the active layer of OPV cells, due to its huge carrier mobility, thermal and chemical stability, and its compatibility with the solution process. In this work, we report on the improvement of the optoelectronic properties and photovoltaic performance of graphene nanoplatelet (GNP)-doped P3HT:PCBM photoactive blended layers, integrated into a bulk heterojunction (BHJ) organic-photovoltaic-based device, using PEDOT:PSS on an ITO/glass substrate. First, the light absorption capacity was observed to increase with respect to the GNP content, while the photoluminescence showed clear quenching, indicating electron transfer between the graphene sheets and the polymeric matrix. Then, the incorporation of GNP into the BHJ active layer resulted in enhanced PV performance with respect to the reference cell, and the best PV performance was obtained with 3 wt.% of GNP loading, with an open-circuit voltage of 1.24 V, a short-circuit current density value of 6.18 mA cm-2, a fill factor of 47.12%, and a power conversion efficiency of about 3.61%. We believe that the obtained results contribute to the development of organic photovoltaic devices and to the understanding of the impact of sp2-bonded carbon therein.

Synthesis and performance evaluation of nanostructured NaFe x Cr1-X (SO4)2 cathode materials in sodium ion batteries (SIBs).

This research work focuses on the synthesis and performance evaluation of NaFe x Cr1-X (SO4)2 (X = 0, 0.8 and 1.0) cathode materials in sodium ion batteries (SIBs). The novel materials having a primary particle size of around 100-200 nm were synthesized through a sol-gel process by reacting stoichiometric amounts of the precursor materials. The structural analysis confirms the formation of crystalline, phase pure materials that adopt a monoclinic crystal structure. Thermal analysis indicates the superior thermal stability of NaFe0.8Cr0.2(SO4)2 when compared to NaFe(SO4)2 and NaCr(SO4)2. Galvanostatic charge/discharge analysis indicates that the intercalation/de-intercalation of a sodium ion (Na+) into/from NaFe(SO4)2 ensues at about 3.2 V due to the Fe2+/Fe3+ active redox couple. Moreover, ex situ XRD analysis confirms that the insertion/de-insertion of sodium into/from the host structure during charging/discharging is accompanied by a reversible single-phase reaction rather than a biphasic reaction. A similar sodium intercalation/de-intercalation mechanism has been noticed in NaFe0.8Cr0.2(SO4)2which has not been reported earlier. The galvanostatic measurements and X-ray photoelectron spectroscopy (XPS) analysis confirm that the Cr2+/Cr3+ redox couple is inactive in NaFe x Cr1-X (SO4)2 (X = 0, 0.8) and thus does not contribute to capacity augmentation. However, suitable carbon coating may lead to activation of the Cr2+/Cr3+ redox couple in these inactive materials.

The triclinic form of dipotassium cobalt(II) bis-(dihydrogendiphosphate) dihydrate.

In the title compound, K(2)Co(H(2)P(2)O(7))(2)·2H(2)O, the octa-hedrally coordinated Co(2+) ion lies on an inversion centre. Two bidentate dihydrogendiphosphate anions form the equatorial plane of the [CoO(6)] octa-hedron which is completed by two water mol-ecules in axial positions. This results in isolated {Co(H(2)O)(2)[H(2)P(2)O(7)](2)}(4-) entities linked into a three-dimensional network through K-O bonds and O-H⋯O hydrogen-bonding inter-actions involving the dihydrogendiphosphate anions and water mol-ecules. The dihydrogendiphosphate anion, (H(2)P(2)O(7))(2-), is bent and shows an almost eclipsed conformation.

Ni(2)Si(P(2)O(7))(2).

Dinickel(II) silicon bis-[diphosphate(4-)], Ni(2)Si(P(2)O(7))(2), is isotypic with other phosphates of the formula M(2)Si(P(2)O(7))(2) (M = Co, Cd). All atoms except Si (site symmetry 2) are found in general positions. Ni(2)O(10) dimers formed from edge-sharing NiO(6) octa-hedra are linked by corners and O-P-O bridges, forming slabs parallel to (100), which are in turn inter-connected by O-Si-O contacts.

Terbium(III) hydrogendiphosphate(V) tetra-hydrate.

The Tb atom of the title compound, TbHP(2)O(7)·4H(2)O, is coordinated by the O atoms of three symmetrically independent water mol-ecules and by five O atoms belonging to HP(2)O(7) (-) groups. The TbO(8) polyhedra are inter-connected by the diphospate anions, forming a three-dimensional network which is additionally stabilized by O-H⋯O hydrogen bonding between water mol-ecules and O atoms of the HP(2)O(7) (-) anions. Uncoordinated water mol-ecules are situated in channels and are connected via hydrogen bonds with the framework.

Ammonium ytterbium(III) diphosphate(V).

The title compound, NH(4)YbP(2)O(7), crystallizes in the KAlP(2)O(7) structure type and consists of distorted YbO(6) octa-hedra and bent P(2)O(7) (4-) diphosphate units forming together a three-dimensional network. There are channels in the structure running along the c axis, where the NH(4) (+) cations are located. They are connected via N-H⋯O hydrogen bonds to the terminal O atoms of the diphosphate anions.