Synthesis Of Functional Materials Research Articles

Ultrathin LiFePO4/C cathode for high performance lithium-ion batteries: Synthesis via solvothermal transformation of iron hydroxyl phosphate Fe3(PO4)2(OH)2 nanosheet

A novel two-step solvothermal approach was firstly applied to acquire ultrathin lithium iron (II) phosphate (LiFePO4) nanosheet (with thickness about 28 nm) with exposed (010) surface facets. The iron hydroxyl phosphate Fe3(PO4)2(OH)2 nanosheet fabricated in the first solvothermal step was proved to be effective template for ultrathin LiFePO4 formation after solvothermal lithiation in the second solvothermal step. Importantly, the two-step solvothermal lithiation could produce ultrathin nanosheets while one-step solvothermal based on Fe(II) fabrication could only produce nanoplate-like particles. The as-synthesized nanosheets has shortened Li-ion diffusion path and high robustness in the structure during high C-rate electrochemical tests. Based on comparison with bulk LiFePO4 and nano-plate LiFePO4, the LiFePO4 nanosheet exhibits quite high specific discharge capacity of 169, 165, 159, 142, and 121 mAh g−1, at C-rate of 0.1, 0.2, 0.5, 1, and 5C, respectively, and excellent cycling performance with capacity kept at 121 mAh g−1 with no obvious fading under 500 times cycles. The newly developed method can provide useful references to other olivine type LiMPO4 cathodes and even have potential to find more applications in the synthesis of functional materials.

Scalable Room-Temperature Synthesis of Multi-shelled Na3(VOPO4)2F Microsphere Cathodes

Summary The large-scale application of rechargeable batteries in electric vehicles and energy-storage systems is still hindered by their high cost, particularly from the active materials. Here we proposed a concept of integration of extraction-separation and materials-preparation to further reduce the materials' cost. The power of this concept was demonstrated by the large-scale room-temperature synthesis (150 g per batch) of multi-shelled Na3(VOPO4)2F microspheres based on in situ generated bubbles as soft templates. The as-prepared Na3(VOPO4)2F shows superior rate capability with discharge capacity of 81 mAh g−1 at 15 C current rate and capacity retention of 70% after 3,000 cycles. Ex situ UV-vis was first employed to characterize the variation of oxidation state for vanadium during the charging and discharging process. This is the first report of a rapid and facile large-scale room-temperature controllable synthesis of Na3(VOPO4)2F microspheres, and this approach could be extended to synthesize other similar compounds.

Lithium Metal Extraction from Seawater

Ping He obtained his PhD in Physical Chemistry from Fudan University in 2009, and later worked as a postdoctoral fellow at the National Institute of Advanced Industrial Science and Technology (AIST), Japan. He currently is a Professor of College of Engineering and Applied Sciences at Nanjing University, China. His research interests focus on electrochemical functional materials and energy storage systems such as lithium-ion batteries and lithium-air batteries. He has published more than 90 peer-reviewed papers. Haoshen Zhou obtained his bachelor’s degree in Nanjing University in 1985, and received his PhD from the University of Tokyo in 1994. He is the prime senior researcher of the National Institute of Advanced Industrial Science and Technology and the professor in Nanjing University. His research interests include the synthesis of functional materials and their applications in Li-ion batteries, Na-ion batteries, Li-redox flow batteries, metal-air batteries, and new types of batteries/cells. Sixie Yang received his bachelor's degree in 2013 and recently received his PhD degree in materials science and engineering at Nanjing University. During his PhD program, he worked in Prof. Ping He and Prof. Haoshen Zhou's research group studying the reaction mechanisms and electrochemistry in Li-air and Li-CO2 batteries.

Ionic Liquids for Controlled Synthesis of Functional Materials for Energy-Related Applications

The conventional synthesis of functional materials relies heavily on water and organic solvents. Alternatively, the synthesis of functional materials using or in the presence of ionic liquids represents a burgeoning direction in materials chemistry.1-4 Ionic liquids are a family of non-conventional molten salts that can act as both templates and precursors to functional materials, as well as solvents. They offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, tunable solubility of both organic and inorganic molecules, and much synthesis flexibility. The unique solvation environment of these ionic liquids provides new reaction media for controlling formation of porous materials, creating functional groups in biphasic media, and tailoring morphologies of advanced materials. Challenges and opportunities in using ionic liquids for synthesizing functional materials in energy-related applications will be discussed. Acknowledgment: This work was conducted at the Oak Ridge National Laboratory and supported by the Office of Basic Energy Sciences, U.S. Department of Energy, under contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. References (1) Ma, Z.; Yu, J. H.; Dai, S. Preparation of Inorganic Materials Using Ionic Liquids. Adv. Mater. 2010, 22, 261-285. (2) Sun, X. Q.; Luo, H. M.; Dai, S. Ionic Liquids-Based Extraction: A Promising Strategy for the Advanced Nuclear Fuel Cycle. Chem. Rev. 2012, 112, 2100–2128. (3) Huang, K.; Chen, F. F.; Tao, D. J.; Dai, S. Ionic liquid-formulated hybrid solvents for CO2 capture. Curr. Opin. Green Sustain. Chem. 2017, 5, 67-73. (4) Yang, Q. W.; Zhang, Z. Q.; Sun, X. G.; Hu, Y. S.; Xing, H. B.; Sheng Dai, S. Ionic liquids and derived materials for lithium and sodium batteries. Chem. Soc. Rev. 2018, 47, 2020-2064.

High specific surface area porous graphene grids carbon as anode materials for sodium ion batteries

Abstract Although great accomplishments of functional material synthesis have been achieved in sodium ion batteries (SIBs) recently, there are still numerous challenges and problems in preparing carbon-based materials with porous architectures and enough lattice distance for Na+ insertion. Herein we report a templated strategy to synthesize 3D porous graphene girds (PGGs) consisting of several stacking graphene structure with ultrahigh surface area and hierarchical connected structure by employing Ag nanoparticles (NPs). The Ag NPs will regenerate for decreasing the experimental cost, also in line with principles of green chemistry and environmentally friendly strategy. The PGGs obtain advanced specific capacity of 160 mA h g−1 at current density of 50 mA h g−1. Moreover, 112 mA h g−1 capacity can be gained at 1 A h g−1 during 1000 cycles. Due to their porous architecture, ultrahigh surface area and low amorphous graphited structure, PGGs electrode showed the excellent electrochemical performance in high rate capability.

Morphology Evolution and Control of Mo-polydopamine Coordination Complex from 2D Single Nanopetal to Hierarchical Microflowers.

Controllable synthesis of functional materials is of widespread interest for particle engineering. Such a method has not been widely promoted due to the lack of recognition of the fundamental principle, especially for organic-inorganic hybrid materials. Here, as an entrance, the controllable synthesis of Mo-polydopamine coordination flowers is realized through a facile foaming method, and a 2D nanopetal as the building monomer of the flower is synthesized. Depending on the morphology evolution of Mo-dopamine complex under different conditions, and the surface iterative topology growth of the Mo-polydopamine petal, the reasons of why the Mo-polydopamine complex self-assembles into a flower structure can be attributed to the synergistic effect of multicore symbiosis and structural self-protective growth behaviors. Benefiting from the strong structure stability of the Mo-polydopamine nanopetal, a hybrid structure of MoO2 quantum dot in situ anchoring in the N-doped 2D carbon framework is prepared by direct pyrolysis, which shows a highly reversible performance in application for lithium-ion secondary batteries (LIBs). This work enhances the possibility for the controllable synthesis of organic-inorganic hybrid materials by adjusting the multicore intergrowth and inhibiting the interfacial assembly.

Frontal polymerization for smart intrinsic self‐healing hydrogels and its integration with microfluidics

ABSTRACTFrontal polymerization (FP) is applied for the synthesis of β‐cyclodextrin/poly(vinylimidazole‐co‐N‐vinylcaprolactam‐co‐acrylic acid) (β‐CD/P(VI‐co‐NVCL‐co‐AA)) copolymers. The dependence of frontal velocity and temperature on the initiator and cross‐linker are discussed. The synthesized copolymers have been characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The thermo‐pH dual‐stimuli responsive behavior of the hydrogel is determined by swelling measurement at different temperatures and pH values. Besides, the hydrogels show intrinsic self‐healing behavior and their healing efficiency is determined by the mechanical tests. Interestingly, we integrate FP with microfluidic technology, which may realize the execution of FP under continuous condition. Such simple microfluidics‐FP integrated approach has both methodological and practical value for the synthesis of functional materials. This paper mainly presents the synthesis and characterization of β‐cyclodextrin/poly(vinylimidazole‐co‐N‐vinylcaprolactam‐co‐acrylic acid) (β‐CD/P(VI‐co‐NVCL‐co‐AA)) copolymers by using thermal frontal polymerization (TFP). Hydrogels were found to be self‐healing with good mechanical performance and show dual thermo‐pH responsive behavior. Low‐cost, energy‐saving and efficient method of thermal frontal polymerization process was integrated with microfluidics technology to prepare supraball hydrogel. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1412–1423

(Keynote) Recent Progress in Nanomaterials and Smart-Phone Based Biosensors for Biomedical, Environmental, and Food Safety Applications

In this talk, I will briefly discuss our recent progress in synthesis of functional materials based on protein cages, graphene, and nanoflowers for biosensing and bioimaging. I will discuss the development of various biosensors based on DNA assays and immunoassays for point-of care diagnostics and for cancer biomarker detection [1-3]. Nanomaterials loaded with optical or electroactive signal molecules were used for signal amplification tags for enhanced sensitivity for detection of disease biomarkers, environmental pollutants, and food pathogens. I will also discuss the recent work in 3D printing and smart-phone based biosensors for food safety applications [4-5].

Influence of the calcination procedure on the thermoelectric properties of calcium cobaltite Ca3Co4O9

Calcium cobaltite is one of the most promising oxide p-type thermoelectric materials. The solid-state reaction (or calcination, respectively), which is well known for large-scale powder synthesis of functional materials, can also be used for the synthesis of thermoelectric oxides. There are various calcination routines in literature for Ca3Co4O9 powder synthesis, but no systematic study has been done on the influence of calcination procedure on thermoelectric properties. Therefore, the influence of calcination conditions on the Seebeck coefficient and the electrical conductivity was studied by modifying calcination temperature, dwell time, particle size of raw materials and number of calcination cycles. This study shows that elevated temperatures, longer dwell times, or repeated calcinations during powder synthesis do not improve but deteriorate the thermoelectric properties of calcium cobaltite. Diffusion during calcination leads to idiomorphic grain growth, which lowers the driving force for sintering of the calcined powder. A lower driving force for sintering reduces the densification. The electrical conductivity increases linearly with densification. The calcination procedure barely influences the Seebeck coefficient. The calcination procedure has no influence on the phase formation of the sintered specimens.

Synthesis of titanium carbide from the rutile concentrate by low temperature plasma

As a result of the synthesis of titanium-containing mineral raw materials (rutile concentrate), using high-density energies, the metal titanium and titanium carbide were produced. The article presents the results of experiments on the possibility of using high-density energies for the synthesis of functional materials for industrial use.

Supercritical CO2 mediated incorporation of sulfur into carbon matrix as cathode materials towards high-performance lithium–sulfur batteries

A green and facile supercritical CO2 (SC-CO2) synthetic strategy is successfully developed to fabricate high-performance carbon–sulfur cathodes for advanced Li–S batteries, which also could open up a new avenue for the rational design and controllable synthesis of functional materials.

Sustainable Catalytic Amination of Diols: From Cycloamination to Monoamination

N-Alkyl amines are extensively applied in the synthesis of functional materials, pharmaceuticals, and pesticides. The reaction of diols with amines is attractive and has been investigated for more than 30 years by using iridium, ruthenium, and other catalysts. However, the main products with diols as starting materials, especially for C4–C6 diols, are N-heterocyclic compounds because cyclization reaction is favorable in thermodynamics. Here, for the first time, a simple and non-noble catalyst CuNiAlOx prepared by a coprecipitation method was developed for the reaction of C4–C6 diols with amines to give monoamination products. This method offers an efficient and environmentally friendly method for the selective monoamination of diols.

An effective strategy for the preparation of nitrogen-doped carbon from Imperata cylindrica panicle and its use as a metal-free catalyst for the oxygen reduction reaction

Abstract Developing an effective strategy for the large-scale preparation of metal-free catalysts for the oxygen reduction reaction (ORR) is a great challenge. The use of a natural biomass as a green and sustainable precursor for the synthesis of functional materials has attracted significant interest recently. We have successfully synthesized nitrogen-doped carbon as a high-activity catalyst by using Imperata cylindrica panicle as a raw material by combining a simple hydrothermal process with an effective nitrogen-doping technique for thermal annealing in an NH3 atmosphere. Compared to the control sample without nitrogen-doping, the typical product (total N content 2.2 at %) shows a higher catalytic activity in terms of its positive onset potential (0.040 V, vs. Hg/HgO), high current density (5.73 mA cm−2 at −0.8 V vs. Hg/HgO) and approximate four-electron reaction pathway in alkaline media (3.87, at −0.8 V vs. Hg/HgO). In acidic media, these values are approximately 0.500 V (vs. Ag/AgCl), 5.03 mA cm−2 and 3.94 (at −0.2 V vs. Ag/AgCl), respectively. The product also shows superior tolerance to methanol poisoning and outstanding durability in both alkaline and acidic media. In addition, our novel approach to the synthesis of nitrogen-doped carbon materials, in terms of the raw material and preparation method, may guide future efforts for the preparation of carbon-based materials.

A sapphire single-crystal cell for in situ neutron powder diffraction of solid-gas reactions

Solid-gas reactions play an important role in many technologically important processes from ore smelting to hydrogen storage and the synthesis of functional materials. In situ investigations are very useful for unraveling basic steps of such reactions, rationalizing them and gaining control. For investigating time-resolved solid-gas reactions, we have constructed a gas pressure cell for elastic neutron diffraction. By proper orientation of a single-crystal sapphire tube as sample holder, Bragg peaks from the container material can be completely avoided, thus yielding high-quality powder diffraction data with very clean diffraction background. This enables the extraction of high precision crystal structure data as a function of gas pressure and temperature (laser heating) in time-resolved studies. The potential of the gas pressure cell is demonstrated by in situ studies of the reaction of solids with hydrogen, which yielded detailed models of the reaction pathways including high quality crystal structures of reaction intermediates and products. These were used to predict successfully the existence of further metal hydrides, to explain unusual bonding properties, and to optimize the synthesis of metastable compounds.

Concentration-Driven Assembly and Sol-Gel Transition of π-Conjugated Oligopeptides.

Advances in supramolecular assembly have enabled the design and synthesis of functional materials with well-defined structures across multiple length scales. Biopolymer-synthetic hybrid materials can assemble into supramolecular structures with a broad range of structural and functional diversity through precisely controlled noncovalent interactions between subunits. Despite recent progress, there is a need to understand the mechanisms underlying the assembly of biohybrid/synthetic molecular building blocks, which ultimately control the emergent properties of hierarchical assemblies. In this work, we study the concentration-driven self-assembly and gelation of π-conjugated synthetic oligopeptides containing different π-conjugated cores (quaterthiophene and perylene diimide) using a combination of particle tracking microrheology, confocal fluorescence microscopy, optical spectroscopy, and electron microscopy. Our results show that π-conjugated oligopeptides self-assemble into β-sheet-rich fiber-like structures at neutral pH, even in the absence of electrostatic screening of charged residues. A critical fiber formation concentration cfiber and a critical gel concentration cgel are determined for fiber-forming π-conjugated oligopeptides, and the linear viscoelastic moduli (storage modulus G′ and loss modulus G″) are determined across a wide range of peptide concentrations. These results suggest that the underlying chemical structure of the synthetic π-conjugated cores greatly influences the self-assembly process, such that oligopeptides appended to π-conjugated cores with greater torsional flexibility tend to form more robust fibers upon increasing peptide concentration compared to oligopeptides with sterically constrained cores. Overall, our work focuses on the molecular assembly of π-conjugated oligopeptides driven by concentration, which is controlled by a combination of enthalpic and entropic interactions between oligopeptide subunits.

Smart Nanocatalysts with Streamline Shapes.

Particulate catalysts with streamline shapes have important impacts on fluid-related reactions, and they need to be properly characterized. However, utilization of streamline-shaped catalysts for heterogeneous catalysis has remained an unexplored area due to the lack of easy-to-use techniques to produce such shaped catalysts, especially at the small length scale of the submicron to micron regime. Herein, we report our recent development of a class of prototype nanocatalysts with streamline shapes. In this research, the kinetic control is adapted to obtain streamline-shaped supports, followed by functionalizing such supports with catalytically active metal nanoclusters (e.g., Au, Pd, Pt, and Ag or their combinations) in a stepwise manner. Advantages related to the streamline morphology of catalysts have been demonstrated with a number of solid–solution systems such as alcohol oxidation, olefin hydrogenation, and Suzuki–Miyaura coupling. We believe these findings will promote new research on the design and synthesis of functional materials with additional fluid-advanced features.

Perspective Article: Flow Synthesis of Functional Materials

Continuous-flow synthesis of specific functional materials is now seen as a reliable synthesis approach that gives consistent product properties. This perspective article aims to survey recent work in some of the relevant areas and to identify new domains where flow synthesis of functional materials can be better than the conventional synthesis methods. It also emphasizes the need for developing high-throughput integrated synthesis and screening systems for almost all functional materials so that laboratory-scale recipes can be transformed into reliable manufacturing processes. New areas relevant to functional materials which have remained unexplored in flow synthesis are also highlighted.

Factory-on-chip: Modularised microfluidic reactors for continuous mass production of functional materials

Droplet microfluidics provide an advanced platform for functional material synthesis. However, the process has been largely limited to the scale of laboratory study with the device known as lab-on-chip. Here, a multi-dimensional scale-up strategy based on modularised microfluidic reactors is presented to develop large-scale devices defined as factory-on-chip, achieving throughput enhancement to the industrial production scale. Under the guidance of the derived principle, an up-scaling system is demonstrated with eight microchannels parallelized to form an array, ten arrays stacked as the module, and five modules integrated in a system with 400 channels in total. Experiments showed that the circular array arrangement improved the uniformity of product droplets by 42.4% compared to that achieved with a parallel array. The stacking effect was also investigated with two types of material production systems. Chitosan/TiO2 composite microspheres, as advanced wastewater treatment material, were continuously synthesized in mass production with a narrow size distribution of 3.59%, which could hardly be achieved with conventional methods. The material exhibited a methyl-orange dye removal efficiency of 65.3%, which constitutes an improvement of 10.8% compared to single-component chitosan microspheres.

Advances in Droplet-Based Microfluidic Technology and Its Applications

Micro-droplets, with the properties of small size, large surface area, high speed, high throughout, uniform size, closed system, internal stability and etc., are widely used in the fields like drug controlled release, virus detection, synthetic of particulate materials, catalysts and so on. The emergence and development of microfluidic technology provide a new platform for the generation and precise manipulation of size-controlled microdroplet with different structures and functional characteristics. The fundamental principles, generation and manipulation of droplet-based microfluidic technology were introduced in this review. Similarities and differences of droplets' conventional preparation methods and droplet-based microfluidic technology were compared and analyzed. Finally, the applications of droplet-based microfluidic for the synthesis of functional materials, bio-medicine and design of food structure were reviewed. In addition, the potential value and development direction of drop-based microfluidic were discussed and forecasted.

Controlled droplet microfluidic systems for multistep chemical and biological assays.

Droplet microfluidics is a relatively new and rapidly evolving field of science focused on studying the hydrodynamics and properties of biphasic flows at the microscale, and on the development of systems for practical applications in chemistry, biology and materials science. Microdroplets present several unique characteristics of interest to a broader research community. The main distinguishing features include (i) large numbers of isolated compartments of tiny volumes that are ideal for single cell or single molecule assays, (ii) rapid mixing and negligible thermal inertia that all provide excellent control over reaction conditions, and (iii) the presence of two immiscible liquids and the interface between them that enables new or exotic processes (the synthesis of new functional materials and structures that are otherwise difficult to obtain, studies of the functions and properties of lipid and polymer membranes and execution of reactions at liquid-liquid interfaces). The most frequent application of droplet microfluidics relies on the generation of large numbers of compartments either for ultrahigh throughput screens or for the synthesis of functional materials composed of millions of droplets or particles. Droplet microfluidics has already evolved into a complex field. In this review we focus on 'controlled droplet microfluidics' - a portfolio of techniques that provide convenient platforms for multistep complex reaction protocols and that take advantage of automated and passive methods of fluid handling on a chip. 'Controlled droplet microfluidics' can be regarded as a group of methods capable of addressing and manipulating droplets in series. The functionality and complexity of controlled droplet microfluidic systems can be positioned between digital microfluidics (DMF) addressing each droplet individually using 2D arrays of electrodes and ultrahigh throughput droplet microfluidics focused on the generation of hundreds of thousands or even millions of picoliter droplets that cannot be individually addressed by their location on a chip.