Mesoporous carbon, which was templated by colloidal silica, was added to a sulfur cathode as a functional material to confine polysulfides to improve the cyclic performance of lithium–sulfur ...batteries. To investigate the effect of the pore size and the pore volume of mesoporous carbon on the absorption characteristics of the Li-polysulfides, mesoporous carbons with various pore sizes and total pore volumes were prepared by varying the size and the amount of colloidal silica templates. The results show that mesoporous carbon-containing sulfur cathode enhanced the cyclic performance of the batteries significantly. Comparable performances were observed regardless of pore size, suggesting that the pore size is not a critical factor affecting the absorption characteristics of the Li-polysulfides. However, the cyclic performance was affected by the total pore volume, suggesting that a certain pore volume is necessary to confine the majority of the soluble Li-polysulfides generated during cycling and to enhance sulfur utilization. The novel results obtained in this study will contribute to the consolidation of S electrochemistry and further development of high-energy lithium–sulfur batteries.
Lithium (Li) metal is regarded as the most attractive anode material for high‐energy Li batteries, but it faces unavoidable challenges—uncontrollable dendritic growth of Li and severe volume changes ...during Li plating and stripping. Herein, a porous carbon framework (PCF) derived from a metal–organic framework (MOF) is proposed as a dual‐phase Li storage material that enables efficient and reversible Li storage via lithiation and metallization processes. Li is electrochemically stored in the PCF upon charging to 0 V versus Li/Li+ (lithiation), making the PCF surface more lithiophilic, and then the formation of metallic Li phase can be induced spontaneously in the internal nanopores during further charging below 0 V versus Li/Li+ (metallization). Based on thermodynamic calculations and experimental studies, it is shown that atomically dispersed zinc plays an important role in facilitating Li plating and that the reversibility of Li storage is significantly improved by controlled nanostructural engineering of 3D porous nanoarchitectures to promote the uniform formation of Li. Moreover, the MOF‐derived PCF does not suffer from macroscopic volume changes during cycling. This work demonstrates that the nanostructural engineering of porous carbon structures combined with lithiophilic element coordination would be an effective approach for realizing high‐capacity, reversible Li‐metal anodes.
A porous carbon nanoarchitecture derived from metal–organic frameworks is strategically suggested as a dual‐phase lithium (Li) storage host for Li‐metal batteries. Controlled open pores are highly desired for providing abundant free spaces for metallization of Li and atomically dispersed zinc metal and nitrogen play an important role in enhancing affinity toward Li+ and electrical conductivity during Li plating–stripping without any structural degradation.
Although the exceptional theoretical specific capacity (1672 mAh g−1) of elemental sulfur makes lithium–sulfur (Li–S) batteries attractive for upcoming rechargeable battery applications (e.g., ...electrical vehicles, drones, unmanned aerial vehicles, etc.), insufficient cycle lives of Li–S cells leave a substantial gap before their wide penetration into commercial markets. Among the key features that affect the cyclability, the shuttling process involving polysulfides (PS) dissolution is most fatal. In an effort to suppress this chronic PS shuttling, herein, a separator coated with poled BaTiO3 or BTO particles is introduced. Permanent dipoles that are formed in the BTO particles upon the application of an electric field can effectively reject PS from passing through the separator via electrostatic repulsion, resulting in significantly improved cyclability, even when a simple mixture of elemental sulfur and conductive carbon is used as a sulfur cathode. The coating of BTO particles also considerably suppresses thermal shrinkage of the poly(ethylene) separator at high temperatures and thus enhances the safety of the cell adopting the given separator. The incorporation of poled particles can be universally applied to a wide range of rechargeable batteries (i.e., metal‐air batteries) that suffer from cross‐contamination of charged species between both electrodes.
Poling for polysulfide rejection: The fatal shuttling process in lithium–sulfur batteries is effectively suppressed by “poled” BaTiO3 or BTO particles coated on a poly(ethylene) separator. The permanent dipoles of poled BTO particles repel polysulfides via electrostatic repulsion. The coating of BTO particles also provides a resistance against thermal shrinkage of the polyethylene separator at high temperature, thus enhancing the safety of the given cell.
Two-dimensional (2D) transition metal oxide systems present exotic electronic properties and high specific surface areas, and also demonstrate promising applications ranging from electronics to ...energy storage. Yet, in contrast to other types of nanostructures, the question as to whether we could assemble 2D nanomaterials with an atomic thickness from molecules in a general way, which may give them some interesting properties such as those of graphene, still remains unresolved. Herein, we report a generalized and fundamental approach to molecular self-assembly synthesis of ultrathin 2D nanosheets of transition metal oxides by rationally employing lamellar reverse micelles. It is worth emphasizing that the synthesized crystallized ultrathin transition metal oxide nanosheets possess confined thickness, high specific surface area and chemically reactive facets, so that they could have promising applications in nanostructured electronics, photonics, sensors, and energy conversion and storage devices.
•Current progress in the catalytic conversion of bio-based HMF into FDCA are reviewed.•Recent progress in the synthesis of HMF from biomass are discussed.•Biological conversion route of biomass ...feedstock into EG are given.•Future outlooks and challenges of the production of bio-building blocks are provided.
Today, bioplastics are recognised as sustainable alternatives and one of the solutions to the crisis of petro-based plastics. The next-generation polymer poly(ethylene 2,5-furandicarboxlate) (PEF) has gained great popularity since it is associated with significant reduction of energy use and GHG emissions, as well as with superior barrier properties. This drop-in polymer is a promising 100% bio-based alternative to its petro-based counterpart poly(ethylene terephthalate) (PET). PEF can be effectively synthesised by polymerisation between 2,5-furandicarboxylic acid (FDCA) and ethylene glycol (EG), which represent biomass-derived building blocks. These bio-building blocks are an important commodity and platform chemicals that can be used for a variety of applications, including the synthesis of PEF. This review covers recent progress in the production of novel bio-building blocks for the preparation of PEF. Among various synthesis methods, we reviewed the catalytic conversion of biomass-derived hydroxylmethylfurfural (HMF) into FDCA and the biological route from biomass feedstock into EG. In addition, we covered recent progress in the synthesis of HMF from biomass since a reliable supply of HMF is important for the synthesis of FDCA. Finally, research goals and challenges for future development of bio-building blocks production were proposed.
Abstract
Ni-rich LiNi
0.8
Co
0.1
Mn
0.1
O
2
layered oxide cathodes have been highlighted for large-scale energy applications due to their high energy density. Although its specific capacity is ...enhanced at higher voltages as Ni ratio increases, its structural degradation due to phase transformations and lattice distortions during cycling becomes severe. For these reasons, we focused on the origins of crack generation from phase transformations and structural distortions in Ni-rich LiNi
0.8
Co
0.1
Mn
0.1
O
2
using multiscale approaches, from first-principles to meso-scale phase-field model. Atomic-scale structure analysis demonstrated that opposite changes in the lattice parameters are observed until the inverse Li content
x
= 0.75; then, structure collapses due to complete extraction of Li from between transition metal layers. Combined-phase investigations represent the highest phase barrier and steepest chemical potential after
x
= 0.75, leading to phase transformations to highly Li-deficient phases with an inactive character. Abrupt phase transformations with heterogeneous structural collapse after
x
= 0.81 (~220 mAh g
−1
) were identified in the nanodomain. Further, meso-scale strain distributions show around 5% of anisotropic contraction with lower critical energy release rates, which cause not only micro-crack generations of secondary particles on the interfaces between the contracted primary particles, but also mechanical instability of primary particles from heterogeneous strain changes.
Ferrocene and cobaltocene and their derivatives are studied as new redox materials for redox flow cells. Their high reaction rates and moderate solubility are attractive properties for their use as ...active materials. The cyclability experiments are carried out in a static cell; the results showed that these materials exhibit stable capacity retention and predictable discharge potentials, which agree with the potential values from the cyclic voltammograms. The diffusion coefficients of these materials are 2 to 7 times higher than those of other non‐aqueous materials such as vanadium acetylacetonate, iron tris(2,2′‐bipyridine) complexes, and an organic benzene derivative.
Back on the metallo‐scene! Metallocenes are investigated as new redox materials in non‐aqueous redox flow batteries. Several pairs of ferrocene and cobaltocene derivatives are studied. Modification with functional groups and integration of transition‐metal ions can change the electrochemical properties of the redox materials, improving current density and discharge potential.
The uncontrollable dendritic growth of metallic lithium during repeated cycling in carbonate electrolytes is a crucial obstacle hindering the practical use of Li‐metal batteries (LMBs). Among ...numerous approaches proposed to mitigate the intrinsic constraints of Li metal, the design of a functional separator is an attractive approach to effectively suppress the growth of Li dendrites because direct contact with both the Li metal surface and the electrolyte is maintained. Here, a newly designed all‐in‐one separator containing bifunctional CaCO3 nanoparticles (CPP separator) is proposed to achieve the flattening of Li deposits on the Li electrode. Strong interactions between the highly polar CaCO3 nanoparticles and the polar solvent reduces the ionic radius of the Li+‐solvent complex, thus increasing the Li+ transference number and leading to a reduced concentration overpotential in the electrolyte‐filled separator. Furthermore, the integration of CaCO3 nanoparticles into the separator induces the spontaneous formation of mechanically‐strong and lithiophilic CaLi2 at the Li/separator interface, which effectively decreases the nucleation overpotential toward Li plating. As a result, the Li deposits exhibit dendrite‐free planar morphologies, thus enabling excellent cycling performance in LMBs configured with a high‐Ni cathode in a carbonate electrolyte under practical operating conditions.
CPP separator is developed. The one‐body structure minimizes the sacrifice in energy density even with the inorganic particle introduction. Polar CaCO3 alters the solvation structure of Li+, enhancing Li+ mobility and reducing concentration overpotential. Concurrently, CaCO3 reacts with Li to form lithiophilic CaLi alloy spontaneously, reducing the nucleation overpotential. Because of the overall overpotential control, dendrite‐free Li deposition is achieved.
Long and thin: SnO2 nanowires with tetragonal structure were successfully synthesized by a thermal evaporation method without any conventional metal catalysts. The enhanced electrochemical ...performance of SnO2 nanowires is believed to result from the combination of unique nanostructures with a high length/diameter ratio and the absence of traditional metal catalysts.
Glycolytic reprogramming is a key feature of chronic inflammatory disease. Extracellular matrix (ECM) produced by myofibroblasts plays an important role in tissue remodeling of nasal mucosa in ...chronic rhinosinusitis (CRS). This study aimed to determine whether glycolytic reprogramming contributes to myofibroblast differentiation and ECM production in nasal fibroblasts.
Primary nasal fibroblasts were isolated from the nasal mucosa of patients with CRS. Glycolytic reprogramming was assessed by measuring the extracellular acidification and oxygen consumption rates in nasal fibroblast, with and without transforming growth factor beta 1 (TGF-β1) treatment. Expression of glycolytic enzymes and ECM components was measured by real-time polymerase chain reaction, western blotting, and immunocytochemical staining. Gene set enrichment analysis was performed using whole RNA-sequencing data of nasal mucosa of healthy donors and patients with CRS.
Glycolysis of nasal fibroblasts stimulated with TGF-B1 was upregulated along with glycolytic enzymes. Hypoxia-inducing factor (HIF)-1α was a high-level regulator of glycolysis, and increased HIF-1α expression promoted glycolysis of nasal fibroblasts, and inhibition of HIF-1α down-regulated myofibroblasts differentiation and ECM production.
This study suggests that inhibition of the glycolytic enzyme and HIF-1α in nasal fibroblasts regulates myofibroblast differentiation and ECM generation associated with nasal mucosa remodeling.
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