A polymeric composite protective layer for stable Li metal anodes

Guo Suogang,Wang Li,Jin Yuhong,Piao Nan,Chen Zonghai,Tian Guangyu,Li Jiangang,Zhao Chenchen,He Xiangming 나노기술연구협의회 2020 Nano Convergence Vol.7 No.21

Lithium (Li) metal is a promising anode for high-performance secondary lithium batteries with high energy density due to its highest theoretical specific capacity and lowest electrochemical potential among anode materials. However, the dendritic growth and detrimental reactions with electrolyte during Li plating raise safety concerns and lead to premature failure. Herein, we report that a homogeneous nanocomposite protective layer, prepared by uniformly dispersing ­AlPO 4 nanoparticles into the vinylidene fluoride-co-hexafluoropropylene matrix, can effectively prevent dendrite growth and lead to superior cycling performance due to synergistic influence of homogeneous Li plating and electronic insulation of polymeric layer. The results reveal that the protected Li anode is able to sustain repeated Li plating/stripping for > 750 cycles under a high current density of 3 mA cm −2 and a renders a practical specific capacity of 2 mAh cm −2 . Moreover, full-cell Li-ion battery is constructed by using ­LiFePO 4 and protected Li as a cathode and anode, respectively, rendering a stable capacity after 400 charge/discharge cycles. The current work presents a promising approach to stabilize Li metal anodes for next-generation Li secondary batteries.

CO2 Adsorption on the B12N12 Nanocage Encapsulated with Alkali Metals: A Density Functional Study

Haiyan Zhu,Qiyan Zhang,Qinfu Zhao,He Zhao,Yifan Feng,Bingbing Suo,Huixian Han,Qi Song,Yawei Li,Wenli Zou,Haiyan Zhu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.3

Density functional theory (DFT) calculations have been carried out to study the capacity of the B12N12 nanocage encapsulated with alkali metals (Li, Na, K) for the CO2 adsorption and activation. It is found that after encapsulating alkali metals, the alkali metal atoms are closer to one side of clusters instead of exactly lying at the center, and a considerable charge transfers from the inner alkali metal atoms to the B12N12 cage. Besides, the HOMO–LUMO gap (HLG) values of Li@B12N12, Na@B12N12 and K@B12N12 are decreased to about 6 eV, being much smaller than that of the pristine B12N12. Although the geometry structure parameters and the energy differences of M06-2X are slightly different from the ones of ωB97X-D, some identical results of two kinds of functional can be obtained. CO2 can be adsorbed chemically and physically on majority bonds of all the clusters, except for some bonds with large change in bond length and bond indices. The encapsulation of alkali-metal atoms may enhance the physical and chemical adsorption of CO2 on the surface of the clusters, in which Na@B12N12 and K@B12N12 are the most powerful physical and chemical adsorbent for CO2, respectively.

In-situ photocrosslinked hydroxide conductive membranes based on photosensitive poly(arylene ether sulfone) block copolymers for anion exchange membrane fuel cells

He, Rui,Wen, Pushan,Zhang, Hai-Ning,Guan, Shumeng,Xie, Guangyong,Li, Li-Zhong,Lee, Myong-Hoon,Li, Xiang-Dan Elsevier 2018 Journal of membrane science Vol.556 No.-

<P><B>Abstract</B></P> <P>A series of photocrosslinkable multi-block poly(arylene ether sulfone) copolymers containing various block lengths of hydrophilic segments were synthesized. For comparison, a series of random poly(arylene ether) copolymers were also synthesized. The anion exchange membranes(AEMs) were fabricated and in-situ photocrosslinking was carried out by UV irradiation in a swollen state. The microphase-separated morphologies of the multi-block membranes were characterized by SAXS and TEM experiments, and the membrane properties were investigated by measuring ion exchange capacity (IEC), water uptake, water swelling ratio, ionic conductivity, methanol permeability and alkaline stability. IECs and water uptakes of the crosslinked multi-block membranes were in the range of 1.11–1.42 meq g<SUP>−1</SUP> and 14.36–31.01% at 20 °C, respectively. The hydroxide conductivity was in the range of 11.38–25.00 mS cm<SUP>−1</SUP> at 20 °C, and showed a maximum value of 178.77 mS cm<SUP>−1</SUP> at 100 °C. The multi-block membranes exhibited low methanol permeability (2.75 × 10<SUP>−7</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>) at room temperature, which is one order of magnitude lower than that of Nafion® 117 (23.8 × 10<SUP>−7</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>). The crosslinked membranes showed excellent dimensional stability and alkaline stability with only a slight decrease in ionic conductivity. All the multi-block membranes showed superior properties compared to their corresponding random copolymers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Multi-block poly(arylene ether sulfone) copolymers were synthesized for AEMs. </LI> <LI> <I>In-situ</I> photo-crosslinking was carried out by UV irradiation in hydrated states. </LI> <LI> The block copolymers exhibited hydrophilic/hydrophobic phase separated morphology. </LI> <LI> The block copolymers showed superior properties compare to the random copolymers. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microstructural evolution and oxidation resistance of T92 boiler tube steel upon long-term supercritical steam test

Li, Kejian,Ma, Houyu,He, Yinsheng,Chang, Jungchel,Bae, Si-yeon,Shin, Keesam Elsevier 2017 Fusion engineering and design Vol.125 No.-

<P><B>Abstract</B></P> <P>High-chromium heat-resistant steels are widely used as key materials to improve the condition of steam pressure and temperature in the boiler tube system of the supercritical power plants. Material-related failures in boiler system have occurred mainly due to internal oxidation and corrosion. For the stable maintenance of boilers, determination of the corrosion mechanism, microstructural evolution and data collection pertaining to the oxidation is essential. In this study, the supercritical steam test was carried out on T92 steel at the temperatures of 600/650/700°C for 10,000/15,000/20,000h. The matrix of steels and the oxide scale layers were investigated after steam treatment using scanning electron microscopy, back-scattered electron microscopy and electron backscattered diffraction. The oxide scale layers from the outer surface to the matrix consisted of: i) an outer layer of nanoscale iron oxide (Fe<SUB>2</SUB>O<SUB>3</SUB>); ii) inner layer of microscale crystals of Fe<SUB>3</SUB>O<SUB>4</SUB>, and iii) a mixture of chromium oxide and chromite (Cr<SUB>2</SUB>O<SUB>3</SUB> and FeCr<SUB>2</SUB>O<SUB>4</SUB>) adjacent to the matrix.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The matrix and scale layers were subsequently investigated using various electronic microscope analysis. </LI> <LI> The order of scale layers from the surface to the matrix are: i) nanoscaled Fe<SUB>2</SUB>O<SUB>3</SUB>; ii) microscaled Fe<SUB>3</SUB>O<SUB>4</SUB>; and iii) a mixture of Cr<SUB>2</SUB>O<SUB>3</SUB> and FeCr<SUB>2</SUB>O<SUB>4</SUB>. </LI> <LI> The Cr-rich layer was considered as protective for the matrix, which was stable at 600°C and 650°C, but the thickness decreased at 700°C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>(a) EBSD phase mapping of the scale layer, (b) SEM, (c) BSE, and (d∼g) EDS elemental mapping of the steam tested at 650°C for 10,000h.</P> <P>[DISPLAY OMISSION]</P>

Fabrication of highly efficient coatable polarizer from tolane-based smectic reactive mesogen

He, Rui,Oh, Enche,Ye, Yang,Wen, Pushan,Jeong, Kwang-Un,Lee, Seung Hee,Li, Xiang-Dan,Lee, Myong-Hoon Elsevier 2019 Polymer Vol.176 No.-

<P><B>Abstract</B></P> <P>This work is aimed to fabricate ultra-thin coatable polarizers on a single substrate based on “host-guest” effect between highly ordered smectic reactive mesogen (RM) and dichroic dye. We designed and synthesized a new tolane-based RM with a highly ordered smectic A phase at room temperature. Polymerizable “host-guest” mixture was formulated from the host RM, dichroic dye and additives, then spin-coated on a single substrate having an alignment layer. Subsequent in-situ photopolymerization by UV irradiation successfully resulted in a coatable polarizer with good polarizing properties. The fabricated coatable polarizer showed a dichroic ratio (DR) of 16.4 and a degree of polarization (DOP) of 99.3% with the thickness of 4 μm. The resulting coatable polarizer possessed a considerable solvent resistance, good thermal stability and robust mechanical properties. Moreover, we prepared a TN-mode LC cell by using the prepared coatable polarizers inside the cell (in-cell), in which the coatable polarizers acted as a polarizer and an alignment layer, simultaneously. The resulting TN cell with in-cell polarizers exhibited a decent electro-optical behavior. We believe that the coatable polarizer proposed in this study possesses practical application potential in ultra-thin LCDs or flexible OLEDs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Reactive mesogen with smectic A phase was synthesized for coatable polarizer. </LI> <LI> Coatable polarizer was fabricated on a single substrate by “host-guest” method. </LI> <LI> Coatable polarizer exhibits considerable optical property and excellent stability. </LI> <LI> LCD with in-cell structure was demonstrated by using the prepared coatable polarizer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Red, green, and blue fluorescent folate-receptor-targeting carbon dots for cervical cancer cellular and tissue imaging

Li, Shihao,Jiang, Jie,Yan, Yinan,Wang, Ping,Huang, Gang,Kim, Nam hoon,Lee, Joong Hee,He, Dannong Elsevier 2018 Materials science & engineering. C, Materials for Vol.93 No.-

<P><B>Abstract</B></P> <P>Folate receptor targeted photo-luminescent quantum carbon dots (Fr-CDs) were successfully prepared from folic acid and phenylenediamine isomers through hydrothermal approaches. Fr-CDs were spherical particles smaller than 10 nm, and emit stable green, blue and red luminescence under ultraviolet region excitation (λex = 365 nm) with maximum emissive lengths at 530, 429, and 612 nm. And the corresponding photoluminescence quantum yield as 15.4%, 12.6% and 16.2% respectively. Up-converted photoluminescent properties in near infrared 800 nm spectral region located in green, blue and yellow region. In-vitro studies showed Fr-CDs had almost none cytotoxicity (cell viability over 80%) and high affinitive to the Hela celline highly-expressed-folate-receptor membranes, and lighted on cytoplasm as the fluorescent marker. It displayed long luminescent-stability with PL intensity above 90% in ultraviolet illuminant exposure over 24 h. In in-vivo studies, Fr-CDs were internalized and accumulated in targeted cancer tissues of cervical carcinoma and the emitting fluorescence maintains over 30 min.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Multicolor carbon dots was prepared from folic acid and phenylenediamin isomers. </LI> <LI> These carbon dots exhibit targeting abilities with high affinity to ovarian cancer cells and tissues. </LI> <LI> Ultra-violet and near-infrared light excited photo-luminescent spectrums were investigated, and related quantum yield was calculated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>FA-doped CDs can effectively target ovarian cancer cells and aggregate in ovarian tumor tissue in a short 15 min.</P> <P>[DISPLAY OMISSION]</P>

Syntheses and characterizations of high refractive index and low birefringence polyimides containing spirobifluorene in the side chain

Wen, Pushan,He, Rui,Li, Xiang-Dan,Lee, Myong-Hoon Elsevier 2017 Polymer Vol.117 No.-

<P><B>Abstract</B></P> <P>Two new diamine monomers having a spirobifluorene structure were synthesized through four steps, and polymerized with three different dianhydrides (PMDA, CBDA and 6FDA) to obtain six polyimides with spirobifluorene structure in the side chain. All the resulting polyimides displayed excellent thermal stability and high glass transition temperature. These polyimides synthesized from CBDA and 6FDA showed good solubility in typical organic solvents such as NMP, DMF and DMSO. Transparent and flexible cast films can be obtained from soluble polyimides or poly(amic acid) solution. The transmittance of polyimide films was higher than 90% in the visible wavelength range (higher than 80% in case of polyimide containing PMDA). The refractive indices of the result polyimides were found to be in the range from 1.6343 to 1.7007, which is higher than that of normal polymers. In addition, the optical birefringences of these polyimides were extremely low (0.0005–0.0014). The high refractive index and low birefringence of these polyimides as well as other descent physical and thermal properties would offer them possible applications in high performance optical materials such as flexible substrates.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel polyimides containing 9,9’-spirobifluorene unit in the side chain were synthesized. </LI> <LI> The polyimides exhibit high thermal stability (T5 > 420 °C) with excellent optical properties such as high transparency (>90% at 400 nm), high refractive index (1.6342–1.7007) and low birefringence (0.0005–0.0014). </LI> <LI> The resulting polymer materials could be promising candidates for advanced optical applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Novel polyimides containing 9,9′-spirobifluorene unit in the side chain, which exhibit high transparency, high refractive index and low birefringence, have been developed as promising candidates for advanced optical applications.</P> <P>[DISPLAY OMISSION]</P>

Activation of formyl CH and hydroxyl OH bonds in HMF by the CuO(1 1 1) and Co₃O₄(1 1 0) surfaces: A DFT study

Ren, Jun,Song, Kai-he,Li, Zhenhuan,Wang, Qiang,Li, Jun,Wang, Yingxiong,Li, Debao,Kim, Chan Kyung Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.456 No.-

<P><B>Abstract</B></P> <P>The first principle calculations with on-site Coulomb repulsion U terms were carried out to investigate the 5-hydroxymethylfurfural (HMF) adsorption on the CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces, two widely used oxidation catalysts. The adsorption of HMF molecule is energetically favoured in both cases, and HMF is more inclined to bridge adsorption via hydroxyl and formyl groups binding with surface O and metal sites. Moreover, the adsorption energy relies on both the coordination type of surface lattice oxygen to which the H atom binds and the formation of H-bond involving hydroxyl and formyl groups on the adsorbed HMF. Also, the hydroxyl OH bond breaking is very easy and is likely to be the first step in HMF oxidation, and then the OH insertion reaction to produce 2,5-furandicarboxylic acid (FDCA). The corresponding experimental results also show that the CuO and Co<SUB>3</SUB>O<SUB>4</SUB> surfaces are promising candidate catalysts.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces catalyze the oxidation of 5-hydroxymethylfurfural (HMF). </LI> <LI> Initial binding was formed through bridged-adsorption with O atoms in HMF. </LI> <LI> Oxidation reaction proceeds through the OH bond breaking pathway. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Schematic potential energy diagram for the formyl CH and hydroxyl OH bonds of HMF dissociation on CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces. Obviously, the hydroxyl OH bond breaking is easier than that of the formyl CH bond on the two surfaces, which indicates the first step of oxidation of HMF to FDCA should be hydroxyl OH bond breaking.</P> <P>[DISPLAY OMISSION]</P>

Metabolic Regulation of Gene Expression by Histone Lysine β-Hydroxybutyrylation

Xie, Zhongyu,Zhang, Di,Chung, Dongjun,Tang, Zhanyun,Huang, He,Dai, Lunzhi,Qi, Shankang,Li, Jingya,Colak, Gozde,Chen, Yue,Xia, Chunmei,Peng, Chao,Ruan, Haibin,Kirkey, Matt,Wang, Danli,Jensen, Lindy M. Elsevier 2016 Molecular cell Vol.62 No.2

<P><B>Summary</B></P> <P>Here we report the identification and verification of a β-hydroxybutyrate-derived protein modification, lysine β-hydroxybutyrylation (Kbhb), as a new type of histone mark. Histone Kbhb marks are dramatically induced in response to elevated β-hydroxybutyrate levels in cultured cells and in livers from mice subjected to prolonged fasting or streptozotocin-induced diabetic ketoacidosis. In total, we identified 44 histone Kbhb sites, a figure comparable to the known number of histone acetylation sites. By ChIP-seq and RNA-seq analysis, we demonstrate that histone Kbhb is a mark enriched in active gene promoters and that the increased H3K9bhb levels that occur during starvation are associated with genes upregulated in starvation-responsive metabolic pathways. Histone β-hydroxybutyrylation thus represents a new epigenetic regulatory mark that couples metabolism to gene expression, offering a new avenue to study chromatin regulation and diverse functions of β-hydroxybutyrate in the context of important human pathophysiological states, including diabetes, epilepsy, and neoplasia.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lysine β-hydroxybutyrylation (Kbhb) is a new type of histone mark </LI> <LI> 44 non-redundant histone Kbhb sites are identified in human and mouse cells </LI> <LI> Histone Kbhb increases under starvation and STZ-induced ketoacidosis </LI> <LI> Starvation-induced H3K9bhb is associated with active gene expression </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Disruption of endothelial barrier function is linked with hyposecretion and lymphocytic infiltration in salivary glands of Sjögren's syndrome

Cong, Xin,Zhang, Xue-Ming,Zhang, Yan,Wei, Tai,He, Qi-Hua,Zhang, Li-Wei,Hua, Hong,Lee, Sang-Woo,Park, Kyungpyo,Yu, Guang-Yan,Wu, Li-Ling Elsevier 2018 Biochimica et biophysica acta. Molecular basis of Vol.1864 No.10

<P><B>Abstract</B></P> <P>Sjögren's syndrome (SS) is an inflammatory autoimmune disease that causes hyposecretion in salivary glands. Endothelial tight junctions (TJs) play crucial roles in salivation and barrier function of blood vessels. However, whether the alteration of endothelial TJs were involved in pathogenesis of SS was still unknown. Here, the ultrastructure and function of endothelial TJs in submandibular glands (SMGs) were detected by transmission electron microscopy and in vivo paracellular permeability assay in different aged NOD mouse model for SS. CFSE-labeled lymphocytes were injected into tail vein to trace the infiltration, while claudin-5 expression and distribution were detected by immunofluorescence, qRT-PCR, and western blot. Results showed that the stimulated salivary flow rate was gradually decreased and lymphocytic infiltration was found as age increased in 12- and 21-week-old NOD mice, but not 7-week-old NOD mice. Blood vessels were dilated, while endothelial TJ width and paracellular tracer transport were increased in 12-week-old NOD mice. Moreover, the injected CFSE-labeled lymphocytes were observed in SMGs of 12-week-old NOD mice. Claudin-5 level was increased and relocalized from the apical portion of neighboring endothelial cells to lateral membranes and cytoplasm in 12-week-old NOD mice. Additionally, the alteration of claudin-5 expression and distribution was further confirmed in labial salivary glands and bilateral parotid glands from SS patients. In cultured human microvessel endothelial cell line (HMEC-1), IFN-γ stimulation significantly increased claudin-5 expression. Taken together, we identified that the endothelial TJ barrier was disrupted and contributed to the development of salivary hyposecretion and lymphocytic infiltration in SS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Endothelial tight junction barrier is disrupted in hyposecretory submandibular glands from Sjögren's syndrome mouse model </LI> <LI> The disrupted salivary endothelial barrier is linked with lymphocytic infiltration in Sjögren's syndrome mouse model </LI> <LI> The redistribution of claudin-5 is responsible for disrupted endothelial barrier in salivary glands from Sjögren's syndrome </LI> </UL> </P>