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1.
Nanoscale ; 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32388545

RESUMO

Lithium-sulfur batteries (LSBs) have been regarded as potential energy storage devices by virtue of their high theoretical capacity, natural abundance of materials and low cost. However, the notorious shuttle effect and sluggish reaction kinetics are still significant challenges for further development. Herein, Ni12P5 nanoparticles are devised and grown on a reduced graphene oxide (Ni12P5@rGO) framework via a self-template and recrystallization-self-assembly strategy, as the modifier for separators in LSBs for the first time. The support of rGO for Ni12P5 nanoparticles could solve the self-aggregation problem. Ni12P5 nanoparticles not only effectively adsorb polysulfides by polar interaction, but also supply active sites to ameliorate the kinetics of the redox reaction of sulfur. Consequently, when a sulfur-containing commercial acetylene black material (70 wt% sulfur content) is used as the cathode composite without complicated fabrication or surface modification, an LSB with Ni12P5@rGO modified separator shows excellent cycling stability and a capacity degradation of 0.074% per cycle at the current density of 1 C for 500 cycles. When the areal mass of sulfur further increases to 3.5 mg cm-2, the capacity degradation is only 0.071% per cycle at 150 cycles. This study could accelerate the application of phosphides in LSBs.

2.
Small ; : e2000952, 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32378328

RESUMO

Metal sulfides have aroused considerable attention for efficient sodium storage because of their high capacity and decent redox reversibility. However, the poor rate capability and fast capacity decay greatly hinder their practical application in sodium-ion batteries. Herein, a self-template-based strategy is designed to controllably synthesize hierarchical microoctahedra assembled with Cu2 S/MoS2 heterojunction nanosheets in the porous carbon framework (Cu2 S/MoS2 ⊂PCF) via a facile coprecipitation method coupled with vulcanization treatment. The Cu2 S/MoS2 ⊂PCF microoctahedra with 2D hybrid nanosubunits reasonably integrate several merits including facilitating the diffusion of electrons and Na+ ions, enhancing the electric conductivity, accelerating the ion and charge transfer, and buffering the volume variation. Therefore, the Cu2 S/MoS2 ⊂PCF composite manifests efficient sodium storage performance with high capacity, long cycling life, and excellent rate capability.

3.
BMC Pediatr ; 20(1): 200, 2020 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-32386507

RESUMO

BACKGROUND: To report the outcomes of hepatoblastoma resected in our institution. METHODS: We diagnosed 135 children with hepatoblastoma at our institution between January 2010 and December 2017. Patients who underwent liver resection were included for analysis. However, patients who abandoned treatment after diagnosis were excluded from analysis, but their clinical characteristics were provided in the supplementary material. RESULTS: Forty-two patients abandoned treatment, whereas 93 patients underwent liver resection and were included for statistical analysis. Thirty-six, 23, 3, and 31 patients had PRETEXT stages II, III, IV, and unspecified tumours, respectively. Seven patients had ruptured tumour; 9 had lung metastasis (one patient had portal vein thrombosis concurrently). Sixteen patients underwent primary liver resection; 22, 25, and 30 patients received cisplatin-based neoadjuvant chemotherapy and delayed surgery, preoperative transarterial chemoembolization (TACE) and delayed surgery, and a combination of cisplatin-based neoadjuvant chemotherapy, TACE, and delayed surgery, respectively. Forty patients had both PRETEXT and POST-TEXT information available for analysis. Twelve patients were down-staged after preoperative treatment, including 2, 8, and 2 patients from stages IV to III, III to II, and II to I, respectively. Ten patients with unspecified PRETEXT stage were confirmed to have POST-TEXT stages II (n = 8) and I (n = 2) tumours. Seven tumours were associated with positive surgical margins, and 12 patients had microvascular involvement. During a median follow-up period of 30.5 months, 84 patients survived without relapse, 9 experienced tumour recurrence, and 4 died. The 2-year event-free survival (EFS) and overall survival (OS) rates were 89.4 ± 3.4%, and 95.2 ± 2.4%, respectively; they were significantly better among patients without metastasis (no metastasis vs metastasis: EFS, 93.5 ± 3.7% vs 46.7 ± 19.0%, adjusted p = 0.002. OS, 97.6 ± 2.4% vs 61.0 ± 18.1%, adjusted p = 0.005), and similar among patients treated with different preoperative strategies (chemotherapy only vs TACE only vs Both: EFS, 94.7 ± 5.1% vs 91.7 ± 5.6% vs 85.6 ± 6.7%, p = 0.542. OS, 94.1 ± 5.7% vs 95.7 ± 4.3% vs 96.7 ± 3.3%, p = 0.845). CONCLUSION: The OS for patients with hepatoblastoma who underwent liver resection was satisfactory. Neoadjuvant chemotherapy and TACE seemed to have a similar effect on OS. However, the abandonment of treatment by patients with hepatoblastoma was common, and may have biased our results.

4.
Mol Ther ; 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32413280

RESUMO

Base editing technology efficiently generates nucleotide conversions without inducing excessive double-strand breaks (DSBs), which makes it a promising approach for genetic disease therapy. In this study, we generated a novel hereditary tyrosinemia type 1 (HT1) mouse model, which contains a start codon mutation in the fumarylacetoacetate hydrolase (Fah) gene by using an adenine base editor (ABE7.10). To investigate the feasibility of base editing for recombinant adeno-associated virus (rAAV)-mediated gene therapy, an intein-split cytosine base editor (BE4max) was developed. BE4max efficiently induced C-to-T conversion and restored the start codon to ameliorate HT1 in mice, but an undesired bystander mutation abolished the effect of on-target editing. To solve this problem, an upstream sequence was targeted to generate a de novo in-frame start codon to initiate the translation of FAH. After treatment, almost all C-to-T conversions created a start codon and restored Fah expression, which efficiently ameliorated the disease without inducing off-target mutations. Our study demonstrated that base editing-mediated creation of de novo functional elements would be an applicable new strategy for genetic disease therapy.

5.
Int J Med Sci ; 17(8): 1062-1070, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32410836

RESUMO

Objective: To identify the interaction between the MYOC Y437H mutation and TGF-ß2 in a family with primary open-angle glaucoma (POAG). Methods: The MYOC Y437H mutation was identified in a family with POAG; the family was a fourth-generation family with 27 members, of which 6 members were affected. Analysis focused on the secreted myocilin protein and TGF-ß2 found in the aqueous humor. Samples were taken both from normal controls and MYOC mutant carriers and cross-talk between MYOC Y437H and TGF-ß2 were evaluated in the trabecular meshwork (TM) cells. Results: Aqueous humor secreted myocilin protein levels were reduced while TGF-ß2 levels were increased in patients with the MYOC (c.1309T>C) mutation. This inverse relationship indicated that elevated TGF-ß2 may be an important pathogenic mechanism in the progression of myocilin-related POAG. In TM cells expressing the MYOC Y437H mutant, exogenous TGF-ß2 also significantly increased myocilin expression as well as the endoplasmic reticulum (ER) stress markers GRP94 and CHOP. This increase in TGF-ß2 was also associated with increased cell death in cells carrying the MYOC Y437H mutation. Conclusion: These data collectively suggest that the mutual interaction between glaucomatous MYOC mutation and TGF-ß2 contributed to the cell death of TM cells. This relationship also provides a new, therapeutic targets for the treatment of glaucoma.

6.
Artigo em Inglês | MEDLINE | ID: mdl-32323236

RESUMO

In this research, several biochemical variations in plant of Lemna minor L. were investigated to reflect Ag+ toxicity. Lemna minor L. changed colorless AgNO3 to colloidal brown at doses equal to and greater than 1 mg L-1. Optical and fluorescence microscopy revealed the presence of bright spots in roots of tested plant related to Ag/Ag2O-NPs. Photosynthetic pigment contents of Lemna minor L. declined upon exposure to Ag+ with an evidently higher decrease in chlorophyll a than in chlorophyll b. Similarly, Ag+ treatment caused an evident reduction in the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). The reduction in antioxidase activity was significantly higher in POD than in SOD and CAT. Ag+ treatment resulted in a significant increment in the level of malondialdehyde (MDA) content as the judging criteria of cellular injury which showed sign of dose-related. The alterations occurred in RAPD profiles of treated samples following Ag+ toxicity containing loss of normal bands, appearance of new bands, and variation in band intensities compared with the normal plants. In addition, morphological character and biomass of Lemna minor L. subjected to increasing Ag+ concentrations were evaluated to reveal Ag+ toxicity. Our study demonstrated that Lemna minor L. have a high sensitivity to indicate fluctuation of water quality. It would be beneficial that modulating the genotype of Lemna minor L. to bear high proportion of contaminates.

7.
Water Res ; 177: 115789, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32304907

RESUMO

In the 21st century, sludge disposal and resource recycling are global issues. Titanium coagulation has received increasing attention due its strong coagulation capability and sludge recycling. Titanium coagulation is highly efficient for the treatment of algae-laden micro-polluted surface water; however, the safe disposal of titanium-coagulated algae-rich sludge remains a challenge. Here, we report on the recycling of titanium-coagulated algae-rich sludge for the production of functional TiO2 nanoflowers (TNFs) through a simple hydrothermal and calcination process. Anatase TNFs (particle size of 10-15 nm) with petal-like structures (mesoporous), relatively high specific surface areas, i.e. 299.4 m2g-1, and low band gaps, i.e. 2.67 eV (compared to P-25), were obtained. Additionally, oxygen vacancy (OV) was generated on the surface of the recycled TNFs based on electron paramagnetic resonance (EPR) results, which were verified by the first-principles calculations within density-functional theory. These TNFs display high photocatalytic performance for the degradation of diverse phenolic organic contaminants, such as bisphenol A, diphenyl phenol, p-tert-butyl phenol, and resorcinol, i.e. > 95%, under mild ultraviolet light irradiation and without any sacrificial reagents. Formation of OV on TNFs not only efficiently inhibited the recombination of photo-generated electrons and holes but also facilitated contaminant adsorption and photo-generated electron transfer on the surface of the recycled TNFs, thereby promoting the generation of holes and hydroxyl and superoxide radicals which were regarded as the reactive oxygen species for attacking contaminants in the reactions. This study proposes a new perspective on recycling chemical-coagulated sludge for producing functional nanomaterials as photocatalysts.


Assuntos
Esgotos , Titânio , Catálise , Oxigênio , Fenóis
8.
Immunol Lett ; 223: 1-9, 2020 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-32311408

RESUMO

Toll-like receptors (TLRs) belong to a family of pattern recognition receptors (PRRs). It is well known that TLRs play an essential role in activating innate and adaptive immune responses. TLRs are involved in mediating inflammatory responses and maintaining epithelial barrier homeostasis, and they are highly likely to activate various signalling pathways during cancer chemotherapy. For a long time, much research focused on the immune modulating function of TLRs in cancer genesis, pathology and therapeutic strategies. However, recent reports have suggested that except for the innate and adaptive immune responses that they initiate, TLRs can signal to induce regulated cell death (RCD), which also plays an important role in the antitumor process. TLR agonists also have been investigated as cancer therapeutic agents under clinical evaluation. In this review, we focused on the mechanism of RCD induced by TLR signals and the important role that they play in anticancer therapy combined with recent experimental and clinical trial data to discuss the possibility of TLRs as promising targets for cancer therapy. TLRs represent triggers of regulated cell death and targets for cancer therapy. The molecular mechanisms of TLR-induced RCD and relationship between TLR-signalling pathways and cancer remain to be investigated by further studies.

9.
Nat Prod Res ; : 1-7, 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32233654

RESUMO

A new nitrogen-containing iridoid glycoside, named (7 R,3'R)-lonijapospiroside A (1), together with thirteen known iridoid glycosides, were isolated from the flower buds of Lonicera macranthoides. The structures of these compounds were established on the basis of spectroscopic analyses. Among them, compounds 1-4 are four diastereoisomers, and their absolute configurations were accurately established by the NOE spectra as well as comparison of their experimental and calculated ECD spectra. The anti-inflammatory activities of all isolates were evaluated by measuring their inhibitory effects on NO, IL-6, and TNF-α production in LPS stimulated RAW 264.7 macrophages. Compound 14 exhibited anti-inflammatory activities by inhibiting IL-6 with an IC50 value of 54.70 µM, comparable to that of the positive control (hydrocortisone, IC50: 62.6 ± 1.7 µM).

10.
J Cell Mol Med ; 24(8): 4377-4388, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32175696

RESUMO

Extracellular vesicles (EVs) are nanosized, membranous vesicles released by almost all types of cells. Extracellular vesicles can be classified into distinct subtypes according to their sizes, origins and functions. Extracellular vesicles play important roles in intercellular communication through the transfer of a wide spectrum of bioactive molecules, contributing to the regulation of diverse physiological and pathological processes. Recently, it has been established that EVs mediate foetal-maternal communication across gestation. Abnormal changes in EVs have been reported to be critically involved in pregnancy-related diseases. Moreover, EVs have shown great potential to serve as biomarkers for the diagnosis of pregnancy-related diseases. In this review, we discussed about the roles of EVs in normal pregnancy and how changes in EVs led to complicated pregnancy with an emphasis on their values in predicting and monitoring of pregnancy-related diseases.

11.
Ecotoxicol Environ Saf ; 195: 110499, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32208213

RESUMO

The objective of this research was to evaluate Ag+ toxicity in Trifolium pratense L. seedlings subjected to increasing doses of Ag+ by determining photosynthetic pigment and malondialdehyde (MDA) contents, microstructure and hereditary substance alterations, changes in activities of antioxidase-superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) as well as the content of total Ag absorbed in vivo with evaluation of root growth. Doses of approximately 80 mg L-1 Ag+ severely affected photosynthetic efficiency in Trifolium pratense L. seedlings promoted by damages in photosynthetic apparatus evidenced by downward trend in photosynthetic pigment contents and obvious chlorosis. Alterations in enzymatic activity, lipid peroxidation, genic material damage and the presence of Ag+in vivo had impacted on photosynthetic machinery as well. A hormesis effect was observed at 60 mg L-1 Ag+ for the photosynthetic pigments and antioxidase for Trifolium pratense L. seedlings. Tissue changes (i.e., roots, stems and leaves) observed in fluorescence microscope with obvious chlorosis, roots blackening and formation of agglomerated black particles, were related to the lesion promoted by excessive ROS in vivo. Asynchronous change of antioxidase activity corresponded to the alteration in the MDA content, indicating the synchronization in the elimination of ROS. The changes occurred in RAPD profiles of treated samples following Ag+ toxicity containing loss of normal bands, appearance of new bands and variation in band intensity compared to the normal plants with a dose-dependent effect. On average, the roots of Trifolium pratense L. immobilized 92.20% of the total Ag absorbed as a metal exclusion response. Root growth was significantly sensitive to Ag+ stress with obvious hormesis, which corresponded to the changes in Ag uptake, demonstrating the functional alterations in plants. To sum up, we suggest that modulating the genotype of Trifolium pratense L. seedlings to bear higher proportion of pollutants is conducive to contamination site treatment.

12.
Chemistry ; 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32196779

RESUMO

In spite of the valuable advancements in fabricating transition-metal selenides (TMSs)-based hybrid structures, only single-metal selenides has been obtained via the present most methods. Herein, a facile room temperature self-polymerization and subsequent selenization strategy for the the synthesis of bimetallic Mo x W 1-x Se 2  nanosheets with expanded interlayers decorated N-doped carbon matrix assembled flower-like hierarchical microspheres (Mo x W 1-x Se 2 /NC), is first proposed. Depending on the excellent coordination ability of dopamine with metal ions, self-formed flowerlike single precursors are harvested. The unique hybrid architecture benefits the penetration of the electrolyte, accelerates Na +  insertion/extraction kinetics, enhance electron transfer ability, and alleviate the volume expansion and aggregation during cycling processes. Therefore, the bimetallic Mo x W 1-x Se 2 /NC electrode delivers high reversible capacities of 264 mAh g -1  at 1 A g - 1  for 700 cycles, 204.4 mAh g -1  at 4 A g -1  for 1400 cycles, and 153.3 mAh g -1  at 8 A g -1  for 2000 cycles, as well as an excellent rate capability up to 10 A g -1  with a capacity of 188.9 mAh g - 1 . Our study offers an effective strategy to boost sodium storage performance through the elaborate structural engineering.

13.
Sensors (Basel) ; 20(5)2020 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-32121408

RESUMO

Quick and effective detection of biothiols in biological fluids has gained increasing attention due to its vital biological functions. In this paper, a novel reversible fluorescence chemosensor (L-Cu2+) based on a benzocoumarin-Cu2+ ensemble has been developed for the detection of biothiols (Cys, Hcy and GSH) in human urine. The chemosensing ensemble (L-Cu2+) contains a 2:1 stoichiometry structure between fluorescent ligand L and paramagnetic Cu2+. L was found to exclusively bond with Cu2+ ions accompanied with a dramatic fluorescence quenching maximum at 443 nm and an increase of an absorbance band centered at 378 nm. Then, the in situ generated fluorescence sluggish ensemble, L-Cu2+, was successfully used as a chemosensor for the detection of biothiols with a fluorescence "OFF-ON" response modality. Upon the addition of biothiols, the decomplexation of L-Cu2+ led to the liberation of the fluorescent ligand, L, resulting in the recovery of fluorescence and absorbance spectra. Studies revealed that L-Cu2+ possesses simple synthesis, excellent stability, high sensitivity, reliability at a broad pH range and desired renewability (at least 5 times). The practical application of L-Cu2+ was then demonstrated by the detection of biothiols in human urine sample.

14.
Bioresour Technol ; 305: 123073, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32145698

RESUMO

The environmental risks of the sulfonamide antibiotics have attracted much attention recently. In this study, the inhibition effects of sulfadiazine (SDZ) on denitrification electron transfer system (ETS) and ameliorative mechanisms of phosphomolybdic acid (PMo12) were first explored. When denitrification was under 2 mg/L SDZ stress, experiments indicated that PMo12 enhanced NO3--N reduction efficiency and rate from 68.30% to 100.00% and 124.22 to 184.59 N/g VSS/h, respectively. Electron transfer rate and consumption efficiency in denitrification ETS were enhanced to ameliorate SDZ inhibition, which was due to the more secreted riboflavin and cytochrome c and the increased denitrifying enzymes activity with PMo12 mediation. In addition, the microbial growth inhibition and cell membrane damage were ameliorated due to the more EPS surrounding microbe with PMo12 mediation. Higher diversity of denitrifying microbe with PMo12 mediation also promoted denitrification under SDZ stress. This work provided promising strategy to ameliorate antibiotics inhibition in the wastewater bio-treatment.

15.
J Phys Chem Lett ; : 2142-2149, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32108473

RESUMO

Although Mn2+ doping in semiconductor nanocrystals (NCs) has been studied for nearly three decades, the near 100% photoluminescence (PL) quantum yield (QY) of Mn2+ emission has never been realized so far. Herein, greatly improved PL QYs of Mn2+ emissions are reported in Mn2+-doped CsPbCl3 NCs with various Mn2+ doping concentrations after CdCl2 post-treatment at room temperature. Specifically, the near-unity QY and near single-exponential decay of red Mn2+ emission peaking at 627 nm in doped CsPbCl3 NCs are obtained for the first time. The temperature dependence of steady-state and time-resolved PL spectra reveals that the CdCl2 post-treatment significantly reduces the nonradiative defect states and enhances the energy transfer from host to Mn2+ ions. Moreover, the Mn2+:CsPbCl3 NCs after CdCl2 post-treatment exhibit robust stability and high PL QYs after multipurification. The results will provide an effective route to obtain doped perovskite NCs with high performance for white lighting emitting diodes.

16.
Artigo em Inglês | MEDLINE | ID: mdl-32071197

RESUMO

OBJECTIVE: Vitamin D deficiency has recently evolved as a major public health issue worldwide. But the relationship between vitamin D and cardiovascular health in children remains unclear. Accordingly, we aimed to examine the associations between 25-hydroxyvitamin D (25(OH)D) concentrations and cardiometabolic risk factors, and to assess the possible effect modification of obesity on the associations in a Chinese pediatric population. RESEARCH DESIGN AND METHODS: A cross-sectional sample of 6091 children aged 6-18 years was obtained using a cluster sampling method. The 25(OH)D concentrations, and metabolic risk factors, including waist to height ratio, blood pressure, blood lipids, fasting blood glucose (FBG), and insulin were measured. Adjusted ORs and multiplicative or additive interaction were calculated to assess the associations and effect modification, respectively. RESULTS: Triglycerides, FBG, insulin, and homeostasis model assessment of insulin resistance were inversely associated with 25(OH)D concentrations (p<0.05) in both sexes. The OR of hyperglycemia among individuals with insufficient vitamin D was higher than those with adequate vitamin D after adjusting for covariates (OR: 1.47; 95% CI 1.26 to 1.70). Moreover, girls with insufficient vitamin D had significantly higher odds for hypertension and high total cholesterol than those with adequate vitamin D, which was not observed in boys. Thirty-two percent (95% CI 14% to 51%) of the increased odds of hyperglycemia can be explained by the interaction between insufficient vitamin D and obesity. CONCLUSIONS: Vitamin D insufficiency is associated with increased odds of various cardiometabolic risk factors in Chinese children and has a synergistic effect on hyperglycemia with obesity.

17.
Nanoscale ; 12(14): 7586-7594, 2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32057066

RESUMO

Hybrid capacitive deionization (HCDI) has emerged as a promising desalination technique due to its ultra-high salt removal capacity in high brine water. However, the mechanism behind HCDI is seldom discussed anywhere. Herein, we perform a comprehensive investigation to have some insight into the HCDI behavior of NaxCoO2 by varying x as 0.2, 0.5, 0.7, 1.0 and 1.6. Regardless of x, NaxCoO2 are classified as a representative P63/mmc space group with a P2 layered structure. With the increase of the sodium content, the (002) crystal plane of NaxCoO2 shifts significantly toward a high angle as the distance between CoO2 layers decreases. This results from the variation of the Na-O bonding length as well as the bonding energy according to the first-principles simulation. Moreover, it is observed that the Na-O bond broke once the input energy is higher than the Na-O bonding energy, leading to the electrochemical pre-activation of NaxCoO2. As a result, Na0.7CoO2 exhibits the best HCDI performance, i.e. a salt removal capacity of 63.0 mg g-1 and a charge efficiency of 97% in NaCl solutions with an initial conductivity of 2000 µS cm-1. Besides, the intercalation of sodium ions into NaxCoO2 has been confirmed by differentiating the respective contributions of pseudo-capacitance together with crystal phase transformation. Our results show that the desalination behavior of NaxCoO2 can be mediated by controlling the sodium content and electrochemical pre-activation.

18.
J Colloid Interface Sci ; 567: 54-64, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32036114

RESUMO

This study proposed a facile method to prepare echinus-like porous carbon spheres (PCS) with different heteroatom doping for lithium ions battery (LIBs). A metal-organophosphine framework (MOPF) was synthesized by employing riboflavin sodium phosphate as an organic ligand to conjugate with metal ions and then carbonized at mild temperature, leading to the formation of heteroatom doped PCS (H-PCS). As a result, (N, P) co-, (N, P, Ni) tri-, (N, P, Co) tri- and (N, Ni, Co, P) tetra-doped PCS were obtained to examine the insight into lithium-ion storage behavior of H-PCS. It was found that the specific surface area, pore texture and structural defects of H-PCS were dependent on doping of heteroatoms as well as the charge transfer resistance and Li-ion diffusion coefficient. Significantly, the redox reaction potential during the charge/discharge could be mediated upon the doping. Thus, when evaluated as anode for LIBs, the (N, Ni, Co, P) tetra-doped PCS exhibited highly reversible capacity of 680 mAh g-1 at 0.1 A g-1, excellent rate capability (115.9 mAh g-1 at 1.0 A g-1) and superior cycling performance (399.6 mAh g-1 at 0.1 A g-1). Moreover, the cyclic voltammogram measurements demonstrated that the doping of metal atoms was favorable for improving the capacitive contribution of surface limited diffusion. Thus, this work highlighted the importance of HCP with defined doping which could be considered as one of the prominent candidates for high-performance LIBs' anode.

19.
Nanoscale ; 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32101234

RESUMO

Engineering multicomponent electroactive materials is an effective strategy to improve electrochemical performance by adjusting the atomic and electronic structure. In this work, we directly synthesize oriented bimetallic CoNi-MOF nanosheets on CFP (carbon fiber paper). The CoNi-MOF/CFP shows high specific capacitance, outstanding rate capability and long-term cycling stability compared to a monometallic Ni-MOF or Co-MOF. By adjusting the Co/Ni molar ratio, CoNi23/CFP (Co : Ni = 2 : 3) displays the highest specific capacitance (2033 F g-1 at 1 A g-1). The introduction of Co into the Ni-MOF matrix shortens Co/Ni-centered bond distances, resulting in improved bond strength, facilitating the charge transfer and increasing the electrical conductivity of the CoNi-MOF, which were proved by X-ray absorption fine structure (XAFS) spectroscopy, high angle annular dark field (HAADF) imaging, and electrochemical impedance spectroscopy (EIS). Our study demonstrates the origin of performance improvements and, therefore, may provide a feasible scheme to unlock high-performance MOF electrode materials.

20.
Small ; : e1907468, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32068961

RESUMO

Advanced functional materials enable lithium-ion batteries to reach high specific capacity. To achieve this goal, nickel foam (NF), as current collector, is chosen to in situ form aligned nanoarrays composed of CoP3 /carbon polyhedron (CP)/CoO. The CoO nanowire acts as bridge to link NF and CoP3 /CP which not only reinforces the adhesion between active material and NF but also enhances the capacity of whole electrode. Besides, CoP3 is evenly coupled with CP, which can effectively buffer the volume expansion of CoP3 during the charge/discharge process. Moreover, the novel architecture of CoP3 /CP/CoO/NF is beneficial to improve the electronic conductivity. As a result, the CoP3 /CP/CoO/NF anode delivers an ultrahigh specific capacity of 1715 mAh g-1 at 0.5 A g-1 which can remain at 1150 mAh g-1 after 80 cycles, demonstrating the good durability. Thus, this work develops a facile strategy to design self-supporting electrodes for an enhanced energy storage device.

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