Evaluation of Polymetallic Phosphide Cathodes for Sodium-Air Batteries by Distribution of Relaxation Time.

Sodium-oxygen batteries are emerging as a new energy storage system because of their high energy density and low cost. However, the cycling performance of the battery is not satisfying due to its insulating discharge product. Here, we synthesized metallic phosphides with gradient concentration (g-CoNiFe-P) and their uniform counterpart (CoNiFe-P) as cathode catalysts in a Na-O2 battery. Notably, the distribution of relaxation time (DRT) was utilized to identify the rate-determining step in a Na-O2 battery, evaluate the catalytic performance of the catalysts, and monitor the change of every single electrochemical process along the whole cycling process to study the degradation mechanism. The g-CoNiFe-P catalyst presented better initial capacity and cycling performances. The evolution of the kinetic processes resulting in battery degradation has been investigated by DRT analysis, which assists with characterizations. Our work demonstrates the application of DRT in battery diagnosis to evaluate the catalytic performance of catalysts and monitor the changes in different kinetic processes of new energy systems.

Determinants of the Surface Film during the Discharging Process in Lithium-Oxygen Batteries.

Lithium-oxygen batteries have one of the highest theoretical capacities and specific energies, but several challenges remain. One of them is premature death caused by a passivation layer with poor conductivities (both electronic and ionic) on the electrode surface during the discharge process. Once this thin layer forms on the surface of the catalyst and substrate, the overpotential significantly increases and causes early cell death. Therefore, understanding this thin layer is crucial to achieving high specific energy lithium-oxygen batteries. Herein, we quantitatively compared the ratio of lithium carbonate to lithium peroxide during the discharge process in a flow cell at different potentials. We found that the ratio rapidly increased at low potential and high flow rates. The surface route led to significant byproducts on the Au electrodes, and consequently, a 3 nm thick discharge product film passivates the electrode surface in a flow cell.

Thoracic empyema due to nontuberculous mycobacteria in an immunocompetent patient without pulmonary disease: a case report.

BACKGROUND: Pleural involvement by non-tuberculous mycobacteria (NTM), especially NTM empyema in the immunocompetent patient without pulmonary diseases is a rare disease. It is difficult to diagnose with only a few cases of immunodeficient patients in the literature. CASE PRESENTATION: We describe a 63-year-old male with empyema due to NTM and highlight the challenges of diagnosis. CONCLUSIONS: Non-tuberculous mycobacterial infection should be considered as a cause of pleuritis or empyema without pulmonary disease, however it is a real diagnostic dilemma.

One-step cladding metal oxide nanowires with a carbon-dots-embedded ZnO amorphous layer toward boosted photoelectrochemical water oxidation.

An effective method was proposed for constructing carbon dots (CDs)-sensitized multijunction composite photoelectrodes via one-step cladding a CDs-embedded ZnO amorphous overlayer on vertically aligned metal oxide nanowires. This strategy involved the double role of hexamethylenetetramine (HMTA) in the ethylene glycol (EG) solvent mixed with a controllable trace amount of water. In the water-deficient synthetic system, a limited portion of HMTA served as the pH buffer and hydroxyl source to force the hydrolytic process of zinc ions for the production of ZnO. The precipitated ZnO clusters were instantly capped by EG molecules through the activated alkoxidation reaction, and further crosslinked into an amorphous network surrounding the individual nanowires. Meanwhile, the excess HMTA was simultaneously depleted as the precursor for producing CDs in the EG solution through thermal condensation, which were packed in the gradually formed aggregates. We revealed that a CDs-embedded amorphous ZnO overlayer with an appropriate proportion of ingredient could be tailored through an optimal tradeoff between hydrolysis and condensation of HMTA. Benefiting from the synergy of the amorphous ZnO layer and the embedded CDs, the multijunction composite photoanodes exhibited significantly improved PEC performance and stability for water oxidation.

Highly selective CO2 electroreduction to CO by the synergy between Ni-N-C and encapsulated Ni nanoparticles.

Efficient catalysts are highly desirable for the selective electrochemical CO2 reduction reaction (CO2RR). Ni single-atom catalysts are known as promising CO2RR catalysts, while Ni NPs are expected to catalyze the competing HER. In this work, we have modified the Ni NPs by encapsulating them into porous Ni-N-C nanosheets (Ni@Ni-N-C), to boost the synergy between Ni NPs and dispersed Ni-N species towards CO2RR. The CO faradaic efficiency (FECO) reached 96.4% at -0.9 V and retained over 90% in a wide potential window. More importantly, FECO values of over 94% have been obtained from -50 to -170 mA cm-2 with a peak FECO of 99% in a flow cell. Our work demonstrates that the surface modification of Ni NPs can inhibit the unexpected HER and activate the surface sites, offering a practical design strategy for CO2RR catalysts.

Successful treatment of rapid progressive interstitial lung disease in a case of anti-Zo antibody positive anti-synthetase syndrome.

BACKGROUND: Anti-synthetase syndrome (ASS) is a chronic multisystemic autoimmune disease characterized by detectable anti-aminoacyl-transfer-RNA antibodies. Interstitial lung disease (ILD) in anti-synthetase syndrome patients is often severe and rapidly progressive. Anti-Zo (phenylalanyl) antibody is reported rarely in ASS. Therefore, the appropriate treatment of anti-Zo positive ASS is unclear. CASE PRESENTATION: Here we present a case of anti-Zo-positive ASS with rapid progressive ILD (RP-ILD) in a Chinese patient successfully treated with a combination of systemic corticosteroids and tacrolimus. CONCLUSION: We reviewed 13 anti-Zo-positive ASS patients (including our case) and summarized clinical features that have some differences with other ASS. Anti-Zo-positive ASS is a rare autoimmune disease with a high burden of ILD, is often severe and rapidly progressive. Corticosteroids with tacrolimus may improve patient outcomes in anti-Zo antibody positive ASS with RP-ILD.

Molecular sieving of semiconductive NTU-9 coatings on titanium dioxide nanowire arrays: Augmented yet selective photoelectrochemical response enabled by boosting charge separation and transfer in confined space.

Radial heterostructures with titanium dioxide (TiO2) nanowire as core and NTU-9 as shell are synthesized via a surfactant-free approach based on the favorable bonding of linkers with TiO2 nanowire. Relative to the traditional growth strategy of surface modification, the thin NTU-9 shell with ordered arrangement of two-dimensional networks is uniformly formed on the sidewalls of TiO2 nanowire through the orientational growth process. Using the core-shell nanowire arrays as photoanodes, wide-range light absorption and high charge carrier separation efficiency are achieved due to the conjugation of NTU-9, leading to enhanced water oxidation performance in photoelectrochemical (PEC) water splitting. Under appropriately low applied potentials, the photogenerated holes are preferable to accumulate at TiO2/NTU-9/electrolyte three-phase interface and thus the long-range ordered NTU-9 shell can also serve as a size-exclusion filter to improve selectivity toward molecules of different sizes. Consequently, the TiO2/NTU-9 core-shell nanowire array exhibits an augmented and selective PEC response for small size molecules (e.g.,H2O2) at a very low potential (-0.25 V vs Ag/AgCl), outperforming the pure TiO2 nanowire array and the counterpart with a grain-boundary-rich NTU-9 shell that is prepared by pretreatment of the TiO2 nanowires with PVP functionalization.

Heteroatom-doped carbon sheets as metal-free electrocatalysts for promoting the oxygen reduction reaction in Zn-air batteries.

Zn-air batteries are promising energy devices for future sustainable development. It is crucial to promote the cathodic reaction, oxygen reduction reaction (ORR), by applying active electrocatalysts. Herein, a metal-free ORR electrocatalyst has been fabricated by doping S and N atoms into carbon sheets (S-N-C), and it displays high ORR activity and outstanding performance in Zn-air batteries. The S-N-C electrocatalyst exhibits remarkable ORR activity with a half-wave potential of 0.89 V, which is far exceeding that of the commercial Pt/C benchmark and most reported carbon-based electrocatalysts. A full-cell Zn-air battery device with S-N-C as a cathode catalyst is demonstrated, which delivers high power density and good durability.

Enhanced activity towards oxygen electrocatalysis for rechargeable Zn-air batteries by alloying Fe and Co in N-doped carbon.

Large-scale application of rechargeable Zn-air batteries requires low-cost electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as alternatives to noble metals. Herein, FeCo nanoparticles embedded in N-doped carbon (FeCo/N-C) were prepared by a two-step pyrolysis route. FeCo/N-C exhibits excellent activities toward both the ORR (half-wave potential of 0.84 V) and OER (overpotential of 345 mV at 10 mA cm-2), which are comparable to those of commercial Pt/C and RuO2, and by far exceeding their counterparts Fe/N-C and Co/N-C. Furthermore, the FeCo/N-C catalyst was evaluated in a rechargeable Zn-air battery for the full-cell test. The FeCo/N-C based battery is more durable with a smaller round-trip overpotential after 800 cycles than the battery using an expensive Pt/C + RuO2 mixture catalyst.

Redox Mediator-Enhanced Performance and Generation of Singlet Oxygen in Li-CO2 Batteries.

Rechargeable Li-CO2 batteries as a novel system developed in recent years directly use CO2 as the reactant, which enables deeper penetration of energy storage and CO2 utilization. The Li-CO2 battery system, however, is at an early stage, and many challenges remained to be overcome urgently, especially the problem of high over-potential during the charging process. Here, we report a redox mediator, phenoxathiin, to assist the decomposition of Li2CO3 during the charging process, which effectively reduces the over-potential and improves the cycling performance of the battery. Furthermore, we detect the presence of singlet oxygen during the oxidation of Li2CO3 by phenoxathiin, which reveals more of the underlying science of the reaction mechanism of the Li-CO2 battery.

Diagnosing the SEI Layer in a Potassium Ion Battery Using Distribution of Relaxation Time.

Understanding the solid electrolyte interphase (SEI) formation process in novel battery systems is of primary importance. Alongside increasingly powerful in situ techniques, searching for readily accessible, noninvasive, and low-cost tools to probe battery chemistry is highly demanded. Here, we applied distribution of relaxation time analysis to interpret in situ electrochemical impedance spectroscopy results during cycling, which is able to distinguish various electrochemical processes based on their time constants. By building a direct link between the SEI layer and the cell performances, it allows us to track the formation and evolution process of the SEI layer, diagnose the failure of the cell, and unveil the reaction mechanisms. For instance, in a K-ion cell using a SnS2/N-doped reduced graphene oxide composite electrode, we found that the worsened mass transport in the electrolyte phase caused by the weak SEI layer is the main reason for cell deterioration. In the electrolyte with potassium bis(fluorosulfonyl)imide, the porous structure of the composite electrode was reinforced by rapid formation of a robust SEI layer at the SnS2/electrolyte interface, and thus, the cell delivers a high capacity and good cyclability. This method lowers the barrier of in situ EIS analysis and helps public researchers to explore high-performance electrode materials.

Optimal utilization of fluoroethylene carbonate in potassium ion batteries.

This work provides a novel strategy of optimal utilization of fluoroethylene carbonate to generate a uniform and compact solid electrolyte interface film, enhancing the cycle life of potassium ion batteries. With K foil being treated with fluoroethylene carbonate prior to use, enhanced cycling performance up to 1200 hours was achieved. Combining in situ electrochemical impedance spectroscopy with the distribution of relaxation time analysis and XPS analysis, the solubility of KF in the electrolyte is proposed as a crucial factor to determine the quality of a solid electrolyte interface. Our work contributes to understanding the role and manipulating the usage of the fluoroethylene carbonate additive in potassium ion batteries.

Fast operando spectroscopy tracking in situ generation of rich defects in silver nanocrystals for highly selective electrochemical CO2 reduction.

Electrochemical CO2 reduction (ECR) is highly attractive to curb global warming. The knowledge on the evolution of catalysts and identification of active sites during the reaction is important, but still limited. Here, we report an efficient catalyst (Ag-D) with suitable defect concentration operando formed during ECR within several minutes. Utilizing the powerful fast operando X-ray absorption spectroscopy, the evolving electronic and crystal structures are unraveled under ECR condition. The catalyst exhibits a ~100% faradaic efficiency and negligible performance degradation over a 120-hour test at a moderate overpotential of 0.7 V in an H-cell reactor and a current density of ~180 mA cm-2 at -1.0 V vs. reversible hydrogen electrode in a flow-cell reactor. Density functional theory calculations indicate that the adsorption of intermediate COOH could be enhanced and the free energy of the reaction pathways could be optimized by an appropriate defect concentration, rationalizing the experimental observation.

A defective g-C3N4/RGO/TiO2 composite from hydrogen treatment for enhanced visible-light photocatalytic H2 production.

Photocatalytic H2 evolution is a clean technology to alleviate energy and environmental issues. The limited light absorption and the separation efficiency of photogenerated charge carriers are the major hurdles constraining the application of numerous photocatalysts. Herein, we report a simple and effective strategy, a multistep heat-treatment method, to synthesise a defective g-C3N4/RGO/TiO2 composite to increase its rate of activity for H2 production. The defects, nitrogen and oxygen vacancies, are simultaneously introduced on the surface of the g-C3N4/RGO/TiO2 composite. The vacancy defects essentially endow g-C3N4/RGO/TiO2 with a boosted photocatalytic H2 evolution rate (4760 µmol h-1 g-1) under visible-light irradiation, which is higher than that of the most of g-C3N4/TiO2 composites. This is attributed to the improved visible-light absorption as well as the separation and transfer rate of photogenerated charge carriers arising from vacancy defects. This study may provide an avenue for preparing defective photocatalysts for efficient H2 evolution.

A ß-FeOOH/MXene sandwich for high-performance anodes in lithium-ion batteries.

FeOOH is one of the earth abundant and high-capacity anode materials for lithium-ion batteries (LIBs), but faces problems of inevitable structure collapse and thus poor capacity retention. Herein, we report a composite of ß-FeOOH/Ti3C2Tx MXene sandwich by an intercalation of ß-FeOOH nanorods within single-layer Ti3C2Tx MXene flakes. After 100 cycles, the ß-FeOOH/Ti3C2Tx composite retains a capacity of 937.5 mA h g-1 at 200 mA g-1, and 671.4 mA h g-1 at 1 A g-1. The composite as an anode in LIB delivers improved cyclability and better high-rate performance compared to pristine ß-FeOOH, which result from the excellent conductivity of single-layer MXene, facilitating mass transport by the sandwich structure. This work provides a strategy for the design of electrodes, particularly in Na-ion and K-ion batteries, which involve active materials that experience volume change and structural damage during cycling.

Interlaced Pd-Ag nanowires rich in grain boundary defects for boosting oxygen reduction electrocatalysis.

Given the high cost and poisoning issues of Pt, developing Pd-based catalysts as substitutes is highly essential. Although substantial progress has been made, the synthesis of Pd-based electrocatalysts with both high activity and stability in the oxygen reduction reaction (ORR) remains a challenge. In this work, we prepared Pd-Ag nanowires with up to micro-sized length and a diameter of ∼17 nm via a facile modified polyol method. The obtained Pd-Ag nanowires (NWs) exhibit interlaced features and are rich in grain boundary defects. Due to the continuous grain boundaries in the one-dimensional (1D) structure and the optimized composition, the synthesized Pd1Ag1 NWs show half-wave potential of 0.897 V and mass activity of 0.103 A mg-1 in alkaline media toward ORR, higher than those of both state-of-the-art Pt/C and other Pd-Ag counterparts. Significantly, after stability tests over 5000 cycles, Pd1Ag1 NWs shows a 2 mV positive shift, much better than that of Pt/C, exhibiting striking stability for ORR. This work may provide an avenue to construct advanced catalysts by surface defect engineering.

Improving photoelectrochemical response of ZnO nanowire arrays by coating with p-type ZnO-resembling metal-organic framework.

Coupling semiconducting metal-organic frameworks (MOFs) with metal oxide (MO) semiconductor nanowires is an efficient solution to tune the photoelectric properties of both the parties. In this report, we demonstrate a facile surfactant-free growth strategy for modification of zinc oxide (ZnO) single-crystal nanowire arrays (NWAs) with the MOF zinc glycolate (noted as Zn-GA) that contains an embedded continuous 3D Zn-O network. Due to the structural resemblance of the Zn-O network between Zn-GA and ZnO, the prepared ZnO@Zn-GA nanowires present a tight contact at the core-shell interface in a partially epitaxial manner, and the loading amount of Zn-GA can be well controlled in the synthetic process. The inherent p-type Zn-GA in combination with the widely available n-type ZnO assures the construction of tandem n-p heterojunctions at the core-shell interface, which is confirmed by Mott-Schottky analysis. By implementation of the ZnO@Zn-GA NWAs as photoanodes for photoelectrochemical oxidation of water and oxalic acid, improved photocurrent responses are obtained relative to the primary ZnO NWAs. The most significant photoresponse is observed in the ZnO nanowires shelled by a compact Zn-GA particulate thin film with the largest junction region. These results are elucidated by the enhanced spatial separation efficiency of photogenerated charge carriers, which is favored by the built-in electric field at the interface of the n-p heterojunctions.

Disproportionation of Sodium Superoxide in Metal-Air Batteries.

The sodium oxygen battery is a promising metal-air battery; however, the discharge process is not well understood and the major discharge product is still under debate. The discharge products determined the theoretical specific energy and electrochemical performance of the battery. Now it is demonstrated that NaO2 spontaneously disproportionates to Na2 O2 , no matter whether it is dissolved in solution or stays on the surface. The behaviors of NaO2 in solution and on the surface are different. Solvents play a crucial effect on the disproportionation of dissolved NaO2 species, which is fast in low donor number (DN) solvents such as acetonitrile but sluggish in high DN solvents such as DMSO. In situ XRD results exhibited the different product growing processes in various solvents. Surface NaO2 would slowly disproportionate to Na2 O2 anyway, but this process is relatively slow compared to the time span of discharge process and it does not affect the major product on discharge.

The Transmission and Evolution of HIV-1 Quasispecies within One Couple: a Follow-up Study based on Next-Generation Sequencing.

Next-generation sequencing (NGS) has been successfully used to trace HIV-1 infection. In this study, we investigated the transmission and evolution of HIV-1 quasispecies in a couple infected through heterosexual behavior. A heterosexual couple in which both partners were infected with HIV-1 was followed up for 54 months. Blood samples including whole-blood and plasma samples, were collected at various time points. After HIV-1 subtyping, NGS (Miseq platform) was used to sequence the env region of the HIV-1 quasispecies. Genetic distances were calculated, and phylogenetic trees were generated. We found both partners were infected with HIV-1 subtype circulating recombinant form (CRF), CRF65_cpx. The quasispecies distribution was relatively tightly clustered in the phylogenetic tree during early infection. Over time, the distribution of HIV-1 quasispecies gradually became more dispersed at 12th months, with a progressive increase in gene diversity. By 37th months, the sequences obtained for both partners formed different clusters in the phylogenetic tree. These results suggest that the HIV-1 contact tracing results generated by the Miseq platform may be more reliable than other conventional sequencing methods, which can provide important information about the transmission and evolution of HIV-1. Our findings may help to better target preventative interventions for promoting public health.