Pyromellitic dianhydride-based polyimide anodes for sodium-ion batteries

Organic redox-reactive polymers have garnered great attention as a promising alternative for conventional transition-metal compounds in sodium-ion batteries (NIBs) due to their low cost, structural flexibility and diverse structure. Among this class of materials, polyimides with high mechanical strength, excellent thermal stability and high density of electroactive functional groups have shown promise as low-cost electrode materials for NIBs. Herein, a simple hydrothermal method was used to synthesise pyromellitic dianhydride-based polyimides [C16H6O4N2](n). The polyimides consisting of interconnected nanosheets with a microflower-like morphology were tested as an NIB anode. The polyimide electrode exhibited a stable discharge capacity of 125 mAh g(-1) at a current density of 25 mA g(-1) at the 100th cycle. At a high current density of 2 A g(-1), the electrode delivered a discharge capacity of 43 mAh g(-1). The capacity contribution of this polyimide electrode mainly occurred below 1.5 V making it suitable as an organic NIB anode. The mechanism of sodiation and desodiation during discharge and charge was studied using Fourier transform infrared spectroscopy, in which this polyimide experienced two-step enolisation reaction with reversible insertion of two sodium ions during the redox electrochemical reaction. (c) 2018 Elsevier Ltd. All rights reserved

A facilitated synthesis of hierarchically porous Cu-Ce-Zr catalyst using bacterial cellulose for VOCs oxidation

Highly active CuO-CeO2-ZrO2 catalysts were prepared by sol-gel method, using environmentally friendly bacterial cellulose (BC) as structure directing regent. The catalyst designed with commercial BC (Com-BC) exhibited catalytic performances in toluene (T100 =220 oC) and ethyl acetate oxidation (T100 =170 oC) superior to the catalysts prepared by traditional methods. Furthermore, excellent stability was obtained and no deactivation was observed during the 100 h on stream in toluene and ethyl acetate oxidation at T100. The excellent activity and stability of Com-BC can be explained by the hierarchically porous structure, abundant oxygen vacancies, and good reducibility

Lysyl-tRNA synthetase, a target for urgently needed M. tuberculosis drugs

Tuberculosis is a major global cause of both mortality and financial burden mainly in low and middle-income countries. Given the significant and ongoing rise of drug-resistant strains of Mycobacterium tuberculosis within the clinical setting, there is an urgent need for the development of new, safe and effective treatments. Here the development of a drug-like series based on a fused dihydropyrrolidino-pyrimidine scaffold is described. The series has been developed against M. tuberculosis lysyl-tRNA synthetase (LysRS) and cellular studies support this mechanism of action. DDD02049209, the lead compound, is efficacious in mouse models of acute and chronic tuberculosis and has suitable physicochemical, pharmacokinetic properties and an in vitro safety profile that supports further development. Importantly, preliminary analysis using clinical resistant strains shows no pre-existing clinical resistance towards this scaffold

Crowdsourcing hypothesis tests: Making transparent how design choices shape research results

To what extent are research results influenced by subjective decisions that scientists make as they design studies? Fifteen research teams independently designed studies to answer fiveoriginal research questions related to moral judgments, negotiations, and implicit cognition. Participants from two separate large samples (total N > 15,000) were then randomly assigned to complete one version of each study. Effect sizes varied dramatically across different sets of materials designed to test the same hypothesis: materials from different teams renderedstatistically significant effects in opposite directions for four out of five hypotheses, with the narrowest range in estimates being d = -0.37 to +0.26. Meta-analysis and a Bayesian perspective on the results revealed overall support for two hypotheses, and a lack of support for three hypotheses. Overall, practically none of the variability in effect sizes was attributable to the skill of the research team in designing materials, while considerable variability was attributable to the hypothesis being tested. In a forecasting survey, predictions of other scientists were significantly correlated with study results, both across and within hypotheses. Crowdsourced testing of research hypotheses helps reveal the true consistency of empirical support for a scientific claim.</div

Polymer electrode materials for sodium-ion batteries

Sodium-ion batteries are promising alternative electrochemical energy storage devices due to the abundance of sodium resources. One of the challenges currently hindering the development of the sodium-ion battery technology is the lack of electrode materials suitable for reversibly storing/releasing sodium ions for a sufficiently long lifetime. Redox-active polymers provide opportunities for developing advanced electrode materials for sodium-ion batteries because of their structural diversity and flexibility, surface functionalities and tenability, and low cost. This review provides a short yet concise summary of recent developments in polymer electrode materials for sodium-ion batteries. Challenges facing polymer electrode materials for sodium-ion batteries are identified and analyzed. Strategies for improving polymer electrochemical performance are discussed. Future research perspectives in this important field are projected

A hybrid sodium-ion capacitor with polyimide as anode and polyimide-derived carbon as cathode

In this work, pyromellitic dianhydride-based polyimide was hydrothermally synthesised and further thermally treated to prepare porous carbon materials. The porous structure of the polyimide-derived carbon can be controlled by varying the reactant concentrations during the hydrothermal reaction and KOH activation to achieve a highly accessible specific surface area of 1302 m g. A hybrid sodium-ion capacitor fabricated with the polyimide as anode and the polyimide-derived carbon as cathode can be operated at a voltage of 4.2 V, delivering an energy density of 66 Wh kg at power density of 196 W kg, and an energy density of 13.3 Wh kg at power density of 1200 W kg

Three-dimensional nitrogen-doped holey graphene and transition metal oxide composites for sodium-ion batteries

Transition metal oxides (TMOs) such as nickel cobaltite (NCO) and magnetite (FeO) with rich electroactive sites are promising anode materials for sodium-ion batteries (NIBs). However, these materials suffer from large volume change during charge/discharge, poor electron conductivity and severe aggregation of TMO nanoparticles. Here, we report an approach to improve the electrochemical performance of NCO and FeO by stabilizing them on three-dimensional (3D) nitrogen-doped holey graphene (N-HG), forming NCO@N-HG and FeO@N-HG composite materials, respectively. The thin graphene sheets in both composites facilitate the electron transport and buffer the volume changes, while the interconnected 3D macroporous network with a pore size in the range of several micrometers, combined with the nanopores in the N-HG provide pathways for rapid ion transport. As expected, both composites showed high specific capacities, rate capability and cycling performance in NIBs. The good electrochemical performance of the electrode material indicates that using N-HG to support NCO and FeO particles is an effective approach towards developing high-performance anode materials for NIBs

Newly diagnosed diabetes and outcomes after acute myocardial infarction in young adults.

To examine prevalence and characteristics of newly diagnosed diabetes (NDD) in younger adults hospitalised with acute myocardial infarction (AMI) and investigate whether NDD is associated with health status and clinical outcomes over 12-month post-AMI. In individuals (18-55 years) admitted with AMI, without established diabetes, we defined NDD as (1) baseline or 1-month HbA1c≥6.5%; (2) discharge diabetes diagnosis or (3) diabetes medication initiation within 1 month. We compared baseline characteristics of NDD, established diabetes and no diabetes, and their associations with baseline, 1-month and 12-month health status (angina-specific and non-disease specific), mortality and in-hospital complications. Among 3501 patients in Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients study, 14.5% met NDD criteria. Among 508 patients with NDD, 35 (6.9%) received discharge diagnosis, 91 (17.9%) received discharge diabetes education and 14 (2.8%) initiated pharmacological treatment within 1 month. NDD was more common in non-White (OR 1.58, 95% CI 1.23 to 2.03), obese (OR 1.72, 95% CI 1.39 to 2.12), financially stressed patients (OR 1.27, 95% CI 1.02 to 1.58). Compared with established diabetes, NDD was independently associated with better disease-specific health status and quality of life (p≤0.04). No significant differences were found in unadjusted in-hospital mortality and complications between NDD and established or no diabetes. NDD was common among adults≤55 years admitted with AMI and was more frequent in non-White, obese, financially stressed individuals. Under 20% of patients with NDD received discharge diagnosis or initiated discharge diabetes education or pharmacological treatment within 1 month post-AMI. NDD was not associated with increased risk of worse short-term health status compared with risk noted for established diabetes. NCT00597922.The VIRGO study (NCT00597922) was funded by the National Heart, Lung, and Blood Institute (R01 HL081153). IMJOVEN (the Spanish counterpart of the VIRGO study) was supported in Spain by grant PI 081614 from the Fondo de Investigaciones Sanitarias del Instituto Carlos III, Ministry of Science and Technology, and additional funds from the Centro Nacional de Investigaciones CardiovascularesS

Encapsulation of NiCo2O4 in nitrogen-doped reduced graphene oxide for sodium ion capacitors

Sodium-ion capacitors are considered as promising energy storage devices for medium/large-scale energy storage applications including electric vehicles (EVs) and smart grid technologies because of their high energy/power densities and long cycle life. However, finding a high-performance anode material has been one of the great challenges in developing this sustainable electrochemical energy storage technology. Nickel cobaltite (NiCo2O4) with rich electroactive sites is a promising anode material for electrochemical capacitors and hybrid ion capacitors. However, this material is unstable due to large volume changes during repeated cycles. Here, we report an approach to improve the stability of NiCo2O4 against cycling by using a nitrogen-doped graphene framework to encapsulate NiCo2O4 particles. The graphene framework guarantees good electronic conductivity and serves as a buffer to alleviate the volume changes of NiCo2O4. In a sodium half cell, the composite electrode displayed a reversible capacity of about 450 mA h g-1 with a current rate of 0.1 A g-1 at the 100th cycle. A full-cell sodium ion capacitor configured with the composite as the anode and a commercial activated carbon as the cathode delivered an energy density of 48.8 W h kg-1 at a power density of 9750 W kg-1 with a stable cycle life. The good electrochemical performance of the electrode material indicates that using nitrogen-doped graphene sheets to stabilise NiCo2O4 particles is a feasible approach towards developing high-performance anode materials for sodium ion capacitors.</p