Transition metal-doped Ni-rich layered cathode materials for durable Li-ion batteries

Doping is a well-known strategy to enhance the electrochemical energy storage performance of layered cathode materials. Many studies on various dopants have been reported; however, a general relationship between the dopants and their effect on the stability of the positive electrode upon prolonged cell cycling has yet to be established. Here, we explore the impact of the oxidation states of various dopants (i.e., Mg2+, Al3+, Ti4+, Ta5+, and Mo6+) on the electrochemical, morphological, and structural properties of a Ni-rich cathode material (i.e., Li[Ni0.91Co0.09]O2). Galvanostatic cycling measurements in pouch-type Li-ion full cells show that cathodes featuring dopants with high oxidation states significantly outperform their undoped counterparts and the dopants with low oxidation states. In particular, Li-ion pouch cells with Ta5+- and Mo6+-doped Li[Ni0.91Co0.09]O2 cathodes retain about 81.5% of their initial specific capacity after 3000 cycles at 200 mA g−1. Furthermore, physicochemical measurements and analyses suggest substantial differences in the grain geometries and crystal lattice structures of the various cathode materials, which contribute to their widely different battery performances and correlate with the oxidation states of their dopants.

Assessment and investigation of measurement uncertainty of standard samples of substances and materials in physicochemical measurements based on standard test methods

The article assessed and investigated the uncertainty of measurements of standard samples of substances and materials in physicochemical measurements based on standard test methods. A general approach to estimating the sources of uncertainty of standard samples is described. Uncertainties from heterogeneity of standard sample material. uncertainty from instability of standard sample characteristic values. uncertainty from method of setting reference value are investigated. Purity of substances is the main parameter that needs to be paid attention to when studying their properties. This is all the more important when it comes to using a pure substance as some approximation to the prototype reference value. since only this unit of seven main units in the International System of Units (SI system) does not have its own standard. In this sense. an important scientific task is the comprehensive study of pure substances for their practical use as benchmarks for comparison in metrological works and analytical research. The main and very important part of the measurement traceability system are materials with certified (certified) content of components and defined uncertainties of these values (standard samples of the approved type). which require pure substances certified at a higher - reference level. i.e. comparison standards.

Assessment of Macrophyte Biological Index for Rivers, and evaluation of physicochemical parameters in the Sakarya River Basin of Turkey

In this study, the Macrophyte Biological Index for Rivers (IBMR) method and physicochemical measurements were used to assess the trophic status of the Sakarya River Basin in Turkey. The most abundant macrophytes were Phragmites australis, Thypa latifolia, Juncus sp., and Paspalum distichum. The IBMR values varied between 6.00 and 13.00 in spring, and between 6.714 and 14.40 in the fall season. The sampling stations, which are under the influence of agricultural runoffs, domestic effluents, and industrial discharges, had hypoxia accompanied by eutrophic and/or hypertrophic conditions at least in one season. The individual trophy levels of the sampling sites in the basin have been assessed as mesotrophic to eutrophic. However, considering the average IBMR value of all stations, the general trophy level of the basin was close to eutrophic. The results indicate that the physicochemical parameters are affected by various effluents discharged to the basin as observed during field studies, and the obtained data would be useful to apply conservation measures.

Freshwater monitoring by nanopore sequencing

While traditional microbiological freshwater tests focus on the detection of specific bacterial indicator species, including pathogens, direct tracing of all aquatic DNA through metagenomics poses a profound alternative. Yet, in situ metagenomic water surveys face substantial challenges in cost and logistics. Here, we present a simple, fast, cost-effective and remotely accessible freshwater diagnostics workflow centred around the portable nanopore sequencing technology. Using defined compositions and spatiotemporal microbiota from surface water of an example river in Cambridge (UK), we provide optimised experimental and bioinformatics guidelines, including a benchmark with twelve taxonomic classification tools for nanopore sequences. We find that nanopore metagenomics can depict the hydrological core microbiome and fine temporal gradients in line with complementary physicochemical measurements. In a public health context, these data feature relevant sewage signals and pathogen maps at species level resolution. We anticipate that this framework will gather momentum for new environmental monitoring initiatives using portable devices.

The question of metrological traceability of COOMET reference materials. Pt. 1. International practice on traceability establishment of reference materials’ certified values

The multiplication of national units transfer instruments with established values of metrological traceability in international organisations is one of the most actual development directions for a large number of countries, inasmuch as this direction contributes to the solution of a global problem of measurement results comparability which were received for various objects in different times in different parts of the world as well as indicates the high quality of measuring capabilities of an organisation or a country. The paper contains issues of establishment of metrological traceability of results of physicochemical measurements. The international practice on traceability establishment of reference materials’ certified values is described in the work. The authors also provided a brief overview of internationally accepted fundamental concepts of reference materials metrological traceability demonstration.

Freshwater monitoring by nanopore sequencing

ABSTRACTWhile traditional microbiological freshwater tests focus on the detection of specific bacterial indicator species, including pathogens, direct tracing of all aquatic DNA through metagenomics poses a profound alternative. Yet, in situ metagenomic water surveys face substantial challenges in cost and logistics. Here we present a simple, fast, cost-effective and remotely accessible freshwater diagnostics workflow centred around the portable nanopore sequencing technology. Using defined compositions and spatiotemporal microbiota from surface water of an example river in Cambridge (UK), we provide optimised experimental and bioinformatics guidelines, including a benchmark with twelve taxonomic classification tools for nanopore sequences. We find that nanopore metagenomics can depict the hydrological core microbiome and fine temporal gradients in line with complementary physicochemical measurements. In a public health context, these data feature relevant sewage signals and pathogen maps at species level resolution. We anticipate that this framework will gather momentum for new environmental monitoring initiatives using portable devices.