Volume 4, Issue 3 -

Development of highly efficient batteries with more rational understanding and precise control of the underlying microstructural features requires high resolution based characterization tools. Electron microscopy and spectroscopy offers information about the structure, morphology, chemistry and chemical composition of the battery materials on nano and atomic scale enabling us to establish the synthesis-structure-performance relationship and further direct the design of new battery materials with improved and high performance. The key factors for a successful electrochemical system are the structure, morphology, chemistry and chemical information of the component materials. The improvement and further development of energy storage systems is based on detailed knowledge and interpretation of morphology, microstructure and phase composition of the individual components like electrodes, current collector, and separator. Additionally, the long-term stability of batteries is affected by the interaction of several components not only at their common interface but also in the volume of the whole device and in combination with intrinsic emerging mechanical loads. Battery materials require advanced skills and techniques to improve material combinations and synthesis strategies. High quality images, in situ measurements and chemical analysis can contribute to this. The most important reason for the usage of electron microscopy instead of light microscopy is the diffraction limitation of resolution which is dependent of the wavelength. According to the Rayleigh criterion two points are regarded as just resolved when the principal diffraction maximum of one image coincides with the first minimum of the other. The diameter of the corresponding Airy disc is direct proportional to the wavelength. With the Planck constant h = 6.6 · 10 –34  Js, the electron mass m e = 9.1 · 10 –31  kg, e = 1.6 · 10 –19  C, and the speed of light c = 3.0 · 10 8  m/s the wavelength of electrons are given trough the de-Broglie wavelength: λde Broglie=hpe=hme⋅ve=h2⋅me⋅e⋅U≈1.22⋅10−9mUV,$${\lambda _{{\text{de Broglie}}}} = \frac{h}{{{p_e}}} = \frac{h}{{{m_e} \cdot {v_e}}} = \frac{h}{{\sqrt {2 \cdot {m_e} \cdot e \cdot U} }} \approx \frac{{1.22 \cdot {{10}^{ - 9}}{\text{ m}}}}{{\sqrt {\frac{U}{{\text{V}}}} }},$$ where ve${v_e}$ is the velocity of the electrons and U the acceleration voltage for the electrons. For higher acceleration voltages U the relativistic correction is λde Broglie=hpe=hme⋅ve1−ve2c2=≈1.22⋅10−9mUV1+0.9788⋅10−6UV$${\lambda _{{\text{de Broglie}}}} = \frac{h}{{{p_e}}} = \frac{h}{{{m_e} \cdot {v_e}}}\sqrt {1 - \frac{{v_e^2}}{{{c^2}}}} = \approx \frac{{1.22 \cdot {{10}^{ - 9}}{\text{ m}}}}{{\sqrt {\frac{U}{V}\left( {1 + 0.9788 \cdot {{10}^{ - 6}}{\text{ }}\frac{U}{{\text{V}}}} \right)} }}$$ Thus, the wavelength of electrons passed through 1 kV to 30 kV acceleration voltages is in the range from 3.9 · 10 –11  m down to 7.0 · 10 –12  m, which is the magnitude utilized for scanning electron microscopy (SEM). Transmission electron microscopes (TEM) require higher acceleration voltages up to 300 kV because the imaging electrons have to transmit the specimen. Therefore, the wavelength in TEMs is even smaller, i.e. 2.0 · 10 –12  m. Hence, the smaller wavelength implies higher resolution for TEM than for SEM. Another important difference between transmission and scanning electron microscopy is based on the type of electrons used for imaging. TEM is based on transmitted electrons and provides the details about morphology, internal composition, structure and crystallinity. SEM uses backscattered or secondary electrons and focuses on the sample’s surface and its composition. The sample for TEM has to be cut thinner whereas there is no such need for SEM sample. Advanced techniques in state-of-the-art electron microscopy are always under development towards their wide applications in various aspects of materials research. Research in the field of advanced TEM techniques of battery systems is driven by the thirst towards energy storage systems in order to have better energy storage capabilities. Different groups worldwide contribute to a basic understanding of the processes that occur during the charging/discharging of a battery, as a basis for optimizing electrode, electrolyte materials and their interfaces. For both, electron microscopy methods benefit from the multitude of interactions which take place after the electron beam hits the specimen surface or passed the specimen volume. The main aspects in respect to battery materials will be reviewed in the following sections.

This review focuses on the selective catalytic hydrogenation of nitriles to primary amines both homogeneously and heterogeneously with transition metal-based catalysts in the view of nitriles as hydrogen carriers. Nitriles can be reduced with two equivalents of H 2 to primary amines, thus having a great potential to serve as liquid organic hydrogen carriers (LOHCs) for hydrogen storage. Imines are intermediates in the hydrogenation of nitriles to amines, thus they can also serve as potential LOHCs, however with a lower hydrogen storage capacity (HSC).

Recent advances in the development of coupled photoredox systems for the oxygenation of organic compounds are reviewed.

Radiationless resonance electronic excitation energy transfer (ET) is a fundamental physical phenomenon in luminescence spectroscopy playing an important role in natural processes, especially in photosynthesis and biochemistry. Besides, it is widely used in photooptics, optoelectronics, and protein chemistry, coordination chemistry of transition metals and lanthanides as well as in luminescent analysis. ET involves the transfer of electronic energy from a donor (D) (molecules or particles) which is initially excited, to an acceptor (A) at the ground state to emit it later. Fluorescence or phosphorescence of the acceptor that occurs during ET is known as sensitized. There do many kinds of ET exist but in all cases along with other factors the rate and efficiency of ET in common solvents depends to a large extent on the distance between the donor and the acceptor. This dependency greatly limits the efficiency of ET and, correspondingly, does not allow the determination of analytes in highly diluted (10 –9 –10 –15  M) solutions. To solve the problem of distance-effect, the effects of concentrating and bring close together the donor and acceptor in surfactant micelles (liquid nanosystems) or sorption on solid nanoparticles are used. Various approaches to promote the efficiency of ET for improvement determination selectivity and sensitivity using liquid and solid nanoobjects is reviewed and analyzed.

This work provides a description of our experience with designing and implementing green chemistry elements in higher education. It addresses the problem of content and methodology in green chemistry education and provides models of innovative approaches in design and teaching practices. An introductory course, Pollution Prevention, Green Chemistry and Green Engineering , supported by a grant from Michigan Department of Environmental Quality, was designed at Grand Valley State University (GVSU), in Michigan, in 2008 and run for the first time in 2009, with 12 students. The positive response from the students who took the class coupled with increasing visibility of green chemistry initiative at the state level (MI Governor’s Green Chemistry directive and Green Chemistry Round Table) led the GVSU administration to recognize the need of such a course and, after revision, to its inclusion into the Chemistry Department curriculum, under the designation “ Introduction to green chemistry ”, CHM 111. This remains to be a sought-after course for freshmen and upper-level undergraduates interested in the issues of green chemistry who have no chemistry background in their education. Since 2011, the course ran twice a year with a total of 302 students to date (December 2017). From semester to semester, it underwent several modifications, in order to accommodate the most recent, up-to-date developments in green chemistry and green engineering. The repository of teaching materials created is growing continuously. The progress and lessons learned throughout the years in running this course are summarized here.

2-(4-Bromophenyl)-3-(4-hydroxyphenyl)-1,3-thiazolidin-4-one and its selenium analogue were studied in the gas phase using HF and DFT methods. The functionals considered were B3LYP, BP86 and M06. The basis set for all the atoms was 6-311++ G(d,p). Molecular parameters such as bond lengths, bond angles, rotational constants, dipole moments, electronic energies, and vibrational parameters namely harmonic vibrational frequencies and relative intensities were computed for these compounds. Atomization energies, HOMO-LUMO gaps and natural charges on the atoms were also calculated. The molecular parameters and the vibrational spectra of sulfur compound are in good agreement with the experimental data. Therefore, the data for the selenium analogue should be helpful in its future characterization.

Development and design of new batteries require numerous electrical diagnostic methods; impedance spectroscopy is a prevalent one of them. Nevertheless, there occurs to be a gap from laboratory conditions to the final application point of view due to differing accuracy requirements, data availability and data quality. This chapter provides some insight into applicability of analysis methods outside the laboratory scale. The beneficial usage of the impedance spectroscopy approach will be shown for three typical fields of application, namely state of charge determination, temperature detection as well as battery degradation analysis, while several chemistries like innovative LiS or LFP were under investigation.

Inorganic mass spectrometry has been used as a well-known analytical technique to determine elemental/isotopic composition of very diverse materials, based on the different mass-to-charge ratios of the ions produced in a specific source. In this case, two mass spectrometric techniques are explained and their analytical properties discussed: inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionisation mass spectrometry (TIMS), since they are the most used in art and archaeological material studies. Both techniques combine advantageous analytical properties, like low detection limits, low interferences and high precision. The use of laser ablation as sample introduction system in ICP-MS allows to avoid sample preparation and to perform good spatial-resolution analysis. The development of new instruments, improving the mass separation and the detection of the ions, specially multicollection detectors, results in high-precision isotopic analysis. A summary of the important applications of these mass spectrometric techniques to the analysis of art and archaeological materials is also highlighted.

Among the electrochemical energy storage systems, rechargeable lithium batteries are considered very promising candidates for the next generation power sources because of their high gravimetric and volumetric energy density with respect to other cell chemistries. The lithium-ion battery technology is based on the use of electrode materials able to reversibly intercalate lithium cations, which are continuously transferred between two host structures (negative and positive electrodes) during the charge and discharge processes. Commercial lithium-ion batteries commonly use liquid electrolytes based on suitable lithium salts (solute) and organic compounds (solvents). The latter, volatile and flammable, represent serious concerns for the safety of the electrochemical devices, this so far preventing their large diffusion in applications as automotive, storage from renewable sources, smart grids. One of the most appealing approaches is the partial or total replacement of the organic solvents with safer, less hazardous, electrolyte components. Here, a concise survey of ones of the most investigated types of alternative electrolyte components, proposed for safer and more reliable rechargeable lithium batteries, is reported. Graphical Abstract :