The two primary physical methods for identifying lithium titanate, a negative electrode material used commercially, are X-Ray diffraction and Raman spectroscopy. Although there are many publications on this topic, they are focused mainly on chemistry, so there are still some points that require clarification from a physical and methodological point of view. Difference of experimentally observed and theoretically predicted Raman spectra was explained through a combination of experiments and computations. The work comprises experiments and computations to explain why there are different numbers of predicted and observed Raman-active bands. Our low-temperature study and the analysis of thermal shifts during heating led us to conclude that the approach with surplus bands is advantageous and we recommend using major F-2g band shifts to estimate the sample heating.

Electrocatalysts often undergo significant restructuring depending on the applied potential under operating conditions. Although such restructured surfaces govern the catalytic performance, rationally controlling catalyst restructuring via an electrochemical protocol remains...

Lithium battery industry is booming, and this fast growth should be supported by developing industry friendly tools to control the quality of positive and negative electrode materials. Raman spectroscopy was shown to be a cost effective and sensitive instrument to study defects and heterogeneities in lithium titanate, popular negative electrode material for high power applications, but there are still some points to be clarified. This work presents a detailed thermal Raman study for lithium titanate and discusses the difference of the number of predicted and experimentally observed Raman-active bands. The low temperature study and the analysis of thermal shifts of bands positions during heating let us to conclude about advantages of the proposed approach with surplus bands and recommend using shifts of major band to estimate the sample heating.

In the context of the growing popularity of electric cars, it is important to track the sustainability of this emerging industry. This work presents the results of electric vehicle sales up to and including 2021, proposes volatility assessment and short-term forecasting using normalized monthly sales analysis, and discusses why quantitative long-term forecasting is impossible. In cases where authorities and regulators are the main driving forces of change, the electric car market does not need forecasting, but instead requires proper goal setting and timely published market data with open access.

Lithium cobalt oxide is a convenient model material for the vast family of cathode materials with a layered structure and still retains some commercial perspectives for microbatteries and some other applications. In this work, we have used ab initio calculations, x-ray diffraction, Raman spectroscopy, and a theoretical physical model, based on quasi-harmonic approximation with anharmonic contributions of the three-phonon and four-phonon processes, to study a temperature-induced change of Raman spectra for LiCoO2. The obtained values of shift and broadening for E-g and A(1g) bands can be used for quantitative characterization of temperature change, for example, due to laser-induced heating during Raman spectra measurements. The theoretical analysis of the experimental results lets us conclude that Raman spectra changes for LiCoO2 can be explained by the combination of thermal expansion of the crystal lattice and phonon damping by anharmonic coupling with comparable contributions of the three-phonon and four-phonon processes. The obtained results can be further used to develop Raman-based quality control tools.

The laser-induced processes can impede the accurate interpretation of experimentally measured Raman spectra. In this work we have studied how an increase in the excitation laser power can change the parameters Raman spectra for lithium titanate Li 4 Ti 5 O 12 , a commercial anode material for high-power and long-lasting lithium-ion batteries. Although for 633 nm laser of 15.9 mW the measured laser-induced shifts were of few cm –1 , this can correspond to laser-induced heating for more than 100°C. Statistical analysis has demonstrated that this doesn’t induce LTO degradation but, possibly, the combined action of heat and laser-matter interaction is enough for some minor but still measurable change of Raman spectra parameters, which can be attributed to laser-induced structuring.

Abstract The fast-growing lithium battery industry needs quality control tools. Micro-Raman spectroscopy is a popular technique for structural characterization and impurity probing. The problem is that the method resolution can be appropriately quantified for a sample with planar geometry, like a single crystal, but not for a powder consisting of microparticles with irregular shape and surface. In this work, we have examined a series of single LiFePO4 particles on a Raman-active Si substrate. This model experiment let us conclude that vertical resolution for particulate systems with inhomogeneity of shape and structure should be achieved be described not quantitative but qualitative. The observed variation of local probing depths is explained by spatial inhomogeneity of defects/impurities concentration, Mie scattering, blocking properties of pores, and surface plasmon resonance. In conclusion, we provide our recommendations for local and integral measurements using confocal Raman microscopy.

Laser-induced degradation is a common issue for the Raman spectroscopy study of lithium battery materials. In this work, the combination of single-particle Raman measurements with scanning electron microscope imaging helped us reveal the variation of the decomposition pathways and products. For the first time, we observed possible laser-induced melting of the LiFePO4 particles and an unidentified decomposition product, an alternative to previously reported alpha-Fe2O3 and gamma-Li3Fe2(PO4)(3). These results and analysis of the time series of Raman measurements raise doubts about laser-induced heating. We suppose non-thermal amorphization and melting processes due to electronic system excitation by intraband transitions with the following covalent bond destabilization. The role of defects in laser-induced decomposition is discussed. We hope that this article could help develop a non-destructive tool for quality control and the study of the electrochemical or thermal degradation of LiFePO4.

Lithium titanate (Li4Ti5O12) is a commercial anode material used for high-power and long-lifespan lithium batteries. The key drawback of this material is its low electronic conductivity. Although doping is commonly used to solve this problem, the introduction of dopants also diminished lattice stability. In this work, we studied fast and slow laser-induced degradation processes of single Mn-doped lithium titanate particles and proposed a physicochemical model of their degradation mechanism. We suppose that the preferable route of LTO alteration is the formation of amorphous phases rather than crystalline decomposition products. Our results may be useful for not only developing a nondestructive characterization tool utilizing Raman spectroscopy but also for understanding other degradation processes, including thermal alteration and structural changes caused by the intercalation/deintercalation cycles of lithium ions.

The fast-growing lithium battery industry needs quality control tools. Micro-Raman spectroscopy is a popular technique for structural characterization and can be used for impurity revealing. The problem is that the method resolution can be appropriately quantified for a sample with a simple planar geometry, like a single crystal. Much less studied are powders consisting of particles of irregular shape and sizes close to the wavelengths of the probing laser irradiation. In this work, we have examined a series of single particles of transparent lithium iron phosphate (LiFePO4) on a Si substrate. This model experiment revealed the significant spread of local optical properties, blocking properties of pores, and abnormal enhancement of Raman response from a bottom Si layer under some of particles. As the result, we can conclude that vertical resolution of micro-Raman spectroscopy for particulate systems with inhomogeneity of shape and structure should be described not quantitative, but qualitative, and the Raman probing of powder samples can be both multilayer and superficial.

The synthesis of Na2Ti6O13 nanowires (NTNW) was performed at chemical interaction between rutile nano-powder with sodium chloride flux on the surface of molten aluminum under air. Synthesis of NTNW proceeds at two stages reaction at the three-phase boundary "gaseous medium (air)/molten salt/molten metal (Al)" under the quasi-autocatalytic mechanism. SEM, micro-Raman spectroscopy, X-Rays photoelectron spectroscopy, electron dispersive spectroscopy, and XRD are used to characterise NTNWs. The composition and morphology of NTNW can be controlled by experiment parameters. The increasing of synthesis temperature up to 850 degrees C allows getting single-phase product. Further increase in temperature up to 950 degrees C leads to increase in sodium concentration in NTNW. The ratio between the length and diameter of NTNW reaches 50. During high-temperature MS synthesis at 850-950 degrees C NTNW with some reduced Ti3+ were obtained. When the temperature of sodium hexatitanate nanorods and nanowires synthesis in molten salt media elevated to 950 degrees C, the amount of reduced Ti3+ atoms increased, giving a Ti3+/Ti4+ surface atomic ratio of 0.112. The sodium hexatitanate nanorods mainly formed by TiO6 octahedrons connected with corner-shared O-O bridge bands wherein Na ions stay between layers. This position of Na+ ions is prospective for possible application of sodium hexatitanates in sodium-ion batteries.

Titanium oxide nanoparticles are synthesized in a molten mixture of alkali chlorides and nitrates. X-ray diffraction analysis, Raman spectroscopy, and scanning electron microscopy are used to identify the oxide powders. Titanium oxides of various modifications and compositions are synthesized by anodic polarization of high-purity titanium in a molten eutectic mixture of cesium and sodium chlorides containing 5 wt % sodium nitrate. Polarization is carried out under galvanostatic conditions at a current density of 3.5 mA/cm 2 and a temperature of 540–700°C in an argon atmosphere. The phase composition of the oxidation products depends on the synthesis temperature. The particle size is controlled by varying the density and temperature. X-ray diffraction analysis and Raman spectroscopy show that the sample synthesized at a temperature of 540°C is single-phase and consists of Cs 1.36 Ti 6.64 O 16 . The samples synthesized at temperatures of 600 and 650°C form the TiO 2 phase in mixed anatase and rutile modifications. The sample synthesized at a temperature of 700°C consists of TiO 2 titanium dioxide (rutile and brookite modification) and NaTi 8 O 13 . According to scanning electron microscopy, the particle size decreases when the synthesis temperature increases. The sample synthesized at a temperature of 540°C and annealed at a temperature of 200°C contains a mixture of the nano- and microparticles of cesium trititanate (over 50 nm). The titanium dioxide particle size is 20 nm in the sample synthesized at a temperature of 600°C and is 10–20 nm in the samples synthesized at temperatures of 650 and 700°C.

Nowadays, the electrification of the automotive industry in some regions symbolises the transition to a sustainable economy. Moreover, these changes were initiated by regulatory authorities, and not only consumers and manufacturers. The article summarizes the results of the first decade of implementing Chinese governmental policy promoting sales of electric vehicles. Our goal is to acquaint the Russian-speaking audience with the successful practise of state support of the emerging industry. As we focused on reviewing and analysing the information, the main research method is the survey of open sources and academic literature. In the first part of the article, we reported the key role of China in the global electric vehicle market and identified the main driving forces in the transformation of the national automotive industry. In the second part, we closely examined the actions taken by the Chinese authorities to ensure an increase in the share of electric vehicles. In the third part, we summarised and analysed the possible short-term changes, as well as discussed the impact of the described processes on the global economy. The implementation of the aforementioned policy enabled a breakthrough, allowing Chinese automotive industry to reach the leading position in terms of sales and production of electric vehicles. Therefore, this research can be used for both the adoption of successful practice and analysis of the influence of the emerging electric vehicle industry on the Russian and global economy.

This paper reports about new insight into a problem of a laser-matter interaction during Raman probing of lithium iron phosphate (LiFePO4), discusses phase transformation kinetics in powder samples, and provides some methodological recommendations. LiFePO4 is the second most popular positive electrode material in the global lithium battery industry, but the use of Raman spectroscopy for its structural characterization is hampered by the laser-induced degradation. The statistical/big-data approach to Raman spectra measurements is utilized to revise the problem and suggest a simple model of laser-induced phase transformations in powder LiFePO4. The results are proposed to be used for better understanding of the physics and chemistry of other processes taking place in electrochemical cells, namely, lithiation/delithiation and thermal stability/safety studies. Simple recommendations for nondestructive LiFePO4 characterization by Raman spectroscopy are formulated.

Lithium titanate (Li4Ti5O12, LTO) has already occupied its niche as an anode material for high-power and long-lifespan lithium batteries, but some novel directions for basic and applied research are still open. One of the most promising approaches in improving its properties, e.g., electronic conductivity and rate capability, is based on controllable defect engineering. The "defects" may be intentionally introduced into LTO via doping, surface modifications, and the synergy between them. However, the defects, which have significant effects to the electrical and electrochemical properties, are usually extremely dilute. Reliable material characterizations are essential and challenging, but the instrumental tools for revealing dilute defects are still insufficient. Herein, detailed analyses on the surface or subsurface defects of carbon-coated LTO were performed using various material characterization methods. Raman spectroscopy has been identified as a unique tool for the probing of structural defects.

Two-phase composites with a low part of the auxiliary phase (about a few percent) are quite complex objects for qualitative and quantitative characterization. Battery electrode materials are typical example of such composites, comprising the active material with the small amount of conductive additive (carbon-based, mostly). This article presents an original "big-data" approach for morphological and structural characterization of carbon-coating component in Li4Ti5O12/C composites by statistical Raman spectroscopy. Although the most published Raman-spectroscopy-based papers focus on structural characterization only, in this work, we show that morphological study can be even more informative. Our approach proposed for monitoring the carbon coverage efficiency, and morphological mesoscale heterogeneity of low-C composites can be used for optimization of carbon-coating procedure and industrial quality control of carbon-coated electrode materials.

Electric fields of different nature induced in lanthanum doped lead zirconate-titanate (PLZT) ceramics were studied by confocal Raman microscopy. Temperature dependence of the pyroelectric field was determined and the value of pyroelectric coefficient was estimated. An appearance of additional line in Raman spectrum of PLZT after e-beam irradiation was revealed and its spatial distribution was studied. The origin of this spectral line was discussed in terms of defects formation and phase transitions.

The growing popularity of electric vehicles is one of the main drivers of battery industry transformation. Words like "transport system decarbonization", "electromobility", and "environmental-friendly society" are very popular today, but questions remain as to how to measure electric vehicles' adoption progress and how this transition changes the battery industry. This perspective paper provides a review of the electric cars and buses market, estimates the production volumes of some other electric vehicle types, and discusses the role of traction batteries in the global battery market. A simple estimation of the sales rate allows us to evaluate the prospects of electric vehicle adoption in leading countries. Finally, the application of the main battery chemistries is reviewed and topical issues to the research society are addressed and formulated.

The core-shell morphology study is crucial for composite materials, comprised of a low conductive core with a highly conductive thin carbon shell. The study analyzed carbon morphology evolution for the two series of Li4Ti5O12/C samples with carbon content increasing from 0.9 to 5.6 wt%. The conventional X-Ray Photoelectron Spectroscopy (XPS) study allowed us to conclude about the efficiency threshold of carbon layer growth over lithium titanate core for two carbon deposition methods -both sucrose and acetylene decompositions. Although the carbon layer thickness is increasing with carbon concentration growth in LTO/ C composites, the efficiency of carbon coverage was shown to decrease with the threshold carbon concentrations about 1-2%. The chemical bonding analysis based on the same XPS data was used for C@ LTO interface characterization. The proposed approach can be used for optimization of producing different composites with core-shell structure (carbon-based composites, materials with protective layers, and materials with gradient core-shell structure). (C) The Author(s) 2018. Published by ECS.