Recent advances in health risk research on occupational exposure to lithium-ion battery cathode materials

Peering into Batteries: Electrochemical Insight Through In Situ and Operando Methods over Multiple Length Scales

Vaporization of benzene, toluene, ethylbenzene, and xylene (BTEX) compounds pollutes the air and causes health hazards at gasoline stations. This study revealed the risk of BTEX exposure according to the hazardous area classification at gasoline stations. The risk assessment of gasoline workers from a representative group of 47 stations, which followed the United States Environmental Protection Agency-IRIS method of assessing BTEX exposure, was expressed as the hazard index (HI). A result of matrix multipliers of the hazardous exposure index and fire possibility from flammable gas classified hazardous area-I and area-II at the fuel dispensers. BTEX concentrations were actively sampled in ambient air and a flammable gas detector was used to measure the flammability level. Results showed that the BTEX concentrations from ambient air monitoring were in the range of 0.1–136.9, 8.1–406.0, 0.8–24.1 and 0.4–105.5 ppb for benzene, toluene, ethylbenzene, and xylene, respectively, which exceeded the NIOSH exposure limit of 100 ppb of benzene concentration. The risk assessment indicated that five stations reached an unacceptable risk of worker exposure to BTEX (HI>1), which correlated with the numbers of gasoline dispensers and daily gasoline sold. The risk matrix classified hazardous area-I at 4 meters and hazardous area-II at 4–8 meters in radius around the fuel dispensers. This study revealed the hazardous areas at gasoline stations and suggests that entrepreneurs must strictly control the safety operation practice of workers, install vapor recovery systems on dispenser nozzles to control BTEX vaporization and keep the hazardous areas clear of fire ignition sources within an eight-meter radius of the dispensers.

Vaporization of benzene, toluene, ethylbenzene, and xylene (BTEX) compounds pollutes the air and causes health hazards at gasoline stations. This study revealed the risk of BTEX exposure according to the hazardous area classification at gasoline stations. The risk assessment of gasoline workers from a representative group of 47 stations, which followed the United States Environmental Protection Agency-IRIS method of assessing BTEX exposure, was expressed as the hazard index (HI). A result of matrix multipliers of the hazardous exposure index and fire possibility from flammable gas classified hazardous area-I and area-II at the fuel dispensers. BTEX concentrations were actively sampled in ambient air and a flammable gas detector was used to measure the flammability level. Results showed that the BTEX concentrations from ambient air monitoring were in the range of 0.1-136.9, 8.1-406.0, 0.8-24.1 and 0.4-105.5 ppb for benzene, toluene, ethylbenzene, and xylene, respectively, which exceeded the NIOSH exposure limit of 100 ppb of benzene concentration. The risk assessment indicated that five stations reached an unacceptable risk of worker exposure to BTEX (HI>1), which correlated with the numbers of gasoline dispensers and daily gasoline sold. The risk matrix classified hazardous area-I at 4 meters and hazardous area-II at 4-8 meters in radius around the fuel dispensers. This study revealed the hazardous areas at gasoline stations and suggests that entrepreneurs must strictly control the safety operation practice of workers, install vapor recovery systems on dispenser nozzles to control BTEX vaporization and keep the hazardous areas clear of fire ignition sources within an eight-meter radius of the dispensers.

One of the most important indicators of the suitability of new types of fibrous materials for processing in products with specified properties is the degree of grinding. A detailed analysis of the influence of various factors on the quality of grinding of fibrous materials was carried out. The information is necessary for predicting the properties of new types of materials and controlling the technological process for obtaining fibrous materials with improved and controlled characteristics. The advantages of a modern method for analyzing the properties of fibers in the process of obtaining new types of materials are shown, which makes it possible to evaluate the active fiber surface and its fractional composition.

With the continuous development of Chinese science and technology, structured ultra-light porous metal materials are a new type of multifunctional materials that have emerged with the increasing demand for diverse materials preparation and machining technologies in recent years. New topics in feature and performance research. In the field of material manufacturing and machining, ultra-light porous metal materials have appeared. Ultralight porous metal materials have many functional characteristics. As a new type of material that is different from dense materials, porous metal materials are the first to explain the concept of ultralight porous metal materials and the functional characteristics of ultralight porous metal materials. Analysis, and finally the specific application of ultralight porous metal materials is studied. Structured ultralight porous metals are a multifunctional engineering material with excellent performance, have good application prospects, and have become the focus of attention and research.

How has external knowledge contributed to lithium-ion batteries for the energy transition?

Retroreflective materials for traffic control devices are designed to return light from a vehicle’s headlamps back to the driver. Recent advances in material technology have created prismatic retroreflective sheeting. This type of material does not have the predictability in its retroreflective performance of the older, glass-bead material. The ASTM recently recognized three new types of prismatic material for traffic control devices. The on-road performance of these new material types was examined through the use of computer simulation of sign luminance. Inputs to the computer model included vehicle dimensions, headlamp illumination data, material retroreflectivity data, sign placement, and roadway geometry. A variety of sign positions and roadway types was included to illustrate the similarities and differences among the three new types of material. The ranking of the three materials in terms of sign-luminance performance depends on the roadway configuration and the viewing distance. ASTM Type VII is shown to be comparable to Type VIII at long distances with small entrance angles but superior to Type VIII and IX in large entrance-angle situations. ASTM Type IX is shown to have higher luminance at shorter distances associated with sign-legibility distance ranges. Engineers and specifiers are encouraged to evaluate on-road sign performance at night before making material choices.

Since the launching of the first commercial lithium ion batteries (LIBs) in 1991, LIBs have been widely used to power portable electronic devices such as cell phones and laptop computers due to their high energy density. In the past decade, in response to the finite petroleum supply and the associated serious environmental concerns, low emission or even zero emission electric vehicles (EVs) have attracted increasing research and development interests and LIBs have been considered as one of the most potential power sources. However, the widely used layered LiCoO2 cathode material has very limited chance to meet the demand considering its low capacity, high cost and toxicity. Li2MnO3 based layered Li-rich cathode materials as promising cathode candidates of LIBs have attracted much recent attention mainly due to their superior high specific capacity, low cost and high working voltage. To date, although researchers have put much effort to this family of materials, they still face a few serious challenges to overcome in terms of the specific capacity, long-term cycling stability and rate performance. In addition, some fundamental issues are still under debates in the understanding of the crystal structures and the electrochemical reaction mechanisms. This thesis focuses on the development of new high capacity Li-rich cathode materials for LIBs.The first chapter starts with a general introduction of LIBs, followed by a brief summary of the LIBs component, working principle and three types of the well-developed cathode materials in Chapter 2. A detailed review of the recent development on Li2MnO3 based Li-rich cathode materials was also included in Chapter 2. The main objectives and the rationale behind this project are described in Chapter 3. All the experiment details including the material synthesis and characterization, coin cell fabrication and electrochemistry measurement are shown in Chapter 4.Chapter 5 presents a published work on a series of layered-spinel integrated Li-rich cathode materials with controllable capacity. The Co/Mn mole ratio is fixed while the Li/(Mn+Ni) ratio is varied to adjust the ratio of the layered/spinel phases. They exhibit steadily increased specific capacities upon cycling for several dozen of cycles due to the gradual activation of the initial Li-rich layered phase from the surface of the composite particles. Both experimental and computational results suggest that a small amount of Co dopants plays a critical role in the continuous activation process of these materials. In addition, the structural evaluation mechanism is also discussed. Based on this unique feature, controllable discharge capacities of these cathode materials can be achieved in a broad range from 30 to 240 mAh g-1 by deliberately activating the materials at a potential window of 2~4.8 V. Chapter 6 demonstrates a series of low-Co Li-rich cathode materials showing stepwise capacity increase over a few cycles from less than 50 mAh g-1 to around 250 mAh g-1. A systematic analysis on their compositions, crystal structures and the electrochemical performances reveals that the small change of Co content has negligible effect to the crystal structure and morphology, but plays an important role in adjusting the activation rate of the Li2MnO3 phase. In addition, optimized cycling potential window and current rate have been demonstrated to significantly ensure the effective Li2MnO3 activation and good long-term cycling stability.Chapter 7 describes a new class of Li-rich materials Li[Li1/3-2x/3Mn2/3-x/3Nix]O2 (0.09≤x≤0.2) with a small amount of Ni doping as cathode materials for LIBs. Anomalous gradual capacity growth up to tens of cycles due to the continuous activation of the Li2MnO3 phase is observed. Both experimental and computational results indicate that a small amount of Ni doping can promote the stepwise Li2MnO3 activation to obtain increased specific capacity and better cycling capability. On the contrary, excessive Ni will overly activate the Li2MnO3 and result into a large capacity loss in the first cycle. The Li1.25Mn0.625Ni0.125O2 material with an optimized content of Ni has shown a superior high capacity of ~280 mAh g-1 and good cycling stability at room temperature.Chapter 8 proposes a fundamental understanding on the Li2MnO3 activation process. Based on the platform of the low-Ni Li1.87Mn0.94Ni0.19O3 cathode material which exhibits exclusive stepwise capacity increase upon cycling as demonstrated in Chapter 6, the Li2MnO3 activation process was artificially retarded significantly and split into quite a few cycles. A combined study including the powerful in-situ XRD analysis and HAADF-STEM characterization revealed that the oxygen release sub-reaction is much faster than the TM-diffusion reaction. The latter is the key kinetic step to finalize the Li2MnO3 activation and results into the gradual capacity increase. Finally, conclusions and recommendations are presented in Chapter 9 summarising the key findings and achievements of the present work on Li-rich Mn-based cathode materials and also giving insights into the future research and development on this promising cathode material system.

Improving the Lithium-Ion Battery.

The recovery of cathode and anode materials plays an important role in the recycling process of spent lithium-ion batteries (LIBs). Organic binders reduce the liberation efficiency and flotation efficiency of electrode materials derived from spent LIBs. In this study, pyrolysis technology is used to improve the recovery of cathode and anode materials from spent LIBs by removing organic binders. Pyrolysis characteristics of organics in electrode materials are investigated, and on this basis, the effects of pyrolysis parameters on the liberation efficiency of electrode materials are studied. Afterwards, flotation technology is used to separate cathode material from anode material. The results indicate that the optimum liberation efficiency of electrode materials is obtained at a pyrolysis temperature of 500 °C, a pyrolysis time of 15 min and a pyrolysis heating rate of 10 °C/min. At this time, the liberation efficiency of cathode materials is 98.23% and the liberation efficiency of anode materials is 98.89%. Phase characteristics of electrode materials cannot be changed under these pyrolysis conditions. Ultrasonic cleaning was used to remove pyrolytic residues to further improve the flotation efficiency of electrode materials. The cathode material grade was up to 93.89% with a recovery of 96.88% in the flotation process.

Research on the regeneration of cathode materials of spent lithium-ion batteries for resource reclamation and environmental protection is attracting more and more attention today. However, the majority of studies on recycling lithium-ion batteries (LIBs) placed the emphasis only on recovering target metals, such as Co, Ni, and Li, from the cathode materials, or how to recycle spent LIBs by conventional means. Effective reclamation strategies (e.g., pyrometallurgical technologies, hydrometallurgy techniques, and biological strategies) have been used in research on recycling used LIBs. Nevertheless, none of the existing reviews of regenerating cathode materials from waste LIBs elucidated the strategies to regenerate lithium nickel manganese cobalt oxide (NCM or LiNixCoyMnzO2) cathode materials directly from spent LIBs containing other than NCM cathodes but, at the same time, frequently used commercial cathode materials such as LiCoO2 (LCO), LiFePO4 (LFP), LiMn2O4 (LMO), etc. or from spent mixed cathode materials. This review showcases the strategies and techniques for regenerating LiNixCoyMnzO2 cathode active materials directly from some commonly used and different types of mixed-cathode materials. The article summarizes the various technologies and processes of regenerating LiNixCoyMnzO2 cathode active materials directly from some individual cathode materials and the mixed-cathode scraps of spent LIBs without their preliminary separation. In the meantime, the economic benefits and diverse synthetic routes of regenerating LiNixCoyMnzO2 cathode materials reported in the literature are analyzed systematically. This minireview can lay guidance and a theoretical basis for restoring LiNixCoyMnzO2 cathode materials.

Concrete plays an important role in the construction industry worldwide. New technology has made for easier development of new types of construction and alternative materials in the concrete area. Cement is the major component in the production of concrete, but its manufacture causes environmental issues and thus there is a need for alternative materials. Geopolymer concrete is a new type of material with that potential, commonly formed by alkali activation of industrial alumina silicate byproducts, such as fly ash and ground granulated blast furnace slag (GGBS). For this paper, mechanical properties of geopolymer concrete with fly ash and GGBS cured under ambient temperatures were studied. Five different grades of concrete were considered. The results were encouraging: The workability of the geopolymer concrete was similar to that of conventional concrete. Experimental results of flexural and splitting tensile strength revealed insignificant variation compared to conventional concrete. The mechanical properties of fly ash and GGBS-based geopolymer concrete were comparable with conventional concrete.

ALCERU, Lyocell, Newcell, and Tencel (the order is alphabetical and not by importance) are thus alternative hydrated cellulose fibres fabricated by a method with a low degree of harmfulness. Is this only a name or is it also a hope, as for viscose wool fibre 60 years ago? In our opinion, this is much more than only the beginning of a new generation of fibres, yarns, thin strips from film, spun articles, etc. Is this perhaps an overestimation again? No, we are convinced that this is the true path to future developments. In research on this type of processing, the goal should not be to replace natural silk, cotton, or chemical fibres, but to create a totally different type of biodegradable material fabricated with a low degree of harmfulness of the process. A multitude of requirements of modern economic development related to the operation and cost-effectiveness of production could be satisfied in this way. During development, we became convinced that fibrillation is not a defect, but instead a positive effect whose use will make it possible to discover new types of materials. And we should now be bold in using these new fibres and yarns for creating new materials. The reports from Courtaulds (Great Britain) concerning the introduction of three installations with a capacity of 50,000 tons a year each and Lenzing (Austria) concerning an installation with a capacity of 40,000 tons a year in the next three years are convincing evidence of the validity of this opinion.

Composite Materials with Combined Electronic and Ionic Properties

The demand of rechargeable batteries had increased significantly every year during the last decade, driven for the needs associated with technological development (portability, high performance of electronic devices and vehicles). Lithium ion battery is a device of mayor consumption, and it is designed for energy storage and conversion based on intercalation electrodes. Nowadays the efforts are directed to the improvement and replacement of current battery components: anode, cathode (LiCoO2) electrolyte, with materials that have higher efficiency in terms of energy, power, cost, reliability, life time and safety. In recent years there has been significant interest in polyanion-based active materials as safe alternatives for the traditional oxide cathodes. For example, phosphate phases such as LiFePO4 [1], Li3V2(PO4)3, [2], Li2.5V2(PO4)3, [3], LiVOPO4, [4,5] and LiVP2O7[6] have all been proposed. Therefore, the search of new cathode materials is an important task for researchers in materials science. The possibility of using sodium directly in lithium ion cells allows the study of new compositions and structures. In this research work a series of four compounds with formula Na3V2-xAlx(PO4)2F3 (x= 0, 0.02, 0.05, 0.1) were prepared, characterized and applied as cathode materials in lithium ion batteries. These materials were synthesized by sol-gel Pechini method. Aqueous solutions containing appropriate amounts of NH4VO3, NH4H2PO4 and NaF were poured into a mixture of citric acid and ethylene glycol solution. Mixture was then heat treated under reflux at 80°C until gel formation. Fresh samples were heated at 300°C under air to eliminate volatile matter. Resulting powders were grinded and formed into pellets for reaction between 300 to 650°C under nitrogen atmosphere. Thermal stability of materials was evaluated by simultaneous termogravimetric and differential analysis (TGA-DTA). Morphological and microstructural characterization were carried out with field emission scanning electron microscopy (FESEM), textural analysis by N2 physisorption with BET method; chemical composition and crystallographic parameters were determined with Induced coupled plasma – optic emission spectroscopy (ICP-OES), energy dispersive X-ray spectroscopy (EDXS) and X-ray powder diffraction (XRD); the application of materials as cathodes in lithium ion batteries was evaluated through electrochemical charge discharge experiments. Electrodes were prepared using a mixture of each synthesized materials, conductive carbon and PVDF binder. CR2032 coin cells were assembled inside a glove box under Ar atmosphere, using LiPF6electrolyte and Li° as anode. Experiments were performed using a MacPile II by Biologic. Thermal analysis of sol-gel reaction products exhibited an exothermic even between 550 and 750°C attributed to the crystallization of the fluorophosphates. Results from XRD analysis showed that Al doped Na3V2(PO4)2F3 crystalline phase was formed at 650°C for 8h. According to cell parameters Na3V2(PO4)2F3 can incorporate aluminum content up to x=0.1, without the presence of secondary phases or structural transitions. Granular morphology and small particles size of about 40 to 100 nm were observed, this can be attributed to the effect of residual carbon within samples (8% by weight) since this inhibits particle grown and also allows contact among particles, improving electrical conductivity. Materials present average porous size of about 20nm, with surface area of 30m2/g. The sample with x=0.05 of Aluminum content, presents the best textural properties. This material also presents high specific charge/discharge capacity (123/101 mAh/g at a 4.4 V vs Li cell) and good capacity retention (82%), in comparison to the material without doping (128/63 mAh/g and 49% of capacity retention). Aluminum doping of Na3V2(PO4)2F3phase permitted the stabilization of the structure related to cycling processes. These results are promising for future application of the material in lithium and sodium ion batteries. Keywords: Pechini, cathodes, phosphates, lithium ion batteries References [1] A.K. Padhi, K.S. Nanjundaswamy, C. Masquelier, J.B. Goodenough, J. Electrochem. Soc. 144 (1997) 2581. [2] M.Y. Saidi, J. Barker, H. Huang, J.L. Swoyer, G. Adamson, Electrochem. Solid-State Lett. 5 (2002) A149. [3] C. Yin, H. Grondey, P. Strobel, L.F. Nazar, Chem. Mater. 16 (2004) 1456. [4] B.M. Azmi, T. Ishihara, H. Nishiguchi, Yusaku Takita, J. Power Sources 146 (1–2) (2005). [5] J. Gaubicher, T. Le Mercier, Y. Chabre, J. Angenault, M. Quarton, J. Electrochem. Soc. 146 (1999) 4375. [6] J. Barker, R.K.B. Gover, P. Burns, A. Bryan, Electrochem. Solid-State Lett. 8 (9) (2005) 446.