Characteristics and properties of nano-LiCoO2 synthesized by pre-organized single source precursors: Li-ion diffusivity, electrochemistry and biological assessment

Background: LiCoO2 is one of the most used cathode materials in Li-ion batteries. Its conventional synthesis requires high temperature (>800 degrees C) and long heating time (>24 h) to obtain the micronscale rhombohedral layered high-temperature phase of LiCoO2 ( HT-LCO). Nanoscale HT-LCO is of interest to improve the battery performance as the lithium (Li+) ion pathway is expected to be shorter in nanoparticles as compared to micron sized ones. Since batteries typically get recycled, the exposure to nanoparticles during this process needs to be evaluated. Results: Several new single source precursors containing lithium (Li+) and cobalt (Co2+) ions, based on alkoxides and aryloxides have been structurally characterized and were thermally transformed into nanoscale HT-LCO at 450 degrees C within few hours. The size of the nanoparticles depends on the precursor, determining the electrochemical performance. The Li-ion diffusion coefficients of our - LiCoO2 nanoparticles improved at least by a factor of 10 compared to commercial one, while showing good reversibility upon charging and discharging. The hazard of occupational exposure to nanoparticles during battery recycling was investigated with an in vitro multicellular lung model. Conclusions: Our heterobimetallic single source precursors allow to dramatically reduce the production temperature and time for HT-LCO. The obtained nanoparticles of LiCoO2 have faster kinetics for Li+ insertion/extraction compared to microparticles. Overall, nano-sized - LiCoO2 particles indicate a lower cytotoxic and (pro-)inflammogenic potential in vitro compared to their micron-sized counterparts. However, nanoparticles aggregate in air and behave partially like microparticles

Study of titanium amino-alkoxide derivatives as TiO2 Chemical Beam Vapour Deposition precursor

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A combinatorial chemical beam vapour deposition approach to tune the electrical conductivity of Nb:TiO2 films via Si co-doping

Chemical beam vapour deposition (CBVD) is a thin film deposition technique operated under high vacuum conditions in which film growth occurs through the thermally activated chemical decomposition of precursor molecules at the substrate surface. This technique was used in a combinatorial mode to investigate the influence of Si doping on the properties of Nb-doped TiO2 films, a well-known transparent conductive oxide material. The ternary oxide system (Si, Nb, Ti, O) displays good intermiscibility between the elements. By adding a Si precursor flow gradient to homogeneous Ti and Nb precursor flows, it was demonstrated that the resistivity of deposited films increased by over 5 orders of magnitude (from 1 to 100,000 Omega . cm) with Si doping levels between 2 and 21at.%. Meanwhile, only a slight variation of the refractive index of about 10% was observed. A fundamental film morphology study showed that the conductivity variation was due to Si segregation at the grain boundaries of the conductive Nb:TiO2 structure. (C) 2016 Elsevier B.V. All rights reserved

A combinatorial chemical beam vapour deposition approach to tune the electrical conductivity of Nb:TiO2 films via Si co-doping

Chemical beam vapour deposition (CBVD) is a thin film deposition technique operated under high vacuum conditions in which film growth occurs through the thermally activated chemical decomposition of precursor molecules at the substrate surface. This technique was used in a combinatorial mode to investigate the influence of Si doping on the properties of Nb-doped TiO2 films, a well-known transparent conductive oxide material. The ternary oxide system (Si, Nb, Ti, O) displays good intermiscibility between the elements. By adding a Si precursor flow gradient to homogeneous Ti and Nb precursor flows, it was demonstrated that the resistivity of deposited films increased by over 5 orders of magnitude (from 1 to 100,000 Ω·cm) with Si doping levels between 2 and 21at.%. Meanwhile, only a slight variation of the refractive index of about 10% was observed. A fundamental film morphology study showed that the conductivity variation was due to Si segregation at the grain boundaries of the conductive Nb:TiO2 structure