Silica-based thin film solid-state electrolytes for Lithium-ion microbatteries

The emerging market of the Internet of Things, smart objects, wearables and others increases the demand for micro energy sources. Rechargeable lithium-ion batteries are a well-known technology for energy storage. However, safety issues and high production costs constrain progress. Electrolyte solutions based on ionic liquids (ILs) with dissolved lithium salts can be confined into inorganic porous networks forming so-called ionogels, which are investigated as solid electrolytes [1]. Ionogels combine low hazard and good ionic conductivity. However, the growth of lithium dendrites may be observed during cycling, which reduce battery lifetime. In this project, we try to prepare a silica-ionogel to prevent dendritic growth by mechanical hindrance. The ionogel composition was studied to obtain a fast gelation and the correlation between the physical properties of the silica matrix and the electrochemical performances of the ionogel was evaluated.Energy for smart object

Kinetic Optimisation of Zinc Oxide Nanowire Growth For Piezoelectric Nanogenerator Applications Through A SolGel Process

One-dimensional Zinc Oxide Nanowires (ZnO NWs) have attracted a lot of attention due to their remarkable physical and chemical properties for electronic and optical devices, like chemical sensors, field effect transistors, and nanogenerators. Piezoelectric materials, for instance zinc oxide, exhibit an induced voltage under applied stress. This piezoelectric property has interesting applications in energy harvesting systems, like autonomous micro-devices. Compared to the vapour phase synthesis method, a sol-gel process for growing ZnO NWs has many advantages, such as low cost, low processing temperature, and scalability. Furthermore it opens up the possibility to use a wide range of substrates. Therefore a sol-gel process was implemented to grow well-ordered ZnO NWs. The objective was to obtain vertically well-aligned ZnO NWs by controlling the growth rate, shape, and density. The shape and density parameters are correlated and dependent on the concentration of the main reagents: zinc salt, ammonia, and ethanolamine. Recent work in this field has shown that adding a seed layer strongly influences the crystallinity and the growth of the nanowires. The kinetic parameters of temperature and pH were controlled and monitored to develop a scalable, reproducible, and repeatable process. An original seed method was used in order to orientate the growth of ZnO crystals and to control the growth speed.EnS

Structural influence of silica-based ionogels on their performance as electrolytes for all-solid-state Lithium-ion microbatteries

The emerging market of the Internet of Things, smart objects and others increase the demand for micro energy sources. Rechargeable Li-ion batteries are a well-known technology for energy storage. However, safety issues and high production costs constrain progress. Research on solid electrolytes, such as LiPON, was performed to evade leakage. But LiPON suffers from low ionic conductivity and a cost and time intensive production process. Another approach is the substitution of volatile and flammable organic electrolyte solvents with ionic liquids (IL), which display negligible vapor pressure and wide chemical, electrochemical, and thermal stability. Electrolyte solution based on ILs can be confined into inorganic porous networks forming so-called ionogels (IG), which are investigated as solid electrolyte materials. IGs combine low hazard and good ionic conductivity [1]. Silica-based IGs compatible with Li/LiCoO2 systems were prepared in a one-pot sol-gel process. The composition of the IG precursor solution and the influence of trifluoroacetic acid as catalyst were studied to obtain a fast condensation. Homogeneous and transparent IGs were obtained with a gelation time of less than 4 h. The physical properties of the host matrix were characterized by N2 sorption, Hg porosimetry and SEM. The silica host matrices were 3D networks predominantly built from 3-fold condensed silicon centres. The influence of its structural changes on the electrochemical behaviour was studied by varying the catalyst amount and by increasing the IL amount in the gel. The electrochemical performances of the IG were measured with complex impedance spectroscopy and galvanostatic cycling. Results show that IGs with IL amounts nIL/nSiO2~3 may be successfully used as solid electrolyte in Li/LiCoO2 cells. Batteries were prepared, which cycle more than 100 cycles at a rate of C/2 with no evidence of dendritic growth. Impedance characterization reveals the high internal resistivity of these batteries due to the dense structure of the silica matrix

Li7La3Zr2O12/LiCoO2 - cathode for all-solid-state batteries

EnS

Method for the wet deposition of thin films

publication date: 2016; filing date: 2014-12-1

Procédé de fabrication d'un matériau composite

publication date: 2013-11-21; filing date: 2013-05-1

Design of a batch solid-gas reactor for the thermal nitridation of phosphates in ammonia

Phosphage

Aqueous sol-gel synthesis and film deposition methods for the large-scale manufacture of coated steel with self-cleaning properties

A process has been developed to enable the large scale production of pure TiO2 films deposited on 316L stainless steel in order to get an easy-to-clean surface. This large scale process requires an easy aqueous sol-gel procedure for the synthesis of the TiO2 sol. This synthesis has been simplified to facilitate the extrapolation towards an industrial scale. Results of TEM, photocatalytic properties, film hydrophilicity, and texture obtained with the simplified aqueous sol-gel synthesis (IsoP-TiO2 synthesis) show similar properties to those obtained with the standard aqueous sol-gel synthesis of TiO2 (HAc-TiO2 synthesis) developed previously. Only X-Ray Diffraction patterns showed differences, with the presence of anatase-brookite phases in IsoP-TiO2 synthesis while anatase phase only was observed in HAc-TiO2 synthesis. Both the aqueous sol-gel synthesis of pure TiO2 and the film deposition on steel by roll-coating have been successfully extrapolated to a larger scale. The photocatalytic activity and the hydrophilicity of the film were found to be unchanged when compared to films produced at a laboratory scale, thus validating the production of an efficient easy-to-clean material. Although some problems are still to be solved, this study is a hopeful first step in the development of a large scale process for self-cleaning steel production

Wet method for the production of thin films (1)

publication date: 2019-03-06; filing date: 2014-10-31Synthèse par procédé sol-gel de matériaux pour microbatteries en couches mince