Jean-Christophe Daigle

New Avenue for Limiting Degradation in NanoLi4Ti5O12 for Ultrafast-Charge Lithium-Ion Batteries: Hybrid Polymer–Inorganic Particles

Lithium titanium oxide (Li4Ti5O12)-based cells are a very promising battery technology for ultrafast-charge-discharge and long-cycle-life batteries. However, the surface reactivity of lithium titanium oxide in the presence of organic electrolytes continues to be a problem that may cause expansion of pouch cells. In this study, we report on the development of a simple and economical grafting method for forming hybrid polymer-Li4Ti15O12 nanoparticles, which can be successfully applied in lithium-ion batteries. This method utilizes a low-cost and scalable hydrophobic polymer that is applicable in industrial processes. The hybrid materials demonstrated exceptional capability for preventing the degradation of cells in accelerated aging and operating over 150 cycles at 1C and 45 °C.

Polyethylene/polyhedral oligomeric silsesquioxanes composites: Electrical insulation for high voltage power cables

Xylene solution blending was tested as a method for producing low-density polyethylene (LDPE)-based nanodielectrics containing 1 wt% and 5 wt% polyhedral oligomeric silsesquioxanes (POS) of different types — octamethyl POS, octaisobutyl POS, and isooctyl POS. The chemical composition, the morphology, the thermal properties and the dielectric properties of LDPE and its composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, thermal conductivity measurements, broadband dielectric spectroscopy, progressive-stress breakdown tests, and surface partial discharge tests. The results showed that although xylene solution blending was an effective method for producing LDPE/POS dielectric composites, it appeared ineffective in dispersing POS at the nanoscale. Furthermore, some of the composites presented an improved thermal conductivity, a maintained breakdown strength and an enhanced resistance to corona discharges.

Schiff Base as Additive for Preventing Gas Evolution in Li4Ti5O12-Based Lithium-Ion Battery

Lithium titanium oxide (Li4Ti5O12)-based electrodes are very promising for long-life cycle batteries. However, the surface reactivity of Li4Ti5O12 in organic electrolytes leading to gas evolution is still a problem that may cause expansion of pouch cells. In this study, we report the use of Schiff base (1,8-diazabicyclo[5.4.0]undec-7-ene) as an additive that prevents gas evolution during cell aging by a new mechanism involving the solid electrolyte interface on the anode surface. The in situ ring opening polymerization of cyclic carbonates occurs during the first cycles to decrease gas evolution by 9.7 vol % without increasing the internal resistance of the battery.

Polyethylene-based nanodielectric containing Octaisobutyl Polyhedral Oligomeric SilSesquioxanes obtained by hexane slurry blending

Nanodielectrics have attracted the attention of many scientists and industrials as they may present superior dielectric properties compared to conventional dielectric composites. However, the success of these materials relies on a proper dispersion of the nanofiller within the matrix. In this work, the efficacy of hexane slurry blending in obtaining Low Density PolyEthylene (LDPE) based nanodielectric containing 5 wt% Octaisobutyl Polyhedral Oligomeric SilSesquioxanes (OibPOSS) was tested. The resulting dielectric was characterized using atomic force microscopy, optical microscopy, fourier transform infrared spectroscopy, broadband dielectric spectroscopy and progressive-stress breakdown tests. The results showed hexane slurry blending is a possible yet inefficient way to obtain LDPE/OibPOSS nanodielectric.

Polyethylene-based nanodielectrics containing octaisobutyl polyhedral oligomeric silsesquioxanes obtained by solution blending in xylene

Nanodielectrics have attracted the attention of many scientists and industrials as they may present superior dielectric properties compared to conventional dielectrics. Polyhedral Oligomeric SilSesquioxanes (POSS) is a type of filler of great interest in the field of nanodielectrics. In this work, xylene solution blending was used to produce Low Density Polyethylene (LDPE) based nanodielectrics containing 1 wt% and 5 wt% Octaisobutyl POSS (OibPOSS). The resulting dielectrics were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, broadband dielectric spectroscopy and progressive-stress breakdown tests. The results showed that (i) solution blending in xylene seemed to be an effective method to disperse OibPOSS within LDPE in nano to micron sizes and (ii) the resulting dielectrics presented dielectric properties similar to those of LDPE.

Further study on dielectric properties of solid epoxy composites with Graphene Oxide

Knowledge has been pushed further regarding an epoxy composite containing Graphene-Oxide (GO) doped epoxy powder. It was put forward that GO could behave as a curing agent. This would explain the breakdown characteristics of the composites. In spite of being a nanostructured microcomposite, the samples breakdown can be favourably compared to that of neat epoxy. The presence of GO opens the door to tailoring the real permittivity and electrical conductivity, but enlarges somewhat the losses.