Processing of Li4Ti5O12 powder for solid-state battery anodes via extrusion moulding

Electrochemical accumulators possess several desirable features, including pollution-free operation, high round-trip efficiency, flexible power and energy characteristics to meet different grid functions, compact size and long cycle life. Among all the possible types of electrochemical accumulators, this work focuses on lithium-ion accumulators, as they have a vast operating range and are of great importance, especially for the new sustainable mobility trend, which requires high-efficient batteries for electric automobility. All in all, security issues with these devices are yet to be faced due to occasional accidents and explosions, and the development of new, safer constituent materials is a key point of their future. In this Master Thesis the processing of promising lithium titanate oxide (Li4Ti5O12) mixed with 1% (w.) carbon black and different percentages of a pore-forming agent has been studied, in order to obtain an additive-free anode material with optimal characteristics of conductivity, porosity and processability. Four different feedstocks of this material were processed by powder extrusion moulding (PEM) The aforementioned technique comprises rheological tests of four different feedstocks prepared mixing the lithium titanate oxide with carbon black and a pore-forming agent with a binding system (based on polypropylene, paraffin wax and stearic acid). The ratio ceramic powder/binding system was 55/45 (vol.). The foils obtained from the powder extrusion moulding process were debinded and sintered in order to obtain the anodes for the solid-state batteries. Finally, physical, chemical and electrochemical characterization of the pieces was carried out.