Energetic of Lithium Silicates Formed in-Operando Reduction of SiO 2 with Li in Lithium Ion Battery. A Theoretical and Experimental Study

DANIEL BARRACO; GERMAN LENER; EZEQUIEL LEIVA; MANUEL OTERO

Congreso; 20th Topical Meeting of the International Society of Electrochemistry; 2017

Most of materials used for lithium-ion battery are based in anodes with silicon as active material due that the theoretical capacity of silicon is about of 3800 mAhg -1 which is significantlygrater than graphite (420 mAhg -1 ). 1 As well know the silicon expand the volume 400 % in the formation of Li x Si y alloy and it change of volume produce the pulverization of the electrode. Apossible solution is coated silicon with carbon so as avoid the expansion of silicon. 2 However, the reduction of silica to silicon is a process highly activated and expensive. An alternative itcould be use SiO 2 coated with carbon due that the silicon is formed in-operando with theoretical capacities which vary depending of the silicates formed in the reaction. In this work, weanalyze the experimental results of the charge/discharge behavior and rate capability of SiO 2 /C. On the other hand, we obtain free energies for the different reaction that may occur in thelitiathion of silica.