SHEDDING LIGHT ON THE ENTROPY CHANGE FOUND FOR THE LI-ION STORAGE IN GRAPHITE

EDUARDO M. PERASSI; MANUEL OTTERO; AGUSTÍN SIGAL; DANIEL BARRACO; EZEQUIEL M. P. LEIVA

Ciudad Autónoma de Buenos Aires

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

International Society of Electrochemistry

p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { }p.cjk { }p.ctl { }It is well known that intercalation materials are widely used asanodes or cathodes in electrochemical cells to store energy.Materials of intercalation such as lithium cobalt oxide (LiCoO2),lithium iron phosphate (LiFePO4), lithium titanate oxide (LTO),graphite, are commonly found in electrodes of commerciallylithium-ion cells. Particularly, graphite is the most common materialfound in anodes of commercial lithium-ions cell. These materialsallow a fast ion insertion and extraction of them and therefore, highpower densities cells can be obtained. However, Li-ion insertion andextraction generates heat into the cell. This heat can produce hightemperature excursions of the cell and a premature aging of it. Ithas been demonstrated that a great portion of the heat which isgenerated into the intercalation materials comes from theintercalation entropy during discharge. In the present work we use a simplified lattice-gas model withdifferent energy levels associated to stages or phases of thelithium/graphite compound to study the intercalation entropy of thiscompound. Our calculations are madewithin the canonical ensemble.