X. Xia, P. Ping and J. R. Dahn (2012) Studies of the Effect of Triphenyl Phosphate on the Negative Electrode of Li-Ion Cells. Journal/Journal Of the Electrochemical Society 159 A1460-A1466. [In English]
Web link: http://dx.doi.org/10.1149/2.052209jes
Keywords: FLUORINATED ALKYL PHOSPHATES, DIMETHYL METHYLPHOSPHONATE, NONFLAMMABLE, ELECTROLYTES, FLAME RETARDANTS, BATTERIES, PERFORMANCE
Abstract: The effects of the flame retardant, triphenyl phosphate (TPP), on the electrochemical properties of negative electrode materials for Li-ion batteries were studied. Petroleum coke and graphite were chosen for study. Coke/Li half cells with different concentrations of TPP were studied with a home-made automated storage system. The reactivity of intercalated lithium with TPP-containing electrolyte could be inferred from the potential-time graphs of the coke/Li cells during storage. Graphite/graphite symmetric cells with different concentrations of TPP were constructed and tested. Capacity loss in symmetric graphite/graphite cells is caused by reactions of intercalated lithium with electrolyte. The storage test results showed that coke/Li cells with TPP (10%-40% by volume) have similar rates of Li loss to electrolyte reactions at 30 degrees C compared to control cells and show significantly lower rates at 60 degrees C. Graphite/graphite symmetric cells with TPP (10%-40%) have capacities that decrease with TPP content, but show similar rates of% capacity loss per cycle. The impedance of the symmetric cells increases with TPP content. All the results together suggest that TPP forms a stable SEI but a SEI that impedes the transport of Li. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.052209jes] All rights reserved.