New insights into the silicon-based electrode's irreversibility along cycle life through simple gravimetric method

• Published in: Journal of power sources 2012-12, Vol.220, p.180-184
• Main Authors: Mazouzi, D., Delpuech, N., Oumellal, Y., Gauthier, M., Cerbelaud, M., Gaubicher, J., Dupré, N., Moreau, P., Guyomard, D., Roué, L., Lestriez, B.
• Format: Article
• Language: English
• Subjects: Applied sciences; Binder; Chemical Sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrode; Exact sciences and technology; Liquid electrolyte; Lithium battery; Materials; Silicon
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.08.007

The electrolyte degradation process on nano Si-based negative electrodes prepared with a carboxymethylcellulose (CMC) binder is studied by comparing the irreversible loss to ex-situ measurements of the weight and the thickness of the electrode along cycling. The electrode thickness and mass increase in close relationship to the irreversible loss increase, due to the continuous accumulation of insoluble electrolyte degradation products in the Si electrode. The use of a pH 3 buffer solution during the slurry electrode preparation, and the presence of fluoroethylene carbonate (FEC) + vinylidene carbonate (VC) results in much less electrolyte decomposition. The double role of the CMC binder with respect to the mechanical and chemical stability of the composite electrode is highlighted. ▸ Simple gravimetric method gives broad overview of electrode's irreversibility. ▸ Mass and thickness increase due to continuous liquid electrolyte degradation. ▸ CMC grafting decreases reactivity between Silicon and liquid electrolyte. ▸ FEC and VC decrease reactivity between Silicon and liquid electrolyte. ▸ The binder has mechanical and chemical critical role for electrode stability.