Abstract
TiSnSb-electrodes with various binders, mass loadings and porosities are studied (81). CMC shows better performance than CMC/PAAH, CMC buffered at pH3 and Amylopectin (79). Cycle life decreases for electrodes with higher mass loading and lower porosity (79). Rate performance is determined by the electrode polarization resistance (72). TiSnSb/Li 1 Ni 1/3 Co 1/3 Mn 1/3 O 2 cell shows good cyclability with FEC electrolyte additive (84). a b s t r a c t Micrometric TiSnSb is a promising negative electrode material for Li-ion batteries when formulated with carboxymethyl cellulose (CMC) binder and a mixture of carbon black and carbon nanofibers, and cycled in a fluoroethylene carbonate (FEC)-containing electrolyte. Here, other binder systems were evaluated, polyacrylic acid (PAAH) mixed with CMC, CMC in buffered solution at pH 3 and amylopectin. However CMC showed the better performance in terms of cycle life of the electrode. Whatever the binder, cycle life decreases with increasing the active mass loading, which is attributed to both the precipitation of liquid electrolyte degradation products and to the loss of electrical contacts within the composite electrode and with the current collector as a consequence of the active particles volume variations. Furthermore, calendaring the electrode unfortunately decreases the cycle life. The rate performance was studied as a function of the active mass loading and was shown to be determined by the electrode polarization resistance. Finally, full cells cycling tests with Li 1 Ni 1/3 Co 1/3 Mn 1/3 O 2 at the positive electrode were done. 60% of the capacity is retained after 200 cycles at the surface capacity of 2.7 mAh cm À2 .