Novel layered chalcogenides as electrode materials for lithium-ion batteries

Misfit layer compounds of general formula (PbS)(1+delta)(TS2)(2) (T = Ti, Ta) are evaluated as the alternative intercalation electrodes versus lithium metal and in lithium-ion cells versus LiCoO2 and Li7Ti5O12 electrodes. Galvanostatic cycling experiments of lithium anode cells showed an excellent capacity retention, particularly for the (PbS)(1.14)(TaS2)(2) composition The potential stability range of the intercalation compounds of the sulfides (1.5-3.5 V) allows the use of these materials as the positive electrode versus Li7Ti5O12 or as the negative electrode versus the 4 V cathode LiCoO2. The use of litanium oxide anodes requires a previous in situ electrochemical lithiation of Li4Ti5O12 in a three-electrode assembly, Average cell voltages of about 1.0 V were then obtained. The use of LiCoO2 cathodes allows higher cell voltages (1.3-3.0 V) and capacity retentions during the first 50 cycles up to 80%. (C) 1997 Elsevier Science S.A.