A low external temperature method for synthesis of active electrode materials for Li batteries - Part B: Synthesis of lithium iron oxides Li_xFe_yO_z

摘要

Anode materials for lithium-ion batteries based on iron oxides were synthesized using two different methods: a Low External Temperature Method (LETM) and a conventional Solid State Reaction Method (SSRM). Both methods lead to the formation of final products representing a mixture of two phases: approximately 75 percent LiFeO_2 and 25 percent Li_(_x)Fe_5O_8 (0 < X < = 0.1). When compared with the ordinary solid state synthesis, LETM creates conditions for carrying out the synthesis at a lower external calcination temperature (200 deg C) over a shorter period. The properties of the Li_xFe_yO_z obtained by the LETM were compared with those of the same compound obtained by SSR at 700 deg C. Higher initial discharge capacity was displayed by the sample synthesized by the SSR method, while a superior cycling stability was shown by the sample synthesized by the LETM. The latter shows approximately double capacity at the 30th cycle as compared with the sample synthesized by SSRM.