Enhanced capacity retention of Co and Li doubly doped LiMn sub(2O) sub(4)

Cobalt and lithium doubly doped spinel LiMn sub(2O) sub(4) have been synthesized by a solid state reaction. The effect of Co and Li doped spinel LiMn sub(2O) sub(4) was investigated. The undoped and doped spinels were characterised by means of X-ray diffraction (XRD), inductively coupled plasma/atomic emission spectrometer (ICP/AES) and electrochemical test. The results showed that the doped spinel exhibited superior cycling performance than undoped spinel. The capacity retention of graphite/doped spinel full cell was more than 86% after 1000 cycles (2C rate) at room temperature, which maintained 85% after 100 cycles (1C rate) at 55 [deg]C. The differential capacity profiles on doped spinel cathode are more fixed than undoped spinel cathode. Compared with undoped spinel, Mn dissolution into electrolyte at 55 [deg]C was reduced by 41%, the lattice parameter difference Delta a was reduced by 82% on doped spinel cathode after cycling. The greatly suppressed structural change and manganese dissolution are responsible for the improved cycling performance on cobalt and lithium doubly doped spinel.