Comparative studies between oxygen-deficient LiMn2O4 and Al-doped LiMn2O4

Lithium-rich and Al-doped spinel materials with good capacity retention when cycled at high temperature have been synthesized. These materials have been studied in comparison with oxygen-deficient spinel using X-ray diffraction at room temperature (RT, 25 °C) and low temperature (LT, −30 °C). The XRD spectra at LT and RT showed that Al-doped spinel materials have superior structural stability against oxygen loss during heat treatment at 660 °C under Ar atmosphere. The in situ XRD spectra collected during cycling at high temperature (HT, 55 °C) showed that Al-doped spinel materials had better cycle performances and it was closely related to the structural stability against oxygen loss during charge–discharge cycling.