Spinel-Li3.5 + xTi5O12 coated LiMn2O4 with high surface Mn valence for an enhanced cycling performance at high temperature

• Li deficient Li3.5Ti4O12 coated LiMn2O4 were prepared.
• A spinel Li3.5 + xTi4O12 phase coated LiMn2O4 with high surface Mn valence was obtained by annealing at 750 °C.
• This sample demonstrated an enhanced cycling performance at high temperature.

Li3.5 + xTi5O12 and Li4Ti5O12 layers coated LiMn2O4 were prepared via sol–gel route, with subsequent annealing at 750 °C. XRD studies showed coating did not change the structure of LiMn2O4. TEM studies showed coating layers were formed around LiMn2O4 particles, both corresponding spinel LiTiO phase. XPS studies showed the valence of surface Mn for the Li3.5Ti5O12-coated-LiMn2O4 increased after annealing. This sample also demonstrated a favorable cycling performance.