Metal oxide (Co3O4) was coated on spinel Li1.1Mn1.9O4 using glutamic acid. Powder X-ray diffraction pattern of Co3O4-coated spinel Li1.1Mn1.9O4 showed that the Co3O4 coating medium was not incorporated in the spinel bulk structure. Morphology of the Co3O4-coated spinel Li1.1Mn1.9O4 was observed by scanning electron microscopy and transmission electron microscopy. The cycling performance of the Co3O4-coated spinel Li1.1Mn1.9O4 was obviously improved, compared to the pristine Li1.1Mn1.9O4 at elevated temperature (55°C). Improvement of rate capability was also achieved at high C-rates.