Facile synthesis of highly crystalline spinel-type LiMn2O4/multiwalled carbon nanotube (MWCNT) composite by a novel two-step approach is achieved. This approach involves an acetone-assisted hydrothermal reaction in LiOH solution using previously prepared birnessite MnO2/MWCNT composite as a manganese containing precursor. The lithium manganate spinel Li0.81Mn2O4/MWCNT composite delivers a high specific capacity of 145.4mAhg−1 at 0.1C-rate, which is close to the theoretic capacity of LiMn2O4 (148mAhg−1). Besides, it exhibits excellent high-rate capability and cyclability. For example, a discharge capacity of 114.8mAhg−1 is retained even at a high charge/discharge current rate of 20C. When it is repeatedly cycled at 1C rate for 1000 cycles, the specific capacity is decreased from the initial value of 140.4mAhg−1 to an end value of 98.7mAhg−1, giving 70.3% capacity retention.