The electrochemical properties of MXene Ti3C2 multilayer for Li-ion batteries were improved greatly by vacuum calcination, after systematically evaluating its thermal stability in different atmosphere in details. In air, the as-prepared Ti3C2 could not be oxidized up to 429.9 degrees C and the rutile-TiO2 would remain as the oxidation product at 1200 degrees C. The surface functional groups especially F groups can be eliminated by heat treatment. After vacuum calcination at 400 degrees C, the Ti3C2 show much higher capacities due to the removal of OH groups (126.4 mAh.g(-1) at 1C), and exhibited excellent rate capability. Besides, the formation of TiO2 nanoparticles at 700 degrees C further increases the first coulombic efficiency (62%) and capacity retention after 100 cycles (97%). In contrast, the dense microstructures of resulting TiCx formed after calcination at 1000 degrees C results in the worst electrochemical properties. This paper presented a relatively simple and easily scalable post-treatment for improving the electrochemical properties of MXene, and demonstrated a great potential of Ti3C2 of using as anode material for Li-ion batteries. (c) 2018 Elsevier Ltd. All rights reserved.