Ultrasonic spray pyrolysis of nano crystalline spinel LiMn₂O₄ showing good cycling performance in the 3 V range

Spherical lithium manganese oxide spinel was synthesized by an ultrasonic spray pyrolysis method, and has been characterized using X-ray diffraction, scanning electron microscopy, transimission electron microscopy and electrochemical cycling at 3 V regions. The LiMn₂O₄ powders were composed of about 10 nm-sized primary particles. The delivered discharge capacity of the synthesized nano-material was 125 mAh g^-1 between 2.4 and 3.5 V and its retention was about 96% upon 50 cycling. From the high resolution transmission electron microscopic study, it was found that structural transition of the parent material did not occur even after the 50th electrochemical cycling on the 3 V region. It seems that the reversible structural change is possible for nanocrystalline LiMn₂O₄ as observed by the X-ray diffraction and transition electron microscopic observations.