Synthesis and electrochemical properties of nanostructured LiAl _x Mn _2∈-∈x O _4∈-∈y Br _y particles

Nanostructured LiAl _x Mn _2∈-∈x O _4∈-∈y Br _y particles were synthesized successfully by annealing the mixed precursors, which were prepared by roomerature solid-state coordination method using lithium acetate, manganese acetate, lithium bromide, aluminum nitrate, citric acid, and polyethylene glycol 400 as starting materials. X-ray diffractometer patterns indicated that the particles of the as-synthesized samples are well-crystallized pure spinel phase. Transmission electron microscopy images showed that the LiAl _x Mn _2∈-∈x O _4∈-∈y Br _y samples consist of small-sized nanoparticles. The results of galvanostatic cycling tests revealed that the initial discharge capacity of LiAl _0.05Mn _1.95O _3.95Br _0.05 is 119 mAh g ^-1; after the 100th cycle, its discharge capacity still remains at 92 mAh g ^-1. The introduction of Al and Br in LiMn ₂O ₄ bring a synergetic effect and is quite effective in increasing the capacity and elevating cycling performance. © 2008 Springer-Verlag.