Designed synthesis of LiMn2O4microspheres with adjustable hollow structures for lithium-ion battery applications

Abstract

Two types of LiMn2O4 microspheres with similar sizes but adjustable hollow structures have been synthesized using a new and simple approach. Their performance as cathode materials for lithium ion battery applications has been studied and correlated with the hollow structural parameters. Through a solid state reaction between LiOH and mesoporous MnO2 obtained by the complete decomposition of MnCO3, LiMn2O4 hollow spheres with a robust wall and small cavity size are prepared (LiMn2O4-A). The fusion of the mesopores and the Kirkendall effect during the lithiation process are responsible for the hollow interior formation. In another approach through partial decomposition and selective etching, LiMn2O4 hollow spheres with thin walls are prepared (LiMn2O4-B). It is demonstrated that LiMn2O4-A shows larger capacity, superior rate capability, and better cycling stability compared to LiMn2O4-B. The former exhibits an initial discharge capacity of ∼120 mA h g−1, maintains 96.6% of the initial capacity after 105 cycles at 1 C and ∼90% of the capacity at 0.1 C when discharged at 5 C.