Microemulsion-Assisted Synthesis of Nanosized LiMnO Spinel Cathodes for High-Rate Lithium-Ion Batteries

Abstract

Li1.16Mn1.84O4 nanoparticles (50–90 nm) with cubic spinel structure are synthesized by combining a microemulsion process to produce ultrafine Mn(OH)2 nanocrystals (3–8 nm) with a solid-state lithiation step. The nanostructured lithium-rich Li1.16Mn1.84O4 shows stable cycling performance and superior rate capabilities as compared with the corresponding bulk material, for example, the nano-sized Li1.16Mn1.84O4 electrode shows stable reversible capacities of 74 mAh g−1 during the 1000th cycle at a high rate of 40 C between 3.0 and 4.5 V. In addition, Li1.16Mn1.84O4 nanoparticles also show high Li storage properties over an enlarged voltage window of 2.0–4.5 V with high capacities and stable cyclability, for example, delivering discharge capacities of 209 and 114 mAh g−1 at rates of 1 and 20 C, respectively.