화학공학소재연구정보센터
Materials Chemistry and Physics, Vol.99, No.2-3, 451-458, 2006
Nanocrystalline LiMn2O4 derived by HMTA-assisted solution combustion synthesis as a lithium-intercalating cathode material
Nanocrystalline LiMn2O4 was synthesized by a self-sustaining solution combustion method with hexamethylenetetramine as a fuel. Ammonium nitrate was used as an additional oxidant-and-porogen. Thermal analytical studies showed the formation of LiMn2O4 by a single-step decomposition process between 300 and 380 degrees C. The products were highly crystalline with an average crystallite size of similar to 30 nm. Charge-discharge studies showed that the optimal heat treatment protocol was a 10 h calcination at 700 degrees C. A product obtained under these conditions from a precursor containing a 1:1 molar ratio of [LiNO3 + Mn(NO3)(2)] and NH4NO3 sustained 202 cycles between 3.0 and 4.3 V at a charge-discharge rate of 0.1 C before reaching an 80% charge retention cut-off value. Nanocrystalline particles provide small diffusion pathways that lead to an improvement in the lithium-ion intercalation kinetics and minimize surface distortions during cycling. These factors are believed to confer excellent electrochemical properties to the product. (c) 2005 Elsevier B.V. All rights reserved.