Facile synthesis of LiAl0.1Mn1.9O4 as cathode material for lithium ion batteries: towards rate and cycling capabilities at an elevated temperature

To improve the cycling performance of spinel LiMn2O4, Al-doped LiMn2O4, LiAl0.1Mn1.9O4, is synthesized using Mn1.9Al0.1O3 precursor and LiOH·H2O via a low temperature solid-phase reaction. The Mn1.9Al0.1O3 precursor, prepared from the electrolytic manganese dioxide (EMD) and Al(OH)3, is composed of spherical particles with an average diameter of 300 nm, and has a large interspace. Energy dispersive spectrometer (EDS) indicates the Al element is well distributed in Mn1.9Al0.1O3 and LiAl0.1Mn1.9O4. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) images show that the LiAl0.1Mn1.9O4 sample has a high crystallinity with sizes ranging from 300 to 500 nm. Electrochemical properties of LiAl0.1Mn1.9O4 are studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge. The results show that LiAl0.1Mn1.9O4 possesses better rate and cycling capabilities than LiMn2O4 at both 25 °C and 55 °C. At a rate of 5 C, the capacity retention ratio of the LiMn1.9Al0.1O4 electrode after 100 cycles is about 95% at 25 °C and about 90% at 55 °C.