Porous LiMn2O4 cubes architectured with single-crystalline nanoparticles and exhibiting excellent cyclic stability and rate capability as the cathode of a lithium ion battery

Abstract

Porous LiMn2O4 was fabricated with cubic MnCO3 as precursor and characterized in terms of structure and performance as the cathode of a lithium ion battery. The characterizations from SEM, TEM and XRD demonstrate that the fabricated product has a cubic morphology with an average edge of 250 nm, which it inherits from the precursor, and a porous structure architectured with single-crystalline spinel nanoparticles of 50 nm, which imitates the Mn2O3 that results from the thermal decomposition of the precursor. The charge–discharge tests show that the synthesized product exhibits excellent rate capability and cyclic stability: delivering a reversible discharge capacity of 108 mA h g−1 at a 30 C rate and yielding a capacity retention of over 81% at a rate of 10 C after 4000 cycles. The superior performance of the synthesized product is attributed to its special structure: porous secondary cube particles consisting of primary single-crystalline nanoparticles. The nanoparticle reduces the path of Li ion diffusion and increases the reaction sites for lithium insertion/extraction, the pores provide room to buffer the volume changes during charge–discharge and the single crystalline nanoparticle endows the spinel with the best stability.