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.