Small hollow nanostructures as a new morphology to improve stability of LiMn2O4 cathodes in Li-ion batteries

Abstract

Spinel LiMn2O4 is a promising cathode material for lithium-ion batteries. However, bulk LiMn2O4 commonly suffers from capacity fading due to the dissolution of Mn into the electrolyte during cycling. Moreover, bulk LiMn2O4 exhibits a low Li+ diffusion coefficient that limits the volume available to Li+ storage. Herein, we report the synthesis of small hollow porous LiMn2O4 nanostructures with a mean size of 51 nm exhibiting exposed (111) planes, assembled by nanoparticles of about 6 nm in size. The morphological features of these nanostructures ensure a large contact area between the material and the electrolyte, shorten the pathways for Li+ diffusion and provide effective accommodation of the volume change during cycling. Therefore, these hollow nanostructures exhibit improved discharge capacity retention (nearly 82% after 200 cycles) and a greater Li+ diffusion coefficient (3.46 × 10−7 cm s−1) compared with that of bulk LiMn2O4.