ABSTRACT
Spinel LiMn2O4is a promising cathode material for lithium-ion batteries. However, bulk LiMn2O4commonly suffers from capacity fading due to the dissolution of Mn into the electrolyte during cycling. Moreover, bulk LiMn2O4exhibits a low Li+diffusion coefficient that limits the volume available to Li+storage. Herein, we report the synthesis of small hollow porous LiMn2O4nanostructures 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 × 10-7cm s-1) compared with that of bulk LiMn2O4.
ABSTRACT
Thermal neutron attenuation capacity of Li4SiO4 was evaluated to assess its potential capabilities as a beam shaping material for boron neutron capture therapy (BNCT) facilities. Samples of Li4SiO4 were prepared by two different synthesis methods, using different raw materials and were characterized using x-ray, electron diffraction and transmission electron microscopy. Neutron measurements were performed at the BNCT and the neutron radiography facilities of Centro Atómico Bariloche. Considering its natural isotopic abundance, Li4SiO4 proved to be remarkably effective in comparison with other neutron-absorbing materials. Given the availability of natural Lithium in local salt mines and the scalable feasibility, Li4SiO4 qualifies as a potential material for BNCT beam shaping applications.
