Nanoscale Materials for Lithium-Ion Batteries

Abstract

Template synthesis is a versatile nanomaterial fabrication method used to make monodisperse nanoparticles of a variety of materials including metals, semiconductors, carbons, and polymers. We have used the template method to prepare nanostructured lithium-ion battery electrodes in which nanofibers or nanotubes of the electrode material protrude from an underlying current-collector surface like the bristles of a brush. Nanostructured electrodes of this type composed of carbon, LiMn2O4, V2O5, tin, TiO2, and TiS2 have been prepared. In all cases, the nanostructured electrode showed dramatically improved rate capabilities relative to thin-film control electrodes composed of the same material. The rate capabilities are improved because the distance that Li+ must diffuse in the solid state (the current- and power-limiting step in Li-ion battery electrodes) is significantly smaller in the nanostructured electrode. For example, in a nanofiber-based electrode, the distance that Li+ must diffuse is restricted to the radius of the fiber, which may be as small as 50 nm. Recent developments in template-prepared nanostructured electrodes are reviewed.

Nanostructured Sn–C Composite as an Advanced Anode Material in High‐Performance Lithium‐Ion Batteries

“…The use of nanostructures is a popular approach for improving the electrochemical response of these electrodes. [3][4][5][6] It is in fact expected that the passage from bulk to nanostructures results in: i) a higher interfacial area, this leading to higher charge/discharge rates; ii) shorter path lengths for Li + -ion transport, this resulting in an increase in power capabilities; and iii) accommodation of the strain of lithium insertion/removal, this improving the cycle life.Indeed, the key role of nanostructures, such as those based on tin nanoparticle dispersion [2] or on nanopillar architectures, [7] in upgrading the electrode life to hundreds of cycles and at high C rates, have been clearly demonstrated. The use of nanostructures, however, is not the ultimate solution because they are still affected by some drawbacks; these include: i) a low tap density, associated with the large surface-to-volume ratio, which results in a low energy density; ii) a high surface reactivity; and, most worrying, iii) the safety hazard associated with the flammable or explosive tendency of metallic nanopowders.…”

Cathodes - Technological review

“…Porous and textured materials provide high surface area as well. However, as they exhibit problems with cyclability due to structural changes or reactive surface groups [17], nanomaterials seem to be more promising and have gained strong attention [18][19][20][21][22][23]. The most important added value of nanoparticle cathodes is the possibility to use insolating materials.…”

Microstructural Characterization of Nanocrystalline Sn-Coated Carbon Fibre Electrodes Cycled in Li-Ion Cells

“…Enhancements in chemical reactivity with the electrolyte, and the electronic contact with the current collector were noted for 3-dimensional electrodes. [36][37][38] The use of metallic foams [39][40][41] could serve the similar purpose as they were shown to improve the cycling performance of anodes in Li-ion cells. Another surface engineering method applied to the electrode material design makes use of Sn coatings on carbon fibre (CF) paper.…”