Robust lithium-ion anodes based on nanocomposites of iron oxide-carbon-silicate

Robust composite particles containing Fe3O4 cores and porous conductive carbon-silicate layers were synthesized using an aerosol-assisted process followed by vapor coating using organosilanol as the precursor. Such unique synthesis enables the composites with high capacity and good cycle performance, and can be extended towards other oxide composites for energy storage.close5

Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction

Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Here, we demonstrate physical and mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics so that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of lithiated Si by lessening the tensile stress concentrations in Si structures. This study will contribute to improved design of Si structures at the electrode level for high-performance Li-ion batteries.open1