title: Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction.
abstract: 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.
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: Seok Woo
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Hyun-Wook
authors.identifier: 0000000190741619
authors.initials: HW
authors.lastname: Lee
authors.affiliation: School of Engineering, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Ill
authors.initials: I
authors.lastname: Ryu
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: William D
authors.initials: WD
authors.lastname: Nix
authors.affiliation: School of Engineering, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Huajian
authors.initials: H
authors.lastname: Gao
authors.affiliation: 1] Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA [2] Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cui