An integral interface with dynamically stable evolution on micron-sized SiOx particle anode

Abstract

Abstract Micron-sized SiOx particles, owing to their distinct advantages in energy density, processability and cost, have shown promises in Li-ion batteries. However, the huge volume variation of micron-SiOx raises many issues including overgrowth of solid electrolyte interphase (SEI) and pulverization of bulk, which accounts for continuously faded storage performance during repeated Li uptake/release. To address above problems, we propose to stabilize the electrochemistry of micron-SiOx by building an integral interface with dynamically stable evolution on carbon-coated SiOx particles. The interface consists of Li polyacrylate nanolayer interfused with multiwalled carbon nanotubes. Both highly stretchable components maintain the structural integrity of micron-SiOx particles upon volume variation and coalesce the secondary particles in case pulverization occurs. The interface also enables injection of Li+/e– into micron-SiOx for sustaining the (de)lithiation, while restrains the overgrowth of SEI. Micron-SiOx particles protected by the integral interface have demonstrated, both in Li half and full cells, improved lithium storage properties in terms of capacity output and retention, Coulombic efficiency and rate capabilities. With this work, we tend to offer insights on interfacial engineering of micron-sized electrode materials with unstable chemical or structural evolution in practical batteries.