Dynamically Regulated Redox Shuttling and Nucleation of Lithium Polysulfides Through the Built-In Ferroelectric Field

Abstract

Sulfur is highly desired for energy storage devices by virtue of its high theoretical specific capacity and natural abundance. Yet the lithium-sulfur battery becomes practically unstable due to the migration of lithium polysulfides (LiPSs), which is the major challenge for its widespread application. Here, we demonstrate that the polysulfide redox shuttling can be kinetically buffered, which relies on a rational design of ferroelectric/carbon interfaces in a silica-based host structure. We show that a robust sulfur host is constructed by spatially embedding ferroelectric BaTiO3 nanodots within both the shell and bulk of a silica/carbon microsphere that provides rich internal ferroelectric/carbon interfaces. It functions as a LiPSs pocket during the electrochemical cycling process that the synergetic effect of the built-in polarization electric field and abundant LiPSs nucleation sites at the interfaces facilitates the reversible LiPSs conversion and gives rise to long-term stabilization of lithium-sulfur battery.

Keywords: Ferroelectric, Build-in physical field, Polysulfide nucleation, Li-S battery