A Sphere−Sheet Hetero−Interlayer With Mechanoadaptivity and Li + Selectivity for High Performance Anode Free Lithium Sulfur Batteries

Abstract

ABSTRACT Anode free lithium sulfur batteries (AFLSBs) can fully exploit the ultra−high energy density of Li−S systems. However, issues such as irreversible lithium loss caused by uneven solid electrolyte interphase (SEI) on anode during the charging/discharging process, along with severe volume changes leading to structural instability, are key factors limiting their lifespan far below practical application. Herein, a sphere−sheet hetero−interlayer (2DLP−PASF) is designed, which adapts to volume changes and exhibits Li + selectivity. The interlayer is fabricated by electrophoretic deposition of −SO 3 Li rich elastic ionomer emulsion (PASF) particles and laponite nanosheets (2DLP) onto a copper current collector. The elastic PASF particles support 2DLP to form a dispersed stress−buffering structure, which can accommodate volume changes during the charging/discharging process and suppress dendrite growth. Furthermore, rich −SO 3 Li in densely packed PASF shells between 2DLP repel anions electrostatically through the Donnan effect, which facilitates efficient Li + transport and flux homogenization, thereby inhibiting the polysulfide shuttle. Additionally, −C≡N and −CF 3 in PASF cores transform into a stable, Li 3 N/LiF−rich secondary SEI on anode, which in turn synergizes with the tough 2DLP−PASF to further stabilize lithium deposition. As a result, the AFLSB assembled with 2DLP−PASF modified copper current collector and Li 2 S cathode demonstrated significantly improved comprehensive electrochemical performance.