Zero-Strain High-Capacity Silicon/Carbon Anode Enabled by a MOF-Derived Space-Confined Single-Atom Catalytic Strategy for Lithium-Ion Batteries.

Abstract

Developing zero-strain electrode materials with high capacity is crucial for lithium-ion batteries (LIBs). Here, a new zero-strain composite material made of ultrasmall Si nanodots (NDs) within metal organic framework-derived nanoreactors (Si NDs⊂MDN) through a novel space-confined catalytic strategy is reported. The unique Si NDs⊂MDN anode features a low strain (<3%) and a high theoretical lithium storage capacity (1524 mAh g^-1 ) which far surpasses the traditional single-crystal counterparts that suffer from a low capacity delivery. The zero-strain property is evidenced by substantial characterizations including ex/in situ transmission electron microscopy and mechanical simulations. The Si NDs⊂MDN exhibits superior cycling stability and high reversible capacity (1327 mAh g^-1 at 0.1 A g^-1 after 100 cycles) in half-cells and high energy density (366 Wh kg^-1 after 300 cycles) in a full cell. This study reports a new catalog of zero-strain electrode material with significantly improved capacity beyond the traditional single-crystal zero-strain materials.