Manipulation of π-aromatic conjugation in two-dimensional Sn-organic materials for efficient lithium storage

Abstract

Sn-based materials are promising candidates for lithium storage but suffer generally from huge volume change during the (de)lithiation processes. Sn-organic materials with monodispersed Sn centers surrounded by lithium active ligands can alleviate the volume change of anode materials based on reversible (de)lithiation processes. However, the structural factors governing the kinetics of lithium storage and utilization efficiency of active sites are not well understood to date. Herein, we report three two-dimensional Sn-organic materials with enhanced lithium storage performance by manipulation of π-aromatic conjugation of the ligands. The increasing π-aromatic conjugation plays a key role in promoting efficient lithium storage, and the volume expansion during the (de)lithiation reaction is suppressed in these Sn-organic materials. This work reveals that the π-aromatic conjugation of the ligand is crucial for improving the kinetics of lithium storage and the utilization of active sites in metal-organic materials with minimised volume expansion.