Construction of unit structures with Sn-O reversible coordination bonds for high-performance lithium storage

The performance of traditional anode materials for commercial lithium-ion batteries (LIBs) has been unable to meet the demand of today`s world, so it is imperative to develop materials with better performance. Among many candidate materials, metal-organic frames have attracted much attention due to their unique structure and composite materials. Herein, a simple and novel structural design strategy is proposed to obtain three Sn-MOFs (Sn-PPA(1,4-benzoic acid), Sn-MPA(1,3-benzoic acid), Sn-PA(1,2-benzoic acid)) with different Sn-O reversible coordination bonds. The isomerization of the two carboxyl groups on the benzene ring improves the utilization rate of the active site and forms a network extended skeleton structure favorable to reaction kinetics, thus achieving better electrochemical performance, especially with larger capacity and excellent cyclic stability. A series of characterizations provide an in-depth understanding of how Sn-MOFs can combine "synthesis mode-microstructure-lithium storage mechanism" in the process of realizing reversible formation of coordination bonds.