SnO₂/metal organic complex composite derived from low-temperature activated metal organic complex for advanced lithium storage

Sn-based metal organic complexes with coordination bonds, multi-active sites, and high theoretical capacity have attracted much attention as promising anodes for lithium ion batteries. However, the low electrical conductivity and huge volume changes restricted their electrochemical stability and practical utilization. Herein, Sn-based anode with superior electrochemical performance, including a high reversible capacity of 1050.1 mAh·g⁻¹ at 2 A·g⁻¹ and a stable capacity of 1105.5 mAh·g⁻¹ after 500 cycles at 1 A·g⁻¹, was fabricated via a low-temperature calcination strategy from Sn metal organic complexes. The low-temperature calcination process regulates Sn–O bond and prevents the agglomeration of SnO₂, generating highly dispersed SnO₂ decorated metal organic complexes and providing sufficient active sites for ion storage. Ex situ characterizations expound that the undecomposed Sn-based metal organic complexes could be transformed into SnO₂ during lithiation and delithiation, which enhances the electrical conductivity and induces a strong pseudo-capacitive behavior, accelerating the electrochemical kinetics; the multiple solid electrolyte interface with inflexible LiF and flexible ROCO₂Li buffers the volume variation of the electrode, resulting in its high electrochemical stability. This work provides a simple strategy for preparing excellent Sn-based anodes from metal organic complexes and reveals the lithium storage mechanism of the prepared Sn-based anode.