Rapid calcination synthesis of Zn2SnO4@C/Sn composites for high-performance lithium ion battery anodes

Abstract

Zn2SnO4@C/Sn composites were synthesized via the rapid calcination of a zinc-tin binary MOF under a reducing atmosphere for 1 min. Nanometal Sn, which has a good conductivity, and Zn2SnO4 nanoparticles were assembled into secondary particles in the synthesized composites. The metal Sn acted as an active material and a conductive agent. The nanosized Zn2SnO4@C/Sn composites reduced the volume expansion and enhanced the electrochemical performance. Additionally, the carbon provided buffer spaces for the volume expansion of the active material. The metal Sn grew into large particles as the calcination time increased, which transformed the lithium storage process from surface controlled to diffusion controlled. When the Zn2SnO4@C/Sn composites were used as anode materials for LIBs, a superior electrochemical performance was achieved. A reversible capacity of up to 1140 mA h g−1 was obtained at a current density of 100 mA g−1 after 100 cycles. The reason for the capacity fading in the samples that were calcined for a long time was also analyzed, and the results might be helpful for researchers when designing new anode materials.