Sn doped ZnMn2O4 microspheres with excellent electrochemical performance and high cycle stability

Abstract

Sn-doping ZnMn2O4 (Sn-ZMO) porous microspheres with shell structure were synthesized by utilizing SnO as Sn source. The effect of Sn content on its structure, morphology, and performance was investigated. Sn doping can increase the crystal plane spacing of ZnMn2O4 (ZMO) microspheres and enhance the electrochemical performance of ZMO materialis. When the Sn-doping content is 0.5%, the specific capacitance of Sn-ZMO microspheres is 18.5% higher than that of pure ZMO microsphere, which reaches 530 F/g under the current density of 1 A/g. Furthermore, the cycle stability has a significant promotion. 77% of the capacity is maintained after 2000 cycles under the scan rate of 20 mV/s. The enhancement in electrochemical performance is attributed to form a spherical shell with a certain thickness after ZMO microsphere were doped by Sn atom, in which the spherical shell can suppresses the volume expansion during the charge-discharge process.