Delicately designed Sn-based electrode material via spray pyrolysis for high performance lithium-ion battery

Abstract

A new and feasible strategy for preparing Sn@ZnO@N-C composites as high-performance anode materials with respect to lithium ion battery (LIB) was developed through dry spray and followed by high-temperature pyrolysis. Porous MOF ZIF-8 was employed as template to provide spherical interconnected C-N framework as accommodation for active nanosize Sn and ZnO particles (designated as Sn@ZnO@N-C-y, y = 1, 2 and 3). Considering the low melting point of Sn (232 °C), pyrolysis is a sound technique to yield Sn@ZnO@N-C-y products with variable structural features through tailoring the quantity of stock SnCl2 salt in the preparation solutions. Electrochemical performance of the Sn@ZnO@N-C-y composites was examined in a form of anode in coin-type LIB devices. Results indicate that all the produced Sn@ZnO@N-C-y composites exhibit superior electrochemical performance. The quantity of the added raw SnCl2 imposes a profound impact on the formation of physical structures and consequent specific capacity and cycle life of the Sn@ZnO@N-C-y composite based anodes. Of the anode options, it is noted that Sn@ZnO@N-C-2 with a yolk-shell structure delivers the highest cycle stability, which retains a stable capacity of 1114.8 mA h g−1 after 500 cycles at a current density of 100 mA g−1. The void space in Sn@ZnO@N-C-2 is beneficial to buffer against volume variations. Meanwhile, the C-N framework enhances electronic conductivity to a great degree and N contributes dramatically to the excellent capacity retention and superior rate capability. Such a newly designed synthesis pathway provides new guidance to the design and manufacturing of nanostructured anode materials with high performance for next-generation LIB.