Synthesis of a MOF derived porous graphene and pyrolytic carbon supported zinc stannate nanohybrid electrode with enhanced lithium-ion storage performances

Abstract

Compositing nano-sized zinc stannate (Zn₂SnO₄) with supportive carbon skeleton usually brings in improved lithium-ion storage performances. One of the most challenging tasks is to effectively stabilize Zn₂SnO₄ nanocrystals via simplified preparation routes from eco-friendly raw materials. In this work, the water-soluble natural molecule gallic acid (GA) is directly employed to coordinate with Zn²⁺/Sn²⁺ ions, and the corresponding metal-organic framework (MOF) precursor samples of pure Zn-GA MOF and bimetallic ZnSn-GA MOF can be synthesized. The Zn-GA MOF and ZnSn-GA MOF precursors are further converted to a three-dimensional (3D) porous graphene sample (ZMG) and a pyrolytic carbon domain supported Zn₂SnO₄ nanocomposite (Zn₂SnO₄@C), respectively, by taking the advantages of the unique micro-structures and compositions of MOF materials. By rationally mixing the ZMG and Zn₂SnO₄@C in electrode fabrication, the finally obtained Zn₂SnO₄@C/ZMG nanohybrid electrode exhibits a high reversible capacity of 1117 mAh·g⁻¹ after 500 cycles at a current density of 1000 mA g⁻¹ in half-cells as well as inspiring full-cell performance. The favorable synergistic effect in lithium-ion storage for the Zn₂SnO₄@C/ZMG electrode has been investigated. The MOF derived samples and involved sustainable synthesis protocols can be further developed for wider applications.