Synthesis and electrochemical analysis of electrode prepared from zeolitic imidazolate framework (ZIF)-67/graphene composite for lithium sulfur cells

• Published in: Electrochimica acta 2018-01, Vol.259, p.1021-1029
• Main Authors: Hong, Jin Young, Jung, Yongju, Park, Dae-Won, Chung, Sungwook, Kim, Seok
• Format: Article
• Language: English
• Subjects: Diffraction; Electroactivity; Electrocatalysis; Electrochemical analysis; Electrochemical property; Electrode; Electrodes; Field emission microscopy; Graphene; Lithium sulfur batteries; Metal-organic frameworks; Scanning electron microscopy; Studies; Synthesis; Transmission electron microscopy; X-ray diffraction; Zeolitic imidazolate framework
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2017.11.016

A zeolitic imidazolate framework (ZIF)/graphene composite was prepared by the solvothermal reaction using different concentrations of graphene oxide to investigate the effect of graphene addition on the electroactivity of the composite. Field emission scanning electron microscopy (FE-SEM), field emission transmission electron microscopy (FE-TEM), and X-ray diffraction (XRD) were conducted to determine the morphology and micro-structure of the composite. Electrochemical characterizations were measured using the CR2016 type coin cell test. Based on the electrochemical properties and structural characteristics of the composite, the roles and effects of graphene in ZIF/graphene composite were studied. The concentration of graphene oxide used during the synthesis process affect the initial specific capacity and cycle performance of the composite. ZIF-67/graphene composites for lithium sulfur electrode were synthesized by a solvothermal reaction with different concentration of graphene oxide. In the prepared composites, polyhedral ZIF particles were dispersed on graphene sheets uniformly and nano-pores can be observed. ZG300-sulfur which was added with 3 mg mL−1 of graphene oxide showed the highest initial specific capacity (1459 mAh g−1) and retained the capacity of 637 mAh g−1 after 100 cycles. Even, at higher current density, ZG300 showed superior rate capability and retained the capacity of 739 mAh g−1 at returning 100 mA g−1. [Display omitted] •ZIF-67/graphene composites were prepared via solvothermal reaction and annealing with different amount of graphene.•The composites showed improved electrochemical properties of high specific capacity, cycle life, and rate capability.•The properties were ascribed to the high conductivity of graphene and MOF interaction with lithium polysulfide.