Electrochemical deposition of zeolitic imidazolate framework electrode coatings for supercapacitor electrodes

• Published in: Electrochimica acta 2016-04, Vol.197, p.228-240
• Main Authors: Worrall, Stephen D., Mann, Haydn, Rogers, Adam, Bissett, Mark A., Attfield, Martin P., Dryfe, Robert A.W.
• Format: Article
• Language: English
• Subjects: Capacitance; Coated electrodes; Coatings; Crystal structure; Crystallinity; Deposition; electrochemical growth; Electrodes; Graphene; metal-organic frameworks; Modified electrodes; supercapacitors
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2016.02.145

[Display omitted] •ZIF-4, -7, -8, -14 and -67 electrode coatings obtained via anodic dissolution.•Reaction conditions optimised to favour coating formation.•Capacitance of 10.45mFcm−2 for ZIF-67, highest for additive free MOF. Zn and Co electrodes have been successfully coated with five different zeolitic imidazolate frameworks ZIFs (ZIF-4, ZIF-7, ZIF-8, ZIF-14 and ZIF-67) via the anodic dissolution method. Careful control of the reaction conditions allows for electrode coating growth; in contrast to previous reports of electrochemical ZIF growth, which have not succeeded in obtaining ZIF electrode coatings. Coating crystallinity is also shown to be heavily dependent upon reaction conditions, with amorphous rather than crystalline material generated at shorter reaction times and lower linker concentrations. Electrochemical applications for ZIF-coated electrodes are highlighted with the observation of an areal capacitance of 10.45 mF cm−2 at 0.01Vs−1 for additive-free ZIF-67 coated Co electrodes. This is superior to many reported metal organic framework (MOF)/graphene composites and to capacitance values previously reported for additive-free MOFs.