A WATER-SOLUBLE COBALT SULFIDE SUPERATOM FOR FLOW BATTERY APPLICATIONS AND CRYSTALLINE FRAMEWORK SYNTHESIS

1 online resource (107 pages) : PDF

2019

University of North Carolina at Charlotte

Metal sulfide clusters are attractive components for flow batteries owing to the abundance of their constituent atoms and their tunable size, solubility, and redox properties. We prepared an atomically precise cobalt sulfide cluster, Co6S8(PTA)6•4HCl (PTA = 1,3,5-triaza-7-phosphaadamantane) (1), in a single step using low-cost precursors and water solubilizing phosphine ligands. Compound 1 represents the first structurally characterized, water-soluble cobalt-sulfide cluster. Remarkably, cluster 1 undergoes two electrochemically reversible oxidations in aqueous solutions and is stable in air. The first redox process is chemically reversible during charge–discharge experiments using a static cell and aqueous solutions of NaCl. An aqueous cell comprising methyl viologen (MV2+) as the anolyte and an anion exchange membrane provides an operating Vcell = 0.63 V.Additionally, cluster 1 was used as a preformed metalloligand in the synthesis of a novel coordination solid. Heating a 1:2 mixture Co6S8(PTA)6•4HCl and CuI in a solution of acetonitrile/water under solvothermal conditions leads to the formation of dark black crystals. The resulting three-dimensional framework (2) contains three distinct cluster constituents (2[Co6S8(PTA)6•H+]•2[Cu4I4]•[Cu4I62-]) and exhibits reversible redox behavior in the solid state. Framework 2 was structurally characterized using single crystal X-ray diffraction and powder X-ray diffraction. The UV-Vis diffuse reflectance spectrum of framework 2 was measured and used to calculate the band gap (1.98 eV) based on the Kubelka-Munk function.

masters theses

Chemistry

M.S.

Clusters
Copper
Framework
Metal Chalcogenide
Redox Flow Batteries
Superatom

Chemistry

Bejger, Christopher

Smith, Stuart
Merkert, Bernadette
Rabinovich, Daniel

Thesis (M.S.)--University of North Carolina at Charlotte, 2019.

This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). For additional information, see http://rightsstatements.org/page/InC/1.0/.

Copyright is held by the author unless otherwise indicated.

Freeman_uncc_0694N_12202

http://hdl.handle.net/20.500.13093/etd:2605