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Dithiolene Complexes of First Row Transition Metals for Symmetric Non-Aqueous Redox Flow Batteries. / Toghill, Kathryn; Armstrong, Craig; Hogue, Ross.
In: ChemSusChem, Vol. 12, No. 19, 08.10.2019, p. 4506-4515.Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Dithiolene Complexes of First Row Transition Metals for Symmetric Non-Aqueous Redox Flow Batteries
AU - Toghill, Kathryn
AU - Armstrong, Craig
AU - Hogue, Ross
PY - 2019/10/8
Y1 - 2019/10/8
N2 - Five metal complexes of the dithiolene ligand maleonitriledithiolate (mnt2−) with M=V, Fe, Co, Ni, Cu were studied as redox‐active materials for nonaqueous redox flow batteries (RFBs). All five complexes exhibit at least two redox processes, making them applicable to symmetric RFBs as single‐species electrolytes, that is, as both negolyte and posolyte. Charge–discharge cycling in a small‐scale RFB gave modest performances for [(tea)2Vmnt], [(tea)2Comnt], and [(tea)2Cumnt] whereas [(tea)Femnt] and [(tea)2Nimnt] (tea=tetraethylammonium) failed to hold any significant capacity, indicating poor stability. Independent negolyte‐ and posolyte‐only battery cycling of a single redox couple, as well as UV/Vis spectroscopy, showed that for [(tea)2Vmnt] the negolyte is stable whereas the posolyte is unstable over multiple charge–discharge cycles; for [(tea)2Comnt], [(tea)2Nimnt], and [(tea)2Cumnt], the negolyte suffers rapid capacity fading although the posolyte is more robust. Identifying a means to stabilize Vmnt3−/2− as a negolyte, and Comnt2−/1−, Nimnt2−/1−, and Cumnt2−/1− as posolytes could lead to their use in asymmetric RFBs.
AB - Five metal complexes of the dithiolene ligand maleonitriledithiolate (mnt2−) with M=V, Fe, Co, Ni, Cu were studied as redox‐active materials for nonaqueous redox flow batteries (RFBs). All five complexes exhibit at least two redox processes, making them applicable to symmetric RFBs as single‐species electrolytes, that is, as both negolyte and posolyte. Charge–discharge cycling in a small‐scale RFB gave modest performances for [(tea)2Vmnt], [(tea)2Comnt], and [(tea)2Cumnt] whereas [(tea)Femnt] and [(tea)2Nimnt] (tea=tetraethylammonium) failed to hold any significant capacity, indicating poor stability. Independent negolyte‐ and posolyte‐only battery cycling of a single redox couple, as well as UV/Vis spectroscopy, showed that for [(tea)2Vmnt] the negolyte is stable whereas the posolyte is unstable over multiple charge–discharge cycles; for [(tea)2Comnt], [(tea)2Nimnt], and [(tea)2Cumnt], the negolyte suffers rapid capacity fading although the posolyte is more robust. Identifying a means to stabilize Vmnt3−/2− as a negolyte, and Comnt2−/1−, Nimnt2−/1−, and Cumnt2−/1− as posolytes could lead to their use in asymmetric RFBs.
KW - batteries
KW - dithiolenes
KW - electrochemistry
KW - nonaqueous systems
KW - redox chemistry
U2 - 10.1002/cssc.201901702
DO - 10.1002/cssc.201901702
M3 - Journal article
VL - 12
SP - 4506
EP - 4515
JO - ChemSusChem
JF - ChemSusChem
SN - 1864-5631
IS - 19
ER -