Cobalt and Vanadium Trimetaphosphate Polyanions: Synthesis, Characterization and Electrochemical Evaluation for Non-Aqueous Redox-Flow Battery Applications

摘要: An electrochemical cell consisting of cobalt ([CoII/III(P3O9)2]4–/3–) and vanadium ([VIII/II(P3O9)2]3–/4–) bistrimetaphosphate complexes as catholyte anolyte species, respectively, was constructed with a voltage 2.4 V Coulombic efficiencies >90% for up to 100 total cycles. The [Co(P3O9)2]4– (1) [V(P3O9)2]3– (2) have favorable properties flow-battery applications, including reversible redox chemistry, high stability toward cycling, solubility in MeCN (1.09 ± 0.02 M, [PPN]4[1]·2MeCN; 0.77 0.06 [PPN]3[2]·DME). [PPN]4[1]·2MeCN [PPN]3[2]·DME salts were isolated crystalline solids 82 68% yields, characterized by 31P NMR, UV/vis, ESI-MS(−), IR spectroscopy. salt also structurally characterized, crystallizing the monoclinic P21/c space group. Treatment 1 [(p-BrC6H4)3N]+ allowed isolation one-electron-oxidized spin-crossover (SCO) complex, [Co(P3O9)2]3– (3), which is...