Catechol‐Mediated Reversible Binding of Multivalent Cations in Eumelanin Half‐Cells

Abstract

Electrochemical storage systems that utilize divalent cations such as Mg2+ can improve the volumetric charge storage capacities compared to those that use monovalent ions. Here, a cathode based on naturally derived melanin pigments is used in secondary Mg2+ batteries. Redox active catechol groups in melanins permit efficient and reversible exchange of divalent Mg2+ cations to preserve charge storage capacity in biopolymer cathodes for more than 500 cycles.

Aqueous photo(electro)catalysis with eumelanin thin films

“…24 Several devices exploiting protonic transport in eumelanin thin films have been demonstrated, 22,25 though there is also evidence that there may be electronic charge carrier mobility in eumelanin in the form of hopping negative charges stored in the semiquinone structure. 26 Eumelanin thin films can be electrochemically-addressed and intercalated with ions, 27 thus they have been used in sodium ion batteries.…”

Natural melanin pigments and their interfaces with metal ions and oxides: emerging concepts and technologies

“…Nevertheless, promising results have been obtained with synthetic melanin-like polymers, e.g., polydopamine. [10,103] L-dopa [43,55] Natural (Sepia, [48,56] bovine eye [41] ) 5,6-Dihydroxyindole (DHI)-melanin (QI) [57] Mg 2+ Natural (Sepia [58] ) Natural (bovine eye, [41,45] Sepia, [48,56,59] squid [60] ), dopa-melanin [45] Ca 2+ Natural (bovine eye, [41,45] Sepia, [48,56,59,61] squid [60] ), dopa-melanin [45] Fe 3+ Natural (Sepia, [56,59,62] human hair, [63] black rabbit hair [64] ), neuromelanin, [65][66][67] dopa, [68][69][70] catechols, [71] polydopamine, [72][73][74] DHI-melanin, [63] melanin from cys-dopamine, [75] diethylaminedopamine-melanin [74] Neuromelanin, [76] dopa-melanin, [74] natural (Sepia), [74] diethylamine-dopaminemelanin [74] Natural (Sepia), …”

“…[58,79] Polydopamine, a synthetic melanin analog, has been used to selectively extract and separate metal cations from aqueous solutions, leveraging on the different binding affinities of the pigments toward different cations. [67,100,101] Films of polydopamine can reduce Ag + cations into Ag nanoparticles, which impart antibacterial properties to the same films.…”

Materialien und Strukturen für schluckbare elektromechanische medizinische Funktionseinheiten

“…[38][39][40] Melanin kann sowohl als Anode wie auch als Kathode fungieren, je nach Reduktionspotenzial der Gegenelektrode.Z um Beispiel kçnnen wässrige Natriumionen-Primärzellen mit voroxidierten Melanin-Kathoden gekoppelt mit keramikbasierten Anoden bei 0.5 Vb etrieben werden und zeigen nominal-spezifische Energiekapazitäten von 25 mWhg À1 (Abbildung 3). Natürliche Melanin-Pigmente und synthetische Analoga (zur Einfachheit hier als Melanine bezeichnet) kçnnen als Elektrodenmaterial in verschiedenen Konfigurationen wasserbasierter Batterien dienen.…”