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

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. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.