Regulating the metal nodes of 1D conjugated coordination polymers for enhancing the performance of sodium-ion batteries

Abstract

Conjugated coordination polymers (CCPs) have attracted extensive attention for energy storage in the past few years. However, the rational design and controllable synthesis of CCPs remain challenging, which prevents gaining insight into the relationship between structure and electrochemical performance and limits the potential applications of CCPs. Herein, 2,5-dihydroxy-1,4-benzoquinone (H₂DHBQ) is selected to construct one dimensional CCPs M-DHBQ with different metal ions, including Ni²⁺, Mn²⁺ and Zn²⁺. Comprehensive characterizations indicated that the high capacity of Ni-DHBQ was due to the redox reactions of both ligands and non-innocent Ni²⁺ ions. On the other hand, the sodium storage of Mn- and Zn-DHBQ involved the redox reactions of only ligands. These results highlighted the importance of the rational choice of metal ions for high capacity and cycle stability, and deepen our understanding on CCPs for further designing high performance energy storage devices.