Anchoring I<sub>3</sub><sup>–</sup> via Charge-Transfer Interaction by a Coordination Supramolecular Network Cathode for a High-Performance Aqueous Dual-Ion Battery
Yuanming Tan, Zengren Tao, Yuanfei Zhu, Zhao Chen, Anding Wang, Shimei Lai, Yang-Yi Yang
Abstract
Iodine is considered to have broad application prospects in the field of electrochemical energy storage. However, the high solubility of I3– severely hampers its practical application, and the lack of research on the anchoring mechanism of I3– has seriously hindered the development of advanced cathode materials for iodine batteries. Herein, based on the molecular orbital theory, we studied the charge-transfer interaction between the acceptor of I3– with a σ* empty antibonding orbital and the donor of pyrimidine nitrogen with lone-pair electrons, which is proved by the results of UV–vis absorption spectroscopy, Raman spectroscopy, and density functional theory (DFT) calculations. The prepared dual-ion battery (DIB) exhibits a high voltage platform of 1.2 V, a remarkable discharge-specific capacity of up to 207 mAh g–1, and an energy density of 233 Wh kg–1 at a current density of 5 A g–1, as well as outstanding cycle stability (operating stably for 5000 cycles) with a high Coulombic efficiency of 97%, demonstrating excellent electrochemical performance and a promising prospect in stationary energy storage.