Y. Chen, Q. Zhu, K. Fan, Y. Gu, M. Sun, Z. Li, C. Zhang, Y. Wu, Q. Wang, S. Xu, J. Ma, C. Wang*, W. Hu, Successive Storage of Cations and Anions by Ligands of π-d Conjugated Coordination Polymers Enabling Robust Sodium-ion Batteries. Angew. Chem. Int. Ed. 2021, DOI: 10.1002/anie.202106055.

原文链接：http://doi.org/10.1002/anie.202106055

Abstract：The oxidation of π-d conjugated coordination polymers (CCPs) accompanied with anion insertion has the merits of increasing the capacity and elevating the discharge voltages. However, the previous reports on this mechanism either required more investigations or showed low capacity and poor cyclablity. Herein, triphenylene catecholate-based two dimensional CCPs are constructed by employing inactive transition metal ions (Zn²⁺) as nodes, forming Zn-HHTP. Substantial characterizations and theoretical calculations indicated the successive storage of cations and anions by redox of only ligands, leading to a high reversible capacity of ~150 mAh g^-1 at 100 mA g^-1 and remarkable capacity retention of 90% after 1000 cycles. On the contrary, as a control experiment, the analogue CCPs (Cu-HHTP) with Cu²⁺ nodes, involved the redox of both ligands and metal ions and accompanied with the storage of only Na⁺-cations, showing much poorer cyclability. These results highlighted the importance of redox of only ligands for long-term cycle life and the insight into the storage mechanisms would deepen our understanding on CCPs for further design of CCPs with high performance.