Formation of One-Dimensional Coordination Chains for High-Performance Anode Materials of Lithium-Ion Batteries via a Bottom-Up Approach.

Understanding the chemistry of coordination compounds as lithium storage materials is significant for advancing lithium-ion batteries' technology. Coordination compounds have become a new family of versatile anode materials because the metal center, the ligand, and the nonrigid crystal structure can simultaneously contribute to the lithium storage capacity. However, the capacities and cycling abilities of coordination compounds are relatively low in comparison to inorganic nanomaterials, and the mechanism for lithium storage is unclear. This work reports that linking the mononuclear complex [Ni(PBIM)2(HIPA)] (1), where PBIM = 2-(2-pyridyl)benzimidazole, and HIPA = 5-hydroxyisophthalic acid, to a one-dimensional coordination polymer [Ni(PBIM)(HIPA)]n (2) via coordination bonds by a facile bottom-up assembly route can significantly enhance the lithium storage capacity from 554 mA h g-1 of 1 to 1025 mA h g-1 of 2 at 100 mA g-1. A combined experimental and theoretical study shows that the favorable lithium-ion diffusion pathways afforded by the coordination-chain-based structure of 2 are responsible for its superior electrochemical property.