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.