Nanostructured Metal–Organic Conjugated Coordination Polymers with Ligand Tailoring for Superior Rechargeable Energy Storage

Conjugated coordination polymers have become an emerging category of redox-active materials. Although recent studies heavily focus on the tailoring of metal centers in the complexes to achieve stable electrochemical performance, the effect on different substitutions of the bridging bonds has rarely been studied. An innovative tailoring strategy is presented toward the enhancement of the capacity storage and the stability of metal–organic conjugated coordination polymers. Two nanostructured d-π conjugated compounds, Ni[C₆H₂(NH)₄]_n (Ni-NH) and Ni[C₆H₂(NH)₂S₂]_n (Ni-S), are evaluated and demonstrated to exhibit hybrid electrochemical processes. In particular, Ni-S delivers a high reversible capacity of 1164 mAh g⁻¹, an ultralong stability up to 1500 cycles, and a fully recharge ability in 67 s. This tailoring strategy provides a guideline to design future effective conjugated coordination-polymer-based electrodes.