Fe-Based Coordination Polymers as Battery-Type Electrodes in Semi-Solid-State Battery–Supercapacitor Hybrid Devices

One two-dimensional Fe-based metal–organic
framework (FeSC1)
and one one-dimensional coordination polymer (FeSC2) have been solvothermally
prepared through the reaction among FeSO4·7H2O, the tripodal ligand 4,4′,4″-s-triazine-2,4,6-triyl-tribenzoate
(H3TATB), and flexible secondary building blocks p/m-bis­((1H-imidazole-1-yl)­methyl)­benzene
(bib). Given that their abundant interlayer spaces and different coordination
modes, two compounds have been employed as battery-type electrodes
to understand how void space and different coordination modes affect
their performances in three-electrode electrochemical systems. Both
materials exhibit outstanding but different electrochemical performances
(including distinct capacities and charge-transfer abilities) under
three-electrode configurations, where the charge storage for each
electrode material is mainly dominated by the diffusion-controlled
section (i ∝ v0.5) through power-law equations. Additionally, the partial phase transformations
to more stable FeOOH are also detected in the long-term cycling loops.
After coupling with the capacitive carbon-based electrode to assemble
into the semi-solid-state battery–supercapacitor-hybrid (sss-BSH)
devices, the sss-FeSC1//AC BSH device delivers excellent capacitance,
superior energy and power density, and longstanding endurance as well
as the potential practical property.