Kon K., Uchida K., Fuku K. et al. · ACS Applied Materials and Interfaces · 2021 · 38188-38193
Open a family to keep every result attached to its sample, method and conditions.
Paraphrased for this database from the authors’ stated interpretations — never quoted verbatim — and kept separate from reported measurements.
The cathode redox process is assigned primarily to two-electron reduction/oxidation of the dhbq ligand rather than Fe(II)/Fe(III).
Caveat: A new plateau after five cycles remains unassigned by the authors.
4 · Results and Discussion · Figure 8 · Linked to 4 structured results
Fe(dhbq) reversibly adsorbs water up to P/P0 = 0.65 without prominent structural change, but saturated water vapour induces conversion toward Fe(dhbq)(H2O)2.
Caveat: The chemisorption assignment for the second step is explicitly described by the authors as requiring more study.
14 · Water vapor adsorption isotherm · Figure S11 · Linked to 2 structured results
Capacity depends strongly on the acetylene-black fraction because lower electronic accessibility in Fe(dhbq)-rich cathodes leaves some active molecules unused.
Caveat: Capacities include AB double-layer contribution, particularly in high-AB cathodes.
5 · Results and Discussion · Table 1 · Linked to 4 structured results
Fe(dhbq) contains Fe(II) in an approximately five-coordinate square-pyramidal local environment after dehydration.
Caveat: Main and SI report slightly different pre-edge intensities; both support higher pre-edge intensity for Fe(dhbq).
2 · Results and Discussion · Figure 4 · Linked to 4 structured results
Desolvation of Fe(dhbq)(H2O)2 to Fe(dhbq) increases electronic conductivity by about four orders of magnitude and decreases the optical band gap.
Caveat: Conductivity measured on pressed pellets with carbon-paste contacts; exact pellet dimensions not reported.
5 · Conclusions · Linked to 5 structured results
The anhydrous Fe(dhbq) framework retains permanent microporosity after dehydration whereas hydrated Fe(dhbq)(H2O)2 is non-porous.
Caveat: Anhydrous crystal structure is not solved because PXRD peaks are broad; pore structure is inferred from gas adsorption and proposed packing.
3 · Results and Discussion · Figure 5 · Linked to 4 structured results
Fe(dhbq) shows semiconductive transport, but the activation energy is too large for a simple intrinsic direct-band-gap picture, so the authors propose extrinsic limitation such as hopping through defect sites.
Caveat: Mechanism is inferential; no direct defect spectroscopy or hopping model fit beyond Arrhenius activation is reported.
4 · Results and Discussion · Figure 7 · Linked to 3 structured results
Names and aliases are kept exactly within the paper’s own identity model.
| Material | Composition | Structure context | Source |
|---|---|---|---|
| Acetylene black reference | C | unknown · UnknownConductive carbon additive reference used to estimate capacity contribution in cathode composites. | 19 · Discussion about capacity contribution of AB · Figure S18 |
| Fe(dhbq) | Fe(dhbq)Fe(II) centres in a desolvated dhbq coordination framework · dhbq = 2,5-dihydroxy-1,4-benzoquinone | unknown · PristineAnhydrous electron-conductive MOF obtained by dehydrating Fe(dhbq)(H2O)2; PXRD is broadened, XAFS gives ca. five-coordinate Fe(II), and DFT/TEM support an expected dimerised packing model. | 1 · Abstract |
| Fe(dhbq)/acetylene black/PTFE cathode composite | Fe(dhbq) + acetylene black + PTFEFe(II) centres in Fe(dhbq) active material · dhbq in Fe(dhbq); PTFE binder; acetylene black conductive additive | unknown · CompositeComposite cathode/working electrode made by grinding Fe(dhbq), acetylene black and PTFE. | 4 · Results and Discussion · Figure 8 |
| Fe(dhbq)(H2O)2 | Fe(dhbq)(H2O)2Fe(II) ions with equatorial dhbq oxygen donors and two axial water ligands · dhbq = 2,5-dihydroxy-1,4-benzoquinone | 1D · PristineMonoclinic C2/m one-dimensional coordination polymer; dhbq coordinates equatorially in a trans arrangement and water molecules occupy axial Fe sites. | 2 · Results and Discussion · Figure 2 |
| {Fe(Hdhbq)2}2 / Fe2(dhbq)(Hdhbq)2(H2O)4 model systems | {Fe(Hdhbq)2}2; Fe2(dhbq)(Hdhbq)2(H2O)4Fe(II) centres in finite dimer model complexes · Hdhbq/dhbq ligands | 0D · Model SystemDFT-optimised dimer and calculated orbital/spectral models used to rationalise Fe(dhbq) structure and MLCT absorption. | 3 · Results and Discussion · Figure S9 |
| M(dhbq) analogues (M = Mg, Mn, Zn) | M(dhbq)Mg, Mn or Zn nodes in dhbq coordination frameworks · dhbq = 2,5-dihydroxy-1,4-benzoquinone | unknown · PristineIsostructural comparison M(dhbq) materials used for adsorption and PXRD comparisons; no electronic transport is reported here. | 10 · N2 adsorption isotherms · Table S2 |
Sample form, processing state and composition status define the context for measurements.
| Sample | Form and role | Processing and geometry | Source |
|---|---|---|---|
| Acetylene black charge-discharge referenceresearch_0103__mat__ab_reference | Electrode · Model System · Composite | AB reference charge-discharge characteristics used to estimate capacity contribution.LIB cathode reference context | 19 · Discussion about capacity contribution of AB · Figure S18 |
| Fe(dhbq) 10 wt% / AB 80 wt% / PTFE 10 wt% cathoderesearch_0103__mat__fe_dhbq_cathode_composite | Electrode · Composite Sample · Composite | Composite cathode with high acetylene-black fraction for charge-discharge comparison.CR2032 coin-cell cathode | 17 · Charge-Discharge characteristics · Figure S15 |
| Fe(dhbq) 45 wt% / AB 45 wt% / PTFE 10 wt% cathoderesearch_0103__mat__fe_dhbq_cathode_composite | Electrode · Composite Sample · Composite | Composite cathode used for 1.5-3.5 V cycling at 0.3 C.CR2032 coin-cell cathode | 18 · Charge-Discharge characteristics · Figure S17 |
| Fe(dhbq) 50 wt% / AB 40 wt% / PTFE 10 wt% cathoderesearch_0103__mat__fe_dhbq_cathode_composite | Electrode · Composite Sample · Composite | Fe(dhbq), acetylene black and PTFE ground in an agate mortar and assembled in a coin cell with 1 M LiClO4 in EC/DEC 1:1.CR2032 coin-cell cathode; lithium foil anode; Celgard separator | 4 · Results and Discussion · Figure 8 |
| Fe(dhbq) 80 wt% / AB 10 wt% / PTFE 10 wt% cathoderesearch_0103__mat__fe_dhbq_cathode_composite | Electrode · Composite Sample · Composite | Composite cathode with low acetylene-black fraction for charge-discharge comparison.CR2032 coin-cell cathode | 17 · Charge-Discharge characteristics · Figure S15 |
| Fe(dhbq)(H2O)2 polycrystalline powderresearch_0103__mat__fe_dhbq_h2o2 | Powder · Pristine Control · Pristine Framework | Deep brown polycrystalline solid prepared from FeSO4.7H2O, H2dhbq and K2CO3 in aqueous N2 atmosphere; filtered and dried. | 3 · III. Syntheses |
| Fe(dhbq)(H2O)2 single crystalsresearch_0103__mat__fe_dhbq_h2o2 | Single Crystal · Pristine Control · Pristine Framework | Single crystals selected after slow aerial oxidation of THB with FeSO4 solution in air for one week. | 3 · III. Syntheses |
| Fe(dhbq)(H2O)2 compressed pelletresearch_0103__mat__fe_dhbq_h2o2 | Pellet · Pristine Control · Pristine Framework | Pressed at 0.2 ton with a 3 mm pellet die for I-V measurements.carbon paste contacts; 30 um gold wire terminals · 3 mm diameter pellet die; thickness not reported | 2 · Characterization and Instrumental Procedures |
| Anhydrous Fe(dhbq) powderresearch_0103__mat__fe_dhbq | Powder · Target Sample · Pristine Framework | Obtained by desolvation/dehydration of Fe(dhbq)(H2O)2; TGA shows loss of two axial water molecules up to 180 C. | 2 · Results and Discussion · Figure 3 |
| Fe(dhbq) compressed pelletresearch_0103__mat__fe_dhbq | Pellet · Target Sample · Pristine Framework | Pressed at 0.2 ton with a 3 mm pellet die for I-V and temperature-dependent conductivity measurements.carbon paste contacts; 30 um gold wire terminals · 3 mm diameter pellet die; thickness not reported | 2 · Characterization and Instrumental Procedures |
| Fe dimer computational modelresearch_0103__mat__fe_hdhbq_dimer_model | Model · Model System · Model | DFT-optimised finite model; no experimental synthesis. | 12 · Optimized structure · Figure S9 |
| Mg(dhbq) powderresearch_0103__mat__m_dhbq_analogues | Powder · Pristine Control · Pristine Framework | Not described in this paper; used as M(dhbq) adsorption/PXRD comparison. | 10 · N2 adsorption isotherms · Table S2 |
| Mn(dhbq) powderresearch_0103__mat__m_dhbq_analogues | Powder · Pristine Control · Pristine Framework | Not described in this paper; used as M(dhbq) adsorption/PXRD comparison. | 10 · N2 adsorption isotherms · Table S2 |
| Zn(dhbq) powderresearch_0103__mat__m_dhbq_analogues | Powder · Pristine Control · Pristine Framework | Not described in this paper; used as M(dhbq) adsorption/PXRD/spectroscopy comparison. | 10 · N2 adsorption isotherms · Table S2 |