Spectroscopy — Understanding the mechanism of high capacitance in nickel hexaaminobenzene-based conductive metal-organic frameworks in aqueous electrolytes

3 measurement groups · 10 results

Reported values remain attached to the sample, method, conditions, extraction quality and source location that produced them.

X-ray photoemission spectroscopy, N 1s region

NiHAB powder · Powder

PHI VersaProbe 1; X-ray beam diameter 100.0 um; source analyser angle 45.0 degrees; data averaged over four collection points.

Context: Pristine NiHAB powder.
Measurement source: 15921, 15923 · Results and Discussion; Methods, X-ray Photoemission Spectroscopy · Figure 1d

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Benzenoid nitrogen fraction	25% benzenoid nitrogen (-NH-)	0.25 fraction	—	Text Rounded Reported	15921 · Results and Discussion · Figure 1d
Quinoid nitrogen fraction	75% quinoid nitrogen (-N=)	0.75 fraction	—	Text Rounded Reported	15921 · Results and Discussion · Figure 1d
Ligand motif A fraction in pristine NiHAB	25% motif A (Ni1.5C6N6H3)	0.25 fraction	—	Text Rounded Reported	15921 · Results and Discussion · Figure 1e

Electrochemical in situ Raman spectroscopy

Raman spectroscopy

free-standing NiHAB composite electrode · Electrode

Horiba XploRA+ confocal Raman; 532 nm laser; 10x objective; 1% filter; 250 s acquisition; open three-electrode cell; NiHAB on gold current collector working electrode, Ag/AgCl in 1 M KCl reference, activated carbon on gold counter; CV shown in 1 M NaOH.

Temperature: 298
Atmosphere: open aqueous electrochemical cell
Geometry: three-electrode Raman cell
Context: NiHAB electrode in application cell.
Measurement source: 15921, 15923 · Results and Discussion; Methods, In Situ Raman Spectroscopy Measurements · Figure 1b; Figure S7

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Approximate peak current in in situ Raman CV	about 0.14 mA anodic peak and -0.18 mA cathodic peak	—	visual estimate from Figure S7	Visual Estimate Uncertain	S6 · Supporting Information · Figure S7
Raman spectral region showing electrochemical evolution	1400 to 1600 cm-1	—	—	Text Range	15921 · Results and Discussion · Figure 1b

In situ Ni K-edge X-ray absorption spectroscopy / XANES during electrochemical cycling

X-ray absorption spectroscopy

free-standing NiHAB composite electrode · Electrode

Beamline 8-ID (ISS), NSLS-II; transmission and fluorescence modes; PIPS detector in grazing incidence; Ni K-edge calibrated at 8333 eV using Ni foil; pouch-type three-electrode cell with free-standing NiHAB working electrode, Ag/AgCl reference, activated carbon counter, hydrophilic polypropylene separator, 1 M KOH electrolyte; spectra during CV and steady-state holds.

Temperature: 298
Atmosphere: 1 M KOH aqueous electrolyte
Geometry: pouch-type in situ XAS cell
Context: Composite electrode containing pristine NiHAB framework.
Measurement source: 15921, 15923-15924 · Results and Discussion; Methods, In Situ XAS Measurements · Figure 1c; Figure S3; Figure S4

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Nominal Ni oxidation state	+2.5	—	—	Text Approximate	15921 · Results and Discussion · Figure S4
Ni oxidation-state change during charge/discharge	no spectral changes; XAS spectra overlap perfectly	—	—	Qualitative Qualitative	15921 · Results and Discussion · Figure 1c; Figure S3
Ni K-edge weak pre-edge peak A energy	8334 eV	—	—	Text Rounded Reported	15921 · Results and Discussion · Figure 1c
Ni K-edge second pre-edge peak B energy	8340 eV	—	—	Text Rounded Reported	15921 · Results and Discussion · Figure 1c
Ni K-edge main absorption peak C energy	8351 eV	—	—	Text Rounded Reported	15921 · Results and Discussion · Figure 1c