Electrochemistry
Stibnite in carbon sheets stores sodium better
Open access · cc by · source: Europe PMC
Natural Sb2S3 anchored on sulfur-doped carbon sheets delivers much higher reversible sodium-storage capacity and cycle retention than raw stibnite.
Study at a glance
- Design
- Other — Natural Sb2S3 on sulfur-doped carbon sheets tested as a sodium-ion anode
- N
- Battery materials half-cell study — no sample N
- Population
- Sb2S3/SCS composite electrodes in Na-ion half-cells
- Outcome
- Reversible capacity and cycling retention versus raw stibnite
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Sb2S3/SCS kept 455.8 mA h g−1 after 100 cycles at 0.1 A g−1 (70.8% retention), versus 190.1 mA h g−1 and 30.7% retention for raw stibnite. Theoretical Sb2S3 capacity is 946 mA h g−1 via conversion plus alloying (12 Na per formula). Carbon buffering is meant to ease the ~390% volume swing of sodiation.
Methodology
The authors made sulfur-doped carbon sheets by annealing an acetaldehyde/NaOH precursor with SDS at 800 °C, then precipitated natural stibnite onto the sheets from Na2S/H2SO4 and annealed at 300 °C. They characterized the composite by XRD, Raman, and XPS and tested it as a sodium-ion anode in 0.01–2.5 V half-cells.
Limitations
Results are half-cell versus sodium metal, not a full SIB pack. Rate numbers beyond the quoted cycling comparison are limited in the summary claims, and long-term calendar aging or scale-up of ore purity is not proven.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
CV also appears as a supporting characterisation of materials and mechanisms: pore-confined Pt–Ni ORR, a stibnite/carbon sodium-ion composite, and a photoredox trifluoromethylation where CV of 9,10-phenanthrenequinone sits beside EPR and ¹⁸O labelling. Those papers are not primarily about teaching CV, but they still use a voltammogram as evidence.
Evidence for the claim as stated.
A catalytic wave in a molecular CV and a battery half-cell CV are different deliverables. The cobalt HER paper reports overpotential versus a pyridine control; the stibnite composite reports capacity retention versus sodium metal (455.8 mA h g⁻¹ after 100 cycles), not a molecular k⁰. Calling both 'the CV showed it was active' erases that.
Evidence for the claim as stated.
Raman of a stibnite/sulfur-doped-carbon composite is supporting characterisation of a sodium-ion anode, not the capacity number. Sb₂S₃/SCS keeps 455.8 mA h g⁻¹ after 100 cycles at 0.1 A g⁻¹ (70.8% retention) versus 190.1 mA h g⁻¹ and 30.7% retention for raw stibnite. Theoretical capacity is 946 mA h g⁻¹ (12 Na per formula); carbon is meant to buffer a ~390% volume swing. Results are half-cell versus sodium metal, not a full pack.
Evidence for the claim as stated.
Steady-state Raman of a solid and FSRS of a protein photocycle are not the same vibrational experiment. Zn-crystal Raman fingerprints ligands next to a 3.45 eV DFT gap; stibnite/carbon Raman characterises a composite whose headline is 455.8 versus 190.1 mA h g⁻¹; GFP FSRS/AIMD tracks 146 → 101 cm⁻¹ twists on a sub-picosecond shuttle. One sentence of 'Raman confirmed the material' cannot compare those papers.
Evidence for the claim as stated.
A method-index tag is not a guarantee that the teaching numbers came from Raman. The gold adt radical’s 21 μs TM is pulsed EPR in a glass; the Zn gap is DFT; the battery retention is galvanostatic cycling. Raman can be in the characterisation stack without being the quantity you should quote in an exam answer.
Evidence for the claim as stated.
A natural-stibnite/sulfur-doped-carbon anode is the kind of composite EIS is often asked to explain (volume swing, contact loss), but the quoted numbers are galvanostatic. Sb₂S₃/SCS keeps 455.8 mA h g⁻¹ after 100 cycles at 0.1 A g⁻¹ (70.8% retention) versus 190.1 mA h g⁻¹ and 30.7% for raw stibnite. Theoretical capacity is 946 mA h g⁻¹ via conversion plus alloying (12 Na); carbon buffering targets a ~390% volume swing. Half-cell versus sodium metal, not a full pack; the summary does not quote an Rct.
Evidence for the claim as stated.
Capacitance-derived ECSA, galvanostatic capacity, and an XPS Ni³⁺ ratio are three different electrochemical claims that students lump as 'impedance showed it was better.' CoP uses 40 μF cm⁻² to normalise HER current (56 mV at 10 mA cm⁻²). Stibnite quotes 455.8 versus 190.1 mA h g⁻¹ after 100 cycles. LDH quotes Ni³⁺/Ni²⁺ 0.39 → 1.32 and 95.9% O₂ FE. Those are not replications of one EIS equivalent circuit.
Evidence for the claim as stated.
Stability means different things, and none is a fitted EIS ageing study in these summaries. CoP claims 20 h HER stability and ~100% FE; stibnite claims 70.8% capacity retention over 100 cycles versus sodium metal; LDH quantifies O₂ for 10 min at 50 mA without an electrolyzer lifetime. A Nyquist plot taken once does not equal those tests.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
A catalytic wave in a molecular CV and a battery half-cell CV are different deliverables. The cobalt HER paper reports overpotential versus a pyridine control; the stibnite composite reports capacity retention versus sodium metal (455.8 mA h g⁻¹ after 100 cycles), not a molecular k⁰. Calling both 'the CV showed it was active' erases that.
Steady-state Raman of a solid and FSRS of a protein photocycle are not the same vibrational experiment. Zn-crystal Raman fingerprints ligands next to a 3.45 eV DFT gap; stibnite/carbon Raman characterises a composite whose headline is 455.8 versus 190.1 mA h g⁻¹; GFP FSRS/AIMD tracks 146 → 101 cm⁻¹ twists on a sub-picosecond shuttle. One sentence of 'Raman confirmed the material' cannot compare those papers.
- Supports · A new Zn phenanthroline–maleate crystal
- Supports · AIMD maps GFP's excited-state proton shuttle
A method-index tag is not a guarantee that the teaching numbers came from Raman. The gold adt radical’s 21 μs TM is pulsed EPR in a glass; the Zn gap is DFT; the battery retention is galvanostatic cycling. Raman can be in the characterisation stack without being the quantity you should quote in an exam answer.
- Supports · Gold dithiolene radical holds a 21 μs spin qubit
- Supports · A new Zn phenanthroline–maleate crystal
Capacitance-derived ECSA, galvanostatic capacity, and an XPS Ni³⁺ ratio are three different electrochemical claims that students lump as 'impedance showed it was better.' CoP uses 40 μF cm⁻² to normalise HER current (56 mV at 10 mA cm⁻²). Stibnite quotes 455.8 versus 190.1 mA h g⁻¹ after 100 cycles. LDH quotes Ni³⁺/Ni²⁺ 0.39 → 1.32 and 95.9% O₂ FE. Those are not replications of one EIS equivalent circuit.
- Supports · Ultrathin porous CoP nanosheets drive HER
- Supports · NaBH4 raises Ni3+ and speeds NiFe LDH OER
Stability means different things, and none is a fitted EIS ageing study in these summaries. CoP claims 20 h HER stability and ~100% FE; stibnite claims 70.8% capacity retention over 100 cycles versus sodium metal; LDH quantifies O₂ for 10 min at 50 mA without an electrolyzer lifetime. A Nyquist plot taken once does not equal those tests.
- Supports · Ultrathin porous CoP nanosheets drive HER
- Supports · NaBH4 raises Ni3+ and speeds NiFe LDH OER
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