The oxygen stoichiometry of mixed conducting oxides depends on the oxygen chemical potential and thus on the oxygen partial pressure in the gas phase. Also voltages may change the local oxygen stoichiometry and the amount to which such changes take place is quantified by the chemical capacitance of the sample. Impedance spectroscopy can be used to probe this chemical capacitance. Impedance measurements on different oxides ((La,Sr)FeO3-δ = LSF, Sr(Ti,Fe)O3-δ = STF, and Pb(Zr,Ti)O3 = PZT) are presented, and demonstrate how the chemical capacitance may affect impedance spectra in different types of electrochemical cells. A quantitative analysis of the spectra is based on generalized equivalent circuits developed for mixed conducting oxides by J. Jamnik and J. Maier. It is discussed how defect chemical information can be deduced from the chemical capacitance.
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http://dx.doi.org/10.17344/acsi.2016.2302 | DOI Listing |
Adv Mater
January 2025
Shanghai Key Laboratory of Electrical Insulation and Thermal Ageing, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
Achieving optimal capacitive energy storage performance necessitates the integration of high energy storage density, typical of ferroelectric dielectrics, with the low polarization loss associated with linear dielectrics. However, combining these characteristics in a single dielectric material is challenging due to the inherent contradictions between the spontaneous polarization of ferroelectric dielectrics and the adaptability of linear dielectrics to changes in the electric field. To address this issue, a linear isotactic sulfonylated polynorbornene dielectric characterized by ferroelectric-like crystals has been developed.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China. Electronic address:
Transition metal sulfides, despite their abundance of electrochemically active sites, often demonstrate inadequate rate performance and mechanical stability. The development of a multi-dimensional hierarchical architecture has proven to be an effective approach to address the limitations associated with sulfides. In the present study, MoNiCo-S nanorods featuring hierarchical micro-/nano-structures were successfully synthesized through a straightforward methodology that involved "in situ growth-etching-vulcanization".
View Article and Find Full Text PDFACS Environ Au
January 2025
Dow Centre for Sustainable Engineering Innovation, School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
The global transition to clean energy technologies has escalated the demand for lithium (Li), a critical component in rechargeable Li-ion batteries, highlighting the urgent need for efficient and sustainable Li extraction methods. Nanofiltration (NF)-based separations have emerged as a promising solution, offering selective separation capabilities that could advance resource extraction and recovery. However, an NF-based lithium extraction process differs significantly from conventional water treatment, necessitating a paradigm shift in membrane materials design, performance evaluation metrics, and process optimization.
View Article and Find Full Text PDFMorphology control of electrically conductive metal-organic frameworks (EC-MOFs) can be a powerful means to tune their surface area and carrier transport pathways, particularly beneficial for energy conversion and storage. However, controlling EC-MOFs' morphology is underexplored due to the uncontrollable crystal nucleation and rapid growth kinetics. This work introduces a microwave-assisted strategy to readily synthesize Cu-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) with controlled morphologies.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan, 410083, China.
Next-generation advanced high/pulsed power capacitors rely heavily on dielectric ceramics with high energy storage performance. Although high entropy relaxor ferroelectric exhibited enormous potential in functional materials, the chemical short-range order, which is a common phenomenon in high entropy alloys to modulate performances, have been paid less attention here. We design a chemical short-range order strategy to modulate polarization response under external electric field and achieve substantial enhancements of energy storage properties, i.
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