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Magnard NPL, Kirsch A, Jørgensen MRV, Kantor I, Sørensen DR, Huotari S, Rudić S, Bordallo HN, Jensen KMØ. Control of H-Related Defects in γ-MnO 2 in a Hydrothermal Synthesis. Inorg Chem 2023; 62:13021-13029. [PMID: 37537143 DOI: 10.1021/acs.inorgchem.3c01815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Manganese dioxide is a good candidate for effective energy storage and conversion as it possesses rich electrochemistry. The compound also shows a wide polymorphism. The γ-variety, an intergrowth of β- and R-MnO2, has been extensively studied in several types of batteries (e.g., Zn/MnO2, Li-ion) and is a common electrode material for commercial batteries. It is well known that the insertion of protons thermodynamically stabilizes γ-MnO2 with respect to β-MnO2. Protons can enter the structure either by forming groups of 4 hydroxyls around a Mn4+ vacancy, called a Ruetschi defect, or by forming a hydroxyl group near a Mn3+ ion, called a Coleman defect. These defects differently affect the electrochemistry of manganese oxide, and tailoring their amount in the structure can be used to tune the material properties. Previous studies have addressed the proton insertion process, but the role of the synthesis pathway on the amount of defects created is not well understood. We here investigate how the parameters in a hydrothermal synthesis of γ-MnO2 nanoparticles influence the amount and type of H-related defects. Structural investigations are carried out using Pair Distribution Function analysis, X-ray absorption spectroscopy, thermogravimetric analysis, and inelastic neutron scattering. We demonstrate the possibility to control the amount and type of defects introduced during the synthesis. While the amount of Ruetschi defects increases with synthesis temperature, it decreases with extended synthesis time, along with the amount of Coleman defects. Moreover, we discuss the arrangement of the defects in the γ-MnO2 nanoparticles.
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Affiliation(s)
| | - Andrea Kirsch
- Department of Chemistry, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Mads R V Jørgensen
- MAX IV Laboratory, 224 84 Lund, Sweden
- Department of Chemistry & iNANO, Aarhus University, 8000 Aarhus C, Denmark
| | - Innokenty Kantor
- MAX IV Laboratory, 224 84 Lund, Sweden
- Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Daniel R Sørensen
- MAX IV Laboratory, 224 84 Lund, Sweden
- Department of Chemistry & iNANO, Aarhus University, 8000 Aarhus C, Denmark
| | - Simo Huotari
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland
| | - Svemir Rudić
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, STFC, Didcot OX11 0QX, U.K
| | - Heloisa N Bordallo
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Kirsten M Ø Jensen
- Department of Chemistry, University of Copenhagen, 2100 Copenhagen, Denmark
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Differences in Crystallization Behaviors between Cyclic and Linear Polymer Nanocomposites. CHINESE JOURNAL OF POLYMER SCIENCE 2020. [DOI: 10.1007/s10118-020-2403-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Affiliation(s)
- Wenbing Hu
- Department of Polymer Science and Engineering, State Key Lab of Coordination Chemistry, School of Chemistry and Chemical EngineeringNanjing University Nanjing 210023 China
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