The Coupling of Local Strain and K<sup>+</sup>‐Ion Release Induced Phase Transition Heterogeneity in Tunnel MnO<sub>2</sub>

Peng, Haoyang; Xia, Fanjie; Zhang, Chenyu; Zhuo, Haoxiang; Peng, Xin; Sun, Congli; Wu, Jinsong

doi:10.1002/adfm.202113424

Cited by 11 publications

(12 citation statements)

References 31 publications

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“…1f). Previous reports indicated that local strain introduced charge transfer and produced Jahn-Teller active Mn 3+ , which kinetically facilitated electrochemical intercalation and desorption processes by lowering the critical migration barriers 18 . This internal strain accommodated mechanical strains due to volume expansion and avoided material pulverization.…”

Section: Resultsmentioning

confidence: 99%

Sodium preintercalation-induced oxygen-deficient hydrated potassium manganese oxide for high-energy flexible Mg-ion supercapacitors

et al. 2023

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Layered potassium manganese oxides are promising candidates for use in aqueous supercapacitors owing to their wide potential windows, layered feature, and Faradaic redox reactions that occur on surfaces and in bulk regions. However, the practical application is hindered by rapid performance degradation due to their inherently low electrical conductivities and inferior structural stabilities. Here, we develop ultralong nanobelts comprising hydrated Na-intercalated oxygen-deficient potassium manganese oxide (H-Na-D-KMO), in which the Na+ ions are preintercalated and synchronously induce the generation of oxygen vacancies, as high-energy-density and durable electrodes for Mg-ion supercapacitors. The experimental results indicated that preintercalation of Na+ ions and formation of oxygen vacancies improved the electrical properties and ion diffusion, which accounted for the fast reaction kinetics and good cycling performance of H-Na-D-KMO. The optimized H-Na-D-KMO delivered a significantly enhanced specific capacitance and cycling performance compared to those of pure H-KMO. Asymmetric supercapacitors with H-Na-D-KMO as the cathode and as-prepared MoO2@carbon as the anode exhibited an ultrahigh energy density of 108.4 Wh kg–1 at 11,000 Wh kg−1, which is superior to most supercapacitors reported in the literature. Moreover, the assembled device exhibited good cycling stability for over 5000 cycles with a fading rate of 0.002% per cycle and good mechanical flexibility, which opens an avenue for further advancements in high-energy supercapacitors.

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Section: Resultsmentioning

confidence: 99%

Sodium preintercalation-induced oxygen-deficient hydrated potassium manganese oxide for high-energy flexible Mg-ion supercapacitors

et al. 2023

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“…Overall, the lower Mn–O bond strength and fewer number of K + on the high-index crystal facets will provide a powerful environment for the pseudocapacitive energy storage of α-MnO 2 . 46,47…”

Section: Resultsmentioning

confidence: 99%

Engineering the crystal facets of α-MnO₂ nanorods for electrochemical energy storage: experiments and theory

Wang,

Lu,

Wen

et al. 2023

Nanoscale

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“…These results are strong evidence for the varied spin states and altered lattice structure with rich defects induced by high strain. 48,49 By contrast, α-MnO 2 −Ru shows no shift of Raman peaks (Figure 4e). Because of the disordered structure, a slight red shift of vibration modes was also observed for τ-MnO 2 −Ru but to a much smaller extent than that of β-MnO 2 −Ru (Figure 4f).…”

Section: C) a Close Inspection Of The Absorption Edges Finds That The...mentioning

confidence: 95%

Ru-Substituted MnO₂ for Accelerated Water Oxidation: The Feedback of Strain-Induced and Polymorph-Dependent Structural Changes to the Catalytic Activity and Mechanism

et al. 2022

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Heteroatomic modulation of MnO 2 is an effective way to introduce and tailor the catalytically active sites for electrochemical water oxidation. While great efforts have been devoted to parsing the configuration and coordination of dopants in dictating the catalytic activity, less is considered about the feedback from the structurally adapted MnO 2 host to the intrinsic activity of catalytic sites. In this study, the topological effect on oxygen evolution reaction (OER) activity was systemically investigated for partially Ru-substituted MnO 2 of various polymorphs. We show that MnO 2 of different porosities responds differently to the Ru integration, thereby resulting in varied lattice strains and morphological changes. While the highly porous τ-MnO 2 undergoes amorphization upon Ru substitution, the closely packed β-MnO 2 suffers crystal splintering with drastically enhanced structural defects, which lends to a low OER overpotential of 278 mV at 10 mA cm −2 and a high turnover frequency of 2022.2 h −1 that is 19.6fold higher than that of the commercial RuO 2 benchmark. Therefore, the integration of Ru does not simply append active sites to the relatively inert metal oxides but simultaneously modifies the crystal structure of MnO 2 to retroactively modulate the catalytic activity. We further show that OER on the Ru-substituted β-MnO 2 follows a lattice oxygen mechanism as a result of the adapted oxide substrate. This study furnishes a fresh and systemic view on the dopant−substrate interplay for modulating the electrocatalytic activity of tunneled MnO 2 structures.

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The Coupling of Local Strain and K⁺‐Ion Release Induced Phase Transition Heterogeneity in Tunnel MnO₂

Abstract: Multivalent transition metal oxides possess abundant phase and valence states, the transition of which is closely related to a wide range of functionalities that have applications in various areas, such as rechargeable batteries, supercapacitors,

Cited by 11 publications

References 31 publications

Sodium preintercalation-induced oxygen-deficient hydrated potassium manganese oxide for high-energy flexible Mg-ion supercapacitors

Sodium preintercalation-induced oxygen-deficient hydrated potassium manganese oxide for high-energy flexible Mg-ion supercapacitors

Engineering the crystal facets of α-MnO₂ nanorods for electrochemical energy storage: experiments and theory

Ru-Substituted MnO₂ for Accelerated Water Oxidation: The Feedback of Strain-Induced and Polymorph-Dependent Structural Changes to the Catalytic Activity and Mechanism

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The Coupling of Local Strain and K+‐Ion Release Induced Phase Transition Heterogeneity in Tunnel MnO2

Abstract: Multivalent transition metal oxides possess abundant phase and valence states, the transition of which is closely related to a wide range of functionalities that have applications in various areas, such as rechargeable batteries, supercapacitors,

Cited by 11 publications

References 31 publications

Sodium preintercalation-induced oxygen-deficient hydrated potassium manganese oxide for high-energy flexible Mg-ion supercapacitors

Sodium preintercalation-induced oxygen-deficient hydrated potassium manganese oxide for high-energy flexible Mg-ion supercapacitors

Engineering the crystal facets of α-MnO2 nanorods for electrochemical energy storage: experiments and theory

Ru-Substituted MnO2 for Accelerated Water Oxidation: The Feedback of Strain-Induced and Polymorph-Dependent Structural Changes to the Catalytic Activity and Mechanism

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Resources

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The Coupling of Local Strain and K⁺‐Ion Release Induced Phase Transition Heterogeneity in Tunnel MnO₂

Engineering the crystal facets of α-MnO₂ nanorods for electrochemical energy storage: experiments and theory

Ru-Substituted MnO₂ for Accelerated Water Oxidation: The Feedback of Strain-Induced and Polymorph-Dependent Structural Changes to the Catalytic Activity and Mechanism