Search

Lithium supply shortages have prompted the search for alternatives to widespread grid system applications. Potassium-ion batteries (PIBs) have emerged to promising candidates for this purpose. Nonetheless, the large radius of K+ (1.38 Å) impedes the march of satisfactory cathode materials. Here, we used solid-phase synthesis to prepare a layered K0.37MnO2·0.25H2O (KMO) cathode, comprising alternately connected MnO6 octahedra with a large interlayer spacing (0.71 nm) to accommodate the migration and transport of K+ ions. The cathode material achieved initial specific capacities of 102.3 and 88.1 mA h g−1 at current densities of 60 mA g−1 and 1 A g−1, respectively. The storage mechanism of K+ ions in PIBs was demonstrated ex situ using x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy measurements. Overall, our proposed KMO was confirmed as an auspicious cathode material for potential use in PIBs. [ABSTRACT FROM AUTHOR]

Although the performance of the self-standing electrode has been enhanced for aqueous zinc-ion batteries (AZIBs), it is necessary to explore and analyse the deep modification mechanism (especially interface effects). Herein, density functional theory (DFT) calculations are applied to investigate the high-performance cathode based on the VO2/carbon cloth composites with heterostructures interface (H-VO2@CC). The adsorption energy comparisons and electron structure analyses verify that H-VO2@CC has extra activated sites at the interface, enhanced electrical conductivity, and structural stability for achieving high-performance AZIBs due to the presence of built-in electric field at the interfaces. Accordingly, the designed self-standing H-VO2@CC cathode delivers higher rate capacity, longer-life cyclability, and faster electronic/ion transmission kinetics benefiting from the synergistic effects. The risks of active material shedding and dissolution during the dis/charge process of two cathodes were evaluated via ex-situ ultraviolet—visible (UV-vis) spectrum and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) technique. Finally, this investigation also explores the charge storage mechanism of H-VO2@CC through various ex-situ and in-situ characterization techniques. This finding can shed light on the significant potential of heterostructures interface engineering in practical applications and provide a valuable direction for the development of cathode materials for AZIBs and other metal-ion batteries. [ABSTRACT FROM AUTHOR]

VO2 generally has a higher theoretical capacity and layered structure suitable for the intercalation/extraction of zinc ions. However, Zn2+ ions with high charge density interact with the crystal lattice and limit further improvement in electrochemical performance. Defect engineering is a potential modification method with very promising application prospects, but the established procedures for preparing defects are complicated. In this study, VO2–x(B) with oxygen deficiency is prepared by a simple solution reaction with NaBH4. The presence of oxygen deficiencies is confirmed by positron annihilation lifetime spectroscopy, UV/Vis absorbance spectroscopy and others. Owing to the presence of oxygen defects, the aqueous Zn/VO2–x(B) battery exhibits improved specific capacity, excellent reversibility, and structural stability. Ex situ characterization techniques are employed to demonstrate the reversible insertion‐extraction mechanism of Zn2+ ions from and into the host material. In addition, the Zn/VO2–x(B) batteries still exhibit considerable electrochemical performance, even with high‐loading electrodes (about 4 mg cm−2). [ABSTRACT FROM AUTHOR]

Lithium supply shortages have prompted the search for alternatives to widespread grid system applications. Potassium-ion batteries (PIBs) have emerged to promising candidates for this purpose. Nonetheless, the large radius of K + (1.38 Å) impedes the march of satisfactory cathode materials. Here, we used solid-phase synthesis to prepare a layered K 0.37 MnO 2 ·0.25H 2 O (KMO) cathode, comprising alternately connected MnO 6 octahedra with a large interlayer spacing (0.71 nm) to accommodate the migration and transport of K + ions. The cathode material achieved initial specific capacities of 102.3 and 88.1 mA h g -1 at current densities of 60 mA g -1 and 1 A g -1 , respectively. The storage mechanism of K + ions in PIBs was demonstrated ex situ using x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy measurements. Overall, our proposed KMO was confirmed as an auspicious cathode material for potential use in PIBs., (© 2023 IOP Publishing Ltd.)

VO 2 generally has a higher theoretical capacity and layered structure suitable for the intercalation/extraction of zinc ions. However, Zn 2+ ions with high charge density interact with the crystal lattice and limit further improvement in electrochemical performance. Defect engineering is a potential modification method with very promising application prospects, but the established procedures for preparing defects are complicated. In this study, VO 2-x (B) with oxygen deficiency is prepared by a simple solution reaction with NaBH 4 . The presence of oxygen deficiencies is confirmed by positron annihilation lifetime spectroscopy, UV/Vis absorbance spectroscopy and others. Owing to the presence of oxygen defects, the aqueous Zn/VO 2-x (B) battery exhibits improved specific capacity, excellent reversibility, and structural stability. Ex situ characterization techniques are employed to demonstrate the reversible insertion-extraction mechanism of Zn 2+ ions from and into the host material. In addition, the Zn/VO 2-x (B) batteries still exhibit considerable electrochemical performance, even with high-loading electrodes (about 4 mg cm -2 )., (© 2020 Wiley-VCH GmbH.)