Filters

2022 - 20232

More filters

2022 - 20242
Reset filters

Settings

Author: Husmann, Samantha × Author: Presser, Volker × End date: 2024 × Start date: 2020 × End date: 2024 × Start date: 2020 × Publisher: Weinheim : Wiley-VCH ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Mechanically Stable, Binder‐Free, and Free‐Standing Vanadium Trioxide/Carbon Hybrid Fiber Electrodes for Lithium‐Ion Batteries
    (Weinheim : Wiley-VCH, 2023) Bornamehr, Behnoosh; Gallei, Markus; Husmann, Samantha; Presser, Volker
    Binder is a crucial component in present-day battery electrodes but commonly contains fluorine and requires coating processing using organic (often toxic) solvents. Preparing binder-free electrodes is an attractive strategy to make battery electrode production and its end-of-use waste greener and safer. Herein, electrospinning is employed to prepare binder-free and self-standing electrodes. Such electrodes often suffer from low flexibility, and the correlation between performance and flexibility is usually overlooked. Processing parameters affect the mechanical properties of the electrodes, and for the first time it is reported that mechanical flexibility directly influences the electrochemical performance of the electrode. The importance is highlighted when processing parameters advantageous to powder materials, such as a higher heat treatment temperature, harm self-standing electrodes due to deterioration of fiber flexibility. Other strategies, such as conductive carbon addition, can be employed to improve the cell performance, but their effect on the mechanical properties of the electrodes must be considered. Rapid heat treatment achieves self-standing V2O3 with a capacity of 250 mAh g−1 at 250 mA g−1 and 390 mAh g−1 at 10 mA g−1
  • Thumbnail Image
    Item
    Layered Nano‐Mosaic of Niobium Disulfide Heterostructures by Direct Sulfidation of Niobium Carbide MXenes for Hydrogen Evolution
    (Weinheim : Wiley-VCH, 2022) Husmann, Samantha; Torkamanzadeh, Mohammad; Liang, Kun; Majed, Ahmad; Dun, Chaochao; Urban, Jeffrey J.; Naguib, Michael; Presser, Volker
    MXene-transition metal dichalcogenide (TMD) heterostructures are synthesized through a one-step heat treatment of Nb2C and Nb4C3. These MXenes are used without delamination or any pre-treatment. Heat treatments accomplish the sacrificial transformation of these MXenes into TMD (NbS2) at 700 and 900 °C under H2S. This work investigates, for the first time, the role of starting MXene phase in the derivative morphology. It is shown that while treatment of Nb2C at 700 °C leads to the formation of pillar-like structures on the parent MXene, Nb4C3 produces nano-mosaic layered NbS2. At 900 °C, both MXene phases, of the same transition metal, fully convert into nano-mosaic layered NbS2 preserving the parent MXene's layered morphology. When tested as electrodes for hydrogen evolution reaction, Nb4C3-derived hybrids show better performance than Nb2C derivatives. The Nb4C3-derived heterostructure exhibits a low overpotential of 198 mV at 10 mA cm−2 and a Tafel slope of 122 mV dec−1, with good cycling stability in an acidic electrolyte.