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search.filters.applied.f.access: openAccess × Author: Gallei, Markus × Author: Husmann, Samantha × Author: Presser, Volker × Start date: 2020 × Has files: Yes ×

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    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
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    Selective Pb2+ removal and electrochemical regeneration of fresh and recycled FeOOH
    ([Erscheinungsort nicht ermittelbar] : Tsinghua Press, 2023) Wang, Lei; Deligniere, Lexane; Husmann, Samantha; Leiner, Regina; Bahr, Carsten; Zhang, Shengjie; Dun, Chaochao; Montemore, Matthew M.; Gallei, Markus; Urban, Jeffrey J.; Kim, Choonsoo; Presser, Volker
    Heavy metal pollution is a key environmental problem. Selectively extracting heavy metals could accomplish water purification and resource recycling simultaneously. Adsorption is a promising approach with a facile process, adaptability for the broad concentration of feed water, and high selectivity. However, the adsorption method faces challenges in synthesizing high-performance sorbents and regenerating adsorbents effectively. FeOOH is an environmentally friendly sorbent with low-cost production on a large scale. Nevertheless, the selectivity behavior and regeneration of FeOOH are seldom studied. Therefore, we investigated the selectivity of FeOOH in a mixed solution of Co2+, Ni2+, and Pb2+ and proposed to enhance the capacity of FeOOH and regenerate it by using external charges. Without charge, the FeOOH electrode shows a Pb2+ uptake capacity of 20 mg/g. After applying a voltage of −0.2/+0.8 V, the uptake capacity increases to a maximum of 42 mg/g and the desorption ratio is 70%–80%. In 35 cycles, FeOOH shows a superior selectivity towards Pb2+ compared with Co2+ and Ni2+, with a purity of 97% ± 3% in the extracts. The high selectivity is attributed to the lower activation energy for Pb2+ sorption. The capacity retentions at the 5th and the 35th cycles are ca. 80% and ca. 50%, respectively, comparable to the chemical regeneration method. With industrially exhausted granular ferric hydroxide as the electrode material, the system exhibits a Pb2+ uptake capacity of 37.4 mg/g with high selectivity. Our work demonstrates the feasibility of regenerating FeOOH by charge and provides a new approach for recycling and upcycling FeOOH sorbent. [Figure not available: see fulltext.]