Journal: Energy Storage Materials

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Elsevier

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2019 - 201912020 - 20243
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Publications 1 - 4 of 4
  • Influence of precursor morphology and cathode processing on performance and cycle life of sodium-zinc chloride (Na-ZnCl₂) battery cells
    Item type: Journal Article
    Sieuw, Louis; Lan, Tu; Svaluto-Ferro, Enea; et al. (2024)
    Energy Storage Materials
    Replacing nickel by cheap and abundant zinc may enable high-temperature sodium-nickel chloride (Na-NiCl2) batteries to become an economically viable and environmentally sustainable option for large-scale energy storage for stationary applications. However, changing the active cathode metal significantly affects the cathode microstructure, the electrochemical reaction mechanisms, the stability of cell components, and the specific cell energy. In this study, we investigate the influence of cathode microstructure on energy efficiency and cycle life of sodium-zinc chloride (Na-ZnCl₂) cells operated at 300 °C. We correlate the dis-/charge cycling performance of Na-ZnCl₂ cells with the ternary ZnCl₂-NaCl-AlCl₃ phase diagram, and identify mass transport through the secondary NaAlCl4 electrolyte as an important contribution to the cell resistance. These insights enable the design of tailored cathode microstructures, which we apply to cells with cathode granules and cathode pellets at an areal capacity of 50 mAh/cm². With cathode pellets, we demonstrate >200 cycles at C/5 (10 mA/cm²), transferring a total capacity of 9 Ah/cm² at >83% energy efficiency. We identify coarsening of zinc particles in the cathode microstructure as a major cause of performance degradation in terms of a reduction in energy efficiency. Our results set a basis to further enhance Na-ZnCl₂ cells, e.g., by the use of suitable additives or structural elements to stabilize the cathode microstructure.
  • Niobium oxide anode materials with suppressed activity toward hydrogen evolution reaction for aqueous batteries
    Item type: Journal Article
    Becker, Maximilian; Bernasconi, Francesco; Egorov, Konstantin; et al. (2024)
    Energy Storage Materials
    The hydrogen evolution reaction is the most prominent parasitic reaction for aqueous battery chemistries. Although water-in-salt electrolytes show greatly enhanced electrochemical stability, increasing the voltage of aqueous batteries further by lowering the potential of the negative electrode remains a major challenges due to reductive water splitting. Here, we systematically investigate twelve niobium-based anode materials that show much lower activity towards hydrogen evolution reaction than classic titanium-based anode materials such as lithium titanate (Li4Ti5O12) or titanium dioxide and are therefore a much better choice for aqueous batteries. We confirm Zn2Nb34O87 to be the most suitable anode material for aqueous batteries among these niobates and present full-cell cycling data with LiMn2O4 and LiNi0.8Mn0.1Co0.1O2 cathodes in a water-in-salt/ionic liquid hybrid electrolyte. Furthermore, we compare the catalytic activities of Zn2Nb34O87 and Cu2Nb34O87, with the latter being incompatible with aqueous batteries, and discuss the origin of the large difference in activity toward hydrogen evolution reaction.
  • Beyond conventional sodium-ion storage mechanisms: a combinational intercalation/conversion reaction mechanism in Ni-ion modified hydrated vanadate for high-rate sodium-ion storage
    Item type: Journal Article
    Huang, Haijian; Li, Wei; Tian, Tian; et al. (2022)
    Energy Storage Materials
    Exploration of advanced anode materials remains a great challenge in further promoting the performance of sodium-ion batteries. From the perspective of Na+ storage mechanisms, conversion/alloying-type anode materials typically offer high Na+ storage capacities, whereas the volume expansion during operation gives rise to unsatisfactory cycling stability. Intercalation-type anode materials with appropriate crystallographic structures have been identified to deliver decent cycling and rate performances. However, the deformations that the structures can withstand, as well as the limited numbers of available vacant sites in the crystal structures, significantly constrains the Na+ storage capacity. Herein, breaking from the conventional Na+ storage mechanisms, we reveal for the first time the combinational intercalation/conversion reaction mechanism upon Na+ storage in the Ni-ion modified hydrated vanadate (Ni0.24V2O5·nH2O). Based on in-situ/ex-situ characterizations and theoretical analysis, the conversion reaction of the interlayer Ni3+ is found to be triggered after the Na+ intercalation process, which not only contributes to high specific capacities but also leads to fast and stable solid-state Na+ diffusion. Paring Ni0.24V2O5·nH2O with a Zn/Mg dual-doped P2-Na0.67MnO2 cathode material, a high-performance Na-ion battery prototype full cell is fabricated. The unconventional Na-ion storage mechanism that endows the anode material with both high capacity and outstanding cyclic and rate performances has implications for further boosting the comprehensive performance of sodium-ion batteries.
  • Hydrogel-derived foams of nitrogen-doped carbon loaded with Sn nanodots for high-mass-loading Na-ion storage
    Item type: Journal Article
    Pan, Long; Huang, Haijian; Zhong, Ming; et al. (2019)
    Energy Storage Materials
Publications 1 - 4 of 4