Browsing by Subject "Li-ion Battery"

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    DESIGN AND FABRICATION OF MULTI-FUNCTIONAL ENERGY STORAGE COMPOSITES INTEGRATING ULTRATHIN LITHIUM-ION BATTERY WITH ENHANCED ELECTRO-MECHANICAL PERFORMANCE
    (EPFL Lausanne, Composite Construction Laboratory, 2022-06) Biswas, Pias Kumar; Jadhav, Mayur; Ananda Habarakada Liyanage, Asel; Dalir, Hamid; Agarwal, Mangilal
    Exponential advancement in the automotive and aerospace industry promotes the need for Multifunctional Energy Storage Composites (MESCs) to minimize the dependence on fossil fuels and reduce structural weight. This study proposes and evaluates a multi-functional carbon fiber reinforced polymer (CFRP) composite with an embedded lithium-ion polymer battery, demonstrating a structural integrity concept. Here electrospun epoxy-multiwalled carbon nanotubes (epoxy-MWCNT) nanofibers were incorporated precisely on the uncured CFRP surface to enhance adequate interfacial bonding and adhesion between the layers after curing. The mechanical and physical properties of modified CFRP have been evidenced to possess higher mechanical strength than the traditional CFRP composite. Commercial ultra-thin lithium-ion battery with higher energy density has been uniquely integrated into the core of the CFRP composite structure. Comparison with conventional CFRP composite and electro-mechanical testing ensured that the electrochemical property of the embedded battery was preserved in loading/unloading conditions, and the mechanical strength of the composite structure was not compromised.
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    Lithium Storage Mechanisms and Electrochemical Behavior of Molybdenum Disulfide
    (2024-05) Li, Xintong; Zhu, Likun; Hosop, Shin; Wei, Xiaoliang
    This study investigates the electrochemical behavior of molybdenum disulfide (MoS2) when utilized as an anode material in Li-ion batteries, particularly focusing on the intriguing phenomenon of extra capacity observed beyond theoretical expectations and the unique discharge curve of the first cycle. Employing a robust suite of advanced characterization methods such as in situ and ex situ X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM), the research unravels the complex structural and chemical evolution of MoS2 throughout its cycling process. A pivotal discovery of the research is the identification of a distinct lithium intercalation mechanism in MoS2, which leads to the formation of reversible LixMoS2. These phases play a crucial role in contributing to the extra capacity observed in the MoS2 electrode. Additionally, density functional theory (DFT) calculations have been utilized to explore the potential for overlithiation within MoS2, suggesting that Li5MoS2 could be the most energetically favorable phase during the lithiation-delithiation process. This study also explores the energetics of a Li-rich phase forming on the surface of Li4MoS2, indicating that this configuration is energetically advantageous and could contribute further to the extra capacity. The incorporation of reduced graphene oxide (RGO) as a conductive additive in MoS2 electrodes, demonstrating that RGO notably improves the electrochemical performance, rate capability, and durability of the electrodes. These findings are supported by experimental observations and are crucial for advancing the understanding of MoS2 as a high-capacity anode material. The implications of this research are significant, offering a pathway to optimize the design and composition of electrode materials to exceed traditional performance and longevity limits in Li-ion batteries.