| 1. |
- Asp, Leif, 1966, et al.
(författare)
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A structural battery and its multifunctional performance
- 2021
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Ingår i: Advanced Energy and Sustainability Research. - : Wiley. - 2699-9412. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- Engineering materials that can store electrical energy in structural load paths can revolutionize lightweight design across transport modes. Stiff and strong batteries that use solid-state electrolytes and resilient electrodes and separators are generally lacking. Herein, a structural battery composite with unprecedented multifunctional performance is demonstrated, featuring an energy density of 24 Wh kg-1 and an elastic modulus of 25 GPa and tensile strength exceeding 300 MPa. The structural battery is made from multifunctional constituents, where reinforcing carbon fibers (CFs) act as electrode and current collector. A structural electrolyte is used for load transfer and ion transport and a glass fiber fabric separates the CF electrode from an aluminum foil-supported lithium–iron–phosphate positive electrode. Equipped with these materials, lighter electrical cars, aircraft, and consumer goods can be pursued.
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| 2. |
- Carlstedt, David, 1984, et al.
(författare)
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Experimental and computational characterization of carbon fibre based structural battery electrode laminae
- 2022
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Ingår i: Composites Science and Technology. - : Elsevier BV. - 0266-3538. ; 220
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, electrode laminae consisting of carbon fibres embedded in structural battery electrolyte (CF-SBE electrodes) are characterized with respect to their multifunctional (i.e. combined electrochemical and mechanical) performance utilizing experimental and numerical techniques. The studied material is made from commercially available polyacrylonitrile (PAN)-based carbon fibres and a porous SBE matrix/electrolyte, which is composed of two continuous phases: a solid polymer skeleton (vinyl ester-based) and a Li-salt containing liquid electrolyte. Experimental and numerical studies are performed on CF-SBE electrode half-cells, whereby a coupled electro-chemo-mechanical finite element model is exploited. Results show that, similar to traditional batteries, electrode thickness, transport properties of the electrolyte and applied current significantly affect electrochemical performance. For example, increasing the electrode thickness of the studied CF-SBE electrode from 50 μm to 200 μm results in a reduction in specific capacity of approximately 70/95% for an applied current of 30/120 mA g? 1 of fibres, respectively. Further, Li-insertion induced longitudinal expansion of carbon fibre electrodesare video microscopically recorded during charge/discharge conditions. In liquid electrolyte the total/reversible longitudinal expansion are found to be 0.85/0.8% while for the CF-SBE electrode the reversible expansion is found to be 0.6%. The fibre expansion in the CF-SBE electrode gives rise to residual strains which is demonstrated numerically. We expect that the utilized computational framework and experimental data open a route to develop high-performing, both mechanically and electrochemically, carbon fibre based battery electrode laminae for future lightweight structural components with energy storage ability.
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| 3. |
- Duan, Shanghong, 1992, et al.
(författare)
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BUILDING AND CHARACTERIZATION OF SYMMETRIC STRUCTURAL BATTERY
- 2022
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Ingår i: ECCM 2022 - Proceedings of the 20th European Conference on Composite Materials: Composites Meet Sustainability. ; 3, s. 1169-1174
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Konferensbidrag (refereegranskat)abstract
- Recently, a structural battery with multifunctional carbon fibre anode has been reported. The energy density of active material is not fully extracted due to the low ionic conductivity inside the battery. To identify the main region that attributes to the low ion transportation, we assemble a symmetric structural battery with one anode layer in the centre sandwiched between two cathode layers. Such a design can also be treated as a combination of two asymmetric batteries with one full thickness cathode layer plus one half thickness anode layer. Thus, the travelled distance of lithium ions is shortened only in the anode part. It is found that the area energy density of the symmetric structural battery is doubled compared to a reference asymmetric battery. Thus, the additional cathode layer activates the double amount of carbon fibres in the anode. A plausible reason is that only the carbon fibres next to the separator is activated in the battery.
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| 4. |
- Duan, Shanghong, 1992
(författare)
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Characterisation of a structural battery composite and its constituents
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The structural battery composite is a recently successfully developed multifunctional lithium-ion battery. It is safer and capable to carry mechanical load compared to commercially available liquid electrolyte batteries. This makes it possible to apply the structural batteries to replace parts of the structural components in a system and thus reduce the weight of the whole system. The structural battery composite uses carbon fibre, an excellent lightweight material, as the anode material and uses a semi-solid structural battery electrolyte (SBE) material. The entire battery behaves as a solid material. The overall mechanical properties of the structural battery composite material are excellent due to the reinforcement of the carbon fibres and the mechanically robust SBE matrix. In this thesis, first of all, a multifunctional structural battery composite is manufactured. The structural battery composite uses the lithium storage capacity of carbon fibre for the first time and therefore, has an energy density of 24 Wh/kg and an elastic modulus of 25 GPa. Secondly, characterisation methods were developed for a number of important components in the structural battery composite. This includes precise measurements of transverse and shear moduli on micron-scale carbon fibres, the effect of lithiation on the carbon fibre anode mechanical properties, and 3D reconstruction and simulation of the SBE. For the pristine carbon fibres, focused ion beam combined with scanning electron microscopy (FIB/SEM) was used to accurately mill flat surfaces in different orientations on the carbon fibres, followed by indentation test using atomic force microscopy, and nanoindentation. The elastic hysteresis of the carbon fibres was observed in the experiments. For the first time, the moduli in the transverse and shear directions were derived in conjunction with an accurate orthotropic mechanical model. For the study of lithiation effects on the carbon fibre anode, the focus is on volume expansion and modulus changes. The volume expansion was obtained by analysis of SEM and optical micrographs. By using the protection of hydrophobic ionic liquids, the samples were successfully transferred into a vacuum environment in the SEM and subjected to transverse compression experiments. The transverse modulus of the carbon fibres is found to be doubled after lithiation. Finally, the microstructure of the SBE was reconstructed in 3D. The geodesic tortuosity of the SBE was found to be approximately 1.8. Meanwhile, the elastic modulus and ionic conductivity of the SBE were experimentally measured and simulated. In terms of elastic modulus, the results were consistent, and in terms of ionic conductivity, the simulated result overestimated the measured result.
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| 5. |
- Duan, Shanghong, 1992
(författare)
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Characterization of elastic moduli of single fibres
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The carbon fibre is one of most promising materials for high-performance composites since it is lightweight and strong. It has been widely used to build carbon fibre reinforced polymer (CFRP) composites. The carbon fibre dramatically reinforces the composite in the fibre direction. However, carbon fibre does not significantly reinforce the composite transverse to the fibres. The reason is in addition to the fibre geometry, that the mechanical properties of carbon fibre are anisotropic. Even though the strong anisotropy is well known, to date only the properties in axial direction have been accurately measured. Measurements in other directions, like the transverse direction, are challenging because the diameter of carbon fibre is only 5 to 7 µm. Knowledge of the mechanical properties of carbon fibre is important, especially for micro-mechanical models to predict damage formation in CFRP. The small dimension of carbon fibre implies that only a limited set of instruments can be used to perform mechanical tests on it, such as nanoindentation and atomic force microscopy (AFM). Moreover, the high anisotropy of carbon fibre needs a special analysis method. In this thesis, we first study a fabrication routine for preparation of flat surfaces on carbon fibres using a focussed ion beam technique. A necessary and effective cleaning process to remove damaged surface from fabrication process is presented. We then perform indentation tests using both nanoindentation and AFM in two different directions. During the tests, a hysteresis behaviour of carbon fibre was observed and its influence on indentation moduli is discussed. Finally, we successfully determine both transverse and shear moduli of three different carbon fibres.
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| 6. |
- Duan, Shanghong, 1992, et al.
(författare)
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Determination of transverse and shear moduli of single carbon fibres
- 2020
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 158C, s. 772-782
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Tidskriftsartikel (refereegranskat)abstract
- Carbon fibres are extensively used for their high specific mechanical properties. Exploiting their high axial stiffness and strength, they are employed to reinforce polymer matrix materials in advanced composites. However, carbon fibres are not isotropic. Data of the elastic properties in the other directions of the fibres are still largely unknown. Furthermore, standardised methods to characterise these properties are lacking. In the present work, we propose a methodology to determine the transverse and shear moduli of single carbon fibres. An experimental procedure is developed to fabricate high-quality, flat fibre cross-sections in both longitudinal and transverse directions using Focused Ion Beam, which gives full control of the specimen geometry. Indentation modulus on those surfaces are obtained using both Atomic Force Microscopy (AFM) and nanoindentation tests. Hysteresis was found to occur in the nanoindentation tests. The hysteresis response was due to nano-buckling and reversible shear deformation of the carbon crystals. For this reason, indentation tests using AFM is recommended. From the AFM indentation tests the transverse and shear moduli of three different carbon fibres (IMS65, T800 and M60J) are successfully determined.
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| 7. |
- Duan, Shanghong, 1992, et al.
(författare)
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Effect of lithiation on the elastic moduli of carbon fibres
- 2021
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 185, s. 234-241
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Tidskriftsartikel (refereegranskat)abstract
- Carbon fibre electrodes can enable a solid-state battery to carry mechanical load as normal construction materials. The multifunctionality is promising for most lightweight applications. Like all electrode materials, both volume and elastic moduli of the carbon fibre electrodes change during battery cycling. Such changes jeopardize the mechanical integrity of the battery. Due to the challenging corrosion problem of the lithiated component in air, the effect of lithiation on the carbon fibre's elastic moduli has yet to be explored. Also, robust data on the expansion of carbon fibres from lithiation are lacking. In the present work, we demonstrate a method and perform tests of corrosion protected carbon fibres in scanning electron microscope. The volume, and longitudinal and transverse moduli of a carbon fibre at three states of lithiation are determined and compared. The transverse modulus of the lithiated fibre is found to be more than double that of the pristine and delithiated fibres.
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| 8. |
- Duan, Shanghong, 1992, et al.
(författare)
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Three-dimensional reconstruction and computational analysis of a structural battery composite electrolyte
- 2023
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Ingår i: COMMUNICATIONS MATERIALS. - : Springer Nature. - 2662-4443. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Structural batteries are multifunctional composite materials that can carry mechanical load and store electrical energy. Their multifunctionality requires an ionically conductive and stiff electrolyte matrix material. For this purpose, a bi-continuous polymer electrolyte is used where a porous solid phase holds the structural integrity of the system, and a liquid phase, which occupies the pores, conducts lithium ions. To assess the porous structure, three-dimensional topology information is needed. Here we study the three-dimensional structure of the porous battery electrolyte material using combined focused ion beam and scanning electron microscopy and transfer into finite element models. Numerical analyses provide predictions of elastic modulus and ionic conductivity of the bi-continuous electrolyte material. Characterization of the three-dimensional structure also provides information on the diameter and volume distributions of the polymer and pores, as well as geodesic tortuosity. Structural battery composites contain a porous solid phase that holds the structural integrity of the system with a liquid phase in the pores. Here, the porous structure is studied using combined focused ion beam and scanning electron microscopy and transferred into finite element models.
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| 9. |
- Duan, Shanghong, 1992, et al.
(författare)
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Transverse modulus measurement of carbon fibre by atomice force microscope and nanoindentation
- 2019
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Ingår i: ICCM International Conferences on Composite Materials. - : International Committee on Composite Materials.
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Konferensbidrag (refereegranskat)abstract
- Carbon fibre reinforced polymer composite has been widely used in structural component due to lower and not well studied because of the extre modulus was measured by nano-scale indentation tests, which were performed on fabricated flat surfaces, using both atomic force microscopy and nano-indentation. The surface damage induced by the high energy ion beam was also assessed.
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| 10. |
- Liu, Fang, 1975, et al.
(författare)
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Specimen preparation for transverse modulus measurement of carbon fibres using focused ion beam
- 2019
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Ingår i: ICCM International Conferences on Composite Materials. ; 2019-August, s. 1253-1258
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Konferensbidrag (refereegranskat)abstract
- Transverse Young’s modulus of carbon fibres is an important material property for micromechanical modeling and design of carbon fibre reinforced composites. To accurately measure their transverse Young’s modulus is of special importance for applications in novel multifunctional devices, such as structural composite batteries. However, experimental measurement of their transverse Young’s modulus is still largely lacking due to experimental challenges. In this study, we successfully prepared high quality longitudinal cross sections from a commercial carbon fibre using precision ion milling in a combined focused ion beam and scanning electron microscope (FIB/SEM) instrument. These cross sections were then directly used in an atomic force microscope (AFM) and a nanoindentation equipment to measure the transverse Young’s modulus. Here, the entire procedure is described in detail. In particular, the most critical aspects for specimen preparation are identified and discussed.
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