| 1. |
- Pan, Ruijun, et al.
(författare)
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Double-sided conductive separators for lithium-metal batteries
- 2019
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Ingår i: Energy Storage Materials. - : Elsevier. - 2405-8289 .- 2405-8297. ; 21, s. 464-473
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Tidskriftsartikel (refereegranskat)abstract
- A novel double-sided conductive (DSC) separator consisting of two 5 μm-thick carbon nanotube (CNT)/cellulose nanofiber (CNF) composite layers coated on each side of a 20 μm-thick glass-fiber (GF)/CNF composite membrane is described. In a lithium-metal battery (LMB), the DSC separator exhibits a high ionic conductivity (i.e. 1.7 mS cm−1 using an LP40 electrolyte) due to the high porosity (i.e. 66%) of the GF/CNF membrane. More stable Li anodes can also be realized by depositing Li within the porous electronically conducting CNT/CNF matrix at the DSC separator anode side due to the decreased current density. The CNT/CNF layer of the DSC separator facing the cathode, which is in direct electric contact with the current collector, decreases the overpotential for the cathode and consequently improves its capacity and rate performance significantly. A Li/Li cell containing a DSC separator showed an improved cycling stability compared to an analogous cell equipped with a commercial Celgard separator at current densities up to 5 mA cm−2 for Li deposition and stripping capacities up to 5 mAh cm−2. A proof-of-concept LMB containing a lithium iron phosphate (LFP) composite cathode and a DSC separator showed a significantly improved rate capability, yielding capacities of about 110 mAh g−1 at 5 C and 80 mAh g−1 at 10 C. The LMB cell containing a DSC separator also exhibited a capacity retention of 80% after 200 cycles at a rate of 6 C indicating that the two-sided conductive separator design has significant potential in facilitating the development of well-functioning LMBs.
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| 2. |
- Ponrouch, A., et al.
(författare)
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Multivalent rechargeable batteries
- 2019
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8297 .- 2405-8289. ; 20, s. 253-262
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Forskningsöversikt (refereegranskat)abstract
- Rechargeable battery technologies based on the use of metal anodes coupled to multivalent charge carrier ions (such as Mg 2+ , Ca 2+ or Al 3+ ) have the potential to deliver breakthroughs in energy density radically leap-frogging the current state-of-the-art Li-ion battery technology. However, both the use of metal anodes and the migration of multivalent ions, within the electrolyte and the electrodes, are technological bottlenecks which make these technologies, all at different degrees of maturity, not yet ready for practical applications. Moreover, the know-how gained during the many years of development of the Li-ion battery is not always transferable. This perspective paper reviews the current status of these multivalent battery technologies, describing issues and discussing possible routes to overcome them. Finally, a brief section about future perspectives is given.
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| 3. |
- Sångeland, Christofer, et al.
(författare)
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Towards room temperature operation of all-solid-state Na-ion batteries through polyester-polycarbonate-based polymer electrolytes
- 2019
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8289 .- 2405-8297. ; 19, s. 31-38
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Tidskriftsartikel (refereegranskat)abstract
- In an ambition to develop solid-state Na-ion batteries functional at ambient temperature, we here explore a novel electrolyte system. Polyester-polycarbonate (PCL-PTMC) copolymers were combined with sodium bis(fluorosulfonyl) imide salt (NaFSI) to form solid polymer electrolytes for Na-ion batteries. The PCL-PTMC:NaFSI system demonstrated glass transition temperatures ranging from -64 to -11 degrees C, increasing with increasing salt content from 0 to 35 wt%, and ionic conductivities ranging from 10(-8) to 10(-5) S cm(-1) at 25 degrees C. The optimal salt concentration was clearly dependent on the level of crystallinity, which was largely determined by the CL content. At 70 and 80 mol% CL, the PCL-PTMC:NaFSI system was fully amorphous and exhibited high conductivities at lower salt concentrations. When the CL content was increased to 100 mol%, high ionic conductivities were instead observed at high salt concentrations. A decent transference number of ca. 0.5 at 80 degrees C was obtained for a polymer film containing 20 mol% CL units and 25 wt% NaFSI. Finally, a HC vertical bar 80-20(25)vertical bar Na2-xFe(Fe(CN)(6)) all-solid-state polymer electrolyte full cell was assembled to demonstrate the practical application of the material and cycled for more than 120 cycles at similar to 22 degrees C.
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| 4. |
- Jankowski, Piotr, 1990, et al.
(författare)
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Functional ionic liquids: Cationic SEI-formers for lithium batteries
- 2019
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 20, s. 108-117
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Tidskriftsartikel (refereegranskat)abstract
- More stable electrolytes for lithium-ion batteries are urgently needed, and apart from general improvements in thermal and electrochemical stabilities, both stability, safety and performance are connected with the formation of the solid electrolyte interphase (SEI) layer at the negative electrode. A high performant SEI-layer; thin, uniform, highly ion conducting, etc., is difficult to achieve and proper control of its formation process is therefore highly desirable. The idea presented here is based on computational screening of a wide range of modifications of wellknown ionic liquid (IL) cations towards better ability to form SEI-layers - i.e. acting as SEI-formers. Different cation chemistries and kinds of structural modifications were tested, with introduction of nitrile groups and/or double bonds resulting to be the most promising. The latter is outlined as especially beneficial, as apart from enabling an easier initiation reaction it provides a site for polymerization, resulting in polymeric SEI-products poly (IL) s (PILs), which can be expected to provide both protection of the electrode surface and fast Li thorn transport.
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| 5. |
- Liu, Qiao, et al.
(författare)
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Enhanced ionic conductivity and interface stability of hybrid solid-state polymer electrolyte for rechargeable lithium metal batteries
- 2019
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 23, s. 105-111
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Tidskriftsartikel (refereegranskat)abstract
- Compared to conventional organic liquid electrolyte, solid-state polymer electrolytes are extensively considered as an alternative candidate for next generation high-energy batteries because of their high safety, non-leakage and electrochemical stability with the metallic lithium (Li) anode. However, solid-state polymer electrolytes generally show low ionic conductivity and high interfacial impedance to electrodes. Here we report a hybrid solid-state electrolyte, presenting an ultra-high ionic conductivity of 3.27 mS cm −1 at room temperature, a wide electrochemical stability window of 4.9 V, and non-flammability. This electrolyte consists of a polymer blend matrix (polyethylene oxide and poly (vinylidene fluoride-co-hexafluoropropylene)), Li + conductive ceramic filler (Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 ) and a solvate ionic liquid (LiFSI in tetra ethylene glycol dimethyl ether, 1:1 in molar ratio) as plasticizer. The introduction of the solvate ionic liquid to the solid-state electrolyte not only improves its ionic conductivity but also remarkably enhances the stability of the interface with Li anode. When applied in Li metal batteries, a Li|Li symmetric cell can operate stably over 800 h with a minimal polarization of 25 mV and a full Li|LiFePO 4 cell delivers a high specific capacity of 158 mAh g −1 after 100 cycles at room temperature.
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| 6. |
- Maggiolo, Dario, 1985, et al.
(författare)
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Particle based method and X-ray computed tomography for pore-scale flow characterization in VRFB electrodes
- 2019
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Ingår i: Energy Storage Materials. - : Elsevier BV. - 2405-8297. ; 16, s. 91-96
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Tidskriftsartikel (refereegranskat)abstract
- Porous electrodes are pivotal components of Vanadium Redox Flow Batteries, which influence the power density, pressure drop losses, activation overpotentials, limit current density, bulk and contact resistance, and ohmic losses. The quantification of the fluid-mechanic efficiency of porous electrodes based on their real geometry is a useful measure, as it primarily affects the mass transport losses and the overall battery performances. Although several studies, both numerical and experimental, have been devoted to the electrode enhancement, most analyses are carried out under the simplifying assumption of linear, macrohomogeneous and isotropic behavior of the fluid mechanics in the porous material. We present an original approach built on the Lattice-Boltzmann Method and Lagrange Particle Tracking that makes use of pore-scale accurate geometrical data provided by X-ray computed tomography with the aim of studying the dispersion and reaction rates of liquid electrolyte reactants in the flow battery porous electrode. Following this methodology, we compare the fluid-dynamic performances provided by a commonly used carbon felt and an unconventional material, that is, a carbon vitrified foam. Surprisingly, results unveil the possibility of achieving higher fluid-mechanic efficiencies with the foam electrode, whose intrinsic microstructure promotes higher reaction rate.
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