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In this paper, we synthesized Bi 2 Se 3 -NFs@rGO composite and analyzed electro chemical properties. Bi 2 Se 3 -NFs@rGO composite improved specific capacity, cycle stability and ion conductivity by rGO composite. [Display omitted] • The synthesis of Bi 2 Se 3 nanoflakes(NFs) by organic molecules as selenium precursor. • Synthesized homogenously nanoflakes by oleylamine as surfactant. • Bi2Se3-NFs@rGO composite exhibits high specific capacity compared to previous articles. • Analyzed the mechanism of Bi 2 Se 3 -NFs@rGO composite via Ex-situ TEM and Ex-situ XRD. Metal selenides have gained attention as alternative anode materials for lithium-ion batteries, with increasing demand for electro-vehicles and appliances. Bismuth selenide has significant potential as anode materials in lithium-ion batteries. Nevertheless, metal selenides have essential drawbacks, such as volume expansion and poor cycle performance. In this paper, bismuth selenide synthesized homogeneous morphology-like nanoflakes (NFs) using the wet chemical method. We combined these nanoflakes with reduced graphene oxide to improve their structural stability. The Bi 2 Se 3 -NFs@rGO composite showed enhanced specific capacity from 750 mAhg−1 to 1100 mAhg−1 at 100 mAg−1. Furthermore, at a current density of 500 mAg−1, it reached a specific capacity (819 mAhg−1) after 300 cycles and demonstrated a coulombic efficiency of 96 %. [ABSTRACT FROM AUTHOR]

The paper reports a results of series of interlaboratory comparisons of low impedance measurements at frequencies relevant for electrochemical impedance spectroscopy (EIS) of commercial lithium-ion cells. Two comparisons are presented. The first, bilateral comparison has focused on low impedance standards calibration in a full complex plane using digital sampling setups. The second comparison has focused on calibration and use of commercial 4-terminal battery EIS meters. Both comparisons have covered the impedance range from 50 μ ℧ to 100m℧ across the full complex plane in a frequency range from 0.01Hz up to 5kHz. Finally, the paper summarizes practices identified as critical for achieving measurement compatibility among various labs. • Relevant for electrochemical impedance measurements of lithium-ion battery cells. • First interlaboratory comparison of low impedances in full complex plane. • First interlaboratory comparison of low impedance at frequencies down to 0.01Hz. [ABSTRACT FROM AUTHOR]

In this paper we present an all-solid-state lithium-ion battery (ASSB) model that considers electrochemistry and solid mechanics in a fully coupled manner. The model spatially resolves the three-dimensional microstructure of an ASSB cell and is based on non-linear continuum mechanics. The coupling of electrochemistry and solid mechanics is incorporated via lithiation-dependent volumetric changes of the active materials and the consistent formulation of the electrochemical governing equations on deformed geometries resulting in changed percolation paths. As the volumetric changes due to (de-)lithiation are reported to be large for several active materials, we introduce this effect using a multiplicative split of the deformation gradient. To also allow for large deformations in the mass conservation equation, an Arbitrary Lagrangian–Eulerian formulation is employed. Furthermore, we show the central steps to deduce the finite element formulation of our model as well as the adopted monolithic solution procedure to solve this strongly coupled non-linear problem. The linear solver used for large problem setups is adjusted from the advanced, physics-oriented preconditioning technique published in our previous work. In the numerical examples, we investigate three different geometries with up to about 1.3 million degrees of freedom and thereby prove that our approach is applicable to geometrically large and complex scenarios. Moreover, we show that our approach consistently introduces the mass and charge conservation on deformed meshes. Furthermore, the numerical examples demonstrate the high relevance to incorporate current collectors into the ASSB cell simulations. Finally, we show that solid mechanics and the coupling effects have indeed a large impact on the ASSB cell performance and their incorporation is therefore vital for precise results and predictions. [ABSTRACT FROM AUTHOR]

Models that consistently couple particle, electrode, and battery level mechanics and electrochemistry are rare in literature. Within a battery, there are hundreds of layers of electrodes and the inherent multiscale structure of electrodes makes battery level simulations computationally very expensive. This paper presents a multiscale homogenization method that couples mechanics and electrochemistry at the particle, electrode, and battery scales. The method is divided into two parts. Firstly, an electrochemical/mechanical model for a one-dimensional periodic element is applied to determine particle and electrode layer swelling as functions of time and position. Secondly, the layered structure of the battery is homogenized by the use of three-dimensional laminate theory. The homogenized material model can be applied in finite element calculations on the battery level. Layer level stresses can in a second step be back-calculated. The accuracy and efficiency of the method are demonstrated by comparisons to detailed finite element computations where each layer is individually modeled. Predictions of electrode layer stresses are also favorably compared to impedance measurements of electrode layers at different electrode positions. It is furthermore demonstrated that the effects of external battery loadings like battery stacks, casings, and external pressure easily can be captured by the model. • A multiscale homogenization method is presented. • Application of three-dimensional laminate theory to battery modeling. • Layer level stresses are back-calculated from the homogenized model. • Good agreements to detailed finite element computations and experiments. • Efficient method for battery level simulations. [ABSTRACT FROM AUTHOR]