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A highly complex crystal structure of stoichiometric Mg5(en)6(BH4)10 was solved from single crystal synchrotron X-ray diffraction and confirmed by neutron powder diffraction (NPD) on isotopically substituted Mg(en)1.2(11BD4)2. We highlight the role of the amorphous Mg(BH4)2 in the reactivity of the Mg(BH4)2-en system and characterized a previously overlooked phase, Mg(en)2(BH4)2. [ABSTRACT FROM AUTHOR]

In operando powder diffraction remains one of the most powerful tools for non‐destructive investigation of battery electrode materials. While in operando X‐ray, especially synchrotron radiation, powder diffraction is by now a routine experimental technique, in operando neutron powder diffraction is still less established. We present a new electrochemical cell for in operando neutron powder diffraction, which is, first and foremost, easy to use, but can also cycle electrode materials under electrochemical conditions close to those achieved using standard laboratory cells. The cell has been designed in multiple sizes, and high‐quality electrochemical and neutron powder diffraction data is presented for sample sizes as low as 48 mg total active material. The cell handles lithium‐ion and sodium‐ion materials equally well, with no difference in how the cell is prepared and assembled. The cell is intended to be used as sample environment at powder diffractometers at the neutron facilities MLZ, ORNL and ACNS. [ABSTRACT FROM AUTHOR]

A lab-made, multilayered Li-ion battery pouch cell is investigated using in-operando neutron powder diffraction (NPD) and spatially resolved powder X-ray diffraction (SR-PXRD) with the aim of investigating how to compare the information obtained from the two complementary techniques on a cell type with a complicated geometry for diffraction. The work focusses on the anode and cathode lithiation as obtained from the LiC6/LiC12 weight ratio and the NMC111 c/a-ratio, respectively. Neutron powder diffractograms of a sufficient quality for Rietveld refinement are measured using a rotation stage to minimize geometrical effects. Using SR-PXRD, the cell is shown to be non-uniform in its anode and cathode lithiation, with the edges of the cell being less lithiated/delithiated than the center in the fully charged state. The non-uniformity is more pronounced for high charging current than low charging current. The averaged SR-PXRD data is found to match the bulk NPD data well. This is encouraging as it seems to allow comparisons between studies using either of these complementary techniques. This work will also serve as a benchmark for our future studies on pouch cells with novel non-commercial cathode and/or anode materials. [ABSTRACT FROM AUTHOR]

The need for rapid data collection and studies of small sample volumes in the range of cubic millimetres are the main driving forces for the concept of a new high‐throughput monochromatic diffraction instrument at the Heinz Maier‐Leibnitz Zentrum (MLZ), Germany. A large region of reciprocal space will be accessed by a detector with sufficient dynamic range and microsecond time resolution, while allowing for a variety of complementary sample environments. The medium‐resolution neutron powder diffraction option for `energy research with neutrons' (ErwiN) at the high‐flux FRM II neutron source at the MLZ is foreseen to meet future demand. ErwiN will address studies of energy‐related systems and materials with respect to their structure and uniformity by means of bulk and spatially resolved neutron powder diffraction. A set of experimental options will be implemented, enabling time‐resolved studies, rapid parametric measurements as a function of external parameters and studies of small samples using an adapted radial collimator. The proposed powder diffraction option ErwiN will bridge the gap in functionality between the high‐resolution powder diffractometer SPODI and the time‐of‐flight diffractometers POWTEX and SAPHiR at the MLZ. [ABSTRACT FROM AUTHOR]

18650-type cells comprising of LiNi 0.5 Co 0.2 Mn 0.3 O 2 and LiNi 0.9 Co 0.05 Al 0.05 O 2 as cathode blend and graphite as anode are cycled in various SoC ranges. Differing capacity fade is found, indicating that cycling in a medium SoC range results in lower capacity loss and behaves better than including high or low SoC in the cycling ranges. Cycling to low SoC tends to have nonlinear capacity fade (sudden capacity drop). Non-destructive methods, i.e. in situ neutron powder diffraction (NPD) and alternating current (AC) impedance, are employed to study the degradation mechanisms. Lithiated cathode loss and loss of lithium inventory (LLI) are calculated from crystal structure parameters refined from the in situ NPD. LLI is the dominating degradation factor for the differing capacity fade of cells. Lithiated cathode loss and solid electrolyte interphase (SEI) growth are deemed to be main fatigue reasons behind the LLI. By investigating the sensitivity of impedance parameters concerning the change in battery capacity, both ohmic resistance (R 0) and SEI resistance (R 1) present a linear relationship with the change of capacity for both, linear and nonlinear degradation, i.e. R 0 and R 1 follow the sudden capacity drop, which is ascribed to the formation of new SEI as evidenced by scanning electron microscopy (SEM) images. • 18650-type batteries are cycled in different state of charge (SoC) ranges. • Loss of active lithium is the main reason for both linear and nonlinear degradation. • Lithiated cathode loss is quantified from in situ neutron powder diffraction. • Solid electrolyte interphase growth correlates with the nonlinear capacity fade. • Avoiding the battery cycling to low SoC could reduce risk of nonlinear capacity fade. [ABSTRACT FROM AUTHOR]

18650-type cells with 2.5 Ah capacity are cycled at both 25 °C and 0 °C separately, and at 25 °C two charging protocols (constant current, and constant current-constant voltage charge) are used. Differential voltage analysis (dV/dQ) and alternating current (AC) impedance are mainly used to investigate battery degradation mechanisms quantitatively. The dV/dQ suggests that active cathode loss and loss of lithium inventory (LLI) are the dominating degradation factors. Significant microcracks are observed in the fatigued cathode particles from the scanning electron microscopy (SEM) images. Crystal structure parameters of selected fatigued batteries at fully charged state are determined by in situ high-resolution neutron powder diffraction. Obvious increases of ohmic resistance and solid electrolyte interphase (SEI) resistance occur when the battery capacity fade falls beneath 20%. Continuous charge transfer resistance and Warburg impedance coefficient (W.eff) increase are observed in the course of cycling. Correlation analysis is performed to bridge the gap between material loss as well as LLI and impedance increase. The increase of the charge transfer resistance is related to both active cathode loss and LLI, and a functional relationship is revealed between LLI and W.eff regardless of the used cycling protocols. • 18650-type Cells are cycled at 0 °C and 25 °C using two charging protocols. • Main degradation factors are loss of lithium inventory (LLI) and active cathode loss. • Neutron powder diffraction and post-mortem analysis are done for deep understanding. • Correlations between material loss and impedance parameters are revealed. • Warburg impedance coefficient could be correlated to LLI in the course of cycling. [ABSTRACT FROM AUTHOR]