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Due to complex degradation mechanisms, disparities between the theoretical and practical capacities of lithium-ion battery cathode materials persist. Specifically, Ni-rich chemistries such as LiNi0.8Mn0.1Co0.1O2 (or NMC811) are one of the most promising choices for automotive applications; however, they continue to suffer severe degradation during operation that is poorly understood, thus challenging to mitigate. Here we use operando Bragg coherent diffraction imaging for 4D analysis of these mechanisms by inspecting the individual crystals within primary particles at various states of charge (SoC). Although some crystals were relatively homogeneous, we consistently observed non-uniform distributions of inter- and intracrystal strain at all measured SoC. Pristine structures may already possess heterogeneities capable of triggering crystal splitting and subsequently particle cracking. During low-voltage charging (2.7-3.5 V), crystal splitting may still occur even during minimal bulk deintercalation activity; and during discharging, rotational effects within parallel domains appear to be the precursor for the nucleation of screw dislocations at the crystal core. Ultimately, this discovery of the central role of crystal grain splitting in the charge/discharge dynamics may have ramifications across length scales that affect macroscopic performance loss during real-world battery operation.

X-ray computed tomography (X-ray CT) is a non-destructive characterization technique that in recent years has been adopted to study the microstructure of battery electrodes. However, the often manual and laborious data analysis process hinders the extraction of useful metrics that can ultimately inform the mechanisms behind cycle life degradation. This work presents a novel approach that combines two convolutional neural networks to first locate and segment each particle in a nano-CT LiNiMnCoO

Advanced Li-ion batteries adopting new cathode chemistries are required for the successful widespread transition to electric vehicles (EVs) and renewable energy sources, aiming for high energy density, long cycle life, and good rate capability. Commercial candidates for EV batteries include Ni-rich Li(NixMnyCo1−x-y)O2 (NMC) cathodes, with Ni:Mn:Co ratios of 8:1:1 (NMC811) and higher. These are favored because of their high specific capacity (~ 200 mAh g-1)and reduced cobalt content. Despite all of the advantages, these materials suffer from a range of degradation modes, many of which are associated with the redox and crystallographic behavior at high states of charge. In particular, Ni-rich cathodes suffer from several limitations, such as rapid capacity fade in comparison to NMC stoichiometries with lower Ni content. In addition, they also have a lower onset voltage for oxygen release and subsequent surface reconstruction leading to the formation of spinel and rock salt phases which impede (de)lithiation and therefore the achievable capacity of the cell.1 Crystallographic properties of electrode materials are intrinsically linked to the electrochemical performance of the cell. NMC materials suffer from anisotropic changes in the crystal structure during cycling which induces strain and leads to issues such as crack formation, expediting degradation. One method to tackle capacity fade is to switch to single-crystal morphologies (particle size 1-3 μm) which have better mechanical stability than conventional polycrystalline morphologies (secondary agglomerate particles ~ 10 μm made up of primary particles which are 100 nm – 1 μm in size) and have less propensity to form extensive rock-salt layers. It is thought that the single-crystal morphology helps to reduce stress in the material as the anisotropic stress in polycrystalline cathodes is concentrated at grain boundaries. However, there is still a limited understanding of the subtle mechanistic differences between the two materials during cycling.2 A multi-scale approach is required to gain a more comprehensive understanding of the degradation mechanisms at play and how they initiate and propagate. In this work, synchrotron diffraction methods were employed at the crystal, particle and cell scale using a variety of techniques including in-situ Bragg Coherent Diffraction Imaging (BCDI), 3D-XRD and operando high-resolution XRD. Intra-particle, inter-particle and electrode level heterogeneities were observed during cycling, both in pristine and aged samples. It is believed that these heterogeneities accelerate the loss of performance at the cell level by inducing crack formation which can then be observed in X-ray computed tomography data acquired in simultaneous lab studies. The overarching goal of these investigations is to add to the understanding of complex degradation mechanisms for Ni-rich layered transition metal oxide cathodes, ultimately aiding in the informed development of future battery electrode materials. References: 1] Xu, C. et al., Phase Behaviour during Electrochemical Cycling of Ni‐Rich Cathode Materials for Li‐Ion Batteries. Adv. Energy Mater. 2021, 11, 2003404. 2] Yin, S. et al., Fundamental and solutions of microcracks in Ni-rich layered oxide cathode materials of lithium-ion batteries. Nano Energy, 2021, 83, 105854.

Renewable technologies, and in particular the electric vehicle revolution, have generated tremendous pressure for the improvement of lithium ion battery performance. To meet the increasingly high market demand, challenges include improving the energy density, extending cycle life and enhancing safety. In order to address these issues, a deep understanding of both the physical and chemical changes of battery materials under working conditions is crucial for linking degradation processes to their origins in material properties and their electrochemical signatures. In situ and operando synchrotron-based X-ray techniques provide powerful tools for battery materials research, allowing a deep understanding of structural evolution, redox processes and transport properties during cycling. In this review, in situ synchrotron-based X-ray diffraction methods are discussed in detail with an emphasis on recent advancements in improving the spatial and temporal resolution. The experimental approaches reviewed here include cell designs and materials, as well as beamline experimental setup details. Finally, future challenges and opportunities for battery technologies are discussed.

Vast quantities of powder leave production lines each day, often with strict control measures. For quality checks to provide the most value, they must be capable of screening individual particles in 3D and at high throughput. Conceptually, X‐ray computed tomography (CT) is capable of this; however, achieving lab‐based reconstructions of individual particles has, until now, relied upon scan‐times on the order of tens of hours, or even days, and although synchrotron facilities are potentially capable of faster scanning times, availability is limited, making in‐line product analysis impractical. This work describes a preparation method and high‐throughput scanning procedure for the 3D characterization of powder samples in minutes using nano‐CT by full‐filed transmission X‐ray microscopy with zone‐plate focusing optics. This is demonstrated on various particle morphologies from two next‐generation lithium‐ion battery cathodes: LiNi0.8Mn0.1Co0.1O2 and LiNi0.6Mn0.2Co0.2O2; namely, NMC811 and NMC622. Internal voids are detected which limit energy density and promote degradation, potentially impacting commercial application such as the drivable range of an electric vehicle., This work describes a fast preparation method and high‐throughput scanning procedure for the 3D characterization of lithium–ion battery electrode powder in minutes. This employs nanocomputed tomography by full‐filed transmission X‐ray microscopy with zone‐plate focusing optics. The procedure is outlined and subsequently used to qualitatively and quantitatively assess two next‐generation nickel‐rich cathode powders.

Cannabis sativa L., a low-cost, fast-growing herbaceous plant, is seeing a resurgence in widespread cultivation as a result of new policies and product drive. Its biodegradable and environmentally benign nature coupled with its high specific surface area and three-dimensional hierarchal structure makes it an excellent candidate for use as a biomass-derived carbon material for electrochemical power sources. It is proposed that this ‘wonder crop’ could have an important role in the energy transition by providing high-functioning carbon-based materials for electrochemistry. In this article, all instances of C. sativa usage in batteries, fuel cells and supercapacitors are discussed with a focus on highlighting the high capacity, rate capability, capacitance, current density and half-wave potential that can be achieved with its utilisation in the field.

Graphite is the most commonly used anode material in commercial lithium-ion batteries (LiBs). Understanding the mechanisms driving the dimensional changes of graphite can pave the way to methods for inhibiting degradation pathways and possibly predict electrochemical performance loss. In this study, correlative microscopy tools were used alongside electrochemical dilatometry (ECD) to provide new insights into the dimensional changes during galvanostatic cycling. X-ray computed tomography (CT) provided a morphological perspective of the cycled electrode so that the effects of dilation and contraction on effective diffusivity and electrode pore phase volume fraction could be examined. During the first cycle, the graphite electrode underwent thickness changes close to 9% after lithiation and, moreover, it did not return to its initial thickness after subsequent delithiation. The irreversible dilation increased over subsequent cycles. It is suggested the primary reason for this dilation is electrode delamination. This is supported by the finding that the electrode porosity remained mostly unchanged during cycling, as revealed by X-ray CT.

The next generation of automotive lithium‐ion batteries may employ NMC811 materials; however, defective particles are of significant interest due to their links to performance loss. Here, it is demonstrated that even before operation, on average, one‐third of NMC811 particles experience some form of defect, increasing in severity near the separator interface. It is determined that defective particles can be detected and quantified using low resolution imaging, presenting a significant improvement for material statistics. Fluorescence and diffraction data reveal that the variation of Mn content within the NMC particles may correlate to crystallographic disordering, indicating that the mobility and dissolution of Mn may be a key aspect of degradation during initial cycling. This, however, does not appear to correlate with the severity of particle cracking, which when analyzed at high spatial resolutions, reveals cracking structures similar to lower Ni content NMC, suggesting that the disconnection and separation of neighboring primary particles may be due to electrochemical expansion/contraction, exacerbated by other factors such as grain orientation that are inherent in such polycrystalline materials. These findings can guide research directions toward mitigating degradation at each respective length‐scale: electrode sheets, secondary and primary particles, and individual crystals, ultimately leading to improved automotive ranges and lifetimes.

This work was financially supported by the EPSRC (EP/M506631/1, EP/L505079/1) and COST action SM1302 SIPs. M.B. would like to thank EaStCHEM and the School of Chemistry for support; O. L. M. acknowledges financial support from the Grant Agency of the Ministry of Education of the Slovak Republic and Slovak Academy of Sciences VEGA (grant No. 2/0116/17) and from the Slovak Research and Development Agency (grant APVV-15-0726). A series of representative late d-block metal complexes bearing a rigid bis(phosphine) ligand, iPr2P-Ace- PPh2 ( L , Ace = acenaphthene-5,6-diyl), was prepared and fully characterised by various techniques, including multinuclear NMR and single crystal X-ray diffraction. The heteroleptic nature of the peri- substituted ligand L allows for the direct observation of the JPP couplings in the 31P{1H} NMR spectra. Magnitudes of JPP are correlated with the identity and geometry of the metal, and the distortions of the ligand L . The forced overlap of the phosphine lone pairs due to the constraints imposed by the rigid acenaphthene skeleton in L results in large 4JPP of 180 Hz. Sequestration of the lone pairs, either via oxidation of the phosphine, or metal chelation, results in distinct changes in the magnitude of JPP. For tetrahedral d10 complexes ( [LMCl2] , M = Zn, Cd, Hg), the JPP is comparable or larger (193–309 Hz) to that in free ligand L , although the P···P separation in these complexes is increased by ca. 0.4 Å (compare to free ligand L ). The magnitude of JPP diminishes to 26–117 Hz in square planar d8 complexes ( [LMX2] , M = Ni, Pd, Pt, X = Cl, Br) and octahedral Mo0 complex [ LMo(CO)4] , 33 Hz). Coupling Deformation Density calculations indicate the through-space interaction dominates in free L , whilst in metal complexes the main coupling pathway is via the metal atom. Postprint Postprint

A series of representative late d-block metal complexes bearing a rigid bis(phosphine) ligand, iPr