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Driven by the continuous search for improving performances, understanding the phenomena at the electrode/electrolyte interfaces has become an overriding factor for the success of sustainable and efficient battery technologies for mobile and stationary applications. Toward this goal, rapid advances have been made regarding simulations/modeling techniques and characterization approaches, including high‐throughput electrochemical measurements coupled with spectroscopies. Focusing on Li‐ion batteries, current developments are analyzed in the field as well as future challenges in order to gain a full description of interfacial processes across multiple length/timescales; from charge transfer to migration/diffusion properties and interphases formation, up to and including their stability over the entire battery lifetime. For such complex and interrelated phenomena, developing a unified workflow intimately combining the ensemble of these techniques will be critical to unlocking their full investigative potential. For this paradigm shift in battery design to become reality, it necessitates the implementation of research standards and protocols, underlining the importance of a concerted approach across the community. With this in mind, major collaborative initiatives gathering complementary strengths and skills will be fundamental if societal and environmental imperatives in this domain are to be met. [ABSTRACT FROM AUTHOR]

An X‐ray transparent electrochemical cell for operando bench‐top X‐ray diffraction in reflection geometry is presented. Dense glassy carbon (Sigradur‐G) is used as an X‐ray transparent window. The cell and dedicated sample holder are easy to handle and cost efficient thanks to their simple designs. To demonstrate the performance of this new Swagelok‐type operando cell, diffractograms were collected during cycling of the cathode material LixMn2O4 (x ≤ 1) in a lithium‐ion battery. During charging/delithiation, three spinel phases with evolving lattice parameters were found. This observation confirms the expected mixed two‐phase and solid‐solution behaviour and thereby validates our experimental setup. The presented low‐cost setup may enable further battery research units to access operando X‐ray diffraction data for characterization of structural phenomena during battery cycling and degradation mechanisms during prolonged cycling, which will lead to improvement of the battery technology. An X‐ray transparent electrochemical cell with dense glassy carbon windows (Sigradur‐G) for operando bench‐top X‐ray diffraction in reflection geometry is demonstrated. [ABSTRACT FROM AUTHOR]

To improve lithium and sodium ion battery technology, it is imperative to understand how the properties of the different components are controlled by their chemical structures. Operando structural studies give us some of the most useful information for understanding how batteries work, but it remains difficult to separate out the contributions of the various components of a battery stack (e.g., electrodes, current collectors, electrolyte, and binders) and examine specific materials. We have used operando X-ray diffraction computed tomography (XRD-CT) to study specific components of an essentially unmodified working cell and extract detailed, space-resolved structural information on both crystalline and amorphous phases that are present during cycling by Rietveld and pair distribution function (PDF) methods. We illustrate this method with the first detailed structural examination of the cycling of sodium in a phosphorus anode, revealing surprisingly different mechanisms for sodiation and desodiation in this promising, high-capacity anode system. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries may become an inexpensive alternative to lithium-ion batteries for large-scale stationary storage of energy generated by intermittent renewable sources. The key for the deployment of this technology is the development of suitable anode materials which can rival the graphite anodes used in lithium-ion batteries in terms of energy density, cycle life, rate performance, and safety. Here, we demonstrate that the bismuth metalates, BiVO4 and Bi2(MoO4)3, as representatives of ternary metalates, can cope with these requirements. High specific capacities (367 mAh/g and 352 mAh/g, respectively), exceptionally high cycling stability for alloying anodes (up to 79% of the first charge capacity is retained over 1000 cycles at ~1C for Bi2(MoO4)3), better high-rate performance compared to other Bi-based anodes, low environmental load (Bi has low toxicity for a heavy metal), and low manufacturing costs (e.g., BiVO4 is a commercial yellow pigment) make this novel class of anode materials suitable for large-scale electrical energy storage applications. Operando XANES, ex situ XRD, and DFT analysis suggest that the initial compounds are converted into alloying Bi nanocrystallites confined in a matrix of electrochemically active insertion hosts Na3+xVO4 and Na2+xMoO4, respectively. The Bi metalate phases are not reformed on charge, and on subsequent cycles the reaction with Bi metal and vanadate/molybdate phases gives rise to the reversible capacity. The nanostructured composite anode thus obtained has excellent high rate performance and retains its capacity over hundreds of cycles. [ABSTRACT FROM AUTHOR]

A fundamental understanding of de/intercalation processes (single phase versus multi-phase), structural stability and voltage-composition profiles is pivotal for optimization of electrode materials for rechargeable non-aqueous batteries. A fully operational setup (electrochemical cells, sample changer and interfacing software) that enables combined quasi-simultaneous operando X-ray diffraction (XRD) and absorption (XANES and EXAFS) measurements coupled with electrochemical characterization is presented. Combined XRD, XANES and EXAFS analysis provides a deep insight into the working mechanisms of electrode materials, as shown for the high-voltage Li insertion cathode material LiMn1.5Ni0.5O4 and the high-capacity sodium conversion anode material Bi2S3. It is also demonstrated that the cell design can be used for in-house XRD characterization. Long-term cycling experiments on both Li and Na electrode materials prove the hermeticity and chemical stability of the design as a versatile operando electrochemical cell. [ABSTRACT FROM AUTHOR]

In situ powder synchrotron diffraction and X-ray absorption spectroscopy have been used to investigate cation ordered as well as disordered modifications of the LiMn 1.5 Ni 0.5 O 4 spinel-type compound as a Li-ion battery (LIB) cathode during electrochemical cycling. The structural state depends on the adopted heat treatment conditions and is ascertained by Raman and neutron diffraction data. The degree of Mn-Ni ordering (none, partial, complete) is one parameter that influences the electrochemical behaviour. The in situ data reveal significant differences in behaviour with respect to structural phase transitions during electrochemical cycling. Ordered Li 2 Mn 3 NiO 8 ( P4 3 32 ) undergoes two consecutive first order structural phase transitions between spinel type phases during charging - discharging. These are most probably connected with steps in oxidation state for the Ni-atoms as supported by XANES data. The disordered phases ( Fd -3 m ) show a mixed “solid solution - two phase” behaviour accompanied by a smooth decrease in the unit cell volume during charging over the two redox steps involved, Ni 2+ /Ni 3+ /Ni 4+ , however, also with volume jumps at first order transitions. This combined behaviour is explained for the first time for spinel type LiMn 1.5 Ni 0.5 O 4 materials. It is not clear why ordered and disordered phases show different phase behaviors depending on the state of (dis)charge. This could be due to higher valent Mn taking part in the redox activity at higher voltages, however, future verification is required. [ABSTRACT FROM AUTHOR]