| 1. |
- Atkins, Duncan, et al.
(författare)
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Accelerating Battery Characterization Using Neutron and Synchrotron Techniques: Toward a Multi-Modal and Multi-Scale Standardized Experimental Workflow
- 2022
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6840 .- 1614-6832. ; 12:17
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Tidskriftsartikel (refereegranskat)abstract
- Li-ion batteries are the essential energy-storage building blocks of modern society. However, producing ultra-high electrochemical performance in safe and sustainable batteries for example, e-mobility, and portable and stationary applications, demands overcoming major technological challenges. Materials engineering and new chemistries are key aspects to achieving this objective, intimately linked to the use of advanced characterization techniques. In particular, operando investigations are currently attracting enormous interest. Synchrotron- and neutron-based bulk techniques are increasingly employed as they provide unique insights into the chemical, morphological, and structural changes inside electrodes and electrolytes across multiple length scales with high time/spatial resolutions. However, data acquisition, data analysis, and scientific outcomes must be accelerated to increase the overall benefits to the academic and industrial communities, requiring a paradigm shift beyond traditional single-shot, sophisticated experiments. Here a multi-scale and multi-technique integrated workflow is presented to enhance bulk characterization, based on standardized and automated data acquisition and analysis for high-throughput and high-fidelity experiments, the optimization of versatile and tunable cells, as well as multi-modal correlative characterization. Furthermore, new mechanisms, methods and organizations such as artificial intelligence-aided modeling-driven strategies, coordinated beamtime allocations, and community-unified infrastructures are discussed in order to highlight perspectives in battery research at large scale facilities.
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| 2. |
- Gustafsson, Olof
(författare)
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Crystallographic studies of non-equilibrium structural changes in cathode materials
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Battery cathode materials are a key focus for improvement of Li-ion battery chemistries due their limits in terms of capacity and cost. During insertion and extraction of Li, many cathode materials exhibit structural changes, ranging from e.g. phase transitions to amorphization. Such structural rearrangements can be unfavourable for electrochemical performance due to the incompatibility between any intermediate phases formed. The crystalline structure can be readily studied using diffraction techniques such as X-ray and neutron diffraction, making them a versatile tool for identifying and understanding these structural changes. The work in this thesis focuses on utilizing diffraction to study equilibrium and non-equilibrium changes in the crystalline structure of the two cathode materials LiNi0.5Mn1.5O4 and Li2VO2F. Both of these materials display interesting structural behaviour upon electrochemical cycling, some of it which can be linked to how the cations arrange in the structure. As such, the work presented here aims to elucidate further on the cationic structural features of these materials and how these may impact their use in batteries. For both LiNi0.5Mn1.5O4 and Li2VO2F, the (re)arrangement of cations in the structure was found to play a crucial role for both equilibrium and non-equilibrium structural transitions occurring. In particular, the formation of phases that could be regarded as disadvantageous from a battery application perspective could be attributed to cationic diffusion. Due to the many structural similarities of transition metal oxide-based cathode materials, structural reorganization following similar mechanisms involving cationic rearrangement could be expected also in other materials similar to those studied here. As such, strategies for mitigating any unwanted redistribution of cations in the structure should be considered for improving the performance of this class of cathode materials.
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