97HIGHLIGHTS 2020

Uniform lithium electrodeposition for stable lithium-metal batteries, X. He (a,d), Y. Yang (b), M.C. Stan (c), J. Wang (c), X. Hou (a), B. Yan (a), J. Li (a), T. Zhang (a), E. Paillard (a), M. Swietoslawski (d), R. Kostecki (d), M. Winter (a,c) and J. Li (a),

Nano Energy 67, 104172 (2020); https:// doi.org/10.1016/j.nanoen.2019.104172. (a) Helmholtz Institute Münster Forschungszentrum Jülich GmbH (IEK 12), Münster (Germany) (b) ESRF

(c) MEET Battery Research Center, Institute of Physical Chemistry, University of Münster, Münster (Germany) (d) Energy storage & Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley (USA)

[1] B. Liu et al., Joule 2, 833-845 (2018). [2] M. Winter et al., Chem. Rev. 118, 11433-11456 (2018). [3] H. Liu et al., Energy Storage Mater. 16, 505-511 (2019).

CADMIUM DISTRIBUTION AND SPECIATION IN DURUM WHEAT GRAINS USING SYNCHROTRON TECHNIQUES

Understanding how essential and toxic elements are distributed in cereal grains is key to improving the nutritional quality of cereal-based products. Synchrotron techniques helped to provide a clear picture of how cadmium was distributed among grain tissues and to identify the cadmium chemical environment in the grain crease.

PRINCIPAL PUBLICATION AND AUTHORS

REFERENCES

a significant amount of lithium has been plated, and the mesh is fully embedded into the deposit. It is also remarkable that no dendrite has formed despite the inhomogeneities induced by pressing the CNSSM. Instead, a homogenous and dense deposit is observed. The growth of electrodeposited lithium occurs mainly around the CNSSM. This suggests that the CNSSM favours homogeneous lithium nucleation and plating and prohibits the growth of dendritic lithium, and that further growth then remains homogenous due to favourable SEI properties.

Synchrotron X-ray nanotomography provides a clear insight into the evolution of the morphology and components of the CNSSM-Li composite after lithium electrodeposition. It allowed, in

Cadmium (Cd) is a heavy metal contaminant whose toxicity to humans has long been recognised and whose concentration in foodstuffs is regulated in Europe by the Commission Regulation (EC) No. 1881/2006. Durum wheat has a greater tendency to accumulate Cd in grains than common wheat and other cereals, at concentrations sometimes above the regulation limit of 0.2 mg kg-1 set by the European Union. Therefore, particular attention should be paid to reducing the level of Cd in durum wheat grains. Substantial efforts have already been made to understand how Cd is taken up, transported, and allocated to the grains in cereal crops [1]. However, little information is available on how Cd is distributed within the grain, even though the differential accumulation of an element among grain tissues mirrors its internal loading, storage and functions within the grain. This is probably because the level of Cd accumulation

in plant grains is usually too low to be accurately quantified by imaging. Thanks to the combined high sensitivity and lateral resolution of beamline ID21, it was possible to quantitatively image Cd and several nutrients in durum wheat grain.

The micro X-ray fluorescence (µ-XRF) distribution map obtained for Cd from a transversal section of durum wheat grain (Figure 81a) shows a very strong accumulation of Cd in the crease, which is the main entry route for elements to the seed. The high-resolution map of the crease (Figure 81b) pinpoints a curved zone , assumed to be the pigment strand where Cd co-localises with S, and where its concentration locally reaches 600 µg g-1 (when the average Cd concentration in the whole grain is 2.5 µg g-1). This suggests that Cd loading in nucellar projection cells strongly limits its allocation to the seed.

combination with the electrochemical data, to reveal the working mechanism of the CNSSM- Li electrode. The carbon-nitrogen functional groups (e.g., pyridinic nitrogen, pyrrolic nitrogen) adsorb a considerable amount of Li+ ions and regulate the nucleation of metallic lithium. This network structure can further lower local current density, reduce the charge transfer resistance, and accommodate the volume expansion upon lithium plating. The improved output energy and stable cycling performance over 500 cycles from LFP|CNSSM-Li full cells demonstrate the remarkable promise of CNSSM-Li for LMBs. The results serve as a guide for designing Li-anodes for LMBs and also provide an idea to track in situ the electrochemical reaction with X-ray nanotomography.