95HIGHLIGHTS 2020

Multiple mechanical gradients are responsible for the strong adhesion of spider attachment hair, S. Flenner (a,b), C.F. Schaber (c), I. Krasnov (b), H. Stieglitz (a,b), M. Rosenthal (d), M. Burghammer (d), S.N. Gorb (c) and

M. Müller (a,b), Adv. Mater. 32, 2002758 (2020); https://doi.org/10.1002/ adma.202002758. (a) Helmholtz-Zentrum Geesthacht, Geesthacht (Germany) (b) Institute of Experimental and Applied

Physics, Kiel University, Kiel (Germany) (c) Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Kiel (Germany) (d) ESRF

[1] C.F. Schaber et al., J. R. Soc. Interface 16, 20180692 (2019). [2] C.F. Schaber et al., Carbon 94, 396-404 (2015). [3] C.F. Schaber et al., ACS Appl. Mater. Interfaces 10, 37566-37574 (2018).

STABLE 3D HOST FOR UNIFORM LITHIUM ELECTRODEPOSITION IN LITHIUM-METAL BATTERIES

Synchrotron X-ray nanotomography was used to characterise a new lithium metal anode constructed with lithium foil and a conductive carbon-nitrogen modified stainless steel mesh (CNSSM) substrate. The results provide a clear insight into the evolution of the morphology and components of the CNSSM-Li composite after lithium electrodeposition, and could aid the design of Li-anodes for lithium-metal batteries.

PRINCIPAL PUBLICATION AND AUTHORS

REFERENCES

Fig. 79: a-e) SAXS intensity maps of the sequence of different contact conditions of an attachment hair in side view. The arrows indicate the direction of pull-off force. f) Force measured during the experiment. The circles correspond to the individual images

shown in (a)-(e). The numbers mark different experimental regimes.

The nonlinearity of the force curve at pulling-off (marked 3 in Figure 79f) indicated bending of the hair, which ensures that the spatulae stay in contact with the surface at increasing pulling forces. This behaviour is likely caused by the structural gradient in the hair backbone [1]. Pulling on the attached hair caused bending of the microtrichia relative to the hair backbone, as indicated by their gradual increase of angular change from the backbone up to the tips, as measured from the SAXS signals. This increased flexibility facilitates the alignment of the contact elements with the substrate, and reliable adhesion.

The combination of scanning nanobeam SAXS/ WAXS and submicro-Newton force-resolved in- situ manipulation has proven to be an excellent method for the simultaneous characterisation of deformation and the mechanical properties of untreated biological samples. The gradients of the structurally caused mechanical properties of the spider attachment hair on different length scales have evolved to support attachment, stabilise adhesion in contact, and withstand high stress at detachment. They could be an excellent model for the development of new high- performance, residue-free artificial adhesive materials, e.g., based on carbon nanotubes [2] or other natural nanofibres [3].

Lithium-metal batteries (LMBs) currently appear to be the most probable alternative to lithium- ion batteries because of their high achievable

energy densities [1,2]. However, their operation is challenging since lithium metal easily passivates upon contact with the electrolyte to