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Lithium (Li) metal is an ideal anode material for next-generation batteries. However, the commercialization of Li metal-based batteries is impeded by uncontrollable Li dendrite formation and the accumulation of a solid-electrolyte interphase (SEI). Recently, various polymers have been investigated to form a stable SEI layer on Li metal and extend its cycle life. In this study, a polymer film composed of sodium alginate (Na-Alg), which is a natural biopolymer obtained from brown algae, and poly(ethylene oxide) (PEO), was used as a separator. Na-Alg sustained the film structure and PEO facilitated Li-ion diffusion by absorbing the liquid electrolyte. Without using any additives in the commercial carbonate electrolyte, this method extended the cycle life of a Li metal symmetric cell to 1000 h with an overpotential

The practical use of lithium–sulfur battery (LSB) is impeded by the excessive growth of Li dendrite in the anode and the dissolution of soluble intermediates (shuttle effect) in the cathode. In spi...

Although metal-phenolic species have emerged as one of the versatile material-independent-coating materials, providing attractive tools for interface engineering, mechanistic understanding of their film formation and growth still remains largely unexplored. Especially, the anions have been overlooked despite their high concentration in the coating solution. Considering that the anions are critical in the reactivity of metal-organic complex and the formation and/or property of functional materials, we investigated the anionic effects on the characteristics of film formation, such as film thickness and properties, in the Fe3+-tannic acid coating. We found that the film characteristics were strongly dictated by the counteranions (e.g., SO42-, Cl-, and Br-) of the Fe3+ ion. Specifically, the film thickness and properties (i.e., mechanical modulus, permeability, and stability) followed the reversed anionic Hofmeister series (Br- > Cl- > SO42-). Mechanistic studies suggested that more chaotropic anions, such as Br-, might induce a more widely extended structure of the Fe3+-TA complexes in the coating solution, leading to thicker, harder, but more porous films. The reversed anionic Hofmeister effect was further confirmed by the additive effects of various sodium salts (NaF, NaCl, NaBr, and NaClO4).

Traditionally, the manipulation of contact mechanisms has been adopted as the primary strategy to tailor the friction properties of surfaces. On the contrary, the detaching process involving the local deformation and failure at the interface has been considered relatively less important. Here, we present a new approach toward the friction control of amorphous carbon through the plasticity and resultant transition of deformation mode on nanopatterned surfaces. Depending on the topography of the nanopatterns, the mechanical responses of the surfaces alter from elastic fracture to plastic flow, through which the friction coefficient changes by a factor of 5 without manipulation of the intrinsic structure of the material.

Metal–ceramic nanolayered composites have been reported to have high strength because of their effective confinement of dislocations at interfaces; however, this unfortunately results in unstable deformation due to the brittleness of the ceramic layer. This study explores the deformation behavior of a metal–ceramic nanolayered composite in which the ceramic layer thickness is varied to examine the effect of brittle-to-ductile transition of the ceramic layer. The thickness of AZO, which is theoretically expected to be ductile, is first fixed at 9 nm while varying the metal thickness. For further comparison, 150 nm Ag/120 nm AZO is studied, where the AZO layer is expected to be brittle. In-situ SEM pillar compression show stable deformation for samples with 9 nm thick AZO, in which co-deformation of metal and ceramic is confirmed by TEM analysis. A systematic increase in strength is observed with reduction of Ag thickness with stable plastic deformation for nanolayered composite with AZO thickness of 9 nm. For the 150 nm Ag/120 nm AZO, unstable deformation is observed in which brittle fracturing of the AZO layer leads to reduction in flow stresses or strain softening. Finite element analysis shows that the stresses in the Ag and the AZO layers reach the stresses required for co-deformation.