2 research outputs found
One-Dimensional van der Waals Material Tellurium: Raman Spectroscopy under Strain and Magneto-Transport
Experimental
demonstrations of one-dimensional (1D) van der Waals
material tellurium (Te) have been presented by Raman spectroscopy
under strain and magneto-transport. Raman spectroscopy measurements
have been performed under strains along different principle axes.
Pronounced strain response along the <i>c</i>-axis is observed
due to the strong intrachain covalent bonds, while no strain response
is obtained along the <i>a</i>-axis due to the weak interchain van der Waals interaction. Magneto-transport
results further verify its anisotropic property, which results in
dramatically distinct magneto-resistance behaviors in terms of three
different magnetic field directions. Specifically, phase coherence
length extracted from weak antilocalization effect, <i>L</i><sub>ϕ</sub> ≈ <i>T</i><sup>–0.5</sup>, claims its two-dimensional (2D) transport characteristics when
an applied magnetic field is perpendicular to the thin film. In contrast, <i>L</i><sub>ϕ</sub> ≈ <i>T</i><sup>–0.33</sup> is obtained from universal conductance fluctuations once the magnetic
field is along the <i>c</i>-axis of Te, which indicates
its nature of 1D transport along the helical atomic chains. Our studies,
which are obtained on high quality single crystal Te thin film, appear
to serve as strong evidence of its 1D van der Waals structure from
experimental perspectives. It is the aim of this paper to address
this special concept that differs from the previous well-studied 1D
nanowires or 2D van der Waals materials
Monolayer Thiol Engineered Covalent Interface toward Stable Zinc Metal Anode
Interface engineering of zinc metal anodes is a promising
remedy
to relieve their inferior stability caused by dendrite growth and
side reactions. Nevertheless, the low affinity and additional weight
of the protective coating remain obstacles to their further implementation.
Here, aroused by DFT simulation, self-assembled monolayers (SAMs)
are selectively constructed to enhance the stability of zinc metal
anodes in dilute aqueous electrolytes. It is found that the monolayer
thiol molecules relatively prefer to selectively graft onto the unstable
zinc crystal facets through strong Zn–S chemical interactions
to engineer a covalent interface, enabling the uniform deposition
of Zn2+ onto (002) crystal facets. Therefore, dendrite-free
anodes with suppressed side reactions can be achieved, proven by in
situ optical visualization and differential electrochemical mass spectrometry
(DEMS). In particular, the thiol endows the symmetric cells with a
4000 h ultrastable plating/stripping at a specific current density
of 1.0 mA cm–2, much superior to those of bare zinc
anodes. Additionally, the full battery of modified anodes enables
stable cycling of 87.2% capacity retention after 3300 cycles. By selectively
capping unstable crystal facets with inert molecules, this work provides
a promising design strategy at the molecular level for stable metal
anodes