4 research outputs found
The Effects of Different CoreāShell Structures on the Electrochemical Performances of SiāGe Nanorod Arrays as Anodes for Micro-Lithium Ion Batteries
Connected
and airbag isolated SiāGe nanorod (NR) arrays
in different configurations have been fabricated on wafer scale Si
substrates as anodes in micro-lithium ion batteries (LIBs), and the
impacts of configurations on electrochemical properties of the electrodes
were investigated experimentally and theoretically. It is demonstrated
that the Si inner cores can be effectively protected by the connected
Ge shells and contribute to the enhanced capacity by ā¼68%,
derived from an activation process along with the amorphization of
the crystalline lattice. The first-principles calculations further
verify the smaller forces on the Si layers at the atomic level during
the restricted volume expansion with the covering of Ge layers. This
work provides general guidelines for designing other composites and
coreāshell configurations in electrodes of micro-LIBs to accomplish
higher capacities and longer cycle lives
Synergetic SERS Enhancement in a Metal-Like/Metal Double-Shell Structure for Sensitive and Stable Application
Because
of either thermal/chemical instability or high optical loss in noble
metal nanostructures, searching for alternative plasmonic materials
is becoming more and more urgent, considering the practical biosensing
applications under various extreme conditions. In this work, titanium
nitride (TiN), a low-loss metal-like material with both excellent
thermal and excellent chemical stabilities, was proposed to composite
with Ag hollow nanosphere (HNS) nanostructures as an effective surface-enhanced
Raman scattering (SERS) substrate to realize both highly sensitive
and highly stable molecular detection. Because of the multiple-mode
local surface plasmon resonance around the spherical composite nanospheres
and the āgap effectā derived from the ultrasmall nanogaps
within the precisely controlled plasmonic arrays, an intensively enhanced
local field was successfully induced on this SERS substrate. Combined
with the unique charge transferring process between Ag and TiN, a
synergistically enhanced SERS sensitivity involving both physical
and chemical mechanisms was achieved. Especially, with the isolation
of TiN, a time-durable Raman detection on these TiNāAg HNS
arrays was accomplished, showing great potential for practical applications
High Stability Induced by the TiN/Ti Interlayer in Three-Dimensional Si/Ge Nanorod Arrays as Anode in Micro Lithium Ion Battery
Three-dimensional (3D) Si/Ge-based
micro/nano batteries are promising
lab-on-chip power supply sources because of the good process compatibility
with integrated circuits and Micro/Nano-Electro-Mechanical System
technologies. In this work, the effective interlayer of TiN/Ti thin
films were introduced to coat around the 3D Si nanorod (NR) arrays
before the amorphous Ge layer deposition as anode in micro/nano lithium
ion batteries, thus the superior cycling stability was realized by
reason for the restriction of Si activation in this unique 3D matchlike
Si/TiN/Ti/Ge NR array electrode. Moreover, the volume expansion properties
after the repeated lithium-ion insertion/extraction were experimentally
investigated to evidence the superior stability of this unique multilayered
Si composite electrode. The demonstration of this wafer-scale, cost-effective,
and Si-compatible fabrication for anodes in Li-ion micro/nano batteries
provides new routes to configurate more efficient 3D energy storage
systems for micro/nano smart semiconductor devices
ZIFā8 Cooperating in TiN/Ti/Si Nanorods as Efficient Anodes in Micro-Lithium-Ion-Batteries
Zeolite imidazolate framework-8 (ZIF-8)
nanoparticles embedded
in TiN/Ti/Si nanorod (NR) arrays without pyrolysis have shown increased
energy storage capacity as anodes for lithium ion batteries (LIBs).
A high capacity of 1650 Ī¼Ah cm<sup>ā2</sup> has been
achieved in this ZIF-8 composited multilayered electrode, which is
ā¼100 times higher than the plain electrodes made of only silicon
NR. According to the electrochemical impedance spectroscopy (EIS)
and <sup>1</sup>H nuclear magnetic resonance (NMR) characterizations,
the improved diffusion of lithium ions in ZIF-8 and boosted electron/Li<sup>+</sup> transfer by the ZIF-8/TiN/Ti multilayer coating are proposed
to be responsible for the enhanced energy storage ability. The first-principles
calculations further indicate the favorable accessibility of lithium
with appropriate size to diffuse in the open pores of ZIF-8. This
work broadens the application of ZIF-8 to silicon-based LIBs electrodes
without the pyrolysis and provides design guidelines for other metalāorganic
frameworks/Si composite electrodes