2 research outputs found
Flexible Transparent and Free-Standing Silicon Nanowires Paper
If the flexible transparent and free-standing
paper-like materials
that would be expected to meet emerging technological demands, such
as components of transparent electrical batteries, flexible solar
cells, bendable electronics, paper displays, wearable computers, and
so on, could be achieved in silicon, it is no doubt that the traditional
semiconductor materials would be rejuvenated. Bulk silicon cannot
provide a solution because it usually exhibits brittleness at below
their melting point temperature due to high Peierls stress. Fortunately,
when the silicon’s size goes down to nanoscale, it possesses
the ultralarge straining ability, which results in the possibility
to design flexible transparent and self-standing silicon nanowires
paper (FTS-SiNWsP). However, realization of the FTS-SiNWsP is still
a challenging task due largely to the subtlety in the preparation
of a unique interlocking alignment with free-catalyst controllable
growth. Herein, we present a simple synthetic strategy by gas flow
directed assembly of a unique interlocking alignment of the Si nanowires
(SiNWs) to produce, for the first time, the FTS-SiNWsP, which consisted
of interconnected SiNWs with the diameter of ∼10 nm via simply
free-catalyst thermal evaporation in a vertical high-frequency induction
furnace. This approach opens up the possibility for creating various
flexible transparent functional devices based on the FTS-SiNWsP
Vertical Graphene Growth on SiO Microparticles for Stable Lithium Ion Battery Anodes
Silicon-based
materials are considered as strong candidates to
next-generation lithium ion battery anodes because of their ultrahigh
specific capacities. However, the pulverization and delamination of
electrochemical active materials originated from the huge volume expansion
(>300%) of silicon during the lithiation process results in rapid
capacity fade, especially in high mass loading electrodes. Here we
demonstrate that direct chemical vapor deposition (CVD) growth of
vertical graphene nanosheets on commercial SiO microparticles can
provide a stable conducting network via interconnected vertical graphene
encapsulation during lithiation, thus remarkably improving the cycling
stability in high mass loading SiO anodes. The vertical graphene encapsulated
SiO (d-SiO@vG) anode exhibits a high capacity of 1600 mA h/g and a
retention up to 93% after 100 cycles at a high areal mass loading
of 1.5 mg/cm<sup>2</sup>. Furthermore, 5 wt % d-SiO@vG as additives
increased the energy density of traditional graphite/NCA 18650 cell
by ∼15%. We believe that the results strongly imply the important
role of CVD-grown vertical graphene encapsulation in promoting the
commercial application of silicon-based anodes