Multifunctional micro‐force sensing in one device is an urgent need for the higher integration of the smaller flexible electronic device toward wearable health‐monitoring equipment, intelligent robotics, and efficient human–machine interface. Herein, a novel microchannel‐confined MXene‐based flexible piezoresistive sensor is demonstrated to simultaneously achieve multi‐types micro‐force sensing of pressure, sound, and acceleration. Benefiting from the synergistically confined effect of the fingerprint‐microstructured channel and the accordion‐microstructured MXene materials, the as‐designed sensor remarkably endows a low detection limit of 9 Pa, a high sensitivity of 99.5 kPa−1, and a fast response time of 4 ms, as well as non‐attenuating durability over 10 000 cycles. Moreover, the fabricated sensor is multifunctionally capable of sensing sounds, micromotion, and acceleration in one device. Evidently, such a multifunctional sensing characteristic can highlight the bright prospect of the microchannel‐confined MXene‐based micro‐force sensor for the higher integration of flexible electronics.
Rich
chemistry and surface functionalization provide MXenes enhanced
electrochemical activity yet severely exacerbate their self-discharge
behavior in supercapacitors. However, this self-discharge behavior
and its related mechanism are still remaining issues. Herein, we propose
a chemically interface-tailored regulation strategy to successfully
unravel and efficiently alleviate the self-discharge behavior of Ti3C2T
x
MXene-based supercapacitors.
As a result, Ti3C2T
x
MXenes with fewer F elements (∼0.65 atom %) show a positive
self-discharge rate decline of ∼20% in comparison with MXenes
with higher F elements (∼8.09 atom %). Such decline of the
F elements can highly increase tight-bonding ions corresponding to
an individual self-discharge process, naturally resulting in a dramatic
50% increase of the transition potential (V
T). Therefore, the mixed self-discharge rate from both tight-bonding
(contain fewer F elements) and loose-bonding ions (contain more F
elements) is accordingly lowered. Through chemically interface-tailored
engineering, the significantly changed average oxidation state and
local coordination information on MXene affected the interaction of
ion counterparts, which was evidently revealed by X-ray absorption
fine structures. Theoretically, this greatly improved self-discharge
performance was proven to be from higher adsorption energy between
the interface of the electrode and the electrolyte by density functional
theory. Therefore, this chemically interface-tailored regulation strategy
can guide the design of high-performance MXene-based supercapacitors
with low self-discharge behavior and will promote its wider commercial
applications.
As the world marches
into the era of the Internet of Things (IoT),
the practice of human health care is on the cusp of a revolution,
driven by an unprecedented level of personalization enabled by a variety
of wearable bioelectronics. A sustainable and wearable energy solution
is highly desired , but challenges still remain in its development.
Here, we report a high-performance wearable electricity generation
approach by manipulating the relative permittivity of a triboelectric
nanogenerator (TENG). A compatible active carbon (AC)-doped polyvinylidene
fluoride (AC@PVDF) composite film was invented with high relative
permittivity and a specific surface area for wearable biomechanical
energy harvesting. Compared with the pure PVDF, the 0.8% AC@PVDF film-based
TENG obtained an enhancement in voltage, current, and power by 2.5,
3.5, and 9.8 times, respectively. This work reports a stable, cost-effective,
and scalable approach to improve the performance of the triboelectric
nanogenerator for wearable biomechanical energy harvesting, thus rendering
a sustainable and pervasive energy solution for on-body electronics.
The
naturally microstructure-bioinspired piezoresistive sensor
for human–machine interaction and human health monitoring represents
an attractive opportunity for wearable bioelectronics. However, due
to the trade-off between sensitivity and linear detection range, obtaining
piezoresistive sensors with both a wide pressure monitoring range
and a high sensitivity is still a great challenge. Herein, we design
a hierarchically microstructure-bioinspired flexible piezoresistive
sensor consisting of a hierarchical polyaniline/polyvinylidene fluoride
nanofiber (HPPNF) film sandwiched between two interlocking electrodes
with microdome structure. Ascribed to the substantially enlarged 3D
deformation rates, these bioelectronics exhibit an ultrahigh sensitivity
of 53 kPa–1, a pressure detection range from 58.4
to 960 Pa, a fast response time of 38 ms, and excellent cycle stability
over 50 000 cycles. Furthermore, this conformally skin-adhered
sensor successfully demonstrates the monitoring of human physiological
signals and movement states, such as wrist pulse, throat activity,
spinal posture, and gait recognition. Evidently, this hierarchically
microstructure-bioinspired and amplified sensitivity piezoresistive
sensor provides a promising strategy for the rapid development of
next-generation wearable bioelectronics.
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