Novel structured Na-doped MoS
2
nanosheets were developed in situ on Ni foam through a more accessible two-step hydrothermal technique. Benefiting from the synergistic reactions of the superior ...capacitance of Na-doped MoS
2
nanosheet, the superior electrical kinetics of Na-doped, and the porous nanostructure of the composites, the designed Na-doped MoS
2
nanosheet composites electrode achieves notable electrochemical activity. The material’s structural properties investigate using an X-ray photoelectron spectroscope analyzer, X-ray powder diffractions, scanning electron microscope, and transmission electron microscope. The electrochemical activity of the designed electrodes was executed using cyclic voltammograms, galvanostatic charge/discharges, and electrochemical impedance spectroscopy. Compared to the pure MoS
2
electrode, the novel architecture Na-doped MoS
2
nanosheet deremonstrates a higher specific capacity of 374.3 C g
−1
at 1 A g
−1
. In addition, it achieves notable cycling stability performance and retains 87.4% capacity over 5,000 long cycles at 3 A g
−1
. These notable results reveal that the uniquely designed Na-doped MoS
2
nanosheet displays superior electrochemical consequences and higher potential as nanomaterials for supercapacitors.
Ubiquitous energy harvesting technologies require new types of renewable, sustainable, and clean energy to solve the problems of fossil fuels. Although various nanogenerators have been developed over ...the last decade, low current density, requirements for complicated management circuits, generation of direct current (DC) outputs, and significant performance degradation under humid atmospheres have been problems limiting practical applications. This paper reports that the tribovoltaic and moisture‐enabled electricity generation effects can be achieved in a layered double hydroxide (LDH) by applying a metal brushing mode. The ZnAl‐LDH shows enhanced tribovoltaic nanogenerator (TVNG) performance even in a high‐humidity environment coupled with the moisture‐enabled electricity generated by the concentration gradient of a water molecule through the interlamellar structures of the LDHs. The spontaneous dissociation of water in the interior of LDHs removes the hole generated by the tribovoltaic effect, allowing high efficiency of an output voltage of 693.38 mV and current density of 65.48 mA m−2 even under low‐applied force (≈3.5 mN) at relative humidity 80%. The proposed TVNG provides a proof of concept for an all‐in‐one device consisting of a generator and capacitor because the LDH reveals a spontaneous charging performance similar to that of a capacitor.
A synergistic coupled tribovoltaic and moisture‐enabled nanogenerator is demonstrated based on ZnAl‐layered double hydroxide nanosheet scroll structures, which exhibit tribovoltaic and hygroelectric effects. The synergistic nanogenerator shows much‐improved output performances even under low applied force (≈3.5 mN) at the high humidity condition (RH 80%). The synergistic effect enabled the nanogenerator can be used as an all‐in‐one device with the characteristics of a capacitor and a generator simultaneously.
Mn-doped SnO
2
thin films were fabricated to enhance two conflicting properties of the electromagnetic interference (EMI) shielding effectiveness and the infrared (IR) wavelength ranges. As a ...magnetic element, manganese (Mn) was doped into the SnO
2
thin films at an over-doping level of 300 mM to increase its magnetic permeability. As the molar content of Mn increases, the preferred growth plane of the SnO
2
thin films changes from (200) to (115) planes. Although all SnO
2
thin films showed diamagnetic properties due to the strong diamagnetism of the substrate and SnO
2
, the magnetic susceptibility of the Mn-doped SnO
2
films slightly decreased with increasing the Mn content from 0 to 60 mM, while it increased again with the doping content above it. As the Mn doping content increased from 0 to 150 mM, the sheet resistance of SnO
2
films continuously increased from 98 to 128 Ω/sq. As the Mn content increases from 30 to 120 mM, the IR transmittance at 4 μm increases from 37 to 47%, while the EMI shielding effectiveness at 10 GHz increases from 8.7 to 9.0 dB. The abnormal result of increased shielding effectiveness despite increased sheet resistance was due to increased magnetic permeability due to the addition of Mn. As the Mn content exceeds 150 mM, Mn-related metal clusters are formed inside the thin film, reducing the magnetic susceptibility and EMI shielding.
During cancer immunoediting, loss of major histocompatibility complex class I (MHC-I) in neoplasm contributes to the evasion of tumours from host immune system. Recent studies have demonstrated that ...most natural killer (NK) cells that are found in advanced cancers are defective, releasing the malignant MHC-I-deficient tumours from NK-cell-dependent immune control. Here, we show that a natural killer T (NKT)-cell-ligand-loaded tumour-antigen expressing antigen-presenting cell (APC)-based vaccine effectively eradicates these advanced tumours. During this process, we find that the co-expression of Tim-3 and PD-1 marks functionally exhausted NK cells in advanced tumours and that MHC-I downregulation in tumours is closely associated with the induction of NK-cell exhaustion in both tumour-bearing mice and cancer patients. Furthermore, the recovery of NK-cell function by IL-21 is critical for the anti-tumour effects of the vaccine against advanced tumours. These results reveal the process involved in the induction of NK-cell dysfunction in advanced cancers and provide a guidance for the development of strategies for cancer immunotherapy.
•Self-polling effect by metal–organic frameworks was suggested to change the polarity of organics.•The performance of the nanogenerator was enhanced by the self-polling process.•Proof of concept for ...a self-powered signal trigger for a smart home control system was demonstrated.
Metal-organic frameworks (MOFs) exhibit various unique properties, but these properties have not been fully utilized for the performance enhancement of triboelectric nanogenerator (TENG). The MOFs with MIL-101(Cr) structure is a nanomaterial designed for extremely large pore structures than conventional MOF structures to absorb and desorb various solvents, which induces a new phenomenon, self-polling effect (SPE) in the organic materials. We verified and suggested the SPE mechanism of the N, N-dimethylformamide (DMF) solvent by the MIL-101(Cr) structured MOFs in the polyvinylidene fluoride (PVDF) nanofibers. Because of the SPE, the MOFs-based composite NFs showed enhanced TENG output performances by additionally induced β-phase in the PVDF NFs even after the electrospinning process. The composite PVDF NFs with optimal MOF content of 0.8 wt% showed an output power density of 568.8 µW/cm2, which is larger by 8.96 times compared to the pure PVDF NFs. After the SPE process, the output power density increased to 871.2 µW/cm2, which is 13.7 times larger than that of pure PVDF NFs. Different from the pure PVDF NFs, the MOFs-based composite PVDF NFs showed improved output powers after the SPE process regardless of MOF contents. Based on excellent performance, the TENG with the MOFs-based composite PVDF NFs was sufficiently utilized as a self-powered triggering sensor for smart home devices that can wirelessly operate various electronic devices.
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•We investigated the morphological evolution of NiCo hydroxides due to carbonate ions.•The NCCH16//AC device shows the maximum energy densities of 31.1 Wh·kg−1.•The hierarchical NiCo ...hydroxides exhibit excellent electrochemical performance.
Pseudocapacitors can exhibit higher capacity compared to traditional electrostatic or electric double-layer capacitors while they can provide faster power delivery and longer cycling ability than lithium–ion batteries. In this study, we demonstrate the hierarchical structures of NiCo hydroxides, which are grown on Ni foam via facile hydrothermal method and show enhanced pseudocapacitor performance. Moreover, we suggest the intriguing phase transformation of NiCo-layered double hydroxide (LDH) to NiCo-carbonate hydroxide (CH) and elucidate the morphological evolution mechanism from nanosheet to nanowire structures by increasing the concentration of carbonate anions during the synthesis procedure. The experimental results confirm that an increase of carbonate anions causes the phase and morphology of NiCo–LDH to transform into NiCo–CH. Consequently, the asymmetric device using NCCH16 electrode achieves excellent electrochemical performance, with an energy density of 31.1 Wh·kg−1 at a power density of 424.3 W·kg−1 due to their structural benefits, which provide effective electrolyte transport, charge transfer, and active site accessibility.
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•Mica/nylon 66 composite nanofibers were fabricated by electrospinning process.•The electric field loss was diminished by incorporation of mica into the nylon 66 ...nanofibers.•Triboelectric nanogenerator with composite nanofibers showed robust performances under harsh environment.
The triboelectric nanogenerator (TENG) is a fascinating energy-harvesting device that utilizes the triboelectric effect caused by contact electrification and electrostatic induction. Nylon 66 is used widely in TENG applications because it is a representative tribo-positive polymer with excellent biocompatibility. On the other hand, the generated charges are vulnerable to discharge due to moisture in the air, which impedes the TENG performance in harsh environments. Moreover, the dielectric loss, which generates heat by consuming the considerable electric charge in triboelectric materials, significantly degrades the TENG performances. This study fabricated the composite nanofiber (NF) structure of nylon 66 and mica, which has excellent electrical insulation, low dielectric loss, high thermal conductivity, and enhanced tribo-positive properties, to circumvent these problems. Embedding the mica into the nylon NFs enhanced the TENG performance and prevented performance degradation even in harsh environments at a relative humidity of 70%. Furthermore, after 100,000 cycles of friction, the nylon/mica composite NFs showed smaller temperature increments than the pristine nylon NF because of the low dielectric loss and efficient heat dissipation of the mica. The nylon/mica composite NFs were applied to a sustainable and wearable power generator operating in a humid and hot environment by attaching the device to the forearm and soles of the feet. The generators were efficient enough to turn on 80 light-emitting diodes.
The recent application of the internet of things demands the ubiquitous utilization of data and electrical power. Even with the development of a wide variety of energy‐harvesting technologies, few ...studies have reported a device transporting electrical energy and data simultaneously. This paper reports an electrostatic induction nanogenerator (ESING) consisting of a one‐dimensional metastructure that can modulate the output voltage based on the resonance of ultrasound waves to transmit energy and data simultaneously. The ESING device is fabricated using electronegative poly(vinylidene fluoride) (PVDF) membrane using a phase inversion process. The output voltage from the ESING device exhibits periodic resonant peaks as the gap between the PVDF membrane and the Al electrode changes, showing an up to 35‐fold difference between the maximum and minimum output voltages depending on the resonance state. The energy and electrical signal can be transmitted simultaneously in free space because the ESING converts energy from high‐frequency ultrasound waves. This paper provides proof of concept for a data and energy‐transferable smart tag device based on ESING devices exhibiting resonant and non‐resonant states. A device consisting of four ESINGs for a 4‐bit signal is implemented to demonstrate 16 signals.
An electrostatic induction nanogenerator is demonstrated based on a one‐dimensional metastructure, which boosts the output voltage up to 35 times. The electrical energy and signal can be transferred simultaneously in free space. Proof of concept for a data and energy‐transferable smart tag device is demonstrated based on the nanogenerator exhibiting resonant and non‐resonant states for a 4‐bit signal.
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