ABSTRACT
Lithium metal batteries (LMBs) are prominent among next-generation energy-storage systems because of their high energy density. Unfortunately, the commercial application of LMBs is hindered by the dendrite growth issue during the charging process. Herein, we report that the triboelectric nanogenerator (TENG)-based pulse output with a novel waveform and frequency has restrained the formation of dendrites in LMBs. The waveform and operation frequency of TENG can be regulated by TENG-designed and smart power management circuits. By regulating the waveform and frequency of the TENG-based pulse output, the pulse duration becomes shorter than the lithium dendrite formation time at any current of pulse waveform, and lithium ions can replenish in the entire electrode surface during rest periods, eliminating concentration polarization. Therefore, the optimized TENG-based charging strategy can improve the Coulombic efficiency of lithium plating/stripping and realize homogeneous lithium plating in LMBs. This TENG-based charging technology provides an innovative strategy to address the Li dendrite growth issues in LMBs, and accelerates the application of TENG-based energy collection systems.
ABSTRACT
The development of flexible electronics has extended the limit of the intelligent devices, which are highly sensitive, soft and capable of sustaining arbitrary deformation. Here, we report a liquid-polymer tubular triboelectric nanogenerator (L-P TENG) that is filled with liquid for a shape-adaptive sensor in various working modes. The L-P TENG is based on liquid-solid contact electrification with the use of displacement current and excited by the shape change of the tubular structure. The high softness of the device makes it possible to be twisted to any curve and bear extreme strain. It can be used to detect a slight difference in pressure from touch, pressing and stretching and is suitable for a wide-range force recognition with high sensitivity. The independent and multifunctional properties of the L-P TENG extend the potential applications through combinations. Such assembled units with crossings can sense the approaching object. This study provides a new direction for flexible electromechanical sensing and has potential applications in self-powered sensors, wearable electronics, smart human-machine interaction and auxiliary motion correction.
ABSTRACT
Core-shell-structured BaTiO3-poly( tert-butyl acrylate) (P tBA) nanoparticles are successfully prepared by in situ atom transfer radical polymerization of tert-butyl acrylate ( tBA) on BaTiO3 nanoparticle surface. The thickness of the P tBA shell layer could be controlled by adjusting the feed ratio of tBA to BaTiO3. The BaTiO3-P tBA nanoparticles are introduced into poly(vinylidene fluoride) (PVDF) matrix to form a BaTiO3-P tBA/PVDF nanocomposite. The nanocomposites keep the flexibility of the PVDF matrix with enhanced dielectric constant (â¼15@100 Hz) because of the high permittivity of inorganic particles and the ester functional groups in the P tBA. Furthermore, the BaTiO3-P tBA/PVDF nanocomposites demonstrate the inherent small dielectric loss of the PVDF matrix in the tested frequency range. The high electric field dielectric constant of the nanocomposite film was investigated by polarization hysteresis loops. The high electric field effective dielectric constant of the nanocomposite is 26.5 at 150 MV/m. The output current density of the nanocomposite-based triboelectric nanogenerator (TENG) is 2.1 µA/cm2, which is above 2.5 times higher than the corresponding pure PVDF-based TENG.
ABSTRACT
Private and security information for personal identification requires an encrypted tool to extend communication channels between human and machine through a convenient and secure method. Here, a triboelectric-based transparent secret code (TSC) that enables self-powered sensing and information identification simultaneously in a rapid process method is reported. The transparent and hydrophobic TSC can be conformed to any cambered surface due to its high flexibility, which extends the application scenarios greatly. Independent of the power source, the TSC can induce obvious electric signals only by surface contact. This TSC is velocity-dependent and capable of achieving a peak voltage of ≈4 V at a resistance load of 10 MΩ and a sliding speed of 0.1 m s-1, according to a 2 mm × 20 mm rectangular stripe. The fabricated TSC can maintain its performance after reciprocating rolling for about 5000 times. The applications of TSC as a self-powered code device are demonstrated, and the ordered signals can be recognized through the height of the electric peaks, which can be further transferred into specific information by the processing program. The designed TSC has great potential in personal identification, commodity circulation, valuables management, and security defense applications.
ABSTRACT
Triboelectric nanogenerators (TENG) have been proven to be effective for the collection of low-frequency vibrational energy in the environment. However, most polymer materials as friction layers are highly susceptible to mechanical damage during operation, which reduces the performance and lifetime of TENG. Herein, we report a high-performance, flexible triboelectric nanogenerator with reproducible self-healing electronic characteristics. Based on its soft and flexible polymers, the self-healing triboelectric nanogenerator (SH-TENG) can achieve a peak power of 2.5 W m-2 and triboelectric charge density of about 100 µC m-2. High-conductance Ag nanowires (AgNWs) are semi-embedded in the polymer to fabricate all-in-one friction layers and for an enhanced self-healing process. Both the output voltage and current of the healed device can reach up to about 99% of their original values even after five cutting/healing cycles. The fabricated SH-TENG has excellent stability and flexibility, which presents a significant step towards the fabrication of reliable triboelectric nanogenerators with recoverability and low maintenance costs.