Nano Energy最新文献

Triboelectric nanogenerators (TENGs) have been widely used in energy harvesting from low-frequency, irregular motions due to their unique characteristics and excellent electromechanical conversion efficiency. Harvesting ocean energy to build a marine Internet of Things (MIoTs) has become an important research field for TENGs. However, the output power density of TENGs must be further enhanced for promoting their practical applications, by effective means such as the coupling of TENGs and electromagnetic generators (EMGs). Herein, we report a triboelectric-electromagnetic hybrid nanogenerator (TEH-NG) for self-powered ocean buoy to harvest water wave energy efficiently for the first time. The buoy consists of a self-engineered wave energy converter for converting wave energy into simple turbomachinery energy through the pressure difference created by the relative motion, and a TEH-NG for converting the turbomachinery energy into electrical energy. The TENG delivers an average output power of 3.40 mW (with power density of 141.7 W m⁻³), and the EMG achieves an average power of 0.04 W (with power density of 400.0 W m⁻³). The excellent performance of the TEH-NG makes it a potential candidate for constructing the MIoTs to achieve distributed marine environmental monitoring networks.

P2-type cathode has received extensive attention due to its faster Na⁺ diffusion and a high theoretical capacity in sodium-ion batteries (SIBs). However, undesirable phase transformations have induced dramatic capacity decay of SIBs during the cycling process. In this study, heteroatom anchoring through Cu/Mg dual doping is introduced into P2-type Na_0.67Ni_0.33Mn_0.67O₂ cathode to enhance high-voltage electrochemical reversibility and modulate interfacial Na⁺ kinetics. The as-prepared Na_0.67Ni_0.23Mg_0.05Cu_0.05Mn_0.67O₂ exhibits an outstanding capacity retention (83.4 % after 2000 cycles at 10 C) and rate performance (73 mAh g⁻¹ at 10 C, accounting for 58.7 % of that at 0.1 C) over the voltage range of 2.5–4.4 V. Intensive explorations further manifest that the modified mechanism of dual-ion doping strategy is attributed to the synergistic coupling effect of a substantial change in Na occupancy distribution and an increase in oxygen vacancy buffer. Thus, the optimized cathode expedites Na⁺ diffusion and reduces detrimental phase transformation, which favors high-rate performance and long-term cycling stability. This study develops a route to rationally design high-voltage cathode materials for SIBs.

The design of cathode materials that remain chemically and structurally stable during repetitive ion insertion and extraction poses a significant challenge in developing multivalent batteries. The cycling stability of traditional metal oxide-based cathode is challenged by sluggish diffusion of multivalent cations and parasitic reactivity at interfacial regimes, including the cathode electrolyte interphase layer (CEI). Understanding the reactions at the cathode-electrolyte interface, particularly those induced by non-stoichiometric surface layers, is a crucial design parameter for both cathode materials and electrolytes. In this study, we employed multimodal analysis, including in situ and ex situ X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS) to examine the surface reactions and subsequent structural and chemical evolutions of the CEI on high voltage magnesium vanadium oxide (MgV₂O₄) spinel cathode during the Mg²⁺ insertion/extraction processes. The results revealed that the presence of non-stoichiometric surface layers in the magnesium vanadium oxide cathode drive the decomposition of bis(trifluoromethanesulfonyl)imide (TFSI^-) anion, leading to the formation of the CEI layer. The CEI layer could inhibit the Mg²⁺ ion transfer processes. Accompanying this reactivity-driven degradation, the magnesium vanadium oxide cathode undergoes pulverization, forming clusters of nanosized particles. This process likely improves cycling ability by creating new intercalation sites and shortening the diffusion pathway for the Mg²⁺ cations. This study demonstrates that controlling surface stoichiometry and engineering morphological properties are critical design parameters for high performance cathodes for multivalent batteries.

Silicon suboxides (SiO_x) have achieved partial success in commercialization as high-capacity anode materials to replace graphite because of optimal electrochemical properties over silicon. Unfortunately, the further development has been sluggish, jeopardizing the urgent need of green energy. The daunting challenges to tackle include low initial coulombic efficiency (ICE) and low charging rate due to poor electron and ionic conductivity. In the context of thin film microbattery, we propose to precisely control the chemical states of SiO_x films through varying sputtering power followed by dry-state pre-lithiation through Li-metal thermal evaporation, superior to the current pre-lithiation approaches for SiO_x thin-film anodes. We addressed the leading roles of the surface chemical states of the as-deposited SiO_x in the formation of the high ionic conductive Li₄SiO₄ phase as the pre-solid electrolyte interphase during the proposed dry-state prelithiation process. Ultimately, the prelithiated SiO_x successfully mitigated the most confronted issues as low ICE and C-rate limitation, achieving an unprecedented rate performance of 72.8 % at 20 C, and ultra-long-cycle retention of 54.2 % over 5000 cycles at 10 C. These results strongly prove that appropriate pre-lithiation provides tremendous advantages to SiO_x thin film anode not only in prolonging electrode stability but also promoting a significant fast-cycling.

Exogenous electrical stimulation (ES) can significantly enhance the wound healing acceleration. However, most power-generating devices and materials are limited due to structural complexity, external power dependence, and low bio-safety. Here, we design and synthesize a porous hydrogel with gas-solid contact-separation triboelectricity (GSHL). It exhibits excellent physicochemical properties and bio-safety. Also, its inner pores provide a gas-solid interface, which generates a stable self-powered triboelectric potential difference due to the deformation of the interior pores when pressed by the motion of hosts. This exogenous triboelectric stimulation can enhance the proliferation, migration, and adhesion of keratinocytes. In vivo experiments show that GSHL can generate ES at wound bed in situ through the movements of rats, accelerate re-epithelization, and enhance collagen deposition, thereby enhancing the healing of skin wounds. Compared to traditional methods that depending on an external power source to achieve ES for wound healing, this study introduces a novel triboelectric method that is self-powered solely through the intrinsic movement of the organism without any external electrical input.

With the exponential development of the Internet of Things (IoTs), big data, and artificial intelligence (AI), smart home technologies have become crucial to people's lives and the construction of smart cities, driving an increasing demand for distributed sensors. In this work, we have for the first time successfully fabricated smart ceramic tiles (SCTs) that integrate electrodes with ceramic tiles using a layer-by-layer temperature gradient sintering method. These SCTs, which are based on triboelectric nanogenerator (TENG) technology, not only demonstrate high sensitivity and good stability, but also offer the potential for high concealment by adjusting glaze composition and color. Under various motion triggers, the SCTs produced high-discrimination electrical output signals, which proves their potential in behavior recognition. Extreme environmental tests further confirmed the SCTs' superior responsiveness. A wireless security monitoring system for SCT sensing, which was developed using IoT chips, enables remote monitoring via mobile devices. This study not only demonstrates the commercial feasibility of SCTs but also highlights their immense potential for imperceptible monitoring within the smart home domain.

This work proposes a novel acoustic nanocomposite fibrous membrane-based triboelectric nanogenerator (NFM-TENG) with excellent acoustical-to-electrical conversion performance. The optimal combination for the triboelectric pairs of NFM-TENG is identified: a polyvinylidene fluoride-multiwalled carbon nanotubes (PVDF-MWCNTs ( 1 wt$\text{\%}$)) nanofibrous membrane as the tribo-positive layer, and a corona-charged fluorinated ethylene-propylene (FEP) solid membrane as the tribo-negative layer, resulting in higher electric output than single-friction-layered NFM-TENG (32 times). Under the acoustic excitation of 116 dB at 200 Hz, the acoustic NFM-TENG can generate a maximum areal power density of 3.78 W/ m${}^2$. The NFM-TENG can be used not only as a acoustic energy harvester, but also as a self-powered triboelectric acoustic sensor (TAS) for real-time voice recording and control. For convenience, for the first time, an advanced tiny TAS (TTAS, diameter: only 9.7 mm) based on the NFM-TENG is developed and its sensitivity is calibrated as -50 dB according to the International standard IEC61094. Experimental results also verified that the TTAS with broadband response ability (20–20,000 Hz) is fully competent for commercial applications such as real-time voice control, HMI, and other multi-scenarios. The TTAS is smart, reliable and customizable, potentially leading to a new revolution in intelligent interaction.

Electronic skins (e-skins) for monitoring human and robot activities under extreme circumstances are significant for human-machine interaction in multiple scenarios, which is challenging to realize on fabric/textile materials. Herein, a core filling-encapsulation strategy for multi-layer weaving is explored to achieve a triboelectric triple-layer sandwich woven e-skin (TSW e-skin) for durable self-powered sensing in extreme environments. To construct a robust structure with environment adaptability, ultra-high molecular weight polyethylene (UPE) fibers or polyimide (PI) fibers are integrated into the triple-layer sandwich woven to provide mechanical/thermal/chemical stability, and carbon fibers (CF) are protectively embedded as a core layer for electricity collection, heat management and adaptive sensing. Hydrophobic encapsulation is improved by polydimethylsiloxane (PDMS) thin coating with morphology and mechanical compliances. The TSW e-skin demonstrates excellent mechanical strength (∼20 MPa) and thermal stability (154.5 ℃), durable superhydrophobicity (>150°), and corrosion resistance (pH 1–13), which demonstrates an open-circuit voltage of 53 V and maintains electrically stable at above 150 ℃. The weaving structure enables the e-skin regulatable electrode patterns for sensitive motion perception and touch identification for human and robotic limbs, with real-time tactile feedback even under extreme scenarios. This robust all-fabric e-skin proposes a common strategy for human-robot perception in harsh environments.

Asymmetric (viz. Janus or one-way transport) fabrics that can promote directional sweat transport from the next-to-the-skin surface to the outer surface by the hydrophobic-hydrophilic difference across the fabric thickness have been developed. However, the hydrophobic next-to-the-skin surface inevitably increases the inherent resistance to sweat transportation into the fabric, fundamentally hampering its moisture management property. In this work, by selectively coating a poly-pyrrole (ppy) film with Turing patterns on one side of the fabric to achieve superspreading property, we demonstrated an all-hydrophilic asymmetric fabric with outstanding one-way liquid sweat transport property. Benefiting from the low resistance of sweat absorption, the all-hydrophilic fabric exhibited a dramatically increased directional sweat transport rate of 13.6 mm/s, which is 5.9 times that of the untreated fabric, and significantly enhanced sweat evaporation rate (1.56 times of the untreated fabric) and cooling performance. Furthermore, the conductive ppy-fabric, during the process of ultra-fast sweat transport, generated a potential of 150 mV over an area of 2×2 cm² or scalable electrical energy output of 2.5 mW/m² under continuous sweat transportation. The finding in this work not only provided new insight into the design and development of asymmetric fabric for ultrafast sweat transport but also proposed a novel method for the in-situ energy harvesting during the sweat transportation process, which has potential applications in self-powered smart wearables and functional clothing.

Direct-current triboelectric nanogenerators (DC-TENGs) have recently become more attractive to convert mechanical energy into electricity due to their high current density with no need for rectification. Interfacial charge transfer, induced by the sliding contact on semiconductor materials, is critical to generate DC output but usually limited by the interfacial properties. Here, we report Schottky DC-TENGs based on the atomic-crystal transition-metal dichalcogenides (TMDs) with single crystallinity, monolayer thickness and atomic flatness to enhance the interfacial charge transfer. A record-high current density of 10¹⁰ A/m², two orders of magnitude higher than the state-of-the-art performance, can be directly generated by sliding a conductive-atomic force microscope tip on an atomic-crystal molybdenum disulfide. Density functional theory calculation and finite element simulation reveal that this ultrahigh current density can be attributed to the enhanced interfacial property owing to the atomic flatness of TMDs and strong local electrical field of nanoscale tip. We further demonstrate their excellent scalability by a high-crystalline monolayer film with sliding electrode. This work may guide and accelerate the development and application of high-performance DC-TENGs.