Nano Energy最新文献

Two-dimensional (2D) materials have shown great potential in harvesting osmotic power due to their high membrane selectivity, but the high resistance from tortuous pathways of 2D nanofluidic membranes still impedes the further improvement in output performance. Here, we report an innovative 2D MXCT (MXene/Cu-TCPP) lamellar membrane with ultralow resistance for highly efficient osmotic power generation. The incorporation of 2D Ti₃C₂T_x MXene with rich functional groups not only resolves the water-stability issue of 2D metal-organic framework (MOF) Cu-TCPP, but provides large surface charges for selective ion transport. The orderly sub-2 nm framework channels of Cu-TCPP provide much shorter permeation pathways for fast ion transport, thus endowing the MXCT membrane with ultralow resistance. Consequently, the MXCT membrane reaches an ultrahigh power output of ∼8.29 W/m² by mixing seawater and river water, which is ∼275 % higher than that of the pristine MXene membrane. Additionally, it outperforms all the reported single-layer 2D nanosheet-based osmotic power generators under the same experimental conditions in terms of output power and internal resistance (9 kΩ). This work presents a reliable strategy for stabilizing 2D Cu-TCPP MOF in electrolytes, opening new avenues for designing promising 2D nanofluidic membranes for efficient blue energy harvesting and ionic devices.

FeOF as an intercalation-conversion cathode features a high theoretical capacity toward high energy density lithium-ion batteries (LIBs). However, the inadequate intercalation process and poor reversibility of redox reaction deteriorate its practical capacity and cycling stability. Herein, a S-substitution strategy in FeOF (FeOF-S) is proposed to boost the intercalation reaction and enhance the reaction kinetics, achieving a record-high capacity of 668 mAh g⁻¹ at 0.05 A g⁻¹ and a long cycling stability up to 1500 cycles at 0.5 A g⁻¹. Under this strategy, the Li⁺ intercalation energy of FeOF-S is remarkably reduced in thermodynamics, promoting the intercalation capacity to 230 mAh g⁻¹ which is 50% higher than that of FeOF. Furthermore, a nearly zero band gap with superior electronic conduction is achieved in FeOF-S, leading to excellent rate capability with much enhanced pseudo-capacitance contribution. This work presents new insights into the regulation of thermodynamics and kinetics toward the boosted electrochemical performance of conversion-type electrodes for high energy density LIBs.

Transparent conducting electrodes (TCEs) serve as essential components in various devices, including smart windows, thin film heaters, and sensors. Historically, indium tin oxide (ITO) thin films have served as the primary TCE material. However, the scarcity of indium in the Earth’s crust and costly vacuum-based deposition processes have prompted researchers to seek alternatives. While silver nanowire (Ag NW) networks have emerged as the leading candidate for TCEs among various alternatives, the presence of polyvinyl pyrrolidone (PVP) layer surrounding Ag NWs often leads to substantial contact resistances at the junction areas. Given the diverse characteristics of Ag NWs, including length, diameter, PVP thickness, and deposition methods, the efficacy of a specific post-treatment method on the same Ag NW batch remained unknown. This work collected effective post-treatment methods from existing literature and innovatively developed in-house approaches to optimize the treatment of Ag NW networks. Following post-treatment, the resulting electrodes exhibited a 70 % reduction in sheet resistance, with only a marginal 1 % decrease in optical transmittance. The optical figure of merit (FoM) for the optimized networks showed a remarkable five-fold improvement, rising from 66 to 305. The optimized Ag NW networks were then utilized as current collectors in water droplet-based TENG sensors, showcasing the device's effectiveness in pH and chemical concentration sensing. The fabricated TENG recorded peak Voc and Isc values of 22 V and 370 nA, respectively. Furthermore, we developed a sensor-integrated device capable of gauging the incident droplets’ pH level, signaling acid rain safety. In addition, the droplets activate a large-area Ag NW-based transparent thin film heater. Rapid defogging and defrosting capabilities of the heater was also demonstrated. The device holds the potential to be applied to the side-view mirrors of cars, providing an anti-fogging display for a significantly safer journey.

High performance, cost-efficient anion exchange membrane water electrolysis (AEMWE) is of great current interest for industrial-level hydrogen production. However, the lack of active and robust catalytic electrode severely impedes the development of this technology. Herein, a versatile strategy of 3D hierarchical porous monolithic electrode enabling industrial hectoampere-level current AEMWE is successfully explored for the first time. By a facile electroless plating technique coupled with corrosion engineering process, a series of low-cost and highly active 3D transition metal boride (etched-TMB, TM=Ni, Co, NiP, NiMo, CoP, CoMo, CoNi) catalytic electrodes have been prepared. A distinctive hierarchically structured etched-NiPB@MS alloy monolithic electrode exhibits a superior bifunctional hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalytic activity and large-current stability, which derive from enhanced intrinsic activity, sufficient electrochemical active sites, mechanical stability as well as efficient gas/liquid transport pathways. An AEMWE electrolyzer with 10$\times$10 cm² etched-NiPB@MS as both anode and cathode works efficiently at large current of 100 A (1 A cm⁻²) and reaches a H₂ production rate of 41.78 L h⁻¹, verifying its huge potential for industrial hydrogen production. This study paves out a new approach for high-efficient catalytic electrode and industrial-level current AEMWE.

Constructing heterostructure is a valid method to reinforcing sodium storage performance of transition metal chalcogenides materials. Herein, a simple, safe and controllable one step hydrothermal method is proposed to synthesize MoS₂/NiS₂ heterostructure. Due to the difference in band gaps and work functions of MoS₂ and NiS₂, the charges are redistributed at the MoS₂/NiS₂ heterointerfaces, thereby accelerating the migration of electrons and Na⁺. The heterointerfaces provide extra active sites for storing Na⁺, thus increasing the sodium storage capacity of the heterostructure. Furthermore, the distinct redox potentials of NiS₂ and MoS₂ promote the structural stability of MoS₂/NiS₂ heterostructure during the electrochemical reaction processes. Consequently, the obtained MoS₂/NiS₂ heterostructure exhibits superior rate properties (339.4 mAh g⁻¹ at 10 A g⁻¹) and ultra-stable cycling stability (480.5 mAh g⁻¹ after 350 cycles at 1 A g⁻¹). This paper presents a valid strategy for creating heterostructure anodes with excellent sodium storage properties.

As an efficient mechanical energy harvester, the triboelectric-electromagnetic hybrid generator (TEHG) stands as a cornerstone in self-powered systems. Nevertheless, significant impedance disparities between triboelectric nanogenerators (TENGs) and electromagnetic generators (EMGs) often hamper systems’ energy utilization efficiency, attributed to impedance mismatch at the load. Here, a variable impedance strategy is proposed, aimed at maximizing the utilization of mechanical energies converted by TEHG. This approach capitalizes on electronic components with dynamic impedance from GΩ to kΩ in response to OFF-ON state transitions, thus matching the impedance of TENG and EMG. Experimentally, an ultraviolent gas discharge tube (UV-GDT) is integrated into the self-powered variable impedance system. Operated at 240 rpm, the TEHG-driven UV-GDT extracts energy amounting to 1304.27 mJ with an 87.5 % utilization efficiency. These metrics outperform the situation where UV-GDT is individually powered by either EMG (0 mJ, 0 %) or TENG (18.24 mJ, 60.7 %). Furthermore, the mechanical energy-activated UV system demonstrates promise for sterilization, curing, and photo-chemical reactions. This variable impedance strategy resolves the impendence mismatch between TEHG and load, more importantly, provides a valuable guideline for developing hybrid generator systems with enhanced energy utilization efficiency.

Self-propelled soft robots have attracted extensive attention because of their unique application in exploring dangerous and complex environments that are unsuitable for human beings. However, these soft robots require cyclical chemical stimulation or external power and have short locomotion times, which limits their practical applications. It remains challenging to create self-propelled soft robots exhibiting long-term locomotion. Here, we couple an active hydrogel with a solar absorbing coating to realize self-propelled soft robots with long-term locomotion. The active hydrogel can move freely on the water surface by continuously establishing asymmetric surface tension through dynamic wetting. The sunlight absorbers promote water evaporation inside the self-propelled soft robot to delay or even disrupt the swelling equilibrium of the hydrogel, thus establishing dynamic balance between water absorption and evaporation. In this way, the locomotion time of this self-propelled soft robot under constant light irradiation equivalent to 1 sun (1 kW/m²) is 6.5 times higher than that of active hydrogel reported previously. Owing to the enhanced locomotion time through solar water evaporation water, this self-propelled soft robot is expected to be applied to oil pollution exploration, cargo transportation, and debris cleaning in small water areas.

Seawater electrolysis is a promising technique for H₂ production on a large scale. However, the electrocatalytic activity and stability will be deteriorated as the increase of salt concentrations which happened in the seawater splitting. Herein, through the electrodeposition and rapid Joule heating method, the Fe-NiO/MoO₂ heterostructure is designed as a highly active bifunctional electrocatalyst. During the OER possess, Fe-NiO/MoO₂ is reconstructed to the Fe, Mo-NiOOH with Fe and Mo co-doping. Based on the theoretical analysis, more electrons were transferred to the O atoms on the surface of Fe, Mo-NiOOH, thereby forming a more negatively charged surface. Moreover, that surface is found to repel Cl⁻ ions while enriching H₂O molecules to form a thin water layer on Fe, Mo-NiOOH surface based on molecule dynamics (MD) simulation, thereby improving the anti-corrosion capacity of Fe, Mo-NiOOH. The reconstructed Fe, Mo-NiOOH achieved an overpotential of 399 mV at 1000 mA cm⁻² in alkaline seawater, and the increase of overpotential for Fe, Mo-NiOOH was about 0.02 V at 500 mA cm⁻² from 0 M to 3 M NaCl in 1 M KOH electrolyte. For the HER, Fe-NiO/MoO₂ achieved an overpotential of 169 mV and 417 mV at 100 and 1000 mA cm⁻² in alkaline seawater, respectively, and the increase of overpotential for Fe-NiO/MoO₂ was about 0 mV at 500 mA cm⁻² from 0 M to 3 M NaCl in 1 M KOH electrolyte. This work sheds fresh light into the development of efficient electrocatalysts for salinity tolerance seawater splitting.

Wireless signal transmission plays an increasingly imperative role in numerous aspects of modern society, but it still remains challenging to achieve it with low-cost and efficient way. Herein, we demonstrate a long-distance wireless signal transmission system, which mainly includes an electrodeless triboelectric nanogenerator coupled with linear motion and rotational motion (LR-TENG) as a transmitter and a receiver located at a distance. Based on the varying electric field originated from Maxwell's displacement current, the maximum transmission distance of LR-TENG can reach 86 cm under the external excitation of 1 Hz, creating the highest record among the relevant researches. In addition, the influence of obstacle type, thickness, size and position on signal transmission has been systematically investigated for the first time, and the distribution of time-varying electric field in space is also analyzed qualitatively. Furthermore, a Labview interface is developed for accurate positioning in complex scenes relying on the received signals from multiple receivers at different positions. This work illustrates a simple and feasible design method for extending the distance of wireless signal transmission based on TENG, and promotes its application in the field of wireless communication.