DeCarbon最新文献

Thin films exhibit substantial potential in energy management and utilization as the development of micro- and nanofabrication technologies. It is well known that thermal radiation is one of the fundamental ways of energy transfer. However, the potential of hyperbolic films for radiative heat transfer is always ignored. Whether the radiative heat flux between hyperbolic films surpasses that of the bulk materials remains insufficiently explored. In this work, we theoretically investigate the radiative heat transfer between hexagonal boron nitride (hBN) at a separation from 20 ​nm to 2 ​μm. The results show that when the optical axis of hBN is oriented in-plane, the near-field radiative heat flux of hBN with a thickness of 10 ​nm exceeds that of hBN bulk by 47% and exceeds the blackbody limit by two orders of magnitude at a gap distance of 20 ​nm. The physical mechanism is attributed to the volume-confined hyperbolic polaritons can be excited in a higher wavevector space. Conversely, when the gap distance is 600 ​nm, the heat flux between films is considerably lower than that of bulk material. This work opens up potential avenues for developing hyperbolic film-dependent thermal devices and strategies for thermal management.

The molten electrolysis of CO₂ and its simultaneous transformation to graphene nanocarbons is a growing path to decarbonization of both anthropogenic CO₂, and CO₂ directly from the air. By tuning the electrolysis conditions a variety of pure graphene nanocarbons are produced from CO₂. The carbon in CO₂ is transformed at the cathode, growing as a carbanogel containing a matrix of the Graphene NanoCarbons (GNCs) and the molten electrolyte. This study demonstrates that one GNC product, carbon nanotubes from CO₂, can be effectively separated from the carbanogel by removing the majority of the electrolyte for reuse in the electrolysis chamber. A molten electrolyte extraction efficiency of 98.5% from the carbanogel is achieved using filtration at high temperature and pressure. Optimization of the (1) press time, (2) filtration pressure applied to the carbanogel, and (3) filter type leads to a sequential increase in optimization. An increase of press time from 5 to 17 ​min increases the electrolyte extraction from 53.8% to 92% at 540 psi, and to 97.8% at 3700 psi. An increase in electrolyte extraction of 98.5% from the carbanogel occurs with the inclusion of a Dutch-weave screen in the multilayer filter. The optimization is conducted on 10 ​kg carbanogel samples, but instrumentation for up to 0.25-tonne carbanogel electrolyte separation is shown.

In this work, we present a design of a paper-based microfluidic fuel cell (μFC), which employs the spontaneous capillary flow of reactant solutions in a filter paper to accomplish passive conveyance of the fuel and oxidant. This self-pumping device uses methanol vapor as a fuel. The gas phase in the microfluidic fuel cell increases the fuel supply to the anode due to a higher diffusion coefficient of 1.5 ​× ​10⁻⁵ ​m² ​s⁻¹ compared with 5 ​× ​10⁻⁹ ​m² ​s⁻¹ for liquid phase. An air-breathing cathode is incorporated to paper-based μFC through which atmospheric oxygen is continuously supplied. The paper-based μFC performance is studied by polarization curves and chronoamperometry to determinate the power output and stability. Peak power of 1.49 ​mW and a stable current of 1.35 ​mA at 0.35 ​V for 28 ​h can be achieved with this prototype under room temperature. To interpret the device performance a numerical model is developed and validated with the experimental polarization curve. The fuel and oxidant concentration profiles in the electrodes from the model demonstrates a constant species availability at the cathode and anode and explains the stable current obtained in the experimental measurements. Subsequently, a stack of four MμFCFP was developed and evaluated in both series and parallel connections. In the parallel configuration, a maximum open circuit potential (OCP) of 0.69 ​V with a maximum current and power output of 34.53 ​mA and 4.14 ​mW are delivered, respectively. Conversely, in the series connection, a total current of 7.35 ​mA, an OCP of 2.39 ​V and a maximum power of 3.57 ​mW are reached. As a proof of concept, the stack successfully operates a 3 green LEDs array, each requiring a 2.1–2.5 ​V and 4.2–5 ​mW power to function, for a continuous duration of 3 ​h.

The contact electrification (CE) between DI water and SiO₂ or fluorinated polymer has been proven to be mainly due to electron transfer, which is significantly influenced by ions in solution. However, how these ions in water affect the charge transfer at the liquid-solid (L-S) interface is still unresolved, especially for the already charged friction layer. Here, a direct current droplet-based electricity generator (DC-DEG) which is sensitive to the change of charge transfer at the L-S interface is adopted to detect the effects of ions in the neutral salt solution on the charged PTFE surface. The distribution of ions on the charged L-S interface (the change of electric potential on the solid surface) and its effects on the output of DC-DEGs have been studied. The results indicate that the charge transfer of droplets and then the output of DC-DEGs are closely related to the concentrations of salt solutions. Anions can enhance the surface potential of PTFE due to their adsorptions on PFTE while cations can reduce it due to their screen effect. At low ionic concentrations, the surface potential enhancement caused by anion adsorption is larger than that surface potential reduction caused by screen effect from cations. At high ionic concentrations, the electrostatic screen effect of cations increases a lot to weaken the surface potential and reducing the charge separation of droplets induced by electrostatic induction (EI). This work explains the redistribution process of ions at the L-S interface and also provides a clever solution for improving the electrical output performance of DEGs.

Harvesting the mechanical energy dissipated by vehicles passing over road to power micro-electromechanical systems (MEMS) in intelligent transportation systems (ITS) is an important way to realize self-powered traffic condition monitoring. However, the limitations of traditional vehicle energy harvesting speed bumps such as single functionality and heavy-shock on vehicles are not conducive to developing energy harvesting speed bumps for multi-functionalization, versatility and intelligence. In this work, a compact hybridized triboelectric-electromagnetic road energy harvester (CHREH) device is designed. The vehicle's wheels impact force drives the sliding plate movement and triggers the triboelectric generator (TENG) unit and electromagnetic generator (EMG) unit to produce electricity. The enhanced TENG built by multi-layer folded structure is assembled using rGO and surface-patterning modified polydimethylsiloxane (PDMS) composite film. Furthermore, the mechanism and electrical output performance of EMG and TENG are theoretically simulated and experimentally tested. Particularly, TENG unit achieved a peak power of 7.21 ​mW and the EMG unit reached a peak power of 0.74 ​mW at an excitation frequency of 5 ​Hz, in addition to the superior durability. Further, the demonstration of application of self-powered car warning and speed monitoring were conducted. The CHREH offers a feasible approach for self-powered applications deployable to the low power consumption electronic devices and ITS.

Introduction of vacancies is a widely practiced method to improve the performance of active materials in different energy systems, such as secondary batteries, electrocatalysis, and supercapacitors. Because vacancies can generate abundant localized electrons and unsaturated cations, the incorporation of vacancies will significantly improve the electrical conductivity, ion migration, and provides additional active sites of energy storage materials. This article systematically reviews different methods to generate oxygen, nitrogen, or selenium vacancies, and techniques to characterize these vacancies. We summarize the specific roles that vacancies play for the active materials in each type of energy storage devices. Additionally, we provide insights into the research progress and challenges associated with the future development of vacancies technology in various energy storage systems.

Numerous reports have suggested that the performance of organic optoelectronic devices based on organic field-effect transistors (OFETs) is largely dependent on their interfaces. Self-assembled monolayers (SAMs) have been commonly used to engineer the interfaces of high-performance devices, particularly due to their well-defined structures and simple operation process through simple chemical adsorption growth. In this review, the structures of OFETs and SAM-modified OFETs are described, while different SAMs have been characterized. Furthermore, recent advances in the interface engineering of OFETs are described, the applicability of SAMs in functional devices of OFETs is reviewed, and existing problems and future developments in this field have been identified.

The ever-rising demand for lithium-ion batteries (LIBs) in the coming two decades has created a substantial market for battery recycling industry. The rejuvenation of spent batteries will not only transform the huge quantity of solid wastes into valuable resources but also promote the sustainable use of natural resources, while mitigating the environmental risks in association with landfills. Despite the significant progress made in the recovery efficiency through various recycling methods, including pyrometallurgy, hydrometallurgy and direct recycling, each of the currently-used methods is not an entirely pollution-free activity. Herein, the concept of “green” approach is proposed to encompass the “3L” criteria, which denotes Less energy consumption, Less greenhouse gas emissions, and Less operational cost. To achieve this great objective, the green potential for various recycling methods is examined in this overview. Additionally, we systematically discuss the optimal approaches for enhancing environmental friendliness while maintaining high recovery efficiency, with particular emphasis on the mild leaching and relithiation processes. Furthermore, in targeting of the main challenges of inadequate scalability, poor battery traceability, and high labor consumption, a multiple closed-loop recycling roadmap that includes regulation, artificial intelligence-assisted pretreatment, targeted recycling and other novel applications, is developed, highlighting the green-sustainable concept for the next-generation battery recycling industry.

Aligning with ambitious targets and commitments towards carbon neutrality, countries around the world are desperately seeking an energy transition to cope with the stark reality of the climate crisis and the surge in demand for heating and cooling. Increased penetration of renewable power is foreshadowing a shift in global energy dominance, from fossil fuel based heating to renewable power based heating. However, we have to address four underlying challenges in energy transition, including (1) to achieve heat electrification, (2) to utilize decommissioned thermal power plants, (3) to meet the demand for large-scale heat storage, and (4) to puzzle out the final “10 ​%” emissions. Given the above challenges, we put forth four heat pump-assisted approaches to break the bottleneck of energy transition and facilitate effective incentive strategies for policymakers. We highlight that the efficiency and flexibility of heat pumps in thermal energy regulation enable them to push forward an immense influence on the future energy transition for the heating/cooling supply that accounts for 50 ​% of the energy consumption for users and the last “10 ​%” carbon emissions.

Biomimetic structures involve design and fabrication to mimic the natural world, taking inspiration from the unique shapes, patterns, and functions of biological organisms. This approach has proven to be highly effective in building new functional and efficient structures for many applications. While it is often challenging to fabricate some of the complex biomimetic structures, the development of 3D printing technologies in recent years has made it more feasible, being a powerful tool for fabricating complex structures with high precision and accuracy, at the much reduced use of starting materials. In this review, we will examine the current state of biomimetic structures fabricated by 3D printing techniques and their specific applications in energy and environmental fields for the decarbonization demand. The different selected types of biomimetic structures that have been constructed using 3D printing, the materials used, and the unique properties obtained will be explored. Subsequently, some typical biomimetic structures for energy and environmental applications, such as supercapacitors, zinc-air batteries, oil/water separation, self-cleaning, water collection, droplet manipulation, etc., will be discussed. Finally, the opportunities in this rapidly changing area will be analyzed, hoping to provide insights into the innovative pathways that 3D-printed biomimetic structures can be used to address some challenges in energy and environmental areas.