Energy-related Fields Research Articles

Improved corrosion resistance of AZ31 Mg alloy coated with MXenes/MgAl-LDHs composite layer modified with yttrium

MXenes, a novel two-dimensional (2D) material of Ti3C2, present wide applications in energy-related fields. However, a mass of sedimentary multilayer Ti3C2 was discarded and non-recyclable due to incomplete exfoliation in the preparation of single layer Ti3C2. In this work, a composite structure, mixing MXenes/magnesium aluminum-layered double hydroxides (MXenes/MgAl-LDHs) with Y(OH)3, was synthesized in-situ as a smart coating on Mg alloy AZ31 via (i) exfoliating those multilayer Ti3C2 to few-layer MXenes (FLMs), and (ii) adding Y(NO3)3 to FLMs solution for a one-step hydrothermal treatment. Results show the electronegative mainboard of MXenes can effectively absorb cations in the reaction solution, and promote growth of MgAl-LDHs and Y(OH)3 on its surface. Moreover, MgAl-LDHs being the intermediate connector facilitate growth of MXenes upon the surface of Mg alloy AZ31. The corrosion tests indicated that the composite coating modified with yttrium had an excellent anticorrosion performance (Ecorr = −0.36 VSCE, Icorr = 9.12 × 10−9 A cm−2) and self-healing ability. Further, the formation and corrosion mechanism of composite coatings were finally proposed.

Summary of Gridding-based Planning Method for Electric Energy Substitution Supporting Network

Electric energy substitution technology is of great significance for optimizing the final energy consumption structure, promoting energy conservation and emission reduction, and preventing air pollution. This paper aims to review the current research status of electric energy substitution technology and related fields, summarize the planning methods of electric energy substitution supporting network, and provide reliable network support for large-scale promotion of electric energy substitution. Firstly, the connotation, strategic significance and characteristics of electric energy substitution technology are summarized, and the basic structure of electric energy substitution technology is proposed. Then, the characteristics of network planning and gridding planning ideas are integrated into the gridding planning framework under the background of electric energy substitution is proposed. Finally, the development challenges of gridding planning methods in the current electric energy substitution background in terms of technology, mechanism and infrastructure are summarized, and looking forward to the development direction of the electric energy replacement supporting network plan under the background of the 14th Five-Year Plan and the new round of power system reform.

Preface

Being as one of the conference chairs for this 1st International Conference on Electrical Energy and Power Engineering (ICEEPE) 2020, it is my pleasure to welcome you all to this important and prestigious event. This conference goes to the heart of all matters relating to engineering as a whole, and it brings together the best research professionals and experience academicians from respective fields. There are delegates not only from Malaysia, but also delegates from around the globe.This ICEEPE 2020 provides a platform to scientists, researchers, professors, scholars and academicians to share, discuss, debate, and dissect significant new developments and scientific advancements that will impact the future of electrical energy and power engineering or related fields. This ICEEPE 2020 is a unique and unmissable opportunity to meet face to face with colleagues from different parts of the world. It is a major contribution for the development and consilience of knowledge.Although the world has been affected on the Covid -19 issue that has changed our daily life, ICEEPE 2020 has received tremendous supports and responses from researchers internationally and locally from various backgrounds in science and technology areas. The presentations of all research papers were successfully done via online plat form.List of Committees are available in this pdf.

Advances in photothermal nanomaterials for biomedical, environmental and energy applications.

Materials that exhibit photothermal effect have attracted enormous research interests due to their ability to strongly absorb light and effectively transform it into heat for a wide range of applications in biomedical, environmental and energy related fields. The past decade has witnessed significant advances in the preparation of a variety of photothermal materials, mainly due to the emergence of many nano-enabled new materials, such as plasmonic metals, stoichiometric/non-stoichiometric semiconductors, and the newly emerging MXenes. These photothermal nanomaterials can be hybridized with other constituents to form functional hybrids or composites for achieving enhanced photothermal performance. In this review, we present the fundamental insight of inorganic photothermal materials, including their photothermal conversion mechanisms/properties as well as their potential applications in various fields. Emphasis is placed on strategic approaches for improving their light harvesting and photothermal conversion capabilities through engineering their nanostructured size, shape, composition, bandgap and so on. Lastly, the underlying challenges and perspectives for future development of photothermal nanomaterials are proposed.

Biopolymer Nanofibers for Nanogenerator Development.

The development of nanogenerators (NGs) with optimal performances and functionalities requires more novel materials. Over the past decade, biopolymer nanofibers (BPNFs) have become critical sustainable building blocks in energy-related fields because they have distinctive nanostructures and properties and can be obtained from abundant and renewable resources. This review summarizes recent advances in the use of BPNFs for NG development. We will begin by introducing various strategies for fabricating BPNFs with diverse structures and performances. Then, we will systematically present the utilization of polysaccharide and protein nanofibers for NGs. We will mainly focus on the use of BPNFs to generate bulk materials with tailored structures and properties for assembling of triboelectric and piezoelectric NGs. The use of BPNFs to construct NGs for the generation of electricity from moisture and osmosis is also discussed. Finally, we illustrate our personal perspectives on several issues that require special attention with regard to future developments in this active field.

Recent progress on pristine two-dimensional metal-organic frameworks as active components in supercapacitors.

Two-dimensional (2D) metal-organic frameworks (MOFs) are a new generation of 2D materials that can provide uniform active sites and unique open channels as well as excellent catalytic abilities, interesting magnetic properties, and reasonable electrical conductivities. Thus, these MOFs are uniquely qualified for use in applications in energy-related fields or portable devices because they possess fast charge and discharge ability, high power density, and ultralong cycle life factors. There has been worldwide research interest in 2D conducting MOFs, and numerous techniques and strategies have been developed to synthesize these MOFs and their derivatives. Thus, this is the opportune time to review recent research progress on the development of 2D MOFs as electrodes in supercapacitors. This review covers synthetic design strategies, electrochemical performances, and working mechanisms. We will divide these 2D MOFs into two types on the basis of their conductive aspects: 2D conductive MOFs and 2D layered MOFs (including pillar-layered MOFs and 2D nanosheets). The challenges and perspectives of 2D MOFs are also provided.

Preparation of silica antireflection film based on sol-gel method

Glass antireflection membrane can effectively increase the collection and utilization of sunlight by daylighting equipment, and has been widely used in solar energy related fields. Therefore, exploring the development of high-performance glass antireflection membrane is an essential topic in the current energy utilization research. This paper introduces the general situation of the preparation technology of antireflection membrane internationally, especially the specific method of producing antireflection membrane of silica by sol-gel method in the research. According to the analysis of the results, the significance of membrane surfactant which is similar to Triton X-100 was obtained, and the development prospect of this technology was discussed.

CoMoP2 nanoparticles anchored on N, P doped carbon nanosheets for high-performance lithium-oxygen batteries

Transition metal phosphides with superior electrical conductivity and a large number of electrochemically active sites, have become a research hotspot in various energy-related research fields. However, CoMoP2-based materials were rarely reported, especially in the rechargeable batteries. Herein, CoMoP2 nanoparticles anchored on N, P co-doped carbon nanosheets (CoMoP2@NPC) were prepared through the simple pyrolysis of organic precursor in the presence of phosphoric acid. When used as electrode materials, the as-prepared CoMoP2@NPC electrode exhibited good electrocatalytic activities towards oxygen reduction and oxygen evolution reactions for Li-O2 batteries. With the unique structure, NPC nanosheets could not only improve electrical conductivity of the composite, but also relive volume changes during cycling to expose the active sites of CoMoP2 nanoparticles. This work introduces a highly-effective strategy for preparing carbon materials embedded bimetal phosphides for energy storage and conversion devices.

Two Dimensional Electrically Conductive Metal-Organic Frameworks

Metal-organic frameworks(MOFs) are a class of crystalline porous materials formed by self-assembly of metal ions or clusters and organic ligands through coordination bonds. Due to the high porosity and functional designability, MOFs have found wide applications of which make them widely used in various fields. However, most traditional MOFs have poor conductivity, which severely restricts their development in electrical related fields. In recent years, electrically conductive MOFs, especially two dimensional electrically conductive MOFs(2D ECMOFs), have attracted a great deal of research attention due to their semiconducting or metallic properties closely-related to their unique π-π stacking and π-d conjugation structures, which have great application potentials in electrical and energy related fields such as sensors, electronics, electrocatalysts, batteries, and supercapacitors. In this review, the recent progress in conducting mechanisms, structures, synthesis strategies and applications of 2D ECMOFs are summarized and highlighted. Furthermore, future challenges and opportunities based on the current research status are prospected.

Interface Inversion: A Promising Strategy to Configure Ultrafine Nanoparticles over Graphene for Fast Sodium Storage.

Due to the merits of high activity and rapid reaction kinetics, ultrafine nanoparticles loaded on conductive scaffolds are of great potential in energy-related fields. Usually, the nucleation and uniform growth of these active nanoparticles in high density on scaffolds is governed by the local ion concentration gradient and nucleation sites at the interfaces. On account of this, a novel interface-inverting strategy is developed to modulate the diffusion of metal ions toward the nucleation sites, leading to the tuned growth of ultrafine nanoparticles anchored on graphene. Typically, the Ni(OH)2 deposited on graphene initially enables the interface inverting from oil-water-solid consisting of liquid paraffin (LP), water, and GO to water-oil-solid, finally resulting in LP-enveloped Ni(OH)2 /GO structure. In response, the inert-infiltrated LP layer inhibits the solubility and diffusion of nickel ions, which functions to modulate the growth and aggregation of adjacent nanoparticles. As a demonstration, the phosphorized Ni2 P@C/G as anode in sodium-ion capacitor can deliver a high energy density of 54Wh kg-1 at a high power density of 23kW kg-1 yet with a remarkable rate performance due to the surface-enhanced energy storage and fast Na+ transport enabled by the tuned surface/interface.

Porous Membranes with Special Wettabilities: Designed Fabrication and Emerging Application

Porous materials have become a burgeoning research interest in materials science because of their intrinsic porous characteristics, versatile chemical compositions, and abundant functionalities. Re...

Recent advances in screening two-dimensional materials for high-performance energy storage and conversion devices based on electronic structure theory

With the ever-growing global energy demands and environmental pollution issues, developing high-performance energy storage and conversion materials has become a hot topic in the material science community. In this regard, substantial progress has been made in theoretically predicting new materials for energy-related fields, experimentally synthesizing these materials, and further improving their properties for high performance in energy storage and conversion devices. In particular, two-dimensional (2D) materials have shown great potential in the field of energy storage and conversion. However, it remains challenging to explore 2D materials that render high efficiency of energy storage and conversion while guarantee long-term stability and safety. Over the past decades, theoretical calculations based on density functional theory (DFT) have become a practical toolkit to address this issue by revealing the reaction mechanism at an atomic scale and screening high-performance energy storage and conversion materials on a large scale. In particular, DFT calculations enable us to establish the relationships between the intrinsic properties of materials and their performance for energy storage and conversion, and provide theoretical guidance for screening and experimentally synthesizing the promising materials. In this review, we summarize the DFT calculations’ applications in recent studies of developing high-performance and reliable energy-related 2D materials for Li-ion battery (LIB), water splitting, fuel cells, and electrochemical carbon dioxide reduction (CRR). First, we introduce the reaction mechanism of LIB, hydrogen evolution reaction (HER), oxygen evolution reaction/oxygen reduction reaction (OER/ORR), and CRR in detail and the application of 2D material in these fields. Then, we highlight the role of DFT calculations in unveiling the intrinsic relationships between the electronic structure and the performance of 2D materials by comprehensively discussing the descriptors in predicting the performance of 2D materials. For example, the occupancy of d orbital and energy required to fill empty states serve as descriptors to predict the electrochemical performance of the electrode in ion intercalation battery. The d orbital center, lowest unoccupied states, and oxygen vacancy formation energy serve as descriptors to predict the catalytic performance of electrode in HER. The energy difference between the lowest valance electron orbital center and Fermi level, occupancy of p z orbital, and the energy difference between p z and p x /p y orbital center serve as descriptors to predict the catalytic performance of electrode in ORR. Even though these descriptors can help to further understand the relationships between the electronic structure and the performance of the electrochemical electrode, they are only reliable to specific materials and inapplicable to the electrode with a complex structure or complex reaction path, such as the electrode in CRR. Newly developed machine learning methods may bring a breakthrough to the exploration of a universal descriptor, which is a key factor in the large-scale screening of potential electrode materials with excellent performance and the dependable guidance to experimental synthesis. Finally, we summarize the disadvantage of DFT calculation, such as the underestimation of bandgap and incorrect description of van der Waals interaction, and give a perspective of DFT calculations in the study of new energy-related materials. The method to simulate the ambient environment of the electrode (including the electrolyte, external electric field, and non-cooperative transfer of proton and electron) based on DFT calculation is needed to be developed, which is vital to reflect the actual working condition of the electrode. The universal descriptor applicable to the electrode with a complex structure is also needed to explore to overcome the poor versatility of single intrinsic property of the material in predicting the performance of the electrochemical electrode.

Preparation of hierarchical graphdiyne hollow nanospheres as anode for lithium-ion batteries

Carbon-based hollow nanostructures offer promising potential for a variety of energy-related fields, owing to their special structural characteristics and fascinating physicochemical properties. In this paper, graphdiyne hollow nano spheres (GDY-HNSs) were reported to be prepared through a facile solvothermal synthesis technique with copper oxide nanospheres as both template and source of catalyst. The surface morphologies and the shell thickness of the prepared GDY-HNSs can be easily controlled by simply adjusting the amount of the precursor. Besides, the GDY-HNSs exhibit hierarchical nanostructures, large specific surface areas, and appropriate hollow interior, which offer substantial active sites and contact area between electrode and electrolyte while applied as anode, reducing the diffusion paths for both relative ions and electrons. Thus, while applied in lithium-ion batteries, GDY-HNSs show enhanced electrochemical properties, including higher reversible specific capacity, improved rate capacity and cycling performance compared with most of other carbon materials, even in a large mass loading of 2.0 mg cm−2.

Electrostatic Assembly Technique for Novel Composites Fabrication

Electrostatic assembly is one of the bottom–up approaches used for multiscale composite fabrication. Since its discovery, this method has been actively used in molecular bioscience as well as materials design and fabrication for various applications. Despite the recent advances and controlled assembly reported using electrostatic interaction, the method still possesses vast potentials for various materials design and fabrication. This review article is a timely revisit of the electrostatic assembly method with a brief introduction of the method followed by surveys of recent advances and applications of the composites fabricated. Emphasis is also given to the significant potential of this method for advanced materials and composite fabrication in line with sustainable development goals. Prospective outlook and future developments for micro-/nanocomposite materials fabrication for emerging applications such as energy-related fields and additive manufacturing are also mentioned.

Synergistic effect of NiII and Co/FeIII in doped mixed-valence phosphonate for enhancing electrocatalytic oxygen evolution

Metal organophosphonates have been explored in energy-related fields due to their high chemical and thermal stability as a type of uniformly precursor, but only few of pristine metal organophosphonate are directly used for oxygen evolution reaction (OER) catalysts. Here, a mixed-valence iron phosphonate (Fe3-ppat) has been constructed and applied to OER catalysis considered the potential active sites in pillars FeII(H2O)4(COO)2 and inorganic layers FeIII(μ2–OH)PO3. Specifically, isostructural trimetallic framework Fe1.7Co0.3Ni1.0-ppat possesses a minimum overpotential (291 mV), small Tafel slope (91.65 mV dec−1), and high stability up to 83 h. The enhanced catalytic performance could be mainly ascribed to the synergistic effect of NiII equivalent occupancy in pillars and Co/FeIII in layers.

Nickel foam-supported starfish-like Ni(OH)2@CoS nanostructure with obvious core–shell heterogeneous interfaces for hybrid supercapacitors application

The design and preparation of electrode materials with unique nanostructure are regarded as a significant strategy to increase the capacitance and cycling stability of energy storage devices. Herein, a starfish-like core–shell Ni(OH)2@CoS material grown on Ni foam (Ni(OH)2@CoS/NF, denoted as NOCS-1/NF) was successfully fabricated via a stepwise hydrothermal method. Benefiting from the unique starfish-like core–shell nanostructure, obvious and abundant heterogeneous interfaces, and good synergy between every component, the specific capacitance of the as-prepared Ni(OH)2@CoS-1/NF electrode can reach up to 981 F g−1 at 1 A g−1 and maintained 73.2% of initial value at a high current density of 10 A g−1 in 2 M KOH aqueous solution. Moreover, a hybrid supercapacitor was prepared by using core–shell NOCS-1/NF as positive electrode and activated carbon coated on the NF (AC/NF) as negative electrode. The HSC delivered a high energy density of 17.9 Wh kg−1 at a power density of 749 W kg−1 and a satisfying cycling life with 90.1% capacitance retention after 4000 cycles. Eventually, two such devices in series successfully illuminated a red light-emitting diode. Meanwhile, this work probably provides a simple and convenient strategy to fabricate novel materials for the applicability of various energy-related fields.

Controllable syntheses and potential applications of two-dimensional metallic transition metal dichalcogenides

Two-dimensional (2D) metallic transition metal dichalcogenides (MTMDCs) have received great research attention due to their exotic physical properties (such as charge-density wave (CDW) order, superconductivity, and magnetism) and potential applications in nano-electronics and energy-related fields. To fully promote the fundamental researches or the versatile applications of such 2D MTMDCs, the preparation of mono- or multilayered nanosheets/films with high crystalline quality is highly needed. In this review, recent research achievements towards the controllable syntheses of MTMDCs through chemical vapor deposition (CVD) method, the exotic physical properties of MTMDCs, as well as their applications in FET devices and electrocatalytic HER are highlighted. CVD method can meet many sample requirements such as large domains, adjustable layer thickness, and high crystal quality. Meanwhile, it is compatible with modern semiconductor technology. Thus, this strategy has been extended to the growth of MTMDCs, and allowed for the successful synthesis of tunable thickness MTMDCs nanosheets, large-area-uniform ultrathin MTMDCs films, vertically oriented 1T-TaS2 nanosheets and high-quality MTMDCs nanosheet powders. All of these synthetic routes and corresponding crucial influencing factors are summarized. The different growth mechanisms via the one-step reaction and deposition of gaseous metal and chalcogen feedstocks, or the sulphurisation of pre-deposited metal-based precursors are introduced. In addition, the differences in growth behaviour caused by commonly used amorphous SiO2/Si, insulating single crystal substrates (e.g., mica), unique conducing substrates (e.g., Au foil), porous substrates (e.g., nanoporous gold), and novel microcrystalline NaCl crystals are comparatively presented. Simultaneously, the exotic physical phenomena in 2D MTMDCs, such as CDW order, unconventional superconductivity, and magnetism are comprehensively discussed. In particular, this review focuses on the introduction about the origin of CDW order and its thickness-dependence in MTMDCs, as well as the interplay between CDW order and superconductivity in the 2D limit. The challenges regarding the exploration of fundamental physical properties are also proposed. The next part deals with the potential applications of 2D MTMDCs in advanced nano-electronics and energy-related fields. Notably, the excellent electrical conductivities endow MTMDCs as electrodes to improve the electrical contact of semiconducting TMDC field effect transistor (FET) devices. Typically, lateral VS2-MoS2 contact contributes to 6-fold improved field-effect mobility for monolayer MoS2, compared to the conventional on-top nickel contacts. More intriguingly, the 2D metal-semiconductor TMDCs heterostructures present either 2D Schottky barrier diodes or Ohmic contact-type junctions depending on different band alignments (e.g., VSe2 with WSe2 or MoSe2). Motivated by those experimental results, we believe that significant research interests would be sparked about the oriented syntheses of 2D metal-semiconductor TMDCs heterostructures towards versatile applications in electronic and optoelectronic devices. Furthermore, both theoretical predictions and experimental results have proven the superior electrocatalytic performances of MTMDCs in hydrogen evolution reactions (HERs) compared to semiconducting TMDCs, due to their abundant active sites located on both the edges and basal planes and their excellent electrical conductivities. Therefore, MTMDC materials are promising candidates as the non-noble metal catalysts for HER in view of their excellent surface/edge activity, high stability, and compatibility with the batch production methods. Finally, challenges regarding the preparation of MTMDC are discussed, and the future research directions in the advanced nano-electronics and energy-related fields are also proposed.

Carbon Dots in Porous Materials: Host-Guest Synergy for Enhanced Performance.

Carbon dots (CDs) are emerging as a new class of carbon nanomaterials, which have inspired growing interest for their widespread applications in anti-counterfeiting, sensing, bioimaging, optoelectronic and energy-related fields. In terms of the concept of host-guest assembly, immobilizing CDs into porous materials (PMs) has proven to be an effective strategy to avoid the aggregation of bare CDs in solid state, in particular, the host-guest synergy with both merits of CDs and PMs affords composites promising properties in afterglow and tunable emissions, as well as optimizes their performance in optics, catalysis, and energy storage. This Minireview summarizes the recent progress in the research of CDs@PMs, and highlights synthetic strategies of constructing composites and roles of porous matrices in boosting the applications of CDs in diverse areas. The prospect of future exploration and challenges are proposed for designing advanced CDs-based functional nanocomposite materials.

Interfaces modulation strategy to synthesize bifunctional electrocatalyst for highly efficient overall water splitting

The synthesis of high efficient bifunctional non-noble metal electrocatalysts for overall water splitting is crucial for sustainable energy conversion. Here, a free-standing and heterointerfaces-rich fluffy rectangular spongy-like core-shell NiS/CoS/CC-3 bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is designed and synthesized by optimizing the thickness of the NiS shell. The electrochemical performance of the NiS/CoS/CC-3 electrocatalyst is investigated in alkaline solutions. Benefiting from the unique rectangular spongy-like structural features, the abundant heterointerfaces between NiS and CoS, as well as the good synergy between its each component, the obtained NiS/CoS/CC-3 catalyst shows outstanding electrocatalytic activities and stability for both HER and OER. The overpotential is 102 mV for HER and 290 mV for OER at 10 mA cm−2, respectively. Moreover, the two-electrode electrolyzer with NiS/CoS/CC-3 as both the cathode and anode catalyst in alkaline solution achieves a current density of 10 mA cm−2 at a potential of 1.57 V. Meanwhile, the electrolyzer shows outstanding electrochemistry durability with an unchanged current density for 72 h. The results illustrate that the as-prepared heterointerfaces-rich NiS/CoS/CC-3 electrocatalyst can be used as a high-efficiency catalyst for overall water splitting (OWS). This synthetic strategy is also important for other composite materials in a variety of energy-related application fields.

Confined Thermolysis for Oriented N-Doped Carbon Supported Pd toward Stable Catalytic and Energy Storage Applications.

Carbon-based nanomaterials have been widely utilized in catalysis and energy-related fields due to their fascinating properties. However, the controllable synthesis of porous carbon with refined morphology is still a formidable challenge due to inevitable aggregation/fusion of resulted carbon particles during the high-temperature synthetic process. Herein, a hierarchically oriented carbon-structured (fiber-like) composite is fabricated by simultaneously taking advantage of a confined pyrolysis strategy and disparate bond environments within metal-organic frameworks (MOFs). In the resultant composite, the oriented carbon provides a fast mass (molecule/ion/electron) transfer efficiency; the doping-N atoms can anchor or act as active sites; the mesoporous SiO2 (mSiO2 ) shell not only effectively prevents the derived carbon or active metal nanoparticles (NPs) from aggregation or leaching, but also acts as a "polysulfide reservoir" in the Li-S batteries to suppress the "shuttle" effect. Benefiting from these advantages, the synthesized composite Pd@NDHPC@mSiO2 (NDHPC means N-doped hierarchically porous carbon) exhibits extremely high catalytic activity and stability toward the one-pot Knoevenagel condensation-hydrogenation reaction. Furthermore, the oriented NDHPC@mSiO2 manifests a boosted capacity and cycling stability in Li-S batteries compared to the counterpart that directly pyrolyzes without silica protection. This report provides an effective strategy of fabricating hierarchically oriented carbon composites for catalysis and energy storage applications.