2024 4th International Conference on Energy Engineering, New Energy Materials and Devices (NEMD 2024)

History of NEMD 2023

2023 International Conference on Energy Engineering, New Energy Materials and Devices (NEMD 2023) was successfully taken place online on September 22-24, 2023!

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All accepted papers has been published in Journal of Physics: Conference Series, Volume 2563, and has been indexed by EI Compendex and Scopus.

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Conference Proceedings of NEMD 2023

Chapter 1: Solar Energy System and Power Generation Technology



012001

Succinonitrile Plastic Crystal Polymer Electrolyte for Lithium Metal Battery

Yuefeng Su, Youxiang Bai and Yun Lu

Open abstract
Polymer electrolyte has attracted wide attention due to the advantages of easy fabrication, lightweight, and good mechanical flexibility. However, polymer electrolyte exhibits limited ionic conductivity at room temperature, so the batteries can only be used above room temperature. Here, a succinonitrile plastic crystal polymer composite electrolyte (SCPE) with high content of succinonitrile (SN) was fabricated by in-situ polymerization. SCPE exhibits high ionic conductivity, which can be used at room temperature. In addition, SCPE exhibits excellent stability to lithium and can stable cycle over 1500 h without short circuits. Furthermore, LFP|SCPE|Li can achieve 150 stable cycles, presenting excellent cyclic stability performance. This research provides a feasible method for high room temperature ionic conductivity plastic crystal polymer electrolyte.


012002

Experimental study on cleaning efficiency of independent traveling solar panel cleaning machine

Yongchao Zhu, Yanwei Chen, Qi Li and Weifeng Ma

Open abstract
As a kind of clean energy, solar energy plays a great role in helping China achieve the "double carbon" goal. However, dust cover will greatly affect the power generation efficiency of solar panels. In order to solve this problem, based on the self-designed independent traveling solar panel cleaning machine, orthogonal experiments were carried out, to study the influence of factors such as the no-load rotating speed of the roller brush, the flow rate of the front water spray component, the flow rate of the rear water spray component and the nozzle type on the improved value of the cleanliness after cleaning. The experimental verification of the optimal parameters of the power generation was also conducted. The results show that the nozzle type has the greatest impact on the cleaning effect, followed by the spray flow of the spray components on both sides of the roller brush. Taking the cleaning effect as the optimization index, the water mist nozzle should adopt the wide-angle small-aperture fan-shaped nozzle (11004 type), the cleaning water flow on both sides of the roller brush should be controlled at 500 L/h, and the rotational speed of the roller brush off the plate should be controlled at 200 rpm. If it is necessary to pay attention to water conservation, the water spray flow of the two ways can be moderately reduced. The optimized cleaning efficiency parameter configuration scheme has an obvious cleaning effect on the photovoltaic array, which can greatly improve the power generation of the array.


012003

Reinforcing Poly (Metaphenylene Isophthalamide) Fibers by Cellulose Nanocrystal

Qingquan Song, Junrong Yu and Yan Wang

Open abstract
Typical poly (metaphenylene isophthalamide) fibers exhibit excellent heat resistance and excellent flame retardancy but very poor breaking strength, which limits their diversified applications severely. Therefore, it becomes urgently important to develop new strategies to improve their breaking strength. In this regard, a new composite fiber was prepared by wet spinning through a blend solution of poly (metaphenylene isophthalamide) and cellulose nanocrystals. Poly (metaphenylene isophthalamide) composite fibers with excellent breaking strength blended with cellulose nanocrystals were prepared through a simple and scalable blending strategy. In contrast to the pristine poly (metaphenylene isophthalamide) fiber, its mechanical properties were significantly improved, such as maximum breaking strength of 4.89 cN/dtex, which is 86.8% higher than pristine poly (metaphenylene isophthalamide) fiber. This work provides a new way of thinking to fabricate high-performance poly (metaphenylene isophthalamide) fibers for high-tech applications.


012004

Selective extraction of lithium from spent LiCoO2 cathodes by two-step calcination with ammonium chloride

Dai-xiang Wei, Wei Wang, Long-jin Jiang, Zhi-dong Chang, Bin Dong, De-kun Gao and Hira Anwar

Open abstract
This paper reported a strategy for selective lithium extraction from spent LiCoO2 (LCO) cathodes by two-step chlorination calcination combined with water-leaching. The feasibility of selective lithium extraction by two-step chlorination calcination was predicted by the thermodynamic analysis. The elements of Li and Co in the LiCoO2 cathode material were converted into water-soluble LiCl and CoCl2 respectively after pretreatment at 350 °C. Afterward, the generated CoCl2 reacted with the remaining LiCoO2 and converted into water-soluble LiCl and water-insoluble Co3O4 with temperatures increased. The results showed that 96.56% of the lithium can be recovered as LiCl and 95.23% Co in the form of Co3O4.


012005

Study on the Coordination Effect of Different Flexible Polybenzimidazoles with Copper Ions

Tianmeng Liu, Yan Wang and Zuming Hu

Open abstract
High-performance polymers such as polybenzimidazole (PBI) can have their thermomechanical properties greatly enhanced by the coordination of their rich imidazole groups with metal ions. The molecular chain's flexibility influents on metal ion coordination greatly. In this paper, PBI with different chain flexibility was synthesized by varying the number of ether bond-containing monomers during the polymerization process. Rheological characterization of supramolecular networks obtained by coordination of different flexible PBI with copper ions was performed to explain in depth the effect of molecular chain flexibility on the reaction between copper ions and imidazole groups. The enhanced mechanical properties of the copper ion coordination polymer networks were compared to provide insight into the enhanced toughening mechanism of PBI with metal ion coordination.


012006

A self-supporting Cu2S/CP lithium-ion battery anode

Ruixia Chu, Wanyou Huang, Jun Yang, Kesong Zhang, Fangyuan Qiu, Shiwei Tan, Peidong Zhu and Dongying Liu

Open abstract
Lithium-ion (Li-ion) batteries have been widely used in portable electronic devices and new energy vehicles in recent years. Although commercial graphite anode has good safety and low cost, its low theoretical capacity cannot better meet the demand for higher-capacity of power batteries. As an excellent electrode material, copper sulfide (Cu2S) has the advantages of high capacity and stability. Herein, Cu2S deposited on carbon paper (Cu2S@CP) was prepared by simple copper electrodeposition on carbon paper and sulphidation, which can be used to the anode of Li-ion batteries directly. Based on the three-dimensional structure of carbon paper and the high capacity of copper sulfide, the composite anode shows good lithium storage performance, which provides a new possibility for commercial power lithium-ion battery anode materials.


012007

Evaluation of Carbon Reduction Potential and Economic Performance of Photovoltaic Charging System for Campus Electric Bicycles

Jinjun Pan, Peng Xia and Xiang Ma

Open abstract
This study considers the roof characteristics of different types of buildings in the Yuntang campus of Changsha University of Science and Technology, and evaluates the overall potential for photovoltaic power generation and carbon reduction performance of the campus by simulating the roof solar radiation at multiple time scales. In addition, a photovoltaic charging system for electric bicycles suitable for the campus is proposed based on the usage of electric bicycle charging stations on campus. The Monte Carlo method is used to simulate the hourly probability distribution of the charging load, and the capacity of the photovoltaic charging system is optimized by integrating the simulated solar radiation, outdoor temperature and other data, in order to strengthen the relationship between electricity demand and energy supply of the campus.


012008

Interfacial Structural and Dynamical Properties of [BMI+] [PF6-] Ionic Liquids on the MXene Electrode: A Molecular Dynamics Simulation Study

Chenxuan Xu, Wenjin Zheng, Binbin Wen, Xiaolin Chen, Jing Hua, Xinhao Wang, Xu Qian, Linjun Si, Gang Chen and Huachao Yang

Open abstract
Two-dimensional MXene nanomaterials are attracting more and more research interests as electrodes in energy storage applications. In this work, the interfacial structural and dynamical properties of solvent-free ionic liquids ([BMI+] [PF6-]) on the MXene electrode are investigated using molecular dynamics simulation. Multiple alternating structures of [BMI+] cation and [PF6-] anions on the MXene surface are observed. Interestingly, the ion diffusion coefficients are remarkably reduced (by 30~40%) in the interfacial Helmholtz layer. Importantly, an asymmetric bell-shaped differential capacitance profile with a maximum capacitance of ~7.04 μF/cm2 is observed. This is chiefly correlated with the structural properties of counterions rather than coins in the interfacial areas.


012009

Preparation of poly (m-phenylene isophthalamide)-ZIF-8 nanofiltration membranes with enhanced filter performance

Wenwen Wu, Na Li, Junrong Yu and Zuming Hu

Open abstract
Poly (m-phenylene isophthalamide) (PMIA) membranes are prepared via evaporating part solvent of the casting solution before its nonsolvent-induced phase separation. Zeolite imidazolate framework-8 (ZIF-8) is added into the PMIA solution as an inorganic filler to improve the filtration capability of the PMIA membrane. The structure of composite membranes is characterized by scanning electron microscopy (SEM), Zeta-potential analyzer (ζ-potential) and X-ray diffractometer (XRD). The filtering capabilities of the membranes for dyes and inorganic salts were deeply evaluated, in order to study the membrane separation performance. The PMIA-ZIF-8 membranes have excellent filtration properties for Congo red dye with a rejection rate of above 99.3%. The PMIA-ZIF-8 composite membranes have excellent properties that point to the possibility of using nanofiltration in commercial applications.


012010

MPPT study of PV cells in complex environments

Haoran Zhou and Xiaohong Zhang

Open abstract
In operation, the solar power generating system's output power from the photovoltaic array is sensitive to external conditions including light intensity and temperature, and displays typical non-linear characteristics. Hence, monitoring the maximum output power of PV cells in real time is necessary to guarantee that the maximum power output of PV cells is constantly maintained, enhancing the efficiency with which PV cells are used. Therefore, this paper is based on the immune algorithm, simulates that the biological immune system will be affected by the antigen infestation and produce resistance to carry out antigen recognition, memory, and other immune response reactions through MATLAB / Simulink simulation, and adopts the traditional perturbation observation method. The results of the simulation show that the Composite algorithm has the benefits of high tracking accuracy, fast tracking speed, stable tracking, and low false positives.


012011

Zeolite Imidazolate Framework-Derived N-Doped Carbon-Supported Ultra-Low Platinum Catalyst for Enhancing Methanol Oxidation Reactions

Yuting Chen, Zhongsu Liu, Chunyu Liu, Shenhang Zhang, Haotian Li, Hong Chen, Xingzheng Dong, Qianqian Chen, Xiaohua Shi and Guohong Ren

Open abstract
Direct methanol fuel cells (DMFCs) have a broad application market due to their merits of high power density, wide source of raw materials, and convenient storage and transportation. At present, the common platinum (Pt) catalysts have some problems, such as low reserves, and expensive and poor reaction kinetics. Therefore, a zeolite imidazolate framework (ZIF) derived N-doped carbon-supported ultra-low platinum catalysts (Pt-Co@ZCN) are prepared using ZIF-67@ZIF-8 as the support. The effects of heating rate on the morphology and electrocatalytic performance of the synthesized materials are investigated. The characterization results reveal that the morphology and structure of Pt-Co@ZCN-900-2 are superior to other samples. The mass activity and stability toward methanol oxidation of the synthesized samples are also better than those of commercial Pt/C catalysts.


012012

Thermochemical Cyclization Forms Core-Shell Structured Rutile TiO2@C-PAN as an Advanced Anode for Lithium-Ion Batteries

Shuang Hao, Kai Zhang, Guoqiang Tan and Jing Wang

Open abstract
Rutile TiO2 is a prospective lithium-ion anode material, which has the advantages of small volume change and excellent cycling performance. The low theoretical capacity and poor conductivity, however, prevent further application. In this work, we proposed a thermochemical cyclization coating strategy and successfully prepared rutile titanium dioxide anode material coated with conductive polymer Polyacrylonitrile (PAN). The coated material has an initial capacity of 246.5 mAh/g and a stable capacity of 125.5 mAh/g after 100 cycles. It is worth noting that this simple and effective coating method will contribute to the further application of rutile TiO2 materials.


012013

The effect of the degree of sulphenylation on the stability of reduced graphene oxide nanofluids

Yi Wang

Open abstract
Dispersion stability of nanoparticles in nanofluids is a prerequisite for allowing the nanofluids to act as convection heat transfer working fluids. This research prepared multiple types of sulfophenylated graphene (PSG) nanoparticles. Two samples subjected to different degrees of sulfophenylation were chosen to formulate different nanofluids with varying sulfophenylated particle concentrations. The nanofluids' measured Zeta potential, electric conductivity, and thermal conductivity coefficients were used to investigate the stability. The research indicates the increase in the degree of sulfophenylation can improve the stability of nanofluids while exerting little influence on thermal conductivity; on the premise of ensuring stability, the number of nanoparticles added in base fluids can increase thermal conductivity. After that, high-sulfophenylated particle concentration nanofluids (2 mg/mL) were formulated using sulfonated-reduced graphene oxide (s-rGO) nanoparticles prepared to demonstrate excellent stability, and their thermal conductivity reached 0.773 W/m. K (55 °C).


012014

Synthesis of High-capacity and High-rate Intergrown Cathodes for Lithium-ion Batteries

Yihong Wang, Ning Li, Duanyun Cao, Yuefeng Su and Feng Wu

Open abstract
Nowadays, general energy storage and electric vehicles urgently need to develop advanced lithium-ion batteries (LIB) with high specific energy and low cost, and one of the great challenges is to invent cheap cathode materials. Manganese-based cathode materials have been widely studied due to the low prices and high reserves of precursors, such as lithium-rich manganese-based (LMR) and Mn-based disordered rock-salt (DRX) cathodes. Inspired by the concept of layered-layered intergrown structure in LMR, we design a spinel-rock salt intergrown nano-composite. The as-developed cathode (Li1.7Ni0.12Mn1.48O4) shows a partially intergrown structure of spinel- and DRX-phases. Most importantly, the material enables the combination of the structural and electrochemical merits of the individual spinel and rock-salt phases, and it yields ultrahigh-capacity in comparison with the LMR or DRX and displays outstanding rate performance. It is hoped this novel intergrown cathode with low cost can inspire the design of advanced cathode for LIB.


012015

Modifying SiO @ C as High-performance Anode of Lithium-ion Batteries

Tao Liu, Ling Zhang and Borong Wu

Open abstract
SiO is a widely prospected anode material, which is an excellent substitute for pure silicon for lithium-ion batteries in the future, with the reason of lower expansion degree. However, the conductivity of SiO is also poor and has a side reaction with electrolytes. Here, we choose melamine as a nitrogen source to modify the carbon layer-coated SiO materials. This study shows that nitrogen and carbon shells lead to forming stable SEI, and improve the conductivity of the anodes. Consequently, at 0.1 C, the modified SiO materials in the anode achieve an excellent specific capacity (1711.5 mAh g-1), in addition, the decay rate of the capacity is 0.6% per cycle in the next 100 cycles. This method makes a new direction for the product of SiO materials.


012016

Synthesis and application of mixed conductive and oxygen-permeable materials based on BaFeO3-δ

Yan Shao, Zaiguo Fu, Binxia Yuan, Yanhua Lei, Changling Quan and Qunzhi Zhu

Open abstract
Cobalt-free perovskite oxide BaFeo3-δ (BFO) exists in mixtures with various phase structures and exhibits poor oxygen ion conductivity, thereby limiting its application as a cathode material in solid oxide fuel cells (SOFC). In this study, the stabilization of a single cubic phase structure of BFO through doping with Gd at the A-site or Cu at the B-site and the lowest temperature required for the synthesis of such a structure are investigated. A large fraction of adsorbed oxygen atoms and a low valence state of Fe are found in BaFe0.9Cu0.1O3-δ, resulting in improved performance. Furthermore, the ideal sintering temperatures for Ba0.9Gd0.1FeO3-δ cathode and BaFe0.9Cu0.1O3-δ cathode are 900 °C and 850 °C, respectively. At 700 °C, the polarization resistance of the BaFe0.9Cu0.1O3-δ cathode is 0.439 Ω·cm2 and that of the Ba0.9Gd0.1FeO3-δ cathode is 0.545 Ω·cm2.


012017

Surface Modification of Micro-Silicon Anode for High-performance Lithium-Ion Batteries

Tongren Chen, Wengang Yan, Dong Yu, Siyuan Ma, Liang Ma, Qing Huang and Ning Li

Open abstract
Advanced lithium-ion batteries are urgently needed in consumer electronic products, electric vehicles, and energy storage, while the traditional carbonaceous anode materials with relatively low specific capacity gradually become difficult to meet the practical requirements in the market. Silicon-based anodes are considered one of the most promising alternatives in LIBs with high specific energy due to their considerable theoretical specific capacities. However, the large volume variation and severe surface parasitic reactions still limit the practical application of silicon anode. In this work, to suppress the surface side reactions and great volume changes, the electrochemical inert Li3PO4 is proposed to be coated as the physical barrier between the silicon and electrolyte. The as-coated micro-silicon has been successfully prepared via a facile spray drying method with a low-temperature thermal treatment. Li3PO4 coating layer with high shear modules can not only passivate the surface but also enable to suppression of the severe volumetric expansion and shrinkage of the silicon particle, thus enhancing the initial columbic efficiency and structural integrity of the silicon materials during long-term cycling. The optimized silicon anode with the proper amount of Li3PO4 displays a superior initial columbic efficiency higher than 90% and a highly reversible capacity of 1394 mAh g-1 after charging and discharging 200 times. It is hoped this work should shed light on the modification of high-capacity anode materials.


012018

Monoatomic Fe and Pt-Co alloys on NC/Ti4O7 for efficient and durable oxygen reduction

Yangjun Luo, Youyuan Wang, Huijuan Zhang and Yu Wang

Open abstract
The combination of metal monoatomic with alloys on carbon support facilitates the promising activity in oxygen reduction. However, the alloys still suffer from the degradation of catalyst stability due to carbon corrosion. Herein, the NC/Ti4O7 support was loaded with both monoatomic Fe and Pt-Co alloys using a one-step calcination method. The results indicate that chelation of Fe3+ with α-D-glucose, physical segregation of excess α-D-glucose and binding to N species at high temperatures are essential to increase the loading of monatomic Fe in Fe1/PtCo-NC/Ti4O7. Fe1/PtCo-NC/Ti4O7 demonstrates a half-wave potential of 0.941 V and a mass activity of 3.16 A mgPt-1. This mass activity is as high as 6.87 times that of Fe/PtCo-NC/Ti4O7 (without α-D-glucose during the synthesis, 0.46 A mgPt-1). Meanwhile, Fe1/PtCo-NC/Ti4O7 exhibits a peak power density of 210.5 mW cm-2 and a specific capacity of 771.1 mAh gZn-1 in a zinc-air battery. This dual-substrate strategy provides a new perspective on the multilevel construction of catalysts.


012019

Design and preparation of carbon fiber, carbon particle doped C4H10O4 phase change thermal storage materials and performance

Bingnan Chen and Jun Liu

Open abstract
C4H10O4 is an environmentally friendly phase change material that can release high phase change enthalpy, but its high super-cooling degree and low thermal conductivity hinder its wide application. This paper adopted C4H10O4 as a phase change material, and the composite phase change material was prepared by melting and blending C4H10O4 with carbon fiber, carbon particles. The results indicate that the composite phase change material with 1.5% filler has better comprehensive properties. Compared with pure C4H10O4, 167% improvement in thermal conductivity, the under-cooling decreases by 42%, and 3% increase in enthalpy of phase change. FT-IR analysis shows that no new substances are produced, and TG analysis shows that the chemical stability is good. Heat storage/release analysis shows that the exothermic time reaches 4 hours, and the exothermic time is 5 °C higher.

Chapter 2: Energy Device and Distribution Strategy Optimization



012020

Modulation Technique Design of An Improved Zero Common Mode Voltage (CMV)

Yujing Guo and Junhuai Zhang

Open abstract
Voltage imbalance of neutral-point and CMV are hot issues in the research of three-level inverters. This paper first introduces the three-level topology of the neutral-point clamped (NPC) inverter. Aiming to eliminate CMV of three-level NPC and balance the voltage of the neutral point simultaneously, a virtual space vector pulse modulation (VSVPWM) strategy is proposed. Virtual voltage vectors of this strategy are composed of 3 medium vectors. The voltage of the neutral point is balanced since the average current of the neutral point is 0. Therefore, the balance index is introduced to redefine virtual voltage vectors, so the voltage of the neutral point can recover quickly when the capacitors' voltage of the dc-link is imbalanced.


012021

Electrochemical Copolymerization of Poly (MET-EDOT) with Enhanced Cyclic Stability

Hangchuan Zhang

Open abstract
To enlarge the electrochromic cyclic lifetime of poly (3-methtylthiophene) (PMET), the EDOT was copolymerized with the P3MT by electrochemical polymerization. The constant potential of 2.2 V was applied to the copolymer film growth in the electrolyte with 0.001 M EDOT and 0.1 M MET. The copolymer was achieved through the characteristics of the FT-IR and Raman analysis. The PMET-EDOT retained the vivid EC color from the PMET and the long cyclic stability from the PEDOT. The transmittance contrast of PMET-EDOT only decayed 1.5% after 1000 cycles. During the few components of EDOT in the copolymer, it seems similar that the transmittance spectrum and variation between the PMET-EDOT and PMET.


012022

The study on the conductivity of TCNQ-modified 2D conjugated metal sulfur-dilute nanosheets

Cuicui Sun, Wenchao Wang, Minghui Lu, Mingdong Zhang, Jiacun Wang, Ruichao Hao and Yaqi Wang

Open abstract
Metal-organic frame materials are an important classification of new materials in metal-organic materials, and it is also the most popular area of research. Since the constituent bonds of the metal-organic framework are that the metal ions are connected to the redox-inert organic ligand, the conductivity of the MOF skeleton is not very good. There are many ways to improve the electrical conductivity of MOF skeletons, such as changing the variety of metal atoms and organic skeletons or introducing objects to modify the molecules. The way selected in this article to enhance the conductivity of the 2D conjugated metal sulfur-dilute MOF skeleton is to introduce the object-modified molecule TCNQ into the gap of the MOF material to enhance the conductivity of the material. This paper explores the conductivity of this material. After a series of calculations, the conductivity of 2D conjugated metal sulfur-dilute MOF modified by TCNQ was significantly improved.


012023

Grid black start-up scheme based on the large-scale new energy grid

Jin Liu, Tong Li, Yuanting Hu, Wenbo Hao, Xueting Lei and Zhi Song

Open abstract
The uncertainty and intermittent characteristics of the output of new energy power sources make the output of grid-connected power sources change frequently. The self-excitation problem may occur in the process of black-start, which is one of the key factors to decide whether the black-start restoration scheme is feasible or not. Through theoretical research and simulation analysis, this paper discusses the criterion of hydropower self-excitation in the local power grid, and studies the effect of self-excitation on the system when different black-start schemes are formulated.


012024

Optimal scheduling of integrated energy systems with carbon and hydrogen storage based on IGDT

Meining Qu and Di Bai

Open abstract
To deal with the uncertainties that the integrated energy system will encounter during operation, we propose an optimal scheduling strategy for the integrated energy system considering carbon and hydrogen storage. First, a comprehensive energy system containing a carbon capture system (CCS), power-to-gas technology (P2G), photothermal power station, and other equipment is established, and the combined operation of CCS and P2G is considered. Secondly, the carbon storage device and hydrogen storage device were respectively applied to the carbon capture system and P2G device, and the optimal scheduling model of the comprehensive energy system containing carbon storage and hydrogen storage was constructed. The operational constraints of the energy system will be integrated and the flexibility of the system will be improved. Finally, considering the dual uncertainties of the system source and load, a robust model and a chance model are constructed based on the Information Gap Decision Theory (IGDT). The economy of the real model and the influence of uncertainty on the whole system can be verified by close to real examples.


012025

Facile Synthesis of Nitrogen Doped Porous Carbon Supported Platinum Catalyst and Improvement of Electrocatalytic Ethanol Performance

Guohong Ren, Yuting Chen, Chunyu Liu, Xingzheng Dong, Yi Xu, Hong Chen, Qianqian Chen, Xiaohua Shi and Zhongsu Liu

Open abstract
Direct ethanol fuel cells (DEFCs) have become an alternative to traditional fossil fuels because of their low emissions, fast start-up and high energy density. Platinum (Pt)-based catalysts are the most effective catalysts for DEFCs, but their high cost and poor electrocatalytic performance hinder their practical application. Therefore, there is an urgent need to design Pt-based catalysts with low platinum content, high electrochemical activity and stability. Herein, nitrogen-doped porous carbon-loaded Pt catalysts (Pt@Co-CN) were prepared by in situ polymerization and high-temperature calcination using the metal-organic framework materials (MOFs) ZIF-8@ZIF-67 as the carriers. The effects of the addition of pyrrole monomer on the morphology and electrocatalytic properties of the samples were investigated. The sample with the complete coating layer and uniformly dispersed Pt nanoparticles (Pt@Co-CN) could be obtained by adding an appropriate amount of pyrrole monomer. The results of the electrochemical tests showed that the electrochemical activity of Pt@Co-CN catalytic ethanol is superior to that of commercial catalysts and samples with insufficient or excessive addition of pyrrole monomers. The content of this study provides a new method for the electrocatalyst of DEFCs.


012026

Convenient synthesis of Co-base metal-organic frameworks to effectively adsorb and remove Cr(VI) from aqueous

Xiong Xie, Xu Li and Lichun Dong

Open abstract
Herein, we reported the synthesis of a series of well-defined regular cobalt-based metal-organic frameworks (MOFs) from 3D to 2D phases through a facile synthesis method and confirm their effective adsorption behavior for Cr(VI) in aqueous. The equilibrium adsorptive capacities of ZIF-67, ZIF-L-Co-H, ZIF-L-Co-L, and ZIF-L-Co were 27.7, 28, 28.2, and 32 mg/g, respectively. ZIF-L-Co nanosheet morphology exhibited excellent adsorption performance for Cr(VI) in water for the first time, and sharp adsorption speed was also presented at the relevant initial concentrations. The Cr(VI) adsorption process demonstrated that the result well fitted the Langmuir isotherm model of 32.5 mg g-1 with uniform monolayer adsorption. The findings provided a broader understanding of Co-MOFs application as the Cr(VI) removal of wastewater.


012027

Preparation of FeCoM Ternary Layered Double Hydroxides

Yanling Wu, Mingqian Hou, Liping Ma, Fangzhou Li, Zhijie Chen and Kexin Xu

Open abstract
LDHs have unique laminar structures, large interlaminar spacing ions, and highly adjustable components, which have been widely used in the field of electrochemistry. However, it is still a considerable challenge to regulate the microstructure and electronic structure of LDHs through reasonable design to obtain electrode materials with high activity. In this paper, three novel ternary-layered dihydroxide nano-compounds have been synthesized. Firstly, three LDHs materials (named as FeCoNi-LDHs, FeCoCu-LDHs, and FeCoZn-LDHs, respectively) were prepared by using the ZIF-67 framework material as a precursor by cation exchange strategy. Finally, the applications of these materials as electrode materials in oxygen evolution reactions (OER) and supercapacitors are explored based on current energy problems.


012028

The Anomalous Reflection and Refraction of Metasurface in the View of Solar Concentrators

Qiyuan Jin, Jingwen He, Zhifeng Wang and Minghuan Guo

Open abstract
Solar thermal power generation integrates photothermal conversion power generation and low-cost, large-scale heat storage, which is the primary support for constructing a green power system with new energy as the main body. The concentrating system is a critical component of solar thermal power plants. However, traditional concentrators are bulky and require complex solar tracking systems, limiting the reduction of solar thermal power costs. The metasurface can freely regulate electromagnetic waves and can be used in the field of solar concentrators, making it suitable for developing lightweight, low-cost, tracking-free solar concentrators and being a transformative technological solution in the energy field. Considering that the solar position varies with respect to a fixed planar metasurface concentrator, in this paper, we investigate the anomalous reflection and refraction phenomenon on the metasurface when the incident plane is not parallel to the direction of the static phase gradient of the metasurface. Utilizing vector equation derivation, Matlab calculation, and full-wave simulation based on the Finite difference-time domain (FDTD) method, all found the new property of the metasurface: its refracted ray, reflected ray, and normal are in the same plane, which is called the exit plane, and is at a certain angle to the incident plane.


012029

Controllable Preparation and Size-Dependent SERS Performance of 35–410 nm Quasi-spherical Au NPs

Peina Zhang, Tao Liu, Jingxuan Zheng, Zhichao Zhang and Mengjiao Zuo

Open abstract
Uniform Au NPs with definite but different sizes will serve as a perfect model for studying the influence of NP size on surface-enhanced Raman scattering (SERS) performance. In this study, using tri-hydroxymethyl aminomethane (Tris-base) as a stabilizer and FeCl2 as a reducing agent, Au NPs with the size of 110–410 nm were prepared by a one-step method by simply changing the amount of FeCl2. In the preparation of small particle size Au NPs, sodium citrate was introduced as an auxiliary stabilizer, and 35–85 nm Au NPs were prepared in one step. In addition, the synthetic Au NPs of different sizes were loaded onto the glass substrate and 4-MOTP was used as the probe molecule to monitor their SERS properties. The results showed that the SERS activity results showed a "volcanic shape" with the change of nanoparticle size at a fixed excitation wavelength. The 160 nm Au NPs have the best SERS performance when the excitation wavelength is 633 nm.


012030

Polysaccharide-modified conductive hydrogel for flexible electronic devices

Chongkai Ji, Lijie Li, Yulin Nie, Rang Ping, Jiong Peng and Xin Li

Open abstract
In recent years, conductive hydrogels, as an ideal flexible material, have quite broad application prospects in various flexible electronics fields, such as flexible supercapacitors, flexible batteries, and flexible sensors. However, mechanical stress such as stretching, fracture, and compression will affect the performance of conductive hydrogel during the application, which limits its further application. Polysaccharides, such as cellulose and chitosan, are widely distributed and easy-to-obtain biological macromolecules, which contain a large number of polar functional groups (carboxyl, amino, etc.), which can be formed with polymer hydrogel molecular chains, thereby improving the performance of the hydrogel. Herein, we prepared a kind of conductive hydrogel with high toughness, high conductivity, and self-adhesion by introducing carboxymethyl chitosan and maltose to induce a dynamic Schiff base reaction in the hydrogel. It is conceived that this study proposed a potential approach for the progress of conductive hydrogels in various flexible electronics fields.


012031

A carbonized coconut husk for supercapacitor electrode

Ruixia Chu, Shiwei Tan, Yi Qiao, Wenjun Fu, Kesong Zhang, Peidong Zhu, Dongying Liu and Wanyou Huang

Open abstract
As a new environment-friendly green device for energy storage, supercapacitor has been favored for its advantages of long service life and huge power density. As the material produced electrode of double-layer supercapacitors, much attention are given arise to carbon materials owning to their wide source, low price, environmental protection and other characteristics, especially biomass-based carbon materials. In this paper, coconut husk was used as raw material, which was carbonized by common hydrothermal pre-treatment and high-temperature pyrolysis carbonization. The materials obtained under different reaction conditions were tested in three-electrode system. The electrochemical tests implied that the carbonized coconut husk has the best energy storage characteristics when the pre-treatment time was 24 h and the activator was KOH. This study explored a carbon electrode derived by a new raw biomass material for energy storage in supercapacitors.


012032

Photoelectric properties and persistent photoconductivity of GaN-based ultraviolet photodetectors

Zhongyu Yue

Open abstract
Persistent photoconductivity deeply affects the performance of the photodetector, and has been studied in a variety of semiconductor optoelectronic devices. In this work, AlGaN/GaN metal-heterojunction-metal (MHM) ultraviolet (UV) detectors and GaN metal-semiconductor-metal (MSM) ultraviolet detectors were prepared using transverse Schottky contacts, and characterized at different temperatures, light intensity and bias voltage. The two-dimensional electron gas (2-DEG) at the Schottky heterojunction of AlGaN and GaN is used to generate high-speed electron mobility, which significantly improves the response speed and responsivity of photogenerated carriers. Under the illumination of 365 nm center ultraviolet light with an intensity of 4.4 mW/cm2, the photocurrent can reach 434 μA-MHM and 38 μA-MSM (25 °C), and the attenuation rate increase by 2.8 times, 5 times and 3.7 times with temperature (25 °C-250 °C), bias voltage (5/10/15 V), and light intensity (0.33/1.1/4.4 mW/cm2), respectively, and the attenuation rate reaches 50∼80 times.


012033

Investigation of the impact of annealing temperature on characteristics of porous SiOCH films

Min Zeng, Jing Zhang and Yanrong Wang

Open abstract
Porous SiOCH films with different porosity and low dielectric constant (k) were prepared by sol-gel and spin coating using methyltrimethoxy-silane (MTMS) and 1, 2-bis (trimethoxysilyl) ethane (BTMSE) as precursors and cetyltrimethylammonium chloride (CTAC) as porogen. The impact of different annealing temperatures on the chemical composition, hydrophobicity, pore arrangement, and dielectric constant of porous SiOCH films was investigated. The experimental results show that the SiOCH films with MTMS and BTMSE as precursors contain -C-C-bond and terminal methyl (Si-CH3). After annealing at 400 °C, the chemical composition of the films is stable. The water contact angle (WCA) is larger than 90°, and the films have good hydrophobicity.


012034

Scaling Mechanism and Permeability Evolution of Sandstone Reservoir

Fei Lv, Hongnian Chen, Xianfeng Tan, Xiao Liu and Fan Zhang

Open abstract
Knowledge of scaling mechanisms and the permeable behavior of rocks is highly important for geothermal energy development. In this study, the sandstone was soaked in a solution with the same chemical composition as geothermal water in Linyi City, Shandong Province. Permeability tests, scanning electron microscope tests, and nuclear magnetic resonance tests were performed on sandstone samples after different soak times (0, 30, 60, and 90 days) and temperatures (25 and 85 °C) to characterize the changes in microstructure and permeability properties. In addition, the changes in ion concentration in chemical solutions were compared. The results show that the wet mass and porosity of sandstone increase with the increase of soak time (0-70 d), and then entered the stable periods (70-90 d). As the soaking time, the medium and large pores inside the sandstone are transformed into small pores. The permeability of sandstone shows an overall decreasing trend, with the maximum decline when the soaking time is 30 d. At 25 °C, the scaling behavior is mainly involved by Ca2+, but at 85 °C Mg2+ is also involved in the scaling behavior. The scaling mechanism becomes the joint participation of Ca2+ and Mg2+. The results of the PHREEQC simulations are almost the same as the laboratory test results, indicating that sodium feldspar, potassium feldspar, and chlorite are generated slowly during the fouling process.


012035

Optimal sizing design of the hydrogen-based system for the stand-alone island

Miao Li, Ran Huo and Pingwen Ming

Open abstract
The main barriers to using Renewable Energy Sources (RES) to generate electricity are intermittency with low penetration in the electricity network and high seasonal demand fluctuation. An optimum hydrogen-based system configuration is designed for absorbing the maximization of RES curtailments using water electrolysis to produce and store hydrogen. This paper also developed a simulation model to optimize the proper size of electrolyzers and other parameters of the whole system. In order to validate the model, a hybrid electricity network for relatively stand-alone islands, located in eastern coastal China, has been used as a case study. Our analysis showed that the sizing of the required electrolyzer was determined by the operational temperature, the cell U-I curves, and the input of usable RES curtailments. For the application, a large amount of available hydrogen could be produced from the RES curtailments with an average conversion efficiency higher than 75.4%. And almost half of the rejected RES energy (54.7%) was returned to the electrical network through fuel cell stacks during high demand periods.


012036

Preferred Selection of Fractured Sweet Spot Section for Horizontal Shale Oil Well in West 233 Area

Zhidi Liu, Zhenglong Xie, CiXun Wang and Leizhao Zhang

Open abstract
Six parameters, which can effectively reflect the reservoir quality and the completion quality, have been selected, including the sand structure index, the physical parameters, the oil content index, the brittleness index reflecting, the stress difference coefficient and the fracture pressure. The evaluation index of fracturing sweet spots in shale oil horizontal wells was constructed, and the fracturing sweet spot selection criteria for shale oil horizontal wells in the study area were established. Combined with dynamic production data, the fracturing sweet spots were classified into Class I (high quality reservoir), Class II (secondary reservoir) and Class II (non-fracturing sweet spot), which provided technical support for the preferential selection of fracturing formations in shale oil horizontal well.