INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2020
·Vol. 45
·期 5
·7675-7688
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IF 3.741
Qinrong Sun,Nan Zhang,Xiaoping Yu,Fali Ju,Imre Miklós Szilágyi,Yanping Yuan
Summary Phase change materials (PCMs) have limited use in thermal storage because of their poor conductivity and lack of multi driving energy. Therefore, to overcome these problems, polyethylene glycol-calcium chloride/expanded graphite (PEG-CaCl 2 /EG) functional composite PCMs with high electrical and thermal conductivities were synthesized by ligand substitution using PEG-CaCl 2 as the PCM and EG as the highly electrically and thermally conductive framework material. The PEG-CaCl 2 /EG PCMs were thoroughly investigated, and the experimental results revealed the significance of EG in the composite structure, which leads to high electrical conductivity and high thermal conductivity. The resistivity of the functional PCM decreased to 1.67 Ω m, and the thermal conductivity ( k ) increased to 8.4 W/(m K) when the EG content was 10 wt%. In addition, the electro-thermal conversion efficiency of the functional PCM reached 86.9%, and its energy storage could be inspired at low voltages (2.0-5.0 V). The heating and energy storage rates increased with the working voltage and EG content, respectively. Melting-crystallization experiments and electro-thermal cycle tests showed that the functional PCMs had good thermal stability. Therefore, this study provides a new perspective for various fields of energy conversion and storage.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2020
·Vol. 45
·期 2
·3305-3314
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IF 3.741
Zhong Ma,Shuai Zhang,Yonggang Lu
Summary NiFe 2 O 4 presents high redox activity and good promoted application prospect in chemical looping processes. However, phase segregation caused by outward diffusion of Fe cations often lead to low cycling stability for NiFe 2 O 4 . In this study, the inherent mechanism of phase segregation for NiFe 2 O 4 was investigated deeply. The results indicated that reduction degree exhibited significant influence on the phase segregation of NiFe 2 O 4 in successive redox cycles. When NiFe 2 O 4 was reduced to Ni and Fe 3 O 4 in redox cycles, NiFe 2 O 4 displayed stable redox activity without phase segregation. As the reduction degree reached to FeO and FeNi, a needle-like structure with Fe enrichment was formed on the surface of the first cycled NiFe 2 O 4 . In the subsequent redox cycles with deep reduction degree, both severe phase segregation and deactivation were occurred for spent NiFe 2 O 4 sample. It can be seen that phase segregation is the main reason for the deactivation of NiFe 2 O 4 instead of surface sintering in redox cycles. The results of this work provide guidance for the development of NiFe 2 O 4 -based oxygen carriers with high redox performance.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2021
·Vol. 45
·期 6
·8577-8592
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IF 5.164
Wei Han,Wei Wang,Yongqiang Zhang,Yijie Wang,Mei Li,Yang Sun
Summary To recover Pr from molten chlorides, the electrode reactions of Pr 3+ on Sn-coated W and liquid Sn electrodes were studied by a group of electrochemical techniques. CV and SWV results exhibited that the electrochemical signals pertaining to the formation of Pr-Sn alloy compounds and solid solution appeared at less negative potentials than that of Pr 3+ on W electrode. The thermodynamic data of Pr-Sn alloy compounds and the kinetic parameters for PrSn 3 /Pr 3+ pair were determined employing OCP, LP, and Tafel methods, separately. The measured diffusion coefficient ( D ) of Pr in liquid Sn metal was 9.40 × 10 −6 cm 2 s −1 . Furthermore, the electrochemical recovering Pr from molten salt was performed using liquid Sn as a working electrode, and the formed Pr-Sn samples characterized by XRD and SEM-EDS were composed of Sn and PrSn 3 phases.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2020
·Vol. 45
·期 4
·6273-6284
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IF 3.741
Xiaolin Shao,Qi Zhang,Xurui Zhang,Jin Yi,Yuyu Liu,Jiujun Zhang
Summary A facile method is developed to fabricate nanoporous, structured, Sn-based catalyst electrodes. Sn, Zn, and multiwalled carbon nanotubes (MWCNTs) are co-electrodeposited on a copper substrate, followed by chemical dezincification in NaOH aqueous solution to remove Zn. By controlling variables such as the contents of Zn and MWCNTs, a series of Sn-MWCNT/Cu (S Z MC) electrodes are fabricated. Experimental results show that using such novel S Z MC electrodes can achieve a HCOO − Faradaic efficiency of over 91% at −0.99 V versus RHE for 10 hours in CO 2 -saturated 0.5 M KHCO 3 aqueous solution. The high performance is attributed to the addition of MWCNTs and Zn, followed by chemical dezincification to remove Zn and then create vacancies in the catalyst structure, which results in a special porous structure of S Z MC with large surface area. Then ECSA is used for enhancing the catalytic activity and selectivity of HCOO − production, as well as promoting intermediate adsorption and mass transfer.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2019
·Vol. 43
·期 6
·2075-2085
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IF 3.343
Rong Dai,Ziliang Zheng,Chenshuai Lian,Xing Li,Xu Wu,Xia An,Xianmei Xie
Summary A novel Pt-based Beta encapsulated CeO 2 yolk-shell catalyst was successfully synthesized via a RF layer in the synthetic process. The CeO 2 @Pt-Beta catalyst showed high catalytic activity and stability toward the LT-ESR with respect to the reference Pt-Beta, CeO 2 -Pt-Beta, which benefited from the special yolk-shell structure and the synergistic effect between the CeO 2 movable core and Pt metal. The confinement effect of the yolk-shell architecture contributed to the high dispersion of Pt nanoparticles as well as to the accumulation of reactant molecules in the enclosed void space, which ensured the reactants reacted with CeO 2 and Pt to achieve a complete reaction.
研究领域:
化学工程
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材料科学
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能源科学
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INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2019
·Vol. 43
·期 8
·3823-3836
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IF 3.343
Xiang Luo,Yu Hong,Honglei Zhang,Kaiqi Shi,Gang Yang,Tao Wu
Summary Steam reforming of ethanol (SRE) over non-noble metal catalysts is normally conducted at high temperature (>600°C) to thermodynamically favour the catalytic process and carbon deposition mitigation. However, high temperature inhibits water-gas shift reaction (WGSR) and therefore restrains the yield of H 2 and leads to the formation of an excessive amount of CO. The modification of non-noble metal catalyst to enhance WGSR is an attractive alternative. In this study, CeO x was firstly loaded onto a nano-scaled Ni x Mg y O matrix and subsequently used as the catalyst for hydrogen production via SRE. Morphology of the catalyst materials was characterized by using a series of technologies, while H 2 -temperature programmed reduction (H 2 -TPR), CO-temperature programmed deposition (CO-TPD), and X-ray photoelectron spectroscopy (XPS), were employed to study the surface nickel, ceria clusters, and their interactions. The catalytic activity and durability of the catalyst were studied in the temperature region of 500°C to 800°C. The CeO x -coated nano Ni x Mg y O matrix exhibited an outstanding hydrogen yield of 4.82 mol/mol ethanol under a high gas hourly space velocity (GHSV) of 200 000 hour −1 . It is found that the unique Ni 0 -CeO x structure facilitates the adsorption of CO on the surface and therefore promotes the effective hydrogen production via WGSR. Moreover, this modified Ni x Mg y O matrix was found to be a more robust and anticoking nanocatalyst because of reversible switch between Ce 4+ and Ce 3+ .
研究领域:
催化化学
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材料科学
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能源化学
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2019
·Vol. 43
·期 9
·4473-4482
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IF 3.343
Dixuan Cheng,Gang Cheng,Zhangxing He,Lei Dai,Ling Wang
Summary In this paper, titanium dioxide (TiO 2 ) nanoparticles were employed as catalysts towards V 2+ /V 3+ redox couple of vanadium redox flow battery (VRFB). The effect of TiO 2 phase on the electrocatalytic performance for negative couple was systematically investigated. The electrochemical properties of TiO 2 with different phase were assessed via cyclic voltammetry and electrochemical impedance spectroscopy by using AB as conductive agent. Obtained from the results, anatase TiO 2 (α-TiO 2 ) exhibits superior electrocatalytic activity to rutile TiO 2 (γ-TiO 2 ). The VRFB cell performs well at discharge capacity, voltage efficiency, and energy efficiency by employing α-TiO 2 -modified negative electrode with current density varying between 50 and 100 mA cm −2 . The discharge capacity of α-TiO 2 -modified cell with vanadium ion concentration of 1.6 M comes up to 113.5 mA h at 100 mA cm −2 current density, which is increased by 39.1 mA h after modification for negative electrode. Moreover, the corresponding energy efficiency increases by 7.5% after modification of α-TiO 2 . Experimental results show that TiO 2 is an ideal catalyst for VRFB. Moreover, α-TiO 2 demonstrates superior electrocatalytic performance to γ-TiO 2 towards V 2+ /V 3+ reaction.
研究领域:
材料科学
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电化学
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2020
·Vol. 44
·期 11
·8442-8454
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IF 3.741
Abdul Haleem,Zeeshan Haider,Rafi u Shan Ahmad,Uzabakiriho Pierre Claver,Afzal Shah,Gang Zhao,Wei-Dong He
Summary There have been tremendous efforts made to investigate various materials to enhance the electrical performance of triboelectric nanogenerators (TENGs) but there is still demand for some techniques to further enhance the performance of tribomaterials. Therefore, we fabricated a bimetallic hybrid cryogel via cheap and facile UV-radiation as well as in situ reduction method. Fabricated TENG device made up of porous hybrid bimetallic cryogel film containing silver and gold nanoparticles as tribopositive material and poly dimethyl siloxane (PDMS) as a tribonegative layer with dimension of 1 × 2 cm 2 has the ability to produced output voltage of 262.14 V with current density of 27.52 mA/m 2 and 7.44 W/m 2 peak power density, which was sufficient to light up more than 120 white light emitting-diodes (LEDs). Porous and rough structure, interaction of nanoparticles was the reason behind the performance enhancement of tribopositive material. Thus, this study introduces a very stable and easily synthesized bimetallic hybrid cryogel as a tribopositive material to enhance the performance of tribomaterials to design high performance TENG devices.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2020
·Vol. 44
·期 9
·7580-7590
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IF 3.741
Jiale Mao,Shuang Wang,Lei Zhang,Yu Chen,Yonghong Cheng
Summary Energy storage media is the kernel for the rapidly developing new energy systems, while it remains a challenge to achieve admirable service capability at high temperature. This manuscript purposes crosslinking as an effective method to address the issue. The epoxy is innovatively studied as energy storage media in this research. We figure out that crosslinking density is a critical factor to determine its energy storage performance. With adequate crosslinking, attractive energy storage density/efficiency (6.9 J/cm 3 /90%@room temperature; 1.2 J/cm 3 /90% and 1.7 J/cm 3 /75%@100°C) can be achieved. However, excessive crosslinking density and lack of crosslinking point are found to induce obvious energy storage performance decaying at high electric field and high temperature, respectively. This manuscript demonstrates that the general epoxy materials can be used as energy storage media and concludes that proper crosslinking can improve the energy storage performance of polymers, which provides directions for future research on high-temperature energy storage films.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2020
·Vol. 44
·期 8
·6873-6884
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IF 3.741
Guorui Gao,Tongxing Zhang,Chenglong Guo,Shaokai Jiao,Zhonghao Rao
Summary The development of high-efficient working fluids with excellent photo-thermal conversion and heat storage properties is an important factor to solar thermal utilization. In this work, magnetic phase change microcapsules (MPCMs) were prepared via in situ polymerization, where melamine-formaldehyde (MF) resin and octadecane containing oleic acid-coated magnetic nanoparticles (OA-MNs) were used as the shell and core, respectively. The microstructure, magnetic and thermal properties of MPCMs were investigated, and the photo-thermal conversion and heat storage properties of slurries prepared by dispersing MPCMs into multi-walled carbon nanotubes (MWCNTs) nanofluids were explored. The encapsulation efficiency of MPCMs with superparamagnetic nature achieved 63.51%, while the thermal conductivity of MPCMs was slightly increased with regard to phase change microcapsules (PCMs) and the thermal stability of octadecane was enhanced after being encapsulated. Moreover, the slurry with 0.01 wt% MWCNTs and 15 wt% MPCMs had the optimal photo-thermal conversion properties and thermal storage capacity. Beyond that, the recycled MPCMs represented excellent recyclability. Our research demonstrated that the MWCNTs-dispersed MPCMs slurry is one of ideal working fluids with excellent photo-thermal conversion and heat storage characteristics for direct absorption solar collector.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2020
·Vol. 44
·期 11
·8769-8780
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IF 3.741
Tao Li,Fang Luo,Xudong Fu,Lanxin Li,Jiayuan Min,Rong Zhang,Shengfei Hu,Feng Zhao,Xiao Li,Yanhua Zhang,Xujin Bao,Qingting Liu
Summary Star copolymers with good film-forming and mechanical properties were in situ synthesized for fabricating proton exchange membranes. The monomers of 3,4-diaminobenzoic acid were first grafted onto glycidyl-polyhedral oligomeric silsesquioxane (G-POSS) cores and then propagated to the poly(2,5-benzimidazole) (ABPBI) chains. The introduction of the star copolymer improves the movement of the ABPBI polymer chains, resulting in a lower internal viscosity and larger free volume that favor increased membrane flatness and absorbilities of water and phosphoric acid molecules, respectively. It was found that the star copolymers with 1.0 wt% of incorporated POSS (ABPBI-1.0POSS) had the best balance of the acid retentivity and film-forming property as well as mechanical properties that are desirable for proton exchange membranes without PA loss operating at high temperatures. The enhanced cell performance characteristics obtained using the ABPBI-1.0POSS-based membranes indicate that star copolymers are promising materials for use in high-temperature proton exchange membrane fuel cells.
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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2020
·Vol. 44
·期 13
·10295-10306
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IF 3.741
Huijia Huang,Changjiang Zhao,Fei Ding,Huan Li,Shuoqing Zhang,Xingjiang Liu,Qiang Xu
Summary Lithium-sulfur (Li-S) batteries have a great potential for the future development of energy industry. However, the high-temperature performance of Li-S batteries is still facing great challenge due to the high flammability of the electrolyte, sulfur cathode as well as the separator. The separator modification is an effective method to improve the thermal stability of separator and the electrochemical performance of Li-S batteries under elevated temperatures. However, the reported methods of separator coating are too complicated to be applied in the industrial production. Here, a novel thermo-stable composite separator (M-Celgard-p), in which a layer of silicon dioxide-poly (propylene carbonate) based electrolyte (nano-SiO 2 @PPC) with a high ionic-conductivity of 1.03 × 10 −4 S cm −1 is coated on the commercial Celgard-p separator, is prepared by using a simple dipping method. Compared to the Li-S battery assembled with Celgard-p separator, the M-Celgard-p separator combined with a sulfur/polyacrylonitrile (S/PAN) cathode can improve the electrochemical performance of Li-S batteries, especially their high-temperature stability. As a result, the (S/PAN)/M-Celgard-p/Li cell delivers a high specific capacity of 724.7 mAh g −1 at 1.0 A g −1 after 200 cycles and presents a good rate capability of 1408 mAh g −1 at 1.0 A g −1 and 1216 mAh g −1 at 2.0 A g −1 . More importantly, the (S/PAN)/M-Celgard-p/Li cell can exhibit a capacity retention ratio of 69.4% after 200 cycles at 60°C. The M-Celgard-p separator with high Li-ion conductivity can not only block the “shuttle-effect” of polysulfides during cycling but also enhance the thermal stability under elevated temperatures. This work presents a simple dipping method to prepare composite separator with excellent thermal stability, which enhance the rate performance and cyclic stability of Li-S batteries under elevated temperatures. We believe this work can provide a new way to develop more reliable Li-S batteries for practical applications.
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高影响因子
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