Efficient and Stable Inverted Perovskite Solar Modules Enabled by Solid-Liquid Two-Step Film Formation

A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells.The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs.In this work,we adopted a solid-liquid two-step film formation technique,which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films.This method possesses the advantages of integrating vapor deposition and solution methods,which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform,large-area perovskite film.Furthermore,modification of the NiO_(x)/perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization.As a result,a large-area perovskite film possessing larger grains,fewer pinholes,and reduced defects could be achieved.The inverted PSM with an active area of 61.56 cm^(2)(10×10 cm^(2)substrate)achieved a champion power conversion efficiency of 20.56%and significantly improved stability.This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.

Improving advantages and reducing risks in increasing cyclone height via an apex cone to grasp vortex end

For a cyclone, it is possible to improve separation efficiency and reduce pressure drop by increasing the cyclone height. However, an exceeded height increase could result in a dramatical drop in separation efficiency. In this study, experimental and computational fluid dynamics simulation results exhibit that the introduction of an apex cone at the dust outlet could avoid the risk of separation efficiency drop but lead to a continuous reducing of the pressure drop. Generally, the optimal cyclone height should be closely related to the natural vortex length. While, when the vortex end contracts into the separation space in the cyclone with an exceeded height, severe back-mixing of particles always occurs, which will result in the decrease of separation efficiency. Herein, it is found that when an apex cone is installed at the dust outlet, the vortex end can be grasped by the cone so as to weaken the back-mixing of particles.Meanwhile, the introduction of this apex cone can enhance the secondary separation to capture the back-mixed particles again so as to protect the efficiency. In addition, it is found that the enhanced secondary separation could come from either the stagnant current of axial velocity in the center or the improved tangential velocity of inner vortex whereas the forcibly extending the length of vortex to exceed its natural length will not significantly increase efficiency.

A potential-responsive ion-pump system based on nickel hexacyanoferrate film for selective extraction of cesium ions

A nickel hexacyanoferrate(NiHCF)film electrode was prepared with NiHCF,conductive carbon black,and polyvinylidene difluoride,which was coated on graphite plate substrate for selective extraction of Cs^(+)ions by using electrochemically switched ion exchange(ESIX)technology.A potential-responsive ionpump system for efficient extraction of Cs+ions was designed,and the effect of wet film thicknesses,charging modes,flow rates,and chamber widths on Cs+ions extraction performance was investigated.In the system,the adsorption capacity and removal percentage of Cs^(+)ions on the NiHCF film electrode reached as high as 147.69 mg·g^(-1)and 92.47%,respectively.Furthermore,the NiHCF film electrode showed high selectivity for Cs^(+)ions and stability.After seven cycles of adsorption/desorption,the desorption percentage could reach about 100%.The excellent Cs^(+)extraction performance should be attributed to the strong driving force produced by the potential-responsive ion-pumping effect in the ESIX process,as well as the low ion transfer resistance of the film electrode which is caused by the special crystal structure of NiHCF.In addition,the NiHCF film electrode was implemented to work together with the bismuth oxybromide(BiOBr)film electrode to accomplish the simultaneous extraction of Cs^(+)and Br^(-).And the adsorption capacity and removal percentage of Br^(-)ions on the BiOBr film electrode reached 69.53 mg·g^(-1)and 77.32%,correspondingly.It is expected that such a potential-responsive ion-pump system based on NiHCF and BiOBr film electrodes could be used for the selective extraction and concentration of Cs^(+)and Br^(-)ions from salt lake brine.

Removal of biomass tar by steam reforming over calcined scallop shell supported Cu catalysts

In this study, the main purpose is to develop low-cost catalysts with high activity and stability for high quality syngas production via steam reforming of biomass tar in biomass gasification process. The calcined waste scallop shell（CS） supported copper（Cu） catalysts are prepared for steam reforming of biomass tar. The prepared Cu supported on CS catalysts exhibit higher catalytic activity than those on commercial CaO and Al;O;. Characterization results indicate that Cu/CS has a strong interaction between Cu and CaO in CS support, resulting in the formation of calcium copper oxide phase which could stabilize Cu species and provide new active sites for the tar reforming. In addition, the strong basicity of CS support and other inorganic elements contained in CS support could enhance the activity of Cu/CS. The addition of a small amount of Co is found to be able to stabilize the catalytic activity of Cu/CS catalysts,making them reusable after regeneration without any loss of their activities.

Multi-fluid Eulerian simulation of binary particles mixing and gas–solids contacting in high solids-flux downer reactor equipped with a lateral particle feeding nozzle

The performance of binary particles mixing and gas-solids contacting,which is considered qualitatively to have a significant influence on the heat transfer in internal heated circulating fluidized beds,is carefully investigated by means of a numerical approach in the newly developed high solids-flux downer lignite pyrolyzer(φ0.1 m×6.5 m).Since binary particles are used in this system,a reasonably validated 3 D,transient,multi-fluid model,in which three heat transfer modes relating to the convection,conduction and radiation are considered,is adopted to simulate the flow behavior,temperature profiles as well as volatile contents.The simulation results showed that the solids stream impinges the left wall surface initially and turns towards the right wall in the further downward direction and then shrinks during this process resulting in that the solids concentrate a little more at the central region.In the further downward section of the downer,the particle flow disperses near the right wall and develops uniformly.Meanwhile,the coal phase is slowly heated in the downer and it is found that most of the heat absorbed by the coal is from the convection heat transfer mode.To explore the heat transfer mechanism more quantitatively,two indexes(mixing index and contacting index)are proposed,and it is found that the mixing index initially increased fast and later remained at a relatively flat state.For the contact index,it shows a trend with a first rising and then falling,finally rising continuously.Also,it is found that the convection heat transfer is closely correlated to the contacting status of gas-coal which indicates that the improving of the gas-coal contacting efficiency should be an effective way to strengthen the coal particle heating process.

Electrodeposited iodide ions imprinted polypyrrole@bismuth oxyiodide film for an electrochemically switched renewable extractor towards iodide ions

Effective extraction and regeneration of radioactive iodide is one of urgent concerns for the safe utilization of nuclear energy.As a novel environmentally benign ion separation technique,electrochemically switched ion extraction(ESIE)process can be applied for effective capture and recovery of iodide ions(I^(-)).Herein,a novel kelp seaweed-like core/shell I^(-)imprinted polypyrrole@bismuth oxyiodide(PPy/I^(-)@BiOI)composite film is successfully prepared for the selective I^(-)capture in the ESIE system.It is found that the I^(-)can be easily trapped in the PPy/I^(-)@BiOI film after I^(-)is in situ desorbed from the film by an electrochemical reduction process since it offers particular electroactive binding sites for I^(-)extraction.The I^(-)imprinted PPy/I^(-)@BiOI film displays an extraction capacity as high as 325.2 mg·g^(-1)for I^(-)with favorable stability.In particular,the extraction and desorption of I^(-)is achieved by adjusting the redox potential and the pristine PPy/I^(-)@BiOI film can be regenerated and reused for multiple times without decrease in extraction capacity.It is expected that such a PPy/I^(-)@BiOI film would be useful as an electrochemically switched renewable extractor that could capture and regenerate I^(-)from radioactive water.

Simulation of gas-solids heat transfer in cyclone pyrolyzer using CFD-DEM model

Fast heat transfer in the pyrolyzer can increase the yield of pyrolysis gas and tar,and improve the quality of tar.Compared with the downer pyrolyzer,the cyclone pyrolyzer can simultaneously achieve high solids holdup and violent turbulence,and correspondingly faster heat transfer.In this work,the heat transfer behavior in the cyclone pyrolyzer is specifically studied using the computational fluid dynamics-discrete element method.The simulation results reveal that the gas-solids heat convection contributes mainly to the heat transfer process,and the heat radiation and conduction are relatively small and almost negligible,respectively.Compared with the downer pyrolyzer under the same operating conditions,the heating rate is significantly increased in the cyclone pyrolyzer.By analyzing the flow characteristics in the cyclone pyrolyzer,it is found that the region of high convective heat transfer rate coincides with that of natural cyclone length.Additionally,the final coal temperature increases with the increase of gas velocity and exists a maximum value.These results can offer some qualitative understanding of the heat transfer behavior in the cyclone pyrolyzer.

The swirl and pyrolysis reaction synergistically enhance solid-solid heat transfer and product separation in cyclone pyrolyzer Author links open overlay panel

Cyclone pyrolyzer is a novel type of downer that combines centrifugal force field and double-layer cyclone vortex.Research on transfer behavior is helpful to optimize the pyrolyzer to meet the needs of pyrolysis.In this study,the Computational Particle Fluid Dynamics(CPFD)model is used to analyze the transfer behavior of binary particles,and finds that the swirl and reaction have a synergistic effect.This effect can increase the heating rate of the particles to the range of flash pyrolysis,and its mechanism lies in the flow field structure of the pyrolyzer.Due to the centrifugal force field,the particles gather to the near wall.The rapid swirl,which facilitates intense gas-solid heat transfer,leads to the rapid heating and pyrolysis of biomass particles.As the pyrolysis proceeds,the mass of the biomass particles becomes smaller and they are more easily affected by the gas flow in pyrolyzer.Under the action of gas flow,char particles serve as new heat carrier to form the inner cycle of particles,which strengthens the heating process.The pyrolysis products are discharged from the exhaust port in time with the flow field of the pyrolyzer to achieve separation from the heat carrier and inhibit the occurrence of secondary reactions.

High entropy materials based electrocatalysts for water splitting:Synthesis strategies,catalytic mechanisms,and prospects

Among various electrocatalysts,high entropy materials(HEMs)have attracted great attention due to the distinctive designing concept and unique properties with captivating electrocatalytic activity and stability.To date,HEMs have been a new family of advanced electrocatalysts in the research field of water electrolysis.In this work,the structural features and synthesis strategies of high entropy catalysts are reviewed,especially,their performances for catalyzing hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in water electrolysis are presented,in which the crucial roles of structure,composition,multisites synergy,and“four core effects”for enhancing catalytic activity,stability,and resistance of electrochemical corrosion are introduced.Besides,the design tactics,main challenges,and future prospects of HEM-based electrocatalysts for HER and OER are discussed.It is expected to provide valuable information for the development of low-cost efficient HEM-based electrocatalysts in the field of water electrolysis.

Application of ionic liquids in CO_(2)capture and electrochemical reduction:A review

As a new type of green solvent with non-volatility,high thermal stability,high conductivity and various adjustable properties,ionic liquid(IL)has been widely used in the capture and electrochemical reduction of carbon dioxide(CO_(2)).To date,many studies have been made to investigate CO_(2)capture by using different types of ILs and CO_(2)electrochemical reduction(CO_(2)ER)with ILs as either electrolyte or other catalytic active components.Some structure-activity relationships between the structure and adsorption or catalytic properties of ILs have been found.Herein,the absorption performances and mechanisms of conventional ILs,amino-functionalized ILs,non-amino functionalized ILs and supported ILs for CO_(2)capture,as well as the performances and action mechanisms of ILs as the electrolyte,electrolyte additive,and/or electrode modifier in the process of CO_(2)ER are summarized.Many researches indicate that the unique interaction between the anion or cation of IL and CO_(2)has a significant contribution to promote the absorption and conversion of CO_(2).However,the ILs used for CO_(2)capture and electrochemical reduction should be further explored.Especially,a more in-depth investigation of the adsorption and catalytic mechanisms with the help of quantum chemical calculation,molecular simulation,and in situ characterization techniques is necessary.It is expected to design and develop more efficient ILs used for CO_(2)capture and conversion on a large scale.

Construction of nitrogen-doped carbon cladding LiMn_(2)O_(4) film electrode with enhanced stability for electrochemically selective extraction of lithium ions

Reducing the dissolution of Mn from LiMn_(2)O_(4)(LMO)and enhancing the stability of film electrodes are critical and challenging for Li+ions selective extraction via electrochemically switched ion exchange technology.In this work,we prepared a nitrogen-doped carbon cladding LMO(C-N@LMO)by polymerization of polypyrrole and high-temperature annealing in the N2 gas to achieve the above purpose.The modified C-N@LMO film electrode exhibited lower Mn dissolution and better cyclic stability than the LMO film electrode.The dissolution ratio of Mn from the C-N@LMO film electrode decreased by 42%compared to the LMO film electrode after 10 cycles.The cladding layer not only acted as a protective layer but also functioned as a conductive shell,accelerating the migration rate of Li+ions.The intercalation equilibrium time of the C-N@LMO film electrode reached within an hour during the extraction of Li+ions,which was 33%less compared to the pure LMO film electrode.Meanwhile,the C-N@LMO film electrode retained evident selectivity toward Li+ions,and the separation factor was 118.38 for Li+toward Mg2+in simulated brine.Therefore,the C-N@LMO film electrode would be a promising candidate for the recovery of Li+ions from salt lakes.

Forming and breaking the ceiling of inlet gas velocity regarding to separation efficiency of cyclone

The maximum-efficiency inlet velocity(MEIV)is a ceiling of inlet gas velocity that defines separation efficiency during cyclone design and operation.Experiment and computational fluid dynamics(CFD)simulation exhibited that an apex cone at the dust outlet can break the ceiling and improve the sepa-ration efficiency.The phenomenon is closely related to the effect of excessive high inlet gas velocity on the back-mixing escape of fine particles,which is the final result of back mixing,entrainment by the rapid upward airflow,and secondary separation of the inner vortex.In the center of the inner vortex,the airflow rotates slowly and moves rapidly upward.This elevator type of airflow delivers re-entrained particles to the vortex finder.A higher inlet gas velocity accelerates the elevator,causing more entrained particles to escape.This explains the decrease in efficiency at an excessively high inlet gas velocity.When an apex cone is installed at the dust outlet,the back-mixing is significantly weakened because the vortex core is bounded to the center of separator,while the transport effect of rapid upward airflow is weakened by the decrease in axial velocity in the center.Therefore,particle escape is weakened even at excessive high inlet gas velocities.Instead,the centrifugal effect is enhanced because of increased tangential velocity of the gas and particles.Consequently,the ceiling of inlet gas velocity is broken.

Effect of nano Al_(2)O_(3) addition on cycling performance of poly(ether block amide)based solid-state lithium metal batteries

A novel poly(ether block amide)(PEBA)based solid-state polymer electrolyte(SPE)was prepared using a casting method,in which 20wt%lithium(Li)bis-(trifluoromethanesulfonyl)imide(LiTFSI)and aluminum oxide(Al_(2)O_(3))nanoparticles were used as the Li salt and solid plasticizer,respectively.In the case of addition of 3wt%Al_(2)O_(3) nanoparticles,ion conductivity of the obtained PEBA 2533-20wt%LiTFSI-3wt%Al_(2)O_(3) SPE was 3.57×10^(−5) S cm^(−1) at 25°C.Furthermore,the Li symmetrical battery assembled with it showed excellent cycling stability(1000 h)at 0.1 mA cm^(−2).While,the assembled all-solid-state Li/PEBA 2533-20%LiTFSI-3wt%Al_(2)O_(3)/LiFePO 4(areal capacity:0.15 mAh cm^(−2))battery maintained 94.9%of the maximal capacity(133.9 mAh g^(−1@0.1) mA cm^(−2))at 60°C even after 650 cycles with a superior average coulombic efficiency(CE)of 99.84%.By using X-ray photoelectron spectroscope(XPS),self-aggregation layer(SAL)of polyamide 12(PA12)of PEBA 2533 was discovered,which should contribute to promoting the robustness of lithium fluoride(LiF)enriched solid-electrolyte interphase(SEI)layer.In addition,it is considered that the state of interface between SPE and cathode should be the cause of voltage polarization of the full cell.

电控离子(交换)膜分离技术——从ESIX到ESIPM

电控离子膜(Electrically Switched Ion Membrane,ESIM)分离是近年来发展起来的一种新型离子选择性高效分离技术,已被用于多种金属阳离子及阴离子的选择性分离与回收。电控膜分离源于电控离子交换(Electrically Switched Ion Exchange,ESIX)技术,其高效运行依赖于具有离子交换功能的电活性材料(Electroactive Ion Exchange Material,EIXM)。EIXM既能传递电子又能传递离子,通过调节其氧化/还原电位可以控制离子的可逆置入/释放,同时实现目标离子的高效分离和EIXM的再生,因而不产生二次污染。本文从EIXM简介、结构设计与可控合成、各种电控离子选择性分离机制的研究进展以及新型ESIX-ESIM膜组件开发和应用几个方面,分析总结了从最初的ESIX技术到基于ESIX原理的电控离子选择渗透膜(Electrically Switched Ion Permselective Membrane,ESIPM)分离的发展历程。展望未来ESIM分离技术,应针对目标离子的选择性分离要求,设计合成新型结构ESIM材料和研发相关膜组件系统,可望最终实现ESIM技术的工业应用。

Nanostructured amorphous Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) high-entropy-alloy:an efficient electrocatalyst for oxygen evolution reaction

Proximal configu ration of dissimilar metal atoms in amorphous high-entropy-alloys(HEAs) always re sult in interatomic d-band ligand effect,dense defect distribution,coordinatively unsaturated sites,high potential energy,and loose atom bonding.Herein,nanostructured amorphous Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) HEA ribbon is fabricated via a melt spinning method combined with electrochemical corrosion etching process,which is applied as the potential oxygen evolution reaction electrocatalyst.It is found that there are micro/nano pits on the surface of etched amorphous Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) ribbons.Various elements of HEAs bond with each other to form a highly disordered configu ration,which could result in an optimized bonding energy and enhanced intrinsic catalytic activity.The electrocatalysis activity measurements indicate that the amorphous HEA endows a much higher activity than the crystalline one,which is further improved by the electrochemical etching treatment.Especially,the HEA ribbon etched for 3 h requires a low overpotential of 230 mV to afford 10 mA cm^(-2) current density.In addition,density functional theory calculations demonstrate that the amorphous structure can weaken the interaction between the surface of Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) alloy and the intermediates,leading to an optimized adsorption Gibbs free energy.

Downer reactor simulation and its application on coal pyrolysis:A review

Pyrolysis technology has received increasing attention in recent years due to its great potential in the field of lowrank coal clean and efficient conversion.Since pyrolysis reaction is very fast and prone to overreaction,the downer-type reactor is considered as a pyrolyzer due to its unique plug flow reactor characteristics.However,the low solids holdup,which is not beneficial for the fast heat transfer,limits its industrial application.Thus,how to realize high-density operation is crucial to the successful application of the downer reactor.Herein,the definition and strategies of high-density operation in the downer were introduced at first.And then,considering the increasing influence of computational fluid dynamics(CFD)in the fluidization industry,the state-of-the-art progress in downer simulation was reviewed,in which the newly developed drag models for downers were carefully discussed and compared.Also,to help prediction of the pyrolysis behaviors,the widely used pyrolysis kinetic models were systematically summarized.Combined with the potential of the downer in the field of coal pyrolysis,the relevant research progress of hot-state simulation of the downer pyrolyzer were introduced and analyzed.Finally,the suggestions on how to carry out follow-up work were given.It is expected that this review could give a better understanding for designing and optimizing downer pyrolyzer.

Nanocellulose:Extraction and application

Recently,nanocellulose and its applications gain high attraction in both research and industrial areas due to its attractive properties such as excellent mechanical properties,high surface area,rich hydroxyl groups for modification,and natural properties with 100%environmental friendliness.In this review,the background of nanocellulose originated from lignocellulosic biomass and the typical extraction methods and general applications are summarized,in which the nanocellulose extraction methods related to ball milling are mainly introduced.Also,an outlook on its future is given.It is expected to provide guidance on the effective extraction of nanocellulose from biomass and its most possible applications in the future.

Iron-based oxygen carriers in chemical looping conversions:A review

A solid oxygen carrier is usually applied in a chemical looping conversion process to transfer oxygen from the gaseous oxygen source to the fuel,which can avoid the direct contact of these two reactants and hence decrease the energy penalty of separation.Among the solid oxygen carriers,iron-based oxygen carrier is an attractive option due to its inherent properties of low cost and environmentally-friendly.Several processes such as chemical looping combustion(CLC),chemical looping gasification(CLG),chemical looping reforming(CLR),and chemical looping hydrogen generation(CLHG)have been proposed and investigated based on the iron-based oxygen carrier.In this review,the relevant researches on the iron-based oxygen carrier are summarized,which include the characteristics of iron oxides,the preparations of the iron-based oxygen carrier based on the iron ores and some other low-cost iron contained materials,and their applications in the continuous operated chemical looping conversion processes.It is expected to provide a better understanding for the development and utilization of iron-based oxygen carrier in the practical chemical looping processes.

Citric acid-assisted synthesis of nano-Ag/BiO Br with enhanced photocatalytic activity

In this study, silver nano-particles have been anchored in the surface of Bi OBr photocatalysts by a citric acid-assisted photoreduction method. The citric acid was served as a chelating and reductive agent for the preparation of Ag-decorated Bi OBr photocatalysts(named as Ag/Bi OBr-2). The as-synthesized samples were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and UV-Vis diffuse reflection spectroscopy(DRS). The Ag/Bi OBr-2 photocatalyst exhibited excellent and stable photocatalytic activities on MO and phenol degradation under simulated sunlight irradiation. The enhanced photocatalytic activity could be ascribed to the smaller size, rough surface, and the surface plasma resonance(SPR) effect of Ag. Also, the Schottky junction, between the surface of the Bi OBr and silver nanoparticles, accelerated the efficient transfer and separation of photoinduced electron-hole pairs and promoted the photocatalytic performance. The active species tests indicated that the superoxide radical(·O-2) was responsible for the enhanced photocatalytic performance of Ag/Bi OBr-2. Finally, a possible photocatalytic mechanism was proposed.

Fluoropyridine family:Bifunction as electrolyte solvent and additive to achieve dendrites-free lithium metal batteries

Electrolyte formulation with high stability towards both Li metal anode and high-voltage cathode is considered as one of key points for the high-energy density lithium metal batteries(LMBs).In our previous study,by adding only 2%of 2-fluoropyridine(2-FP)as the additive in the carbonate and ether-based electrolyte formulations effectively suppressed Li dendrite growth.In this study,we further found that the main fluoropyridine(FP)family members can serve as not only the effective additive but also the excellent electrolyte solvent in the electrolyte formulations to enhance the performance of LMBs.For the 2-FP,when it was also used the electrolyte solvent and paired with single-salt lithium bis(trifluoromethylsulfonyl)imide(Li TFSI),the obtained electrolyte formulation of 1 M Li TFSI in pure2-FP solvent not only allowed faster ion transport though solvation effect,but also possessed impressive oxidation stability window over 4.3 V.As a result,the high-voltage LiNi_(1/3)Mn1_(/3)Co_(1/3)O_(2)(1.5 mA h cm^(-2))|Li metal battery with it exhibited a capacity retention of more than 80%over a long-term cycle even at 0.45 m A cm^(-2)with a lean electrolyte(30μL).Meanwhile,for another FP family member(i.e.,3-FP)as the electrolyte additive,the 4.3 V LMBs with the carbonate-based electrolyte containing only 1%of 3-FP maintained 83.9%of initial capacity after 200 cycles at 0.75 m A cm^(-2).Density functional theory(DFT)calculations and experiments confirmed that three typical FPs,i.e.,2-FP,3-FP and 4-FP can not only regulate the initial Li nucleation process,but more importantly also induce a protective layer,leading to a uniform and dendrites-free Li deposition.This bifunction of the FP family member as either electrolyte solvent or additive in the electrolyte formulations should be promising for the achieving of dendrites-free high-energy density LMBs.