Durable Operation Research Articles

Enhanced Activity and Stability via Fe Substitution in Lithium Nickel-Based Electrocatalyst for Oxygen Evolution Reaction in Alkaline Media

The oxygen evolution reaction (OER) is kinetically sluggish and requires a high overpotential compared to the hydrogen evolution reaction (HER) due to its four-electron transfer process. Herein, we have fabricated highly active Fe-substituted LiNiO2 using the electrostatic spray deposition (ESD) technique as scalable electrocatalysts. With this technique, we can modify the electronic and surface structure of LiNixFe1-xO2 by controlling the amounts of Ni and Fe, where x = 0, 0.2, 0.4, 0.6, and 0.8. This substitution can modify the electronic structure of the Ni ions to more electrophilic oxidation states, resulting in the M – O step facilitation, which is considered one of the rate-determining steps in the OER. The electronic structure modification was characterized by X-ray photoelectron spectroscopy (XPS). The surface structural modulation of the electrocatalysts due to Fe substitution was analyzed by scanning electron microscopy (SEM). The OER half-cell electrochemical measurements were carried out using standard three- electrode configuration. These results elucidate that substitution of Ni by Fe increases the electrocatalytic activity significantly. The optimized electrocatalyst, LiNi0.6Fe0.4O2, exhibits an overpotential of 239 mV at a current density of 10 mA cm-2 and a Tafel slope of 41.49 mV dec-1. Moreover, it exhibits excellent operational durability under continuous and dynamic operating environments without any significant performance degradation.

Pure-Water-Fed Forward-Bias Bipolar Membrane CO2 Electrolyzer

Electrochemical CO2 reduction (ECO2R) has emerged as a promising approach to directly produce carbon-containing fuels from renewable sources and CO2, offering a practical opportunity to mitigate greenhouse-gas emissions and climate change. The key challenges to realize this vision are CO2 electrolyzers with high energy efficiency, faradaic efficiency (FE), carbon-conversion efficiency and can also maintain durable operations. As high alkalinity is beneficial for ECO2R reactivity and selectivity, flow cells or zero-gap devices supported by alkaline aqueous electrolytes are used to demonstrate outstanding ECO2R performance. However, this leads to two major challenges. First is the formation of (bi)carbonates (CO3 2-/HCO3 -) and subsequent CO2 crossover issue resulting in either reactant loss or additional energy penalty of regenerating and purifying CO2. Second is that alkali cations transfer through the membrane and build up on the cathode and result in carbonate salt precipitation, which leads to blockage of CO2 transport pathways, efficiency loss and device failure. Therefore, it is an urgent task to develop novel reactions to address both challenges. Herein, we design asymmetrical bipolar membranes assembled into a zero-gap CO2 electrolyzer fed with pure water, solving both challenges. By investigating and optimizing the anion-exchange-layer thickness, cathode differential pressure, and cell temperature, the forward-bias BPM CO2 electrolyzer achieves CO faradic efficiency over 80% with partial current density over 200 mA cm-2 at less than 3.0 V with negligible CO2 crossover. In addition, this electrolyzer achieves 0.61 and 2.1 mV h-1 decay rate at 150 and 300 mA cm-2 for 200h and 100h, respectively. Post-mortem analysis indicates that the deterioration of catalyst/polymer-electrolyte interfaces resulted from catalyst structural change and ionomer degradation at reductive potential shows the decay mechanism. All these results point to future research direction and show a promising pathway to deploy CO2 electrolyzers at-scale for industrial applications.

Cellulose-Based Crosslinked and Reinforced Sulfonated Poly(ether ether ketone) Membranes for Robust Proton Exchange Membranes in Fuel Cells

Proton exchange membrane fuel cells (PEMFCs) are a promising clean energy solution due to their high efficiency and eco-friendly operation. Central to their function is the proton exchange membrane (PEM), typically composed of perfluorosulfonic acid (PFSA) ionomers like Nafion and Aquivion. However, challenges such as cost, gas crossover, and limited temperature range persist. To address these, researchers explore hydrocarbon (HC)-based polymers like sulfonated poly(ether ether ketone) (SPEEK), prized for cost-effectiveness and stability. However, HC-based polymers suffer from issues like unstable mechanical behavior and reduced proton conductivity under low humidity, necessitating further development for practical application.In this study, we propose two approaches to overcome these drawbacks of HC-based PEMs. Firstly, we prepare crosslinked SPEEK membranes with cellulose acetate to enhance proton conduction under low RH conditions and stabilize membrane properties. The crosslinked structure of SPEEK/cellulose membranes is investigated using small-angle X-ray scattering, atomic force microscopy, and transmission electron microscopy. Additionally, we incorporate cellulose-based nanofibers obtained by electrospinning as a reinforcing substrate, enhancing the interaction between the SPEEK matrix and cellulose nanofiber filler. This results in a dense membrane without voids, effectively preventing gas crossover and improving membrane robustness. These investigations using cellulose-containing SPEEK membranes lead to enhanced power density and durable operation of fuel cells, particularly at low RH conditions.

Concurrent Regulation of Surface Topography and Interfacial Physicochemistry via Trace Chelation Acid Additives toward Durable Zn Anodes

AbstractElectrolyte additive engineering is a feasible protocol in improving Zn anode stability. Typical additive designs center on the regulation of Zn deposition; nevertheless, versatile additives are urgently requested to comprehensively manage the surface landscape, interface physicochemistry, and by‐product elimination. Here, a straightforward strategy is presented to meet such needs employing an environmentally‐friendly chelator, hydroxyethyl‐ethylenediaminetriacetate acid (HEDTA), as an additive for ZnSO4 electrolyte. Throughout theoretical computations and experimental investigations, it is demonstrated that protons released from the gradual ionization of HEDTA during rest periods aid in the mild engraving of the Zn surface. Both the amino and carboxyl groups of HEDTA⁻ can be protonated, which effectively buffers the interfacial pH value in the entire battery lifespan and eliminates the formation of by‐products. The HEDTA− anions can also adsorb onto the Zn surface, helping facilitate Zn2⁺ mass transfer and accelerate the desolvation process. Benefiting from the synchronous modulation of surface topography and interfacial physicochemistry, the assembled half cells affording HEDTA additive maintain a durable operation of up to 8821 cycles at 5.0 mA cm−2/1.0 mAh cm−2. Additionally, symmetric cells manifest stable cycling for over 4600 h at 0.5 mA cm−2/0.25 mAh cm−2.

Synchronous Modulation of H-bond Interaction and Steric Hindrance via Bio-molecular Additive Screening in Zn Batteries.

In addressing challenges such as side reaction and dendrite formation, electrolyte modification with bio-molecule sugar species has emerged as a promising avenue for Zn anode stabilization. Nevertheless, considering the structural variability of sugar, a comprehensive screening strategy is meaningful yet remains elusive. Herein, we report the usage of sugar additives as a representative of bio-molecules to develop a screening descriptor based on the modulation of the hydrogen bond component and electron transfer kinetics. It is found that xylo-oligosaccharide (Xos) with the highest H-bond acceptor ratio enables efficient water binding, affording stable Zn/electrolyte interphase to alleviate hydrogen evolution. Meanwhile, sluggish reduction originated from the steric hindrance of Xos contributes to optimized Zn deposition. With such a selected additive in hand, the Zn||ZnVO full cells demonstrate durable operation. This study is anticipated to provide a rational guidance in sugar additive selection for aqueous Zn batteries.

Novel Catalyst Formulations for Enhanced Fuel Cell Efficiency

The quest for enhanced fuel cell efficiency is pivotal in advancing sustainable energy solutions. This paper investigates novel catalyst formulations aimed at improving the performance and longevity of fuel cells. Traditional catalysts, primarily based on precious metals such as platinum, present challenges related to cost and resource availability. In response, this study explores non-precious metal catalysts (NPMCs), composite materials, and nanostructured catalysts, which have shown promising results in recent research. Through rigorous experimental methods, including synthesis and characterization techniques, we evaluate the catalytic activity and efficiency of these novel formulations. The findings demonstrate significant improvements in power output and operational durability compared to conventional catalysts. Mechanistic insights into the reaction dynamics reveal how these new materials enhance performance metrics such as current density and voltage output. An economic analysis highlights the potential for scalability and cost-effectiveness of these innovative catalysts in commercial applications. This research underscores the critical role of catalyst design in optimizing fuel cell technology and sets the stage for future explorations aimed at overcoming existing limitations in the field. By leveraging advanced materials and formulations, we aim to contribute to the development of next-generation fuel cells with enhanced efficiency and practicality.

An active and durable ammonia cracking layer for direct ammonia protonic ceramic fuel cells

Ammonia protonic ceramic fuel cells (NH3-PCFCs) are highly appealing energy conversion technologies due to their high efficiency, environmental responsibility, and benign safety features. Nonetheless, progress in NH3-PCFCs is notably impeded by the restricted performance and insufficient lifespan of standard Ni-cermet anodes for ammonia cracking, especially at 550 °C or below. Herein, we report an efficient ammonia cracking layer with a formula of xCo3O4/100-xBaZr0.8Y0.2O3-δ (Co/BZY) (x=10, 20, 30), which is deposited onto the Ni-BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb) anode to significantly enhance the NH3 decomposition catalytic activity, thereby improving the performance and durability of NH3-PCFCs at low temperatures. The cells with the addition of a 20Co/80BZY anode catalytic layer (ACL) exhibit low area-specific resistance (ASR) and promising operational longevity under NH3 conditions. At 550°C, the NH3-PCFCs with a 20Co/80BZY ACL exhibit a high peak power density of 0.626 W cm−2 and promising operation durability. This study provides important guidance for constructing high-performance and durable NH3-PCFCs.

COFs functionalized self-cleaning loose nanofiltration membranes for efficient dye/salt separation

In spite of the fact that loose nanofiltration membrane (LNFM) technology has certified inspiring prospects in the remediation of dyestuff-comprising wastewater, omnipresent membrane fouling deteriorates its separation competence and hinders its practical application. Herein, a neoteric LNFM with finely tuned anti-fouling and self-cleaning properties was manufactured via the reformative phase inversion procedure integrated with the correctional interfacial polymerization process. By altering the casting solution (i.e., adding nano additives) and coagulation bath (i.e., applying melamine aqueous solution rather than pure water) recipes, the porphyrin-based covalent organic framework (COF-366) and melamine monomers were introduced into the polymeric matrix ingeniously in one step, participating the subsequent interfacial polymerization reaction straightly. The COF-366 with photocatalytic degradation performance and hydrophilicity bestows the resultant LNFM with superior decomposing capacity for organic micro-pollutants under visible light irradiation and better operation durability. Moreover, this substrate-confined amine diffusion combined with the high polarity of melamine enables the formation of a thinner nanofilm for easy mass transport. The best-performing LNFM invented in this work exhibited a high water permeance up to 65 L m−2 h−1 bar−1, excellent dye retention (95.7% against methyl blue), and salt/dye discrimination (27.1 for methyl blue and Na2SO4 selectivity) abilities. Eventually, the membrane could recover to original separation efficacy after the cyclic degradation testing. Overall, this work demonstrates an extensive perspective to pioneer an advanced self-cleaning membrane for dye/salt fractionation.

Supersaturated Doping-Induced Maximized Metal-Support Interaction for Highly Active and Durable Oxygen Evolution.

Metal-support interaction (MSI) is pivotal and ubiquitously used in the development of next-generation catalysts, offering a pathway to enhance both catalytic activity and stability. However, owing to the lattice mismatch and poor solubility, traditional catalysts often exhibit a metal-on-support heterogeneous structure with limited interfaces and interaction and, consequently, a compromised enhancement of properties. Herein, we report a universal and tunable method for supersaturated doping of transition-metal carbides via strongly nonequilibrium carbothermal shock synthesis, characterized by rapid heating and swift quenching. Our results enable ∼20 at. % Ni2FeCo doping in Mo2C, significantly surpassing the thermodynamic equilibrium limit of <3 at. %. The supersaturation ensures more catalytically active NiFeCo doping and sufficient interaction with Mo2C, resulting in the maximized MSI (Max-MSI) effect. The Max-MSI enables outstanding activity and particularly stability in alkaline oxygen evolution reaction, showing an overpotential of 284 mV at 100 mA cm-2 and stable for 700 h, while individual Ni2FeCo and Mo2C only last less than 70 and 10 h (completely dissolved), respectively. In particular, the SD-Mo2C catalyst also exhibits excellent durability at 100 mA cm-2 for up to 400 h in 7 M KOH. Such a significantly improved stability is attributed to the supersaturated doping that led to each Mo atom strongly binding with adjacent heteroatoms, thus elevating the dissolution potential and corrosion resistance of Mo2C at a high current density. Additionally, the highly dispersed NiFeCo also facilitates the formation of dense oxyhydroxide coating during reconstruction, further protecting the integrated catalysts for durable operation. Furthermore, the synthesis has been successfully scaled up to fabricate large (16 cm2) electrodes and is adaptable to nickel foam substrates, indicating promising industrial applications. Our strategy allows the general and versatile production of various highly doped transition-metal carbides, such as Ni2FeCo-doped TiC, NbC, and W2C, thus unlocking the potential of maximized or adjustable MSI for diverse catalytic applications.

Calculation of Maximum Permissible Load of Underground Power Cables–Numerical Approach for Systems with Stabilized Backfill

The maximum permissible load of underground power cables (known in U.S. engineering as “ampacity”) is a function of many parameters, in particular, the thermal resistivity of the native soil. If this resistivity is relatively high, thermal/stabilized backfill is applied, i.e., another material is placed around the cables, providing favourable conditions for heat transfer to the environment. It has a positive impact on the reliability of the power supply and favours the operational durability of the cables. In design practice, however, there is a difficult task—correct determination of the ampacity of the cable line depending on the thermal parameters and the geometry of the backfill. Therefore, this article presents the results of a numerical analysis to determine the ampacity of cable lines in which stabilized backfill is used. A new mathematical relationship is proposed that allows the correction of the ampacity of cable lines depending on their cross-section as well as the thermal and geometric parameters of the cable surroundings.

Application of Machine Learning Methods to Analyze the Dependence of Vibration Acceleration Signals on the Tightening Forces of Bolted Connections

The article is devoted to the application of machine learning methods for the analysis of vibration acceleration signals in bolted joints that occur under impact. The relevance of the work is due to the need to ensure the reliability and operability of bolted joints under loads. One of the promising areas of non-destructive testing is the analysis of the characteristics of vibration acceleration signals that change with changes in the state of structures, for example, with an increase in the tightening torque. This allows for the timely detection of possible defects and the prevention of emergency situations, ensuring the safety and durability of structures. The vibration acceleration signals under impact action on a bolted joint were analyzed. After calculating the signal characteristics, data sets were formed, including the values of tightening torques and the corresponding calculated signal characteristics, a search for a correlation between the tightening torque of bolted joints and the obtained set of vibration signal parameters was carried out. The frequency spectrum of signals, the Higuchi fractal dimension, detrended fluctuations, spectral power density and position of signal peaks were calculated. Machine learning models such as decision trees, the nearest neighbor method, the k-means method and neural networks were used for the analysis. For these methods, an optimal set of parameters correlating with the tightening torque was searched for. The main results show that machine learning methods are effective in classifying signals and finding correlations with stress state parameters. They allow us to detect the relationship between a set of signal characteristics and tightening torque, which opens up opportunities for more accurate and reliable monitoring of the condition of bolted connections. This should help to increase their operational reliability and durability, as well as reduce the likelihood of failures and accidents. The use of such methods can improve the quality of monitoring and diagnostics of bolted connections.

A Direct Current Self-Sustained Moisture-Electric Generator with 1D/2D Hierarchical Nanostructure for Continuous Operation of Off-Grid Electronics.

Ubiquitous moisture is a colossal reservoir of clean energy, and the emergence of moisture-electric generators (MEGs) is expected to provide direct power support for off-grid electronic devices anytime and anywhere. However, most MEGs rely on auxiliary energy storage devices and rectifier circuits to drive small electronic devices, which hinder scalability and widespread deployment, and the development of direct current (DC) MEGs with high power output that can directly drive off-grid electronic devices is highly promising but challenging. Herein, a self-sustained moisture-electric generator (SMEG) with a hierarchical nanostructure based on one-dimensional (1D) negatively charged nanofibers and two-dimensional (2D) conductive nanosheets was demonstrated to generate continuous DC electricity from atmospheric humidity. Sulfation of bacterial cellulose nanofibers lowers the surface potential and increases the surface charge energy, and reduced graphene oxide (rGO) provides a conduction pathway for electrons. The hierarchical nanostructures constructed by the combination of 1D nanofibers and 2D nanosheets endow the SMEG with self-sustained moisture gradients and structural anisotropy, which force the generation of a pseudocurrent. This combination also constructs microcapacitors that further enhance the moisture-electric power output. The SMEG can generate a continuous voltage in excess of 0.54 V for over 2160 h, with a power density of about 822 μW cm-3, demonstrating excellent operational durability. This research provides a feasible solution for the development of sustainable, versatile, and efficient power supplies for off-grid self-powered devices.

A multifunctional biomass-based solar interface evaporator with feather-like structure for efficient selective transport, antibacterial properties, salt resistance, and oil-fouling prevention

Solar interface evaporation technology has gained prominence as an efficient, low-cost, and CO2-neutral method for water purification. However, the development of interface evaporators with high evaporation efficiency, durability, and environmentally friendly, cost-effective materials remains a significant challenge. In this study, we fabricated a novel solar-powered hydrogel membrane using sodium alginate (SA), reduced graphene oxide (RGO), and vegetable-tanned collagen fibers (CF). Utilizing a dual-structural engineering design strategy, which incorporates surface patterning and microfiber channel construction, the resulting sodium alginate/collagen fibers/reduced graphene oxide (CF/SA/RGO) composite membranes exhibited remarkable selective mass transport efficiency. The inclusion of vegetable-tanned collagen fibers notably enhanced the flow rate of free water within the CF/SA/RGO membranes. Moreover, the reduction in water evaporation enthalpy increased with successive GO reduction cycles, thereby further boosting the evaporation rate. The CF/SA/RGO membranes demonstrated an outstanding evaporation efficiency of 2.88 kg m−2 h−1, ion rejection rates of 98 % for K+, Ca2+, Na+, and Mg2+, and a dye removal efficiency of 99.52 % for RhB, MB, MO, and CR. Additionally, these membranes exhibited excellent underwater oleophobicity, antibacterial properties, and salt resistance. This study offers a novel approach to the design and fabrication of solar interface evaporators, presenting an advancement in achieving high solar energy conversion efficiency and superior operational durability.

INNOVATIVE APPROACH TO ENSURING THE QUALITY OF GAS TURBINE ENGINE PARTS PRODUCED BY SELECTIVE LASER SINTERING FOR UAV

The research objects are gas turbine engines parts, manufactured using an innovative method of additive manufacturing – selective laser sintering. The main problem solved in this work is the low quality of the surface layer and the residual porosity of the parts obtained by this method, which significantly limits their operational characteristics and durability. As a result of the experimental studies, rational operating parameters of diamond smoothing were established. This allowed to significantly improve the surface quality and increase the operational characteristics of parts made of heat-resistant alloys INCONEL 718 and an intermetallic alloy based on titanium aluminide OX45-3ODS. The effectiveness of diamond smoothing is explained by local plastic deformation and compaction of the surface layer of parts under the influence of high contact pressures and temperatures. This leads to a significant reduction in surface roughness, an increase in the surface hardness due to strain hardening and a significant reduction in the size and number of residual pores. A characteristic feature of the obtained results is the ability to control the quality parameters of the surface layer by varying the diamond smoothing operating parameters – smoothing force, feed, radius, and geometry of the smoother's working part. The established regularities of the smoothing operating parameters have an impact on the quality characteristics of the surface. This information can be utilized in the development of highly efficient technological processes for the production and restoration of gas turbine engines, critical components of unmanned aerial vehicles, obtained through selective laser sintering. Implementing the elaborated technological recommendations will permit broadening the range of goods produced by additive manufacturing and enhancing their capacity and dependability during operation under conditions of cyclical loads and extreme temperatures.

Aviation aspects of engine oil conveying copper tiny particles embedded in a rotating disk with a binary chemical reaction

Nanofluids have significant industrial applications and motivating heat transfer characteristics for various factors that contribute to the movement of nanofluids are essential significance. The aim of the present study focused on importance of heat transfer analysis on engine oil conveying copper nano particles embedded in a porous rotating disk with potential application in aerospace technology. In this model we considered magnetohydrodynamics, non-linear thermal radiation, thermophoresis and Brownian motion. The present investigation utilized copper nanoparticle and engine oil as a base fluid. The mathematical flow equations are transformed into ordinary differential equations (ODEs) by employing suitable self-similarity variables. The resultant ordinary differential equations are solved numerically by using the Midrich technique in the Maple software. The results are calculated to measure the impact of active parameters on velocity, temperature, concentration equations are presented graphically and in tabular form. Higher values of the magnetic field parameter the velocity profile decreased while the opposite tendency we noticed on energy profile. When increasing the radiation parameter values the energy profile increased. In both cases when increasing the magnetic field and radiation parameter values the Nusselt number profile increased. The research has important implications in a number of real-world situations. In particularly, the advancement of aircraft technology has presented manufacturers with new criteria and problems for the functioning of their devices. It is essential that, in order to guarantee the secure operation of aerospace machinery, the failure mechanisms be identified and the operational durability of critical structural components be improved as quickly as possible.

Supramolecular Association of a Block Copolymer via Strong Hydrogen Bonding to Form Self-Healable Ionogels.

The drive to enhance the operational durability and reliability of stretchable and wearable electronic and electrochemical devices has led to the exploration of self-healing materials that can recover from both physical and functional failures. In the present study, we fabricated a self-healable solid polymer electrolyte, referred to as an ionogel, using reversible hydrogen bonding between the ureidopyrimidone units of a block copolymer (BCP) network swollen in an ionic liquid (IL). The BCP consisted of poly(styrene-b-(methyl acrylate-r-ureidopyrimidone methacrylate)) [poly(S-b-(MA-r-UPyMA)], with the IL-phobic polystyrene forming micellar cores that were interconnected via intercorona hydrogen bonding between the ureidopyrimidone units. By precisely regulating the molecular weight and the composition of the hydrogen-bondable motifs, the mechanical, electrical, and self-healing characteristics of the ionogel were systematically evaluated. The resulting ionogel samples exhibited suitable stretchability, ionic conductivity, and room-temperature self-healability due to reversible hydrogen bonding. To highlight the applicability of the self-healing ionogel as a high-capacitance gate insulator, an electrolyte-gated transistor (EGT) was fabricated using a poly(3-hexylthiophene-2,5-diyl) semiconductor, and the performance of the EGT was fully recovered from a complete cut without any external stimuli.

Capacity configuration of fuel cell hybrid vehicles using enhanced multi-objective particle swarm optimization with competitive mechanism

A well-designed hybrid powertrain is crucial for ensuring the safe, efficient, and durable operation of fuel cell hybrid vehicles. This paper introduces a modular design approach for powertrains, utilizing a Competitive mechanism-based Multi-Objective Particle Swarm Optimization (CMOPSO) algorithm integrated with nested dynamic programming. In this approach, the upper layer employs the CMOPSO algorithm to design the powertrain system, while the lower layer optimizes power coordination for each proposed design. This two-layer optimization framework considers factors such as vehicle economy and durability. Under WLTP conditions, the capacity configuration results are a fuel cell with a rated power of 22 kW, 100 batteries in series, and 7 batteries in parallel. Furthermore, the modular approach outperforms three other algorithms in terms of solution count, diversity, and overall performance metrics. The study also highlights that the vehicle’s power demand characteristics, influenced by different driving cycles, significantly affect capacity configuration results. Sensitivity analysis reveals that both the total operating cost and manufacturing cost of the vehicle are most sensitive to variations in the fuel cell rated power.

NiFe layered-double-hydroxide nanosheet arrays grown in situ on Ni foam for efficient oxygen evolution reaction

Developing efficient and stable oxygen evolution reaction (OER) electrocatalysts under various alkaline conditions is crucial for commercial hydrogen (H₂) production. This study synthesized superhydrophilic NiFe LDH/NF with a nanosheet structure. The strong electronic interactions between the metals modify the electronic structures of Ni and Fe. In-situ Raman spectroscopy reveals numerous high-valent nickel intermediates with high OER activity during the reaction, significantly improving the catalyst's overall performance. At room temperature, the NiFe LDH/NF catalyst exhibits a current density of 50/100 mA cm−2 with only 217/233 mV required in 1 M KOH. Moreover, the catalyst requires only 180 mV under industrial conditions (60 °C, 6 M KOH), 243 mV in alkaline artificial seawater, and 280 mV in alkaline natural seawater to achieve 100 mA cm−2. The catalyst also exhibits long-term operational durability under these conditions, indicating a wide range of potential applications.

High-Efficiency Perovskite Solar Cells with Improved Interfacial Charge Extraction by Bridging Molecules.

The interface between the perovskite layer and electron transporting layer is a critical determinate for the performance and stability of perovskite solar cells (PSCs). The heterogeneity of the interface critically affects the carrier dynamics at the buried interface. To address this, a bridging molecule, (2-aminoethyl)phosphonic acid (AEP), is introduced for the modification of SnO2/perovskite buried interface in n-i-p structure PSCs. The phosphonic acid group strongly bonds to the SnO2 surface, effectively suppressing the surface carrier traps and leakage current, and uniforming the surface potential. Meanwhile, the amino group influences the growth of perovskite film, resulting in higher crystallinity, phase purity, and fewer defects. Furthermore, the bridging molecules facilitate the charge extraction at the interface, as indicated by the femtosecond transient reflection (fs-TR) spectroscopy, leading to champion power conversion efficiency (PCE) of 26.40% (certified 25.98%) for PSCs. Additionally, the strengthened interface enables improved operational durability of ≈1400 h for the unencapsulated PSCs under ISOS-L-1I protocol.

An efficient electrode for reversible oxygen reduction/evolution and ethylene electro-production on protonic ceramic electrochemical cells

Protonic ceramic electrochemical cells (PCECs) have demonstrated great promise for applications in the generation of electricity, and the synthesis of chemicals (for example, ethylene). However, enhancing the electrochemical reactions kinetics and stability of PCECs electrodes is one grand challenge. Here, we present a novel electrode material via a co-doping of cesium (Cs) and niobium (Nb) on PrBaCo2O6−δ with the composition of PrBa0.9Cs0.1Co1.9Nb0.1O6−δ (PBCCN), which naturally decomposes into dual phases of a double-perovskite PBCCN (DP-PBCCN, ∼92.3 wt%) and a single-perovskite Ba0.9Cs0.1Co0.95Nb0.05O3−δ (SP-BCCN, ∼7.7 wt%) under typical powder processing conditions. PBCCN exhibits a low area-specific resistance (ASR) value of 0.107 Ω cm2, an outstanding performance of 2.04 W cm−2 in fuel cell (FC) mode, a current density of −2.84 A cm−2 at 1.3 V in electrolysis cell (EC) mode, and promising reversible operational durability of 53 cycles in ∼212 h at +/− 0.5 A cm−2 and 650 °C. Cs doping generates more oxygen vacancies and accelerates the oxygen exchange kinetics, while Nb doping effectively enhances the stability, as illustrated by the analyses of X-ray photoelectron spectroscopy, and electrical conductivity relaxations. When applied as the positrode for electrochemical non-oxidative dehydrogenation of ethane (C2H6) to ethylene (C2H4) on PCECs, it displays an encouraging C2H6 conversion of 12.75% and a C2H4 selectivity of 98.4% at 1.2 V.