Energy technology最新文献

This study investigates the impact of degradation in perovskite-silicon tandem solar cells by means of energy yield (EY) modelling over the entire lifetime. First, we assess the impact on EY of degradation in the individual solar cell parameters of the perovskite top cell. Our analysis reveals that degradation in fill factor, due to a decline in perovskite top cell shunt resistance (RSh), has the most severe impact on the EY, emphasizing the imperative to rectify perovskite imperfections in thin film processing causing RSh decline. Second, we investigate implications of degradation in the perovskite top cell on the EY of current mismatched tandem solar cells. Third, we examine critical thresholds for the “acceptable degradation levels” in the perovskite top cell with regard to degradation in each solar cell parameter, assuming that the total loss in EY must be comparable to the degradation in state-of-the-art silicon. Overall, our study highlights that degradation of the perovskite top cell needs to be assessed with care when extrapolating the impact on the lifetime EY of perovskite-silicon tandem solar cells. The severity of degradation for different degradation mechanisms in a single junction perovskite solar cell cannot be translated one-to-one to tandem devices.

Accurately predicting the remaining useful life (RUL) of lithium-ion batteries is a challenging task, with significant implications for managing battery usage risks and ensuring equipment stability. However, the phenomenon of capacity regeneration and the lack of confidence interval expression result in imprecise predictions. To tackle these challenges, this article proposes a novel method for predicting RUL by optimizing health features (HFs) and integrating multiple models. First, multiple HFs are collected from the charging curves, and the fusion HF is optimized by kernel principal component analysis. To eliminate local fluctuations caused by capacity regeneration effects, the complete ensemble empirical mode decomposition with adaptive noise is employed to decompose the fusion HF. Second, to address the issue of lacking confidence interval expression, a hybrid model is proposed by integrating bidirectional long short-term memory neural network with Gaussian process regression for effectively capturing the lithium-ion battery capacity-declining trend and accurately predicting the RUL. Finally, the proposed model's effectiveness is validated by comparing it with several other models using National Aeronautics and Space Administration and Center for Advanced Life Cycle Engineering datasets. The results indicate that this model achieves a root mean square error of 0.0023 and a mean absolute error of 0.0058, demonstrating significant improvements in predictive accuracy for RUL with high reliability.

Drying and calendering are critical steps in the manufacture of electrodes for lithium-ion battery that affect their mechanical and electrochemical properties. A 2D representative volume element (RVE) model, including active material and carbon binder domain particles of different shapes and sizes, is developed. The evolution of the RVE structure is simulated using the discrete element method, providing insight into changes in velocity, coordination number, porosity, pore size distribution, tortuosity, and stress. Based on this analysis, a three-step drying scheme is proposed in accordance with the experimental drying results. In addition, the calendering process significantly improves the mechanical integrity and electronic conductivity of the electrode. Through simulations and experimental observations of changes in surface morphology and porosity, an optimal compression ratio of about 20% is determined for the electrode.

Low-volume power density remains a significant barrier to the portable application of direct methanol fuel cell (DMFC). Herein, a shared anode flow field (SAFF) structure is introduced in an active DMFC to reduce stack volume and improve discharge performance. The differences in discharge performance between the bi-cell with SAFF and the bi-cell with traditional anode flow field (TAFF), coupled with the effect of operating conditions on performance, are investigated by polarization curve, electrochemical impedance spectra, and voltage versus time curves. The results show that the SAFF structure enhances anode mass transfer, resulting in an improvement in peak power density and voltage stability of the bi-cell compared to the TAFF structure. In addition, the bi-cell with SAFF achieves its highest peak power density at a lower methanol concentration, alleviating the methanol crossover caused by high concentration. The SAFF structure is an attractive choice for DMFC portable applications.

Under the background of vigorously promoting clean heating, the introduction of phase-change energy storage technology into heating systems has become a new hot issue. In this study, a novel KAl(SO₄)₂·12H₂O/expanded graphite (EG) shape-stabilized composite phase-change material (PCM), with a melting temperature of 91.6 °C, latent heat of 245.7 kJ kg⁻¹, and high heat conductivity of 2.07 W m⁻¹ K⁻¹, is prepared to manufacture a PCM-based module for space heating. This phase-change electric heating module is developed, and its heat storage and release characteristics are investigated through experimental and numerical studies. The numerical model is validated by experimental results. In view of the numerical simulation, the structure of the module is optimized and its thermal performance is studied. Based on the optimized module, a peak-valley time-of-use (TOU) electric heating module is finally proposed. It is revealed that the module exhibits good thermal performance and is capable of satisfying the indoor heating demand. The effective heat storage and release duration is 8.12 and 15.34 h, which can perfectly realize the operating mode under the “peak-valley TOU electricity” mechanism. In this study, it is demonstrated that peak–valley electric energy storage heating devices have broad prospects in building space heating and provides reference for future application.

Proton exchange membrane fuel cell (PEMFC) has become a hotspot due to its high efficiency, compact structure, and good dynamic operation efficiency. However, problems such as poor reliability and short lifespan create bottlenecks in its large-scale applications. There has been a large amount of research on fault diagnosis and health management techniques dedicated to addressing the lifespan issues of PEMFC systems. This article provides an in-depth analysis on the fault mechanism of PEMFC and systematically sorts out the types, causes, and impacts of faults. On this basis, the research progress of PEMFC fault diagnosis technology is summarized, and the measurement characterization methods for fuel cell status monitoring and fault detection are summarized. The literatures of model-based and data-driven fault identification methods are summarized and compared. The relevant mitigation measures for PEMFC faults are discussed. Finally, based on the challenges in the current research of fault diagnosis, people mainly conduct research on fault model, online diagnostic technology, and improving diagnostic mechanisms. Overall, this article can provide useful summary and guidance for future research.

Developing affordable and high-performance catalysts for water electrolyzers and fuel cell devices is an emerging field of research aiming for their feasible implementation and thus addressing sustainable global energy demands. Accordingly, several catalytic systems have been developed for anodic oxidation reactions and cathodic reduction reactions. Specifically, more research attention has been focused on viable catalyst synthesis processes including design, choice of precursors, reaction conditions, and regulation steps for achieving desirable properties and performances. Intriguingly, biomass has been demonstrated as a promising precursor for the potential design of different carbon-based catalysts for electrocatalytic oxidation/reduction reactions. In this review, the recent developments in using biomass precursors to derive different nanostructures are systematically discussed. The biomass-derived catalysts especially applied for reduction reactions (hydrogen evolution and oxygen reduction reactions) are summarized, and the impact of various catalysts’ engineering routes (incorporation of metals and nonmetals into the carbon structures) on the resulting structure–performance relationship is critically discussed. Further, this review highlights the performance of various biomass-derived catalysts toward electrocatalytic reduction reactions that unveil the catalyst's intrinsic features such as selectivity, activity, and durability. The summarized results and the critical discussion will facilitate screening of the best biomass precursor, identifying suitable regulation strategies for accomplishing desirable properties, and thus advancing the next-generation catalysts’ developments. Further, the significance, challenges, and perspectives on biomass-derived catalysts for electrocatalysis are comprehensively discussed.

An anode-support microtubular solid oxide fuel cell (MTSOFC) using an intermediate ring-shaped electrode collector is simulated using COMSOL Multiphysics software to investigate current density distribution and mass transfer in both power generation and electrolysis modes. The cell is converted to power generation mode during continuous electrolysis, and the electrochemical performance of MTSOFC is tested to study the effect of electrolysis on the power generation performance. The power density output of the MTSOFC decreases from 250 to 150 mW cm⁻² after only 40 h of continuous electrolysis. The microstructural changes in different regions during operation are observed through posttest analysis conducted on the fuel inlet, electrochemical reaction concentration region, and fuel outlet of the microtubular cell. The local agglomeration of nickel occurs in the concentrated region of the electrochemical reaction, while the coarsening of nickel oxidation mainly takes place at the fuel inlet and outlet.