Energy advances最新文献

Iron/iron redox flow batteries (IRFBs) are emerging as a cost-effective alternative to traditional energy storage systems. This study investigates the impact of key operational characteristics, specifically examining how various parameters influence efficiency, stability, and capacity retention. IRFB systems with a volume of 60 mL per tank (20.25 Ah L⁻¹) demonstrated superior capacity utilization, achieving a coulombic efficiency (CE) of up to 95% and an energy efficiency (EE) of 61% over 25 charge/discharge cycles. In contrast, systems with lower capacity utilization in larger electrolyte volumes (5.67 Ah L⁻¹) required more charge/discharge cycles to reach the optimal pH-induced kinetic benefits due to increased proton content. Extended charging durations of up to 8 hours facilitated complete redox conversion, enhancing CE, EE, and voltage efficiency (VE). Brief rest intervals of 5 to 10 minutes supported stable discharge capacity retention and energy efficiency throughout the cycles, while more extended rest periods (e.g., 60 minutes) were associated with diminished performance, possibly due to ionic resistance buildup in the membrane or system imbalances occurring during extended idle times. Charge cutoff voltages between 1.6 and 1.65 V provided an optimal compromise between suppressing side reactions, enhancing capacity retention, and improving efficiency. The constant current–constant voltage (CCCV) method yielded better voltage efficiencies than the constant current (CC) approach when sustaining long-term cycling. Additionally, integrating a recombination cell minimized hydrogen-related losses, enhancing operational stability. These findings provide valuable insights for optimizing the operation of IRFBs in energy storage applications.

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Although lead–acid batteries (LABs) often act as a reference system to environmentally assess existing and emerging storage technologies, no study on the environmental impact of LABs based on primary data from Europe or North America since 2010 could be found. All available studies assessing LABs in Europe rely on literature values from the same few outdated sources, further decreasing reliability. To close this research gap, this work provides a cradle-to-grave life cycle assessment (LCA) of an industrial LAB based on up-to-date primary data provided by the German manufacturer Hoppecke Batterien GmbH. The analysis of potential environmental impacts includes all three phases: production, use and end-of-life (EOL), and analyses potential environmental impacts. The impacts are compared to those of a state-of-the-art lithium iron phosphate (LFP) battery in two different use cases: data centre and home storage system (HSS), in order to highlight the influence of selected use cases on overall results. The results show that the combination of the production and EOL phases of the LAB have a lower environmental impact in the majority of categories than the same two phases of the LFP battery. Including the use phase, the results diverge strongly depending on the use case. From an LCA point of view, while the LAB is potentially the better environmental choice for a data centre (with few charge/discharge cycles), an LFP battery should be used in applications with many charge/discharge cycles, like in an HSS. This indicates that batteries always need to be investigated and compared on an application-specific basis.

To advance the application of renewable biowaste in the renewable energy field, biowaste-derived natural dyes (BND) and biowaste-derived carbon materials (BCM) were individually prepared from five common flowers as raw materials and then facilely integrated into dye-sensitized solar cells (DSSCs). The five extracted BNDs contained anthocyanins with subtly different molecular structures, which were employed as photosensitizers to assemble mono-biowaste based devices with a Pt counter electrode, each of which showed a significantly different conversion efficiency (η), varying from 0.17% to 0.43%. The five pyrolyzed BCMs with an amorphous structure were used as counter electrodes to configure mono-biowaste based devices with the photosensitizer N719, and their η values ranged between 1.08% and 2.13%. The high efficiency of the BCM-based devices was mainly derived from their unique microstructure and the N,S-codoped oxygen-group-containing carbon skeleton of the BCM, which provided more catalytic active sites for reduction of the electrolyte. A dual-biowaste device based on crape myrtle violet flower with an η of 0.181% was finally fabricated by using the corresponding BND and BCM. Moreover, a combination strategy was carried out by introducing the BND extracted from willow leaf into the cell with the pyrolyzed crape myrtle violet flower BCM, resulting in an enhanced η of 0.32%.

In the pursuit of sustainable energy solutions, the development of efficient and environmentally friendly catalysts is crucial. This study focuses on the design and synthesis of Rh@GO electrocatalysts for energy conversion processes, particularly the hydrogen evolution reaction (HER). We introduce three innovative preparation methods: conventional (Rh@GO-SN), solvothermal (Rh@GO-ST), and pyrolysis (Rh@GO-PY). Each method utilizes ultralow amounts of rhodium under distinct conditions of heat and pressure to achieve optimal performance. Rhodium nanostructures are renowned for their exceptional stability, selectivity, and catalytic activity, presenting a promising alternative to traditional platinum-based electrocatalysts. Our results indicate that the synthesized Rh@GO catalysts exhibit significantly enhanced electrocatalytic performance in acidic media for the hydrogen evolution reaction. Key performance metrics include increased current density, reduced overpotential, reduced Tafel slope, and improved stability and durability. Notably, the Rh@GO-PY and Rh@GO-ST catalysts achieve overpotentials of just 31 mV and 38 mV, respectively, at a current density of 10 mA cm⁻². This performance surpasses that of the benchmark Pt/C catalyst, which requires an overpotential of 59 mV to reach the same current density.

Producing sustainable hydrogen through water electrolysis is a promising approach to meet the growing demand for renewable energy storage. Developing affordable and efficient electrocatalysts made from non-precious metals to replace platinum-based catalysts for hydrogen evolution reactions (HERs) continues to be a significant challenge. In the present study, pristine CeO₂ and doped solid solutions Ce_0.95Co_0.05O₂, Ce_0.95Ni_0.05O₂ and Ce_0.95Cu_0.05O₂ were evaluated for the HER, and the electrochemical studies in alkaline medium showed superior HER activity for the doped catalysts, with Ce_0.95Ni_0.05O₂ achieving the lowest overpotential and highest mass activity, comparable to Pt/C. Tafel slopes and EIS measurements suggested a Volmer–Heyrovsky mechanism facilitated by oxygen vacancies and hydrogen spill-over. Stability tests confirmed the durability of Ce_0.95Ni_0.05O₂ under prolonged HER conditions. This study highlights aliovalent doping as a viable strategy for engineering oxygen vacancies and enhancing CeO₂-based catalysts for alkaline water electrolysis.

This work introduces an innovative onboard ammonia cracker module integrated with a 100-kW fuel cell system for light-duty automotive fuel cell vehicles. Utilizing a hollow fibre palladium membrane reactor (HFMR), two configurations are explored: a 3 × 3 simultaneous heating and cracking module and a 4 × 4 intermediate heating and cracking module. The 3 × 3 module, arranged in a serpentine configuration, exhibits superior performance with a calculated required volume of 8.9 liters, a total module area of 1.2 m² and a process thermal efficiency of 93.5%. Each reactor in this module operates isothermally at an exit temperature of 475 °C, achieving ammonia conversion rates that increase from 15.8% in the first reactor (R1) to an impressive 99.99% in the final reactor (R8), facilitated by in situ hydrogen removal through the palladium membrane. The steady-state analysis was carried out using Aspen Plus Software, and validated against experimental data from existing literature. The results demonstrated a high degree of agreement, confirming the model's capability to accurately predict system performance. For transient analysis, Aspen Plus Dynamics was employed to assess the system's responsiveness to varying driving conditions. Utilizing the Hyundai Nexo fuel cell car as a case study, the worldwide harmonised light vehicle test procedure (WLTP) was simulated, to model realistic driving cycles, allowing for a rigorous interrogation of the transient performance of the on-board ammonia cracker. Overall, this research establishes a 3 × 3 simultaneous heating and cracking HFMR module as the optimal configuration for on-board ammonia cracking for hydrogen production in fuel-cell vehicles, highlighting its operational efficiency and potential contribution to sustainable transportation solutions. Future research should focus on optimizing heat management and temperature control within the HFMR module, as well as enhancing transient response characteristics and ammonia safety, to boost system performance and support the wider implementation of hydrogen technologies in the automotive industry.

The rising demand for sustainable solutions to global energy and environmental challenges has accelerated research into advanced functional materials. Conductive polymer composites based on polyaniline (PANI), polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) (PEDOT), and chitosan have emerged as promising candidates due to their tunable properties, environmental compatibility, and multifunctionality. This review highlights the energy and environmental applications of polymer-based mixed metal oxide catalysts. These composites show excellent performances in supercapacitance and water splitting applications, offering both efficient energy storage and hydrogen generation solutions and eco-friendly fuel alternatives. Using adsorption and corrosion inhibition techniques, water pollution and corrosion have also been addressed. Polymers such as PANI, PPy, PEDOT, and chitosan, when integrated with metal oxides, heteroatoms, and carbonaceous materials, enhance the functional properties of the composites. These materials demonstrate significant potential in supercapacitors, water splitting, adsorption, and corrosion resistance. The review provides a comparative analysis of different composites, helping readers understand how the incorporation of various components can improve performances. The review emphasizes sustainable approaches to tackle the current energy and environmental issues through advanced polymer-based catalytic systems.

In this study, cubic Mn₂O₃ was synthesized using different urea concentrations (3, 6, 9, and 12 mM) via a hydrothermal method. During synthesis, an increase in urea content resulted in decreased particle and crystallite sizes and increased lattice parameters, with a concomitant increase in the surface area and number of Mn³⁺ ions in Mn₂O₃ particles. The electrochemical performance of the Mn₂O₃-9 mM urea sample outperformed samples prepared with other urea contents. The Mn₂O₃-9 mM urea sample exhibited high specific capacitance (C_sp) values in 1 M and 3 M KOH electrolytes, achieving 881.3 F g⁻¹ and 1043.2 F g⁻¹, respectively, at a scan rate of 1 mV s⁻¹. Furthermore, at a current density of 1 A g⁻¹, the C_sp of Mn₂O₃ in 1 M KOH was 758.5 F g⁻¹. The values increased to 891.4 F g⁻¹ with energy density and power density of 44.7 W h kg⁻¹ and 398.1 W kg⁻¹, respectively, in 3 M KOH. Owing to the superior electrochemical performance of the Mn₂O₃-9 mM urea sample, its electrochemical performance was assessed in basic KOH and NaOH and neutral Na₂SO₄ and NaNO₃ aqueous electrolytes. Moreover, the Mn₂O₃-9 mM urea sample demonstrated a C_sp of 721.0 and 446.3 F g⁻¹ in 3 M concentrations of NaOH and NaNO₃ electrolytes, respectively. The Mn₂O₃-9 mM urea sample with the highest content of Mn³⁺ ions displayed the highest C_sp in KOH electrolytes compared with the others owing to the smaller hydration radii of K⁺ and high ionic diffusivity and conductivity of OH⁻ compared with other basic and neutral salts. These results highlight that the synthesis process, electrolyte choice, and concentration of electrolytes significantly influence the electrochemical properties of Mn₂O₃ battery-type, emphasizing their critical role in optimizing material performance for supercapacitor applications.

The global challenge of water scarcity, intensified by a growing population, climate change, and increased demand for fresh water, requires immediate investigation of innovative and sustainable technologies. Capacitive deionization (CDI) and capacitive mixing (CapMix) have emerged as promising solutions, leveraging the electric double layer (EDL) formed at the interface of charged surfaces and electrolytic solutions. The initial technique represents a promising approach to water desalination and ionic separation, as CapMix is a reciprocal technique for energy obtention from exchanging solutions with varying salinity. This study focuses on the use of carbon electrodes with polyelectrolyte (PE) coatings for capacitive energy extraction based on Donnan potential (CDP) in CapMix systems. This investigation considers the impact of applied current, volumetric charge densities of the PEs, and geometric parameters, such as electrode separation distance, on the efficiency and scalability of these systems. The findings provide valuable insights for enhancing energy extraction performance and overcoming challenges associated with electrode use in these applications.