ACS Applied Energy Materials最新文献

To minimize losses due to recombination in solar cells, the incorporation of a hole transport layer (HTL) has emerged as a promising strategy. However, selecting the appropriate HTL for a given absorber material presents several challenges. This study focuses on modeling and optimization of two solar cell configurations utilizing CuAl_1–xFe_xS₂ [x = 1 (Cell-1) and 0.75 (Cell-2)] as the absorber material and sputtering deposited FeS₂ thin film as the HTL material to enhance their efficiency using the Silvaco ATLAS device simulator. The deposition of FeS₂ thin film by direct current sputtering, followed by annealing in a sulfur environment, is also demonstrated. The sulfurized thin films exhibit a p-type conductivity. Following the incorporation of HTL and the optimization of different parameters, both solar cells exhibit significantly increased hole current toward back contact, indicating less recombination and efficient charge extraction. The experimental efficiencies of Cell-1 (3.58%) and Cell-2 (5.29%) improved to 7.28% and 9.80% in the simulation with an optimized structure, showing enhancements of 103% and 85%, respectively.

Sodium-ion batteries (SIBs) are game-changing in large-scale energy storage technology compared to lithium-ion batteries (LIBs) due to abundant reserves, safety, and cost-effectiveness. However, serious issues in Mn-based P2-type cathodes, such as phase transitions, the Jahn–Teller effect, and Mn dissolution, hinder the success of SIBs. Herein, we report that altering the manganese oxide precursors in the solid-state synthesis of P2-type Na_0.65Ni_0.25Mn_0.75O₂ (NNMO) leads to structural variations and improvements in electrochemical properties. X-ray diffraction with refined data confirms that all samples are in the P2-type phase, with changes in lattice parameters and cell volume. Raman spectroscopy and electron spin resonance verify the presence of oxygen defects in the P2-type NNMO materials. Furthermore, X-ray photoelectron spectroscopy analysis of the Mn₂O₃ precursor-used Na_0.65Ni_0.25Mn_0.75O₂ (NNMO-2) sample reveals slightly higher Mn⁴⁺ and lower Mn³⁺ mixed valence states compared to other samples. The potential profile and dQ/dV plot of NNMO-2 exhibit solid-solution behavior, delivering an initial discharge capacity of 151 mAh/g and 152 mAh/g at 0.1 C. The sample demonstrates excellent capacity retention of 85.34% and 77.28% after 100 cycles at a 1 C rate, with a Coulombic efficiency exceeding 98% in both tested voltage ranges (1.5–4.0 V and 2.0–4.3 V), attributed to Mn charge compensation. Moreover, the Na-ion diffusion coefficient, estimated to be around 10^–10 cm²/s using the galvanostatic intermittent titration technique and the reduced charge transfer resistance, confirmed by impedance measurements, further highlight the electrochemical benefits of the NNMO-2 sample. Overall, the results suggest that the Mn₂O₃ precursor can be a suitable raw material for solid-state reactions synthesizing P2-type Na_0.65Ni_0.25Mn_0.75O₂ cathode materials for sodium-ion battery applications.

This study investigates the imaging and structural analysis of gas diffusion layers manufactured by electrospinning (eGDL). Various three-dimensional (3D) acquisition techniques, including focused ion beam scanning electron microscopy (FIB-SEM) and X-ray computed nanotomography (XCT), are employed, along with stochastic numerical generation of structures. Results show close agreement between numerical and real structures, making stochastic numerical methods of structure generation viable for eGDL studies. A dozen electrospun structures have been designed with variable microstructures and imaged using synchrotron X-ray nanotomography at the european synchrotron radiation facility (ESRF) synchrotron, providing unprecedented insights into the intricate morphology of eGDLs. Relationships between porosity, fiber size, and pore size are established, revealing counterintuitive trends: while pore size increases with fiber size, porosity peaks at around 0.95 for fibers of 500 nm. An optimal structure is found to exhibit maximal diffusion and permeability properties, improving by up to 40% for the diffusion and by an order of magnitude for the permeability. Cell testing confirms the superior performance of optimized structures in low humidity conditions (50% RH), nearing that of the tested commercial GDL. eGDLs offer competitive advantages with simpler fabrication processes compared to commercial GDLs. However, in high-humidity conditions, the tested commercial GDL outperforms despite the eGDL optimization.

The synthesis and application of coordination compounds are a focal point in coordination chemistry. Pyridine, as a type of nitrogen-containing heterocyclic ligand, exhibits a rich coordination chemistry and plays a significant role in incorporating various metal ions into functional materials. Therefore, enhancing the coordination ability of pyridine N lone pair electrons with metal ions, improving the stability of the coordination compounds, and broadening the research on the synthesis and application of pyridine-based coordination compounds are of great importance. Herein, we report a research strategy based on electronic effects─introducing strong electron-donating groups at the para position of pyridine N to enhance the coordination ability of the lone pair electrons with metal ions, thereby increasing the strength of the coordination bonds and the stability of the coordination compounds. Through precise chemical synthesis, coordination compounds of 4-dimethylaminopyridine (DMAP) with Ag⁺, Cr³⁺, Cu²⁺, Co²⁺, In³⁺, and Ce³⁺ were successfully prepared. Notably, the Ag-DMAP compound exhibits a low HOMO–LUMO energy gap (2.31 eV) and a Tafel slope of −972 mV dec^–1. Furthermore, the DMAP-based metal coordination compounds all demonstrate preferable photoelectric applications.

A highly concentrated potassium pyrophosphate (K₄P₂O₇) aqueous solution exhibits not only an increase in the potential window similar to conventional water-in-salt electrolytes (WISEs) but also unique properties such as high stability at low temperatures and superionic conductivity. For exploring active materials for the highly concentrated K₄P₂O₇ aqueous electrolyte, we first conducted discharge–charge evaluations using γ-type K_xNiO₂·nH₂O, which has a large interlayer distance that could potentially allow the migration of potassium ions (K⁺). However, our study reveals that the discharge–charge reaction in the electrode material could be progressed by the insertion and extraction of protons as charge-compensating ions rather than K⁺, even though the electrolyte is near-neutral (weakly basic). Based on the result, our study also reveals that layered nickel hydroxide materials such as Ni(OH)₂ and metal hydride (MH) of hydrogen storage alloys, which are the electrode materials of a nickel–metal hydride (NiMH) battery, are active in the K₄P₂O₇ aqueous electrolyte. In contrast to hydroxide-based alkaline solutions, this is the first NiMH cell that functions in near-neutral electrolytes (pH 11), which is advantageous in terms of material corrosion and safety. Although protons act as charge-compensating ions, it seems that K⁺ also acts as a carrier ion supporting proton transfer in the near-neutral K₄P₂O₇ aqueous electrolyte owing to its high transference number, especially at high currents. Our findings have the potential to pave the way for developing electrolytes not only for WISEs but also for proton batteries.

Sodium-ion batteries are gaining attention for their lower cost, higher earth abundance, improved safety, and wider distribution compared to lithium-ion batteries. Among the promising cathode materials, the vanadium-free sodium superionic conductor (NASICON) stands out due to its sustainability, low cost, and excellent rate performance. Notably, Na₃MnTi(PO₄)₃ WC offers the potential for three-electron reactions, increasing its capacity. However, its application is limited by poor ionic conductivity and the lack of scalable, low-cost synthesis strategies. Additionally, the degradation mechanisms over long-term cycling remain unclear, with no effective solutions to improve durability. Here we report a facile synthesis method using reductive carbon, which enhances both the capacity and long-term cycling performance. The introduced carbon reduces particle size, improving sodium ion diffusion pathways and electronic conductivity. As a result, the assembled coin cell achieved a specific capacity of 123 mAh g^–1 at 0.1C, with 92% capacity retention at 2C after 1000 cycles. Analysis revealed that carbon prevents manganese oxidation during synthesis, supporting better sodium ion intercalation and deintercalation kinetics. Additionally, the carbon layer helps prevent the leaching of transition metal ions, ensuring a stable cycling performance. This approach provides an efficient strategy to improve the electrochemical performance and durability of Na₃MnTi(PO₄)₃ WC, advancing its use in sodium-ion batteries.

Ethylene is one of the most widely used components in the chemical industry, but the main manufacturing route involves significant energy consumption and generates substantial CO₂ emissions. Proton ceramic electrochemical reactors (PCERs) offer great potential for process intensification and could play a key role in ethane dehydrogenation (EDH) by extracting H₂ produced during the reaction. This process not only improves the reaction yield but also enables the production of a pure separated H₂ stream. However, nonoxidative EDH reaction conditions lead to coke formation, which is further increased by H₂ extraction, resulting in a decrease in system performance. Therefore, to successfully integrate PCER technology into ethylene production, it is crucial to develop stable redox electrodes that can withstand both nonoxidative H₂ extraction and coke oxidation conditions. In this work, we study different composite electrodes based on the perovskite La_0.8Sr_0.2Cr_0.5Mn_0.5O_3−δ (LSCM) combined with the proton conductor BaCe_0.55Zr_0.3Y_0.15O_3−δ (BCZY₅₅₁₅). The electrochemical performance was characterized by using electrochemical impedance spectroscopy under both oxidizing and reducing conditions. The data analysis indicates that surface processes limit electrode operation. The infiltration of Pt and CeO₂ nanoparticles in the electrode enhanced the electrochemical performance, improving it by a factor of 10 at 700 °C. The optimal electrochemical performance was observed for the LSCMF/BCZY₅₅₁₅ (La_0.8Sr_0.2Cr_0.5Mn_0.25Fe_0.25O_3−δ/BaCe_0.55Zr_0.3Y_0.15O_3−δ) electrode infiltrated with Pt/CeO₂, demonstrating promising properties as a redox-stable electrode. Finally, we evaluated the nonoxidative EDH reaction using a PCER based on a Ni–SrZr_0.5Ce_0.4Y_0.1O_2.95 (SZCY541) supported cell with a LSCMF/BCZY₅₅₁₅ anode infiltrated with Pt/CeO₂ and a thin BaZr_0.44Ce_0.36Y_0.2O_3−δ electrolyte.

The development of highly efficient photoanodes is crucial for enhancing the energy conversion efficiency in photoelectrochemical water splitting. Herein, we report an innovative approach to fabricating an Au/BiVO₄/WO₃ ternary junction that leverages the unique benefits of WO₃ for efficient electron transport, BiVO₄ for broadband light absorption, and Au nanoparticles (NPs) for surface plasmon effects. The BiVO₄/WO₃ binary junction was constructed by depositing a BiVO₄ layer onto the surface of the WO₃ nanobricks via consecutive drop casting. Au NPs were subsequently integrated into the BiVO₄/WO₃ structure through electrochromic activation of WO₃. The optimal BiVO₄ loading for the highest-performing BiVO₄/WO₃ heterostructure and the light intensity dependence of the photocurrent efficiency were also determined. Flat-band potential measurements confirmed an appropriate band alignment that facilitates electron transfer from BiVO₄ to WO₃, while work function measurements corroborated the formation of a Schottky barrier between the incorporated Au NPs and BiVO₄/WO₃, improving charge separation. The best-performing Au NP-sensitized BiVO₄/WO₃ photoanode thin films exhibited a photocurrent density of 0.578 mA cm^–2 at 1.23 V vs RHE under AM 1.5G (1 sun) illumination and a maximum applied-bias photoconversion efficiency of 0.036% at 1.09 V vs RHE, representing an enhancement factor of 12 and 2.3 compared to those of pristine BiVO₄ and WO₃ photoanodes, respectively. This study presents a promising and scalable route for fabricating noble metal-sensitized, metal oxide-based nanocomposite photoanodes for solar water splitting.

Small-sized CsPbI₃ quantum dots (QDs) are highly promising for fabricating stable pure-red (630–640 nm) light-emitting diodes (LEDs), effectively avoiding the halide segregation issues commonly observed in mixed-halide perovskite nanocrystals. However, synthesizing stable, small-sized colloidal CsPbI₃ QDs for high-efficiency LED fabrication remains a significant challenge. In this study, a combined strategy of metal ion doping and ligand engineering was employed to synthesize small colloidal CsPbI₃ QDs (approximately 5 nm) with pure red emission (630 nm) using the hot injection method. Combined with post-treatment using n-butylammonium iodide (TBAI), the Zn²⁺-doped CsPbI₃ QDs achieved a photoluminescence quantum yield (PLQY) as high as 94% and demonstrated excellent stability, retaining 92% of their initial PL intensity after 80 days of exposure in air. The LED devices fabricated with the obtained CsPbI₃ QDs as emitter layers demonstrated bright electroluminescence at 636 nm with the highest external quantum efficiency value of 10.3%. Furthermore, Zn²⁺-doped CsPbI₃ QDs LEDs also exhibited good operational stability with a half-life of 77 min.

All-inorganic perovskite quantum dots (PQDs) have sparked a research boom due to their superior optoelectronic properties. However, current synthesis methods are complex and unsuitable for large-scale continuous production because the rapid reaction kinetics of quantum dots (QDs) make regulating their nucleation and growth challenging. Herein, we developed an efficient microfluidic technology using temperature-assisted base-acid ligand modulation to control the nucleation and growth of PQDs for mass fabrication. The obtained CsPbBr₃ PQDs exhibited high dispersion, uniform sizes, and high photoluminescence quantum yield. Moreover, CsPbBr₃ maintained high photoluminescence intensity for 120 min under UV irradiation, demonstrating good stability. These results provide a promising pathway for large-scale PQD production, which is crucial for advanced optoelectronic applications. Compared with the traditional hot injection (HI) and ligand-assisted reprecipitation (LARP) methods, microfluidic technology significantly saves materials and reagents. The microfluidic technology is also helpful for precisely controlling the nucleation process of QD growth.