ACS Applied Energy Materials最新文献

This study presents two new structures of compounds in the Mg–Y–Ni ternary system, MgYNi with a hexagonal ZrNiAl-type structure and Mg_2–xY_xNi with an orthorhombic Mg₂Cu-type structure, both obtained through a high-pressure synthesis technique at GPa-order pressures. MgYNi with the ZrNiAl-type structure underwent a phase transformation into an orthorhombic MoAlB-type structure at 622 K in an Ar atmosphere via an exothermic reaction. Additionally, MgYNi with the ZrNiAl-type structure exhibited hydrogen absorption at 313 K under 5 MPa H₂ and formed MgYNiH_∼4.7 with the ZrNiAl-type structure, resulting in volume expansion of approximately 24.7%. Mg_2–xY_xNi with the Mg₂Cu-type structure was obtained at 0.12 < x < 0.26. Hydrogenation of Mg_2–xY_xNi with the Mg₂Cu-type structure at 598 K and 8 MPa resulted in decomposition into monoclinic and orthorhombic phases of Mg₂NiH₄ along with YH₃ and Ni. Hydrogen desorption temperature of the hydrogenated Mg_2–xY_xNi was approximately 50 K lower than that of Mg₂Ni after hydrogenation.

The electrochemical CO₂ reduction reaction (CO₂RR) has attracted attention as a promising strategy for converting CO₂ into value-added products. Gas diffusion electrodes (GDEs) loaded with metallic nanoparticles as electrocatalysts are expected to efficiently reduce CO₂ due to the high specific surface area of such particles and the superior mass transport characteristics of GDEs. In the present study, GDEs loaded with homogeneous layers of gold (Au) nanoparticles were fabricated using a radio frequency sputtering technique that had a low deposition rate. This allowed for precise control of the catalyst loading. The Au-loaded GDEs exhibited a significantly higher CO production efficiency compared with the electrodes fabricated by conventional deposition methods using dispersed Au nanoparticles. Additionally, a Au-loaded GDE having a catalytic layer thickness of 10 nm demonstrated a mass-based CO production activity of 1882 A g^–1 at −0.85 V. This is the highest value yet reported. This work confirmed that the uniform deposition of metallic nanoparticles provides enhanced catalyst utilization. The results of this research provide important insights into the design of efficient CO₂RR electrodes and highlight the potential of radio frequency sputtering to fabricate high-performance CO₂RR electrodes as an approach to realizing carbon-neutral technologies.

Zero-dimensional organic zinc halides have garnered significant attention as efficient and eco-friendly photoluminescent materials. However, its luminance efficiency, which is typically attributed to self-trapped excitons formed within zinc halide tetrahedra, often encounters a serious thermal quenching problem. This issue significantly limits its application in the field of solid-state lighting. Intriguingly, the incorporation of tetra-coordinated Mn²⁺ ions into these organic zinc halides can effectively mitigate unnecessary electron interactions and nonradiative energy transfer between Mn–Mn, achieving significantly improved photoluminescence quantum yield (PLQY) in the alloyed materials. In this work, a series of zero-dimensional Mn²⁺-alloyed 4-benzylpiperidinum zinc chloride hybrids were designed and synthesized by a solvent evaporation method. It is noteworthy that the pure zinc chloride shows a negligible visible emission at 510 nm, whereas (C₁₂H₁₂N)₂Mn_xZn_1–xCl₄ (x = 0.25, 0.5, 0.75, 1) emits visible light ranging from green to yellow at room temperature. Incorporating Mn has led to a remarkable enhancement in PLQY, increasing from a mere 4.02% in the organic zinc halide to an impressive 94.45% in the (C₁₂H₁₂N)₂Mn_0.75Zn_0.25Cl₄. The white LED was successfully fabricated by employing the optimal sample as a single-component yellow phosphor coated on 450 nm chip. The correlated color temperature was determined to be 4770 K with a color rendering index as high as 91. It was also demonstrated with good luminous stability under different working currents. This research provides a straightforward approach for developing eco-friendly, cost-effective, and high-performance single-component yellow phosphors for white LED applications.

We present a structural design for a four-terminal III–V/crystalline silicon (c-Si) multijunction (MJ) device based on optimized bifacial illumination. The proposed configuration consists of a triple-junction top cell incorporating gallium indium phosphide (GaInP), indium gallium arsenide (InGaAs), and germanium (Ge), paired with a tunnel oxide passivating contact (TOPCon) as the bottom cell. The bifacial TOPCon cell effectively enhances the transmission of albedo-reflected light into the c-Si absorber, delivering superior performance compared to conventional heterojunction cells. With an additional rear illumination of 0.3 sun, the bottom cell efficiency increases by 9.61%. Bifacial illumination enhances the overall efficiency of the MJ device by 20.77% compared to the monofacial device. With the power conversion efficiency (PCE) of bifacial GaInP/InGaAs/Ge/TOPCon MJ devices reaching 35.70%, this design demonstrates significant potential for advancing high-efficiency bifacial solar cell technologies.

Incorporation of redox-active centers in metal–organic coordination polymers has gained significant interest due to their tunable electronic properties. To this end, we have electropolymerized a thin film of manganese ions coordinated with a dimercapto thiadiazole metallo-organic polymer (poly-MnDMcT) containing Mn^3+/4+ and S^–2/–1 redox couples. The poly-MnDMcT demonstrated a mixed charge storage mechanism with capacitive and diffusion-controlled contributions coexisting. This metallopolymer symmetric cell setup yielded a specific capacitance of 92.8 F g^–1 at 1 A g^–1 and enhanced cycling stability with retention of 78% over 10,000 cycles @ 4 A g^–1. Correspondingly, the symmetric supercapacitor device produced an energy density of 4 Wh kg^–1 at a power density of 6670 W kg^–1 within a 1.4 V vs Ag/AgCl voltage window. The redox reversibility of manganese ions and ligand disulfide-thiolate units contributes toward enhancement of capacitance and a wider potential window among the class of metallopolymers. Furthermore, the poly-MnDMcT exhibits n-type photoelectrode behavior with repeatable and stable photocurrent responses of 8–10 μA cm^–2 in neutral electrolytes, which opens avenues for photoassisted enhanced charging in energy storage. Moreover, poly-MnDMcT shows enhanced ORR catalytic activity in neutral electrolytes with a current density of −800 μA/cm² at oxygen-saturated conditions. Furthermore, this work enables us to understand and distinguish the current contributions to energy storage and conversion mechanisms when metallo-organic polymers have dual redox sites.

Flexible conducting wires are highly relevant nowadays due to their possible integration into various electronic gadgets, where energy storage devices are also needed. Here a material composed of N-doped holey graphene with aromatic primary amine groups at the edges (N-doped holey graphene amine) takes the dual role of conducting wire and electrode for supercapacitors. A facile ball-milling of graphite with the N-containing milling agent 1-naphthylamine followed by high-temperature treatment led to the formation of N-doped holey graphene as evident from the material characterization using transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, ¹³C NMR spectroscopy, atomic force microscopy and elemental analysis. In addition to pyridinic, pyrolytic, and graphitic N, the NMR spectrum and XPS confirm the presence of -NH₂ attached to aromatic carbon. The graphene inks prepared at different temperatures including room temperature displayed variable conductivity suitable for the required applications; the sample treated at 250 °C was also used as an electrode material for supercapacitors. An areal capacitance of 12.33 mF/cm² at a current density of 0.06 mA/cm² is displayed by the graphene ink supercapacitor device together with an energy density of 1.71 μWh/cm². A power density of 500 μW/cm² at a current density of 1 mA/cm² is displayed, and at 0.5 mA/cm², the device retained 100% of its capacitance after 5000 continuous charge–discharge cycles.

Pure-phase carbides suffer from mismatch in H₂ adsorption–desorption kinetics. Herein, we report on heterostructured CSNi₃C/Fe₃C@C/NFs-600 consisting of Co₃C and Ni₃C nanofibers embedded in a graphitic carbon shell synthesized by the electrospinning-magnesiothermic reduction (MTR) process. The Ni₃C/Fe₃C heterojunction core is encapsulated with a porous carbon shell having a large interfacial area, high conductivity, and more exposed active sites, which resulted in moderate hydrogen adsorption energy (E_Hads), increased desorption kinetics, and intriguingly efficient electron transfer. CSNi₃C/Fe₃C@C/NFs-600 exhibits low overpotentials (HER/OER) of 115/191 mV with a small Tafel slope of 56/53 mV dec^–1 and a stability of over 60 h. The activation energy was calculated for electrolysis using CSNi₃C/Fe₃C@C/NFs-600 at 20.00 kJ/mol. The integrated area/number of active sites of CSNi₃C/Fe₃C@C/NFs-600 (4.60 × 10^–5 AV/5.730 × 10¹⁶) confirmed MOOH* formation. The superaerophobicity was substantiated by fast gas bubble evolution from the catalyst surface. Using CSNi₃C/Fe₃C@C/NFs-600, we have produced H₂ efficiently with a lesser power consumption of 651.3 L_H2 kW h^–1. The bifunctional electrolyzer of CSNi₃C/Fe₃C@C/NFs-600 (1.58 V) released vigorous gas bubbles compared to the benchmark electrolyzer of IrO₂/Pt/C/NF (1.64 V) with great stability in alkaline solution. The synthetic strategy with catalyst properties demonstrated here provides perceptions into the future growth of robust bifunctional catalysts for scalable water splitting.

Z-scheme water splitting was observed for photocatalyst sheets consisting of narrow-band-gap SrTaO₂N (2.1 eV) and La₅Ti₂Cu_0.9Ag_0.1O₇S₅ (1.8 eV) immobilized by filtration of their suspension containing conductive carbon nanotubes. Preloading of carbon nanotubes on SrTaO₂N and refinement of cocatalyst loading allowed the photocatalyst sheet to split water with an apparent quantum yield of 0.13% at 430 nm, which was superior to that reported for the photocatalyst sheet prepared by the particle transfer method using Au as the conductive material. The proposed method offers a facile, low-cost approach for the fabrication of photocatalyst sheets based on long-wavelength visible-light-responsive nonoxides for Z-scheme water splitting.

Perovskite solar cells (PSCs) are acclaimed as remarkable devices for converting light into electricity. The crystallinity of the perovskite layer defines its performance, efficiency, and stability. Defects/trap states may negatively affect photovoltaic device performance. Using additives can enhance the power conversion efficiency (PCE) and the durability of PSCs. The additive approach reduces defects at the perovskite film surface and grain boundaries. In this study, we introduce 1,2,4-triazole (TZL) into a perovskite precursor solution to improve the quality of the perovskite film, larger crystal grains, crystalline structures, PCE, and longevity of carbon-based PSCs. The presence of three nitrogen atoms in TZL strengthens the hydrogen bonding in the perovskite structure, enhancing the material stability. TZL efficiently reduces defects/traps, potentially enhancing charge carrier transportation, and minimizes the nonradiative recombination resulting in enhanced durability, efficiency, and performance of PSCs. Carbon-based PSCs with 5 mg TZL added had an improved PCE of 10.66% when compared to the control MAPbI₃ PSCs (8.32%). Furthermore, 5 mg TZL greatly improves the long-term stability (under the condition of 30 °C and RH = 50% ± 5%) of CPSCs, allowing them to retain 85% of their initial PCE after 500 h of preservation. Our results demonstrate that the TZL additive approach improves perovskite film quality, CPSC performance, and durability.

This paper reports on several mechanisms of carbon aging in a hybrid lithium-ion capacitor operating with 1 mol L^–1 LiPF₆ in an ethylene carbonate/dimethyl carbonate 1:1 vol/vol electrolyte. Carbon electrodes were subjected to a constant polarization protocol (i.e., floating) at various voltages and analyzed postmortem via several complementary techniques. The selected protocol was able to simulate the behavior of the real system. Due to the use of metallic lithium as the counter electrode, the influence of battery-like aging mechanisms was assumed to be limited. Our approach focused on the aging mechanisms related to the carbon electrode and determined the structural and chemical changes leading to energy fading in lithium-ion hybrid capacitors. It was shown that an increase in applied voltage not only results in faster system degradation but directs the aging chemistry to different pathways: at moderate voltage values, both capacitance loss and simultaneous increase in resistance predominate. This could be associated with the decrease in carbon surface area and possible pore clogging with by-products of electrolyte degradation and carbon oxidation disrupting the C sp² network. When high voltage is applied, further oxidation of carbon occurs with an increase in measured resistance that leads to the relevant end-of-life criterion to be reached. Detailed postmortem analysis results attributed it to the formation of phenol and ether groups together with electrolyte decomposition products, higher oxidation levels, and structure degradation. It was evidenced that the decrease in the overall carbon conductivity and, in certain cases, modification of the textural properties ultimately aggravates the capacitor performance.