ACS Applied Energy Materials最新文献

Solid oxide (SOFC/SOEC) and protonic ceramic (PCFC/PCEC) electrochemical cells are key enabling technologies for the future energy transition. These high- and intermediate-temperature devices offer exceptional efficiency and fuel flexibility, positioning them as critical components in decarbonizing sectors where low-temperature systems fall short. Chromium (Cr) poisoning remains one of the most critical degradation mechanisms limiting the performance, durability, and commercial viability of these solid oxide and protonic ceramic electrochemical cells (SOCs and PCCs). Cr volatilization from ferritic stainless steel interconnects and subsequent deposition of volatile Cr species such as CrO₃ and CrO₂(OH)₂ at the oxygen electrode lead to the formation of electrically insulating phases, which compromise triple-phase boundary (TPB) activity, increase polarization resistance, and accelerate performance degradation. While Cr-related degradation has been extensively studied in SOCs, its impact on PCCs, which are promising candidates for efficient hydrogen production remains comparatively underexplored. This review critically analyzes Cr poisoning mechanisms across these electrochemical systems, highlighting the mechanistic differences arising from their distinct configurations, ion conduction modes, and operating environments. Advances in material innovations, including Cr-resistant alloys, protective coatings, and improved electrode formulations, are discussed with a focus on their cross-system applicability and effectiveness. The need for predictive modeling, long-term durability studies, and system-level validation under realistic conditions is emphasized as essential for advancing Cr mitigation strategies. By consolidating current understanding and identifying key research gaps, this review outlines strategic directions for the development of Cr-resilient materials, optimized getter integration, and tailored protection schemes for the unique challenges posed by PCECs. Ultimately, it underscores the urgency of developing robust, scalable solutions to enable the reliable deployment of next-generation high-temperature electrolysis technologies in sustainable energy systems.

Solid-state batteries (SSBs) with lithium metal anodes offer exceptional energy density but suffer from dendrite growth and limited interfacial stability. Here, we report a poly(vinylidene fluoride-co-hexafluoropropylene)-based solid electrolyte incorporating hexagonal boron nitride (h-BN) as a multifunctional filler and lithium bis(trifluoromethanesulfonyl)imide as a salt to simultaneously enhance ionic conductivity and suppress dendrite formation. The optimized composition (3 wt % h-BN, PB3) achieves an ionic conductivity of 6.44 × 10^–4 S cm^–1 and a reduced electronic conductivity of 6.85 × 10^–9 S cm^–1. This balance enables stable lithium plating/stripping for over 200 h in symmetric cells and a capacity retention of ∼93% over 150 cycles in Li||LiNi_0.6Co_0.2Mn_0.2O₂ cells. Mechanistically, the insulating nature of h-BN and anion-trapping capability promote uniform Li-ion flux, mitigating localized dendrite nucleation. This dual functionality of h-BN offers a promising design pathway for safe, high-performance all-solid-state batteries.

The electrode fabrication process remains a critical stage in lithium-ion battery (LIB) manufacturing, where further advancements are needed to improve the energy efficiency and scalability. The conventional route relies on drying slurry-cast electrodes through circulating warm air, followed by vacuum postdrying, a practice that incurs high energy costs and involves multiple processing stages. Here, we investigate infrared (IR) drying to simplify electrode processing while tuning the binder structure at the molecular level. Lithium cobalt oxide (LCO) cathode slurry was cast onto a current collector and subjected to three drying conditions: (i) dried until visibly solvent-free, (ii) further IR-treated after reaching the solvent-free state, and (iii) vacuum-dried following the visibly solvent-free stage. Comprehensive characterization revealed that electrodes subjected to extended IR treatment exhibited superior mechanical adhesion, more effective solvent removal (negligible weight loss between 100 and 300 °C in thermogravimetric analysis), and lower internal resistance with a minimal increase after prolonged cycling, outperforming both counterparts despite the absence of observable morphological differences. Electrochemical testing further demonstrates that extended IR exposure achieves high-rate performance of 112 mAh g^–1 at 2 C and stable capacity retention for 500 cycles at C/3. Analysis of PVDF films prepared under comparable drying conditions confirmed that exposure near the melting temperature of the PVDF with extended IR treatment enhances crystallinity of α-phase, strengthening mechanical stability and improving electrochemical behavior of LCO cathodes. These results highlight IR drying as a practical route to control the binder structure, offering both energy savings and improved performance in LIB electrode manufacturing.

A mixture of A-site cations can improve the stability and performance of organic–inorganic hybrid perovskite solar cells. Although MA⁺, FA⁺, and Cs⁺ are the most commonly used A-site cations in perovskite research, they are thermodynamically unstable at room temperature and tend to crystallize from the α-phase to the δ-phase. Meanwhile, the introduction of Rb⁺ can promote the growth of perovskite films, but its relatively small ionic size often inhibits the formation of the perovskite phase. Here, we introduced the larger dimethylammonium (DMA) cation at the A-site and fabricated organic–inorganic hybrid metal halide perovskite materials containing five distinct A-site cations. It was found that the incorporation of DMA cations can compensate for the small size of rubidium cations, thereby maintaining the average tolerance factor of the perovskite lattice. Furthermore, this approach effectively modulates the crystallization orientation of the perovskite and promotes grain growth. Ultimately, through A-Site Quintuple-Cation Engineering, the champion device achieved a power conversion efficiency (PCE) of 23.69%, significantly improved from the baseline of 22.60%. Moreover, the unencapsulated device retained approximately 84% of its initial efficiency after 1000 h of aging under air conditions at 65 °C and 35 ± 5% relative humidity.

The growing global concern over rising carbon emissions necessitates the development of sustainable alternatives to conventional nonrenewable fuels such as oil and diesel. Current catalysts for biodiesel production via transesterification face drawbacks such as soap formation, leaching, poor reusability, and sensitivity to feedstock impurities. Considering the limitations of current catalytic systems, a pore-engineered covalent organic framework was synthesized. In the present work, a urethane-linked covalent organic framework was functionalized with ethylene diamine to obtain free amine groups in the cavity to obtain a solid base catalyst for transesterification. This pore-engineered UCOF was confined with CuO NPs to enhance its catalytic efficiency. The catalyst was well characterized using various sophisticated techniques like Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The BET surface area and pore diameter analysis also supported the pore engineering and confinement of the CuO NPs. Transesterification of triacetin with methanol as a model reaction for biofuel production was carried out in a one-step process to produce methyl acetate. All the process parameters such as the triacetin/methanol ratio, catalyst amount, temperature, and time were optimized to obtain >99% conversion of triacetin. The reaction follows pseudo-first-order kinetics, and the rate constant was determined to be 1.31 h^–1, and the Arrhenius activation energy was calculated as 76.72 kJ mol^–1. The scope of this catalyst was extended for complete transformation of castor oil to its respective fatty acid methyl ester, i.e., biodiesel. The catalyst opens up horizons for the transformation of nonedible and waste cooking oil to useful biodiesel to solve the global issue of depleting fuels.

Formation during the first cycles of Li-rich layered oxide (LRLO) cathode materials consolidates the interphase and leads to structural changes that are decisive for long-term cyclability. However, the nature and effect of the changes are material-dependent and unknown for the important class of Co-free, Ni-poor LRLOs. Here, we analyze the processes during the tailored formation procedure of a typical class member, Li_1.28Ni_0.15Mn_0.57O₂, and demonstrate that it remarkably changes lattice composition and structure as a prerequisite for stable cycling. We combine electrochemistry, operando mass spectrometry, X-ray diffraction, and X-ray absorption spectroscopy with density functional theory simulations. Activation most prominently compresses the layer spacing along the c-axis and increases reversible structural breathing. The large capacity of ∼250 mAh g^–1 originates from the Ni²⁺/Ni⁴⁺ and O^2–/O^– redox couples. Electron exchange during O-redox is smeared over the entire anionic sublattice rather than localized on specific oxygen atomic sites. This redox mechanism is reversible without detrimental oxygen evolution, avoiding continued degradation common in conventional LRLOs. Sequential Ni- and O-redox during activation irreversibly distorts the coordination of the redox-inactive Mn⁴⁺ centers. This structural evolution of the MnO₆ octahedra appears to enable the superior electrochemical performance of this LRLO phase. These findings define an activation pathway for the important class of Co-free, Ni-poor LRLOs, offering potential guidance for the rational design of high-performance, more sustainable cathode materials.

Antimony selenosulfide (Sb₂(S,Se)₃), as an emerging inorganic photovoltaic material, has garnered significant attention on account of its remarkable optoelectronic characteristics and stability. Spiro-OMeTAD is an organic material that is currently widely used as the hole transport layer (HTL) in Sb₂(S,Se)₃ solar cells. However, this material suffers from issues such as insufficient stability and relatively high cost. Therefore, the development of high-performance inorganic HTL alternatives has become a key focus of current research. In this study, the SCAPS-1D simulation tool was used to thoroughly examine the impacts of several inorganic HTL materials on the properties of Sb₂(S,Se)₃ devices, with a particular focus on crucial aspects such as HTL thickness, doping concentration, and operating temperature. The results demonstrate that molybdenum oxide (MoO₃) exhibits promising potential as an HTL material. Specifically, the thickness of MoO₃ has a minimal impact on device performance, while a doping concentration exceeding 10²⁰ cm^–3 enables an optimized single-junction all-inorganic Sb₂(S,Se)₃/MoO₃ solar cell to attain a power conversion efficiency of 11.82%. The simulation study provides crucial theoretical guidelines and references for future research on efficient and stable HTL materials for Sb₂(S,Se)₃ photovoltaic devices.

The development of solid electrolytes (SEs) for high-performance solid-state batteries (SSBs) requires not only favorable electrochemical stability but also interfacial compatibility with diverse cathode chemistries. In this study, we systematically benchmark recently discovered Li₇Si₂S₇I against the well-established argyrodite Li_5.5PS_4.5Cl_1.5 as an SE in composite cathodes. Despite exhibiting comparable oxidative stability, Li₇Si₂S₇I demonstrates markedly different behaviors depending on the cathode chemistry. In composite cathodes with uncoated LiNi_0.83Co_0.11Mn_0.06O₂ as the cathode active material and Li₇Si₂S₇I as the electrolyte, rapid degradation occurs, with capacity retention dropping to 5% after 30 cycles, driven by fast degradation kinetics and interfacial instability toward the formation of SiO_x species as a thermodynamic sink. In contrast, sulfur–carbon–Li₇Si₂S₇I composite cathodes show good performance in half-cells, comparable to that of the argyrodite benchmark. The reversible oxidative redox processes of Li₇Si₂S₇I in sulfur-based systems highlight its promise for Li–S and other oxygen-free battery chemistries. Overall, this work emphasizes the importance of a holistic approach to SE evaluation, integrating chemical and electrochemical stability with degradation kinetics, to inform the rational design of next-generation SSB materials.

Organic synthesis driven by lead halide perovskite-based photocatalysts has emerged as a powerful route for advanced chemical transformations, propelled by their remarkable light-harvesting capability and efficient charge generation. Among the various factors influencing their activity, charge-transfer dynamics at the nanocrystal–molecule interface dictates the photocatalytic efficiency. Yet, the impact of surface termination on charge transfer with molecular hole acceptors represents a significant knowledge gap, especially in formamidinium lead bromide (FAPbBr₃) nanocrystals. Here, we uncover how ferrocene-functionalized hole acceptors, ferrocenecarboxylic acid (FcA) and (dimethylaminomethyl)ferrocene (FcAm), interact distinctly with FAPbBr₃ and CsPbBr₃ nanocrystals, revealing the critical influence of surface chemistry on charge-transfer pathways. Comprehensive photophysical investigations show that both the molecular functionality of the acceptor and the surface termination of the nanocrystal jointly dictate the interfacial charge-transfer behavior. While FcA is energetically well-aligned, it fails to extract holes from FAPbBr₃ nanocrystals due to the absence of accessible Pb²⁺ binding sites. In contrast, protonated FcAm efficiently extracts holes by engaging the vacant FA⁺ sites on the nanocrystal surface. Time-resolved measurements further confirm that this hole transfer originates from band-edge states rather than hot carriers. CsCl doping experiments substantiate the role of surface termination, as doping effectively suppresses charge transfer to FcAm. Overall, these findings establish surface termination as a key determinant of interfacial charge transfer in perovskite–molecule hybrid systems. They further highlight cation engineering as a powerful approach to tune surface energetics and improve photocatalytic efficiency, providing valuable design principles for next-generation perovskite photocatalysts aimed at overcoming interfacial charge-transfer bottlenecks.

Na₂FePO₄F emerges as a promising cathode material for sodium-ion batteries owing to its low cost, environmental benignity, and reasonably high theoretical capacity. Nevertheless, its practical application is hampered by limited electronic conductivity and ion diffusion rates. This investigation explores low-cost Na₂FePO₄F_1–x (0 ≤ x ≤ 0.1) compounds with fluorine defects as potential cathodes for sodium-ion batteries. Specifically, the Na₂FePO₄F_1–x (x = 0.04, denoted as NFPF-0.04) sample demonstrates a narrow band gap of 0.509 eV and a higher Na⁺ diffusion coefficient of 2.34 × 10^–10 cm² s^–1 and also exhibits a volumetric change of only 1.76% during the first charge/discharge cycle. The NFPF-0.04 sample delivers a discharge capacity of 115.3 mAh g^–1 at 0.1C, and the capacity retained 75.1% at 10C after 500 cycles. These improved electrochemical performances are attributed to changes in Na–O(F) and Fe–F₁/F₂ bond lengths induced by a small amount of fluorine defects. The insights into the enhancement of ion diffusion kinetics and mitigation of volume change are expected to accelerate the optimization of Na₂FePO₄F_1–x electrodes for sodium-ion batteries.