ACS Applied Energy Materials最新文献

The development of high-performance all-solid-state batteries requires solid electrolytes with high ionic conductivity and lithium metal stability. Although Li₇La₃Zr₂O₁₂ (LLZO) garnet is promising, it suffers from interfacial instability and lithium loss. This study proposes a crystallography-based design strategy for Li₇-type garnet electrolytes. By evaluation of the ionic radii and tolerance factors across 247 cationic combinations, 38 compositions with structural compatibility comparable to LLZO were identified. The results emphasize the importance of balanced ionic size matching across crystal sites for framework stability, offering a rational screening method to accelerate the discovery of next-generation solid electrolytes.

Atomic layer deposition (ALD) of HfO_x layers has emerged as a promising strategy for interface passivation in chalcopyrite-based thin-film solar cells. However, the nucleation dynamics of (Ag,Cu)(In,Ga)Se₂ (ACIGS) absorbers remain insufficiently understood, particularly regarding the interplay between absorber composition and alkali postdeposition treatments (PDTs). Here, we employ in situ ambient pressure X-ray photoelectron spectroscopy (AP-XPS) to investigate the initial surface chemistry during HfO_x ALD on ACIGS thin-film solar cell absorbers with high [Ga]/([Ga]+[In]) (GGI) ratio subjected to RbF-PDT and compare the findings with low-GGI counterparts (Martin et al., ACS Appl. Energy Mater. 2025, 8, 461–472). The results show that high-GGI ACIGS surfaces are strongly Cu-depleted and enriched in Se and alkali-metal-containing secondary phases, which hinders tetrakisdimethylamido-hafnium (TDMA-Hf) precursor adsorption and delays oxide nucleation, in contrast to low-GGI ACIGS that allow quicker and more efficient HfO_x growth. Water pulses are identified as essential for reactivating the RbF-treated high-GGI surface by generating hydroxyl groups, thereby enabling metal precursor activation. The distinct formation of Ga–F and In–O species is only observed on high-GGI ACIGS together with increased Na diffusion, reflecting different surface chemistry for a higher Ga content of ACIGS as compared to the low Ga case. These findings demonstrate that bulk composition and alkali-PDT strongly influence ALD reactivity, surface passivation, and interface formation, with direct implications for composition-specific optimization of ACIGS solar cells.

The performance of low-temperature solid oxide fuel cells (LT-SOFCs) is limited by sluggish oxygen reduction kinetics and thermal expansion mismatch between cathode and electrolyte materials. ABO₃-type perovskites, such as SrCoO_3-δ, exhibit excellent oxygen reduction reaction (ORR) activity but suffer from high thermal expansion and limited compatibility with ceria electrolytes in LT-SOFCs. Here, we introduce a codoping strategy in which Ce⁴⁺ is incorporated at the A-site of Nb⁵⁺/Ta⁵⁺ codoped SrCoO_3-δ to simultaneously regulate lattice expansion and oxygen defect chemistry. The optimized composition, Sr_0.95Ce_0.05Co_0.8Nb_0.1Ta_0.1O_3-δ (SCCNT05), shows lattice contraction, improved lattice oxygen stability, and a significant reduction in thermal expansion coefficient to 14.42 × 10^–6 K^–1 down from 17.57 × 10^–6 K^–1 in the absence of Ce doping. Electrochemical impedance spectroscopy reveals competitive ORR performance with an area-specific resistance of 0.429 Ω cm² at 500 °C. Distribution of relaxation time and density functional theory analyses confirm that Ce strengthens A–O bonding and increases oxygen vacancy formation energy, leading to improved thermal stability without severely compromising ORR kinetics. This A–B codoping approach offers a promising pathway for designing thermally compatible LT-SOFC cathodes.

In this work, CuS@PVP nanospheres with large specific surface areas were successfully prepared via a one-step hydrothermal process by introducing the polyvinylpyrrolidone (PVP) surfactant into the precursor and modulating its dosage. As an anode material for aqueous zinc-ion batteries, the prepared CuS@PVP can shorten the transmission distance of Zn²⁺ and electrons and increase the number of reaction sites. CuS@PVP with 0.2 g of PVP added has a specific capacity of 305.4 mAh g^–1 at a current density of 0.2 A g^–1 and an ultralong cycle life of 2000 cycles at a current density of 2 A g^–1. In addition, the capacity of the CuS@PVP||Na–MnO₂ full cell is as high as 220.0 mAh g^–1 at a current density of 0.2 A g^–1, and the capacity retention rate is 85.9% after 100 cycles. The results prove that CuS@PVP is an excellent choice as an anode material for aqueous zinc-ion batteries.

The development of stable and high-performance solid-state electrolytes (SSEs) is essential for next-generation, all-solid-state lithium batteries. In this work, we computationally predict and characterize an oxide-based lithium argyrodite as a perspective solid-state electrolyte, Li₆PO₅I, using first-principles calculations and machine-learned interatomic potentials. Three iodine site configurations were examined: fully ordered (4a/0c) and partially disordered (3a/1c and 2a/2c). While the ordered 4a/0c phase exhibits low ionic conductivity (∼0.001 mS/cm), configurational disorder significantly enhances lithium transport. The 3a/1c and 2a/2c structures demonstrate ionic conductivities of 0.2 and 3.3 mS/cm, respectively, at 300 K with 2% Li vacancies, attributed to increased intercage hopping facilitated by iodine occupation of 4c sites. The thermodynamic, mechanical, and dynamic stability of all metastable phases was confirmed through convex hull analysis, elastic tensor calculations, and phonon dispersion. Ab initio molecular dynamics revealed a thermal stability up to 1400 K. A wide (3 V) electrochemical stability window and water tolerance further support Li₆PO₅I, particularly in disordered configurations, as a promising SSE candidate. This work underscores the critical role of site disorder in optimizing the ionic conductivity in oxide-based electrolytes.

The application of Sillén–Aurivillius (SA) photocatalysts for hydrogen evolution has remained limited, with prior studies relying heavily on noble-metal cocatalysts and offering only modest activity. We identify and address a major gap in the field by demonstrating that SA oxychlorides can be activated for efficient cocatalyst-free hydrogen generation. A dual design strategy is implemented that intrinsically activates SA oxychlorides: A-site cation engineering to optimize the band structure, coupled with controlled surface disorder engineering to generate oxygen vacancies and reduced metal centers, promote carrier separation, water adsorption, and visible-light utilization. The study reveals that A-site Sr content governs the intrinsic reduction potential of the designed Sr_xBa_2–xBi₄Ti₂NbO₁₄Cl (x = 0.8, 0.7, and 0.5) photocatalyst, enabling more efficient proton reduction with increasing Sr content. Moreover, mild ultrasonication of the compounds creates an optimally disordered surface with oxygen vacancies and reduced metal centers, which collectively enhance carrier separation, strengthen water adsorption, and introduce band tailing that extends visible-light absorption. This combined effect boosts the hydrogen-evolution rate of the SA catalyst by 8.7 times, reaching 1.22 mmol g^–1 h^–1 even without a cocatalyst, showing remarkable improvement. These results demonstrate a scalable approach to activate standalone SA photocatalysts and offer critical insights into the role of cation distribution and defect chemistry in layered perovskite systems for efficient solar-to-fuel conversion.

Low catalyst loadings pose challenges to performance stability in proton exchange membrane (PEM) water electrolysis over extended operation. To study the impact of degradation mechanisms and voltage loss rates, different stress tests are applied to membrane electrode assemblies. Potential cycling conditions were observed to induce higher degrees of iridium (Ir) oxide crystallization, ionomer degradation, and catalyst layer (CL) thinning, which likely contributed to higher kinetic loss rates. On the other hand, while Ir migrating into the PEM (Ir band) generally impairs performance, the interconnected and more uniform Ir band formed under a constant 2 V hold may allow for Ir at the catalyst/membrane interface to remain electronically connected and kinetically accessible, as well as indicate greater Ir site access during the applied stressor. The 2 V hold also demonstrates improved kinetic durability through a lower Tafel slope, faster polarization kinetics, and reduced charge transfer resistance. In contrast, potential cycling caused the migration of disconnected Ir agglomerates into the membrane bulk and created a steady increase in charge transfer resistance, a more dramatic decrease in capacitance (46.7% loss), and significant damage to the surrounding ionomer, indicating a decline in both the quality and quantity of active sites in the anode CL. This work underscores the distinct degradation pathways associated with load holds versus cycling, highlighting the role of catalyst–ionomer interactions in kinetic performance and long-term stability. These insights can inform operational strategies for PEM electrolyzers powered by intermittent energy sources, aiming to minimize efficiency losses over extended operation.

Polyelectrolyte composites (PECs) formed through ionic interactions between cationic and anionic polymer chains and PEDOT:PEC, in which a conductive polymer PEDOT (poly(3,4-ethylenedioxythiophene)) is introduced, have been used as materials constituting the membranes of solar vapor generation systems (SVGs). This addresses a critical issue related to the reduction in evaporation rates due to salt crystal formation. In particular, the unique characteristic of PEC is that it can interact with salt. This allows it to efficiently change the state of water for evaporation in salt solutions rather than pure water compared to other hydrogel materials. In addition, porous internal channels can be fabricated through pretreatment with salt. This not only floats on water but also facilitates water supply. Consequently, this substantial improvement in evaporation rates reached 1.88 kg m^–2 h^–1 under conditions similar to actual seawater concentrations.

Lithium–air batteries (LABs) offer ultrahigh energy density, but their practical use is limited by the sluggish oxygen reduction reaction, which requires operation under pure oxygen and yields extremely low power output. Herein, to boost both the power and energy under air oxygen, we investigated the discharge performance of LAB cells with low-viscosity amide-based electrolytes, N,N-dimethylacetamide (DMA) and N,N-dimethylformamide (DMF), dissolving lithium nitrate (LiNO₃) or lithium bis(trifluloromethanesulfonyl)imide (LiTFSI). With viscosities ¹/₃–¹/₄ lower than that of the typical LAB solvent of tetraethylene glycol dimethyl ether (TEG), the amide-based electrolytes ensure rapid transport of oxygen and Li⁺ ions, thereby enhancing battery output. Raman spectroscopy revealed that LiNO₃-based electrolytes exhibit weaker solvation, explaining their lower viscosity with slightly reduced ionic conductivity compared to LiTFSI-based electrolytes, with this effect more evident in DMF. As a result, LAB cells with DMF electrolyte dissolving 1.0 M LiNO₃ (DMF-NO₃) achieved the highest current density discharge of 23 mA cm^–2 with a capacity of 2.2 mAh cm^–2 under dry air, corresponding to an “engine-like” power of 2200 W kg^–1 and an energy density of 210 Wh kg_energy^–1. Galvanostatic discharge–charge cycling tests revealed better cyclability for DMA-based electrolytes due to reduced solvent volatilization. Anion mixing further suppressed the solvent loss and minimized side reactions, providing 200 Wh kg_energy^–1 over 14 cycles. Due to the milder oxidative conditions, LAB cells increased the rechargeability under dry air rather than under pure oxygen. This work paves the way for the development of “true” LABs capable of operating efficiently using atmospheric oxygen.

All-solid-state batteries (ASSBs) using oxide-type solid electrolytes (SEs) have attracted attention, owing to their high chemical stability and intrinsic safety. However, large-scale fabrication remains challenging because of their low sintering density and insufficient solid–solid contact between particles. Recently, multilayered ASSBs constructed by alternately stacking the electrode and SE layers have been commercialized, but their degradation behavior during charge–discharge cycling remains unclear. In this study, multilayered ASSBs were examined for the short- and medium-term degradation behaviors during charge–discharge cycling. A multimodal analysis, combining scanning electron microscopy (SEM) and Raman spectroscopy, was employed to observe cross sections in the pristine state and after cycling. The charge–discharge profiles exhibited discontinuous changes in voltage plateaus and capacities at 303, 313, and 323 K, whereas a monotonic decrease in capacity was observed at 333 K. SEM revealed the formation of a decomposition layer, particularly at 303 K, suggesting the degradation of the SE and the electrode active material. Raman spectroscopy further clarified significant peak shifts at the SE/electrode interfaces, reflecting a collapsed structure of the SE and supporting the SEM observations. Overall, multilayered oxide-type ASSBs undergo decomposition at the interfaces and within the electrode layer, leading to discontinuous capacity changes at lower temperatures during cycling.