ACS Applied Energy Materials最新文献

The thermal and electronic transport properties of Ag-based quaternary compounds, GaAgSnSe₄ and InAgGeSe₄, have been explored by using density functional theory and the Boltzmann transport equation. Both the compounds exhibit ultralow lattice thermal conductivities (κ_l) that originate from the anharmonicity induced by the rattling effects of the loosely bound Ag atoms in their crystals. The lattice thermal conductivities (κ_l,xx(yy), κ_l,zz) at 300 and 800 K are (0.19, 0.23) and (0.07, 0.08) W m^–1 K^–1, respectively, for GaAgSnSe₄, and those for InAgGeSe₄ are (1.07, 0.97) and (0.40, 0.36) W m^–1 K^–1, respectively. Due to the huge and steep total density of states (TDOS) at the band edges in the vicinity of the Fermi level, both direct band gap semiconductors exhibit high Seebeck coefficients (S) with optimum electrical (σ) and electronic thermal conductivities (κ_e). We have projected an outstanding figure of merit (ZT) for both the p-type and n-type of the two compounds. For the p-type and n-type GaAgSnSe₄, the maximum ZT estimated at 800 K along the (x(y), z)-directions are (2.74, 2.35) and (2.51, 1.84), respectively; for the p-type and n-type InAgGeSe₄, the values are (1.31, 1.20) and (0.94, 0.90), respectively. Our study suggests both GaAgSnSe₄ and InAgGeSe₄ as prospective thermoelectric materials.

The development of effective strategies to accelerate the diffusion kinetics of Na⁺ ions and improve the cycle stability of electrode materials is crucial for high-performance sodium-ion energy storage devices. In this article, we present a one-step in situ solid-phase synthesis method for preparing CoZnSe/CNT nanocomposites to address the inherent defects of traditional solid-phase synthesis methods. The three-dimensional (3D) framework constructed from CNTs provides a highly conductive substance, enabling the formation of CoZnSe/CNT nanocomposites with high conductivity, fast Na⁺ diffusion kinetics, and excellent cycle stability, ensuring good performance in both sodium-ion batteries and hybrid supercapacitors. The synthesized CoZnSe/CNT nanocomposite delivers a high reversible specific capacity of 433.14 mAh g^–1 at 0.1 A g^–1 and 280.3 mAh g^–1 at 5.0 A g^–1 when applied in a sodium-ion half-cell device. The assembled sodium-ion hybrid supercapacitor device shows a long cycle life and high capacity retention even at high current density. A high energy density of 152.96 Wh kg^–1 can be delivered at a power density of 2.16 kW kg^–1 with 70.4 Wh kg^–1 delivered even at a high power density of 36 kW kg^–1. A capacity retention rate of more than 79.61% is achieved after 6000 cycles at 1 A g^–1. The CoZnSe/CNT nanocomposite prepared by the proposed method exhibits excellent performance in sodium-ion energy storage devices, comparable to that achieved by liquid-phase synthesis methods, demonstrating its significant advantages and promising application prospects for the synthesis of high-performance sodium-ion energy storage materials.

Layered transition metal dichalcogenides, especially MoS₂, have great potential as cathodes for aqueous zinc ion batteries (AZIBs) due to their flexible interlayer structural characteristics. However, the unsatisfactory diffusion efficiency of Zn²⁺ in pristine MoS₂ severely restricts its application. Herein, a strategy of interfacial heterostructure construction and surface defect fabrication is employed to introduce metallic VS₂ with matchable formation energies into MoS₂ (designated as HD-MVS), thereby exposing active interfaces, increasing the 1T-phase proportion, and expanding interlayer spacing. The GITT, rate-scan CV, and multiple ex situ characterizations confirm that HD-MVS possesses a rapid and reversible Zn²⁺ insertion/extraction ability. Therefore, HD-MVS exhibits satisfactory rate performance (265 mA h g^–1 at 0.1 A g^–1 and 116 mA h g^–1 at 6.0 A g^–1), long cycle durability (92.47% capacity retention over 5000 cycles at 1.0 A g^–1), and stable flexible electrochemistry (91.68% capacity retention after 2000 cycles under 180°), providing assistance for the widespread application of AZIBs in the future.

Lithium-ion batteries (LIBs) are limited by high costs and sustainability issues due to their cobalt content, despite their advantages in energy storage. Sodium-ion batteries (SIBs) emerge as a viable alternative because of their cost-effectiveness and abundant sodium, which is especially suitable for large-scale applications. The O3-type sodium-layered transition-metal oxide (Na_xTMO₂) cathode is pivotal for enhancing energy density, cost-effectiveness, and stability of SIBs. However, these cathodes are affected by poor air stability and irreversible phase transitions that degrade their electrochemical performance. To address these issues, we propose a near-surface structural modulation strategy to convert surface alkali residues into the fast ionic conductor Na₂CaMg(PO₄)₂ (NCMP). This method relieved air sensitivity by forming a protective shield around the cathode and enhanced discharge capacity and cycling stability, demonstrating a significant increase in specific capacity, reaching 159.7 mAh/g at 0.1 C and 106.2 mAh/g at 5 C. This study demonstrates the effectiveness of NCMP coatings in improving the lifetime and performance of SIBs and proposes their general applicability in enhancing sodium-ion-layered oxide cathodes.

Hydrothermal relithiation under oxidative conditions has been reported to be an efficient method to rejuvenate cycle-aged cathode materials. However, the role of surface oxygen is not well understood. In this work, hydrothermal relithiation in LiOH solution with H₂O₂ as an oxidative additive at 125 °C followed by calcination was able to fully recover the capacity of a cycle-aged NMC532 cathode material from end-of-life commercial electric vehicle cells with a state-of-health of 75%. The adsorbed surface oxygen species from H₂O₂ act as catalysts to facilitate both the relithiation and removal of surface fluorine impurities on NMC532. Removal of transition metal fluoride in LiOH solution is a displacement reaction with an *–OH group replacing a *–F group. X-ray photoelectron spectroscopy and Raman spectroscopy combined with electronic structure calculations confirm the conversion of transition metal fluoride to lithium fluoride. The activation energy is reduced via the formation of a peroxide with the adsorbed oxygen to provide more reactive *–OH groups coupled with a redox process. A small amount of lithium fluoride does not significantly influence reversible capacity. However, the presence of transition metal fluorides may have a negative effect. The kinetics of relithiation and impurity removal with the hydrothermal method can be optimized by modifying surface oxygen.

The incorporation of ceramic fillers into polymer electrolytes has proven to be effective in bolstering their mechanical robustness, improving ionic transport efficiency, and ensuring enhanced interface integrity. Nonetheless, the current repertoire of suitable ceramic fillers for such applications is still somewhat limited. Zeolites, renowned for their pronounced adsorption capabilities and potential as sodium-ion conductors, have not been extensively studied regarding their impact on the electrochemical performance of composite electrolytes. In this work, we have developed a novel composite polymer electrolyte (CPE) based on poly(ethylene oxide) (PEO) integrated with LTA zeolite nanoparticles. The cation adsorption on the surface of LTA zeolite particles introduces additional ion migration pathways, while the interaction between hydroxyl groups and ether atoms of the PEO matrix weakens the coordination between Na⁺ and PEO, thereby promoting sodium-ion mobility within the LTA/PEO CPE. The synergistic effect of cation adsorption and Lewis acid–base action on the zeolite surface yields an impressive sodium-ion transference number of 0.44. The integration of the LTA zeolite into the composite electrolyte diminishes the interfacial resistance against sodium metal electrodes, effectively mitigating sodium dendrite formation. The NVP||PEO-10||Na battery incorporating 10 wt % LTA zeolites exhibits a capacity retention of nearly 88% after 100 cycles at 0.2 C, which is significantly better than those without the zeolite.

Palladium metal catalysts have emerged as the preferred choice for alkaline formate oxidation reaction (FOR) due to their high activity. However, their strong binding with adsorbed H (H_ad) allows H_ad to occupy the active site, resulting in slow FOR kinetics. Herein, we developed a ZrO₂/Pd/C catalyst to decrease the H_ad binding strength on Pd active sites, thereby enhancing the FOR in alkaline media. Through experimental investigations and density functional theory (DFT) calculations, we elucidated the relationship between the d-band center of Pd and hydrogen binding energy (HBE). Our findings reveal that electron transfer from ZrO₂ to Pd, driven by the work function disparity, results in a downshift of the d-band center of Pd. This shift weakens the HBE at Pd active sites, facilitating the desorption of H_ad intermediates and thereby improving catalytic efficiency. As a result, the ZrO₂/Pd/C catalyst demonstrated a 2.8-fold increase in activity over commercial Pd/C, exhibiting a lower peak potential and a significantly higher peak current of 1787 mA mg^–1. This work advances our understanding of the interplay between electronic structure and catalytic performance, setting a benchmark for high-performance electrocatalysts in energy conversion technologies.

All-solid-state lithium batteries (ASSLBs) with sulfide electrolytes and high-capacity alloy anodes are among the most promising technologies for achieving high safety and energy density. Herein, we demonstrate a slurry-coated sheet-type electrode consisting of a 99.8 wt % Si–Sn hybrid active material and a 0.2 wt % single-walled carbon nanotube (SWCNT) binder, which could be used as a superior anode in ASSLBs. Compared to the typical composite powder electrode, the sheet-type Si–Sn electrode is free of electrolytes and extra carbon additives, enabling higher energy density at the electrode level but dominantly depending on Li⁺ diffusion and electron transport within the Si–Sn active material. It is identified that the lithiated Si–Sn hybrid is an excellent mixed ion-electron conductor that overcomes insufficient electronic or ionic conductivities of lithiated Si and Sn individuals. In addition, using SWCNT instead of ordinary polymer binders can improve electrode integrity and preserve electrical connections during cycling. When paired with a LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode (a mass loading of 11.3 mg cm^–2), the Si–Sn–SWCNT||NCM811 full cell shows stable cycling for more than 200 cycles at 0.5C with a capacity retention of 85.9%. Even at a high NCM811 loading of 36.4 mg cm^–2, the full cell exhibits a considerable capacity retention of 85.0% (50 cycles, 0.1C) and a maximum areal capacity of 5.8 mAh cm^–2. This work provides an industry-compatible method to produce high-performance alloy anodes for ASSLBs.

Nitrate electroreduction reaction (NO₃RR) to ammonia (NH₃) still faces fundamental and technological challenges. While Cu-based catalysts have been widely explored, their activity and stability relationship are still not fully understood. Here, we systematically monitored the dynamic alterations in the chemical and morphological characteristics of Cu₂O nanocubes (NCs) during NO₃RR in an alkaline electrolyte. In 1 h of electrolysis from -0.10 to -0.60 V vs RHE, the electrocatalyst achieved the maximum NH₃ faradaic efficiency (FE) and yield rate at -0.3 V (94% and 149 μmol h^-1 cm^-2, respectively). Similar efficiency could be found at a lower overpotential (-0.20 V vs RHE) in long-term electrolysis. At -0.20 V vs RHE, the catalyst FE increased from 73% in the first 2 h to ∼90% in 10 h of electrolysis. Electron microscopy revealed the loss of the cubic shape with the formation of sintered domains. In situ Raman, X-ray diffraction (XRD), and in situ Cu K-edge X-ray absorption near-edge spectroscopy (XANES) indicated the reduction of Cu₂O to oxide-derived Cu⁰ (OD-Cu). Nevertheless, a remaining Cu₂O phase was noticed after 1 h of electrolysis at -0.3 V vs RHE. This observation indicates that the activity and selectivity of the initially well-defined Cu₂O NCs are not solely dependent on the initial structure. Instead, it underscores the emergence of an OD-Cu-rich surface, evolving from near-surface to underlying layers over time and playing a crucial role in the reaction pathways. By employing online differential electrochemical mass spectrometry (DEMS) and in situ Fourier transform infrared spectroscopy (FTIR), we experimentally probed the presence of key intermediates (NO and NH₂OH) and byproducts of NO₃RR (N₂ and N₂H _x ) for NH₃ formation. These results show a complex relationship between activity and stability of the nanostructured Cu₂O oxide catalyst for NO₃RR.

Nitrate electroreduction reaction (NO₃RR) to ammonia (NH₃) still faces fundamental and technological challenges. While Cu-based catalysts have been widely explored, their activity and stability relationship are still not fully understood. Here, we systematically monitored the dynamic alterations in the chemical and morphological characteristics of Cu₂O nanocubes (NCs) during NO₃RR in an alkaline electrolyte. In 1 h of electrolysis from −0.10 to −0.60 V vs RHE, the electrocatalyst achieved the maximum NH₃ faradaic efficiency (FE) and yield rate at −0.3 V (94% and 149 μmol h^–1 cm^–2, respectively). Similar efficiency could be found at a lower overpotential (−0.20 V vs RHE) in long-term electrolysis. At −0.20 V vs RHE, the catalyst FE increased from 73% in the first 2 h to ∼90% in 10 h of electrolysis. Electron microscopy revealed the loss of the cubic shape with the formation of sintered domains. In situ Raman, X-ray diffraction (XRD), and in situ Cu K-edge X-ray absorption near-edge spectroscopy (XANES) indicated the reduction of Cu₂O to oxide-derived Cu⁰ (OD-Cu). Nevertheless, a remaining Cu₂O phase was noticed after 1 h of electrolysis at −0.3 V vs RHE. This observation indicates that the activity and selectivity of the initially well-defined Cu₂O NCs are not solely dependent on the initial structure. Instead, it underscores the emergence of an OD-Cu-rich surface, evolving from near-surface to underlying layers over time and playing a crucial role in the reaction pathways. By employing online differential electrochemical mass spectrometry (DEMS) and in situ Fourier transform infrared spectroscopy (FTIR), we experimentally probed the presence of key intermediates (NO and NH₂OH) and byproducts of NO₃RR (N₂ and N₂H_x) for NH₃ formation. These results show a complex relationship between activity and stability of the nanostructured Cu₂O oxide catalyst for NO₃RR.