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.

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.

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.

Electrocatalytic wastewater splitting presents a viable alternative to alleviating the strain on freshwater resources traditionally used for hydrogen production. The critical challenge lies in developing a robust multifunctional catalyst capable of operating efficiently in a wastewater environment. MXenes─transition-metal carbides, nitrides, and carbonitrides─have emerged as potent electrocatalysts for hydrogen generation, attributed to their abundant surface functionalities and active basal planes. However, their performance and stability under wastewater conditions remain unexplored. Given the high organic load in wastewater, MXene engineering at the interface is imperative to ensure stability. This study pioneers the engineering of Ti₃C₂T_x with transition-metal alloys to create a hybrid NiMo/Ti₃C₂ electrocatalyst, evaluated for hydrogen evolution in simulated wastewater (1 M KOH with 5 ppm methylene blue). The NiMo/Ti₃C₂ catalyst was synthesized through dip-coating Ti₃C₂T_x onto Ni foam, followed by optimized NiMo electrodeposition. The catalyst exhibited an overpotential of 45.8 mV at 10 mA/cm² in simulated wastewater and demonstrated prolonged stability at elevated current densities of 50 and 100 mA/cm². Additionally, it achieved approximately 82% degradation of MB within 90 min and a hydrogen production rate of 0.361 mmol/h. In real wastewater samples, the engineered Ti₃C₂T_x showcased significant reductions in chemical oxygen demand, total organic carbon, and turbidity, with a hydrogen production rate of 0.327 mmol/h. Ti₃C₂T_x MXene provides a larger surface area and active basal planes for the adsorption of ions, and NiMo alloy acts as a charge transporter in the HER. These results highlight the potential of the interface-engineered Ti₃C₂T_x system as a multifunctional electrocatalyst for concurrent wastewater treatment and hydrogen production.

Silver bismuth sulfide (AgBiS₂) nanocrystal (NC) is a third-generation photovoltaic material used in solution-processed solar cells. During the NC purification process, the loss of surface ligand induces surface traps, leads to NC aggregation, and damages the device performance and operation stability. To address this issue, we employed an in situ metal passivation strategy for AgBiS₂ NCs to passivate the NC surface and protect the NCs from ligand dissociation. Our findings suggested that sodium is particularly effective in improving the solar cell performance by forming a protective shell on the surface, which passivates traps and inhibits trap recombination pathways. Quantitative NMR spectroscopy proves that the sodium-rich surface can bind with a higher density of oleate ligands after purification, resulting in a trap-reduced, robust thin film, which can further generate a higher photocurrent in the solar cells. The champion device achieved a short-circuit current density (J_SC) over 24 mA cm^–2 and light-soaking stability over 240 h, making it one of the best-performing p–i–n AgBiS₂ solar cells with superior photostability. Our metal-passivation study offers an alternative approach to synthesize trap-reduced AgBiS₂ NCs and fabricate high-performance solar cells.

Developing efficient, stable, and economical catalysts is crucial for the oxygen evolution process. Herein we report cation-vacant Ti-doped NiO as a promising catalyst for the oxygen evolution reaction (OER). Nonprecious titanium dopant is incorporated into the cation vacant cubic rock-salt Ni_1–2x Ti_x V_x^″O (0 < x < 0.1; V_x^″ = Ni²⁺ cation vacancy) via a facile sol–gel method. We utilized the concept of an inductive effect through doping with more electronegative/Lewis acidic Ti⁴⁺ in the NiO to adjust the redox energy of the active Ni²⁺/Ni³⁺ redox couple to enhance the electrocatalytic OER activity in the basic electrolyte. Doping of tetravalent Ti in NiO lattice generates cation vacancy, which promotes higher OER activity by creating lattice vacancies on the surfaces for better adsorption of water molecules. Among the compositions investigated, Ni_0.9Ti₀.₀₅O is the most active as it exhibits excellent electrocatalytic activity with a low overpotential of 304 mV at the current density of 10 mA cm^–2 compared to the commercial RuO₂ benchmark catalyst. This work presents a design principle by coupling cation vacancies along with the inductive effect of neighboring cations to alter redox energies to provide effective electron transfer required for the electrocatalytic OER by utilizing the inductive effect and cationic vacancy.

Unmatched superior electrochemical performance and remarkable robustness of large-area (100 cm²) La_0.6Sr_0.4Co_0.2Fe_0.8O_3–δ-Ce_0.9Gd_0.1O_2−δ (LSCF-GDC) composite cathodes, optimized via a surface modification method with a Sm_0.5Sr_0.5CoO_3–δ/Ce_0.8Sm_0.2O_2−δ (SSC-SDC) nanocatalyst, are reported in this study. A well-dispersed network of SSC and SDC composite nanoparticles adorns a porous LSCF-GDC backbone, fostering the ORR kinetics of indigenous cathodes and showing substantially enhanced electrochemical performance. SOFC cathodes are upgraded with dissimilar amounts of SSC-SDC composite nanoparticles during single and double cycles of infiltration, showing corresponding powers of 46.48 and 53.16 W at 700 °C and a 60 A applied current, representing a breakthrough in performance for commercial-sized SOFCs. Moreover, the SOFCs demonstrate exceptional durability for up to 1500 h of galvanostatic operation under a 30 A applied current at an operating temperature of 700 °C due to the effect of the composite cathode catalyst material, which inhibits nanoparticle coarsening. This study provides a pragmatic approach for realizing the potential of nanocomposite infiltration to ameliorate the surfaces of SOFC cathode materials to promote commercialization of current SOFC technologies.