Carbon Energy最新文献

Full-manganese (Mn) Li-rich materials have gained attention owing to the limited availability of cobalt- or nickel-based cathodes commonly used in batteries, which greatly restricts their potential for large-scale application. However, their practical implementation is hindered by the rapid voltage/capacity decay during cycling and the long-standing problem of redox kinetics due to their poor ionic conductivity based on the ordered honeycomb structure. In this study, the kinetic and thermodynamic properties of intralayer disordered and ordered Li-rich full-Mn-based cathode materials were compared, demonstrating that the disordered $��\; ��R�\; �\overline{3}�\; �m��$ Li_0.6[Li_0.2Mn_0.8]O₂ (D-LMO) delivers a significant advantage of rate capability over the ordered $��\; ��C�\; �2�\; �/�\; �m��$ Li_0.6[Li_0.2Mn_0.8]O₂ (O-LMO). Meanwhile, the D-LMO keeps superior capacity retention of up to 99% after 50 cycles under 25 mA g⁻¹. In comparsion, the capacity retention of the O-LMO drops to just 70%, and its average discharge voltage is 0.2 V lower than that of the D-LMO. Herein, we conducted systematic density functional theory (DFT) simulations, focusing on the electronic structure modulation governing the voltage platform between the ordered and disordered phases. The ab initio molecular dynamics (AIMD) results indicated that the energy of the intralayer disordered structure fluctuates around the equilibrium position without any abrupt drops, demonstrating excellent stability. This study enhances the understanding of intralayer disordered full-Mn Li-rich material and provides insights into the design of low-cost, high-performance cathode materials for Li-ion batteries.

The development of human industry inevitably leads to excessive carbon dioxide (CO₂) emissions. It can cause critical ecological consequences, primarily global warming and ocean acidification. In this regard, close attention is paid to the carbon capture, utilization, and storage concept. The key component of this concept is the catalytic conversion of CO₂ into valuable chemical compounds and fuels. Light olefins are one of the most industrially important chemicals, and their sustainable production via CO₂ hydrogenation could be a prospective way to reach carbon neutrality. Fe-based materials are widely recognized as effective thermocatalysts and photothermal catalysts for that process thanks to their low cost, high activity, and good stability. This review critically examines the most recent progress in the development and optimization of Fe-based catalysts for CO₂ hydrogenation into light olefins. Particular attention is paid to understanding the roles of catalyst composition, structural properties, and promoters in enhancing catalytic activity, selectivity, and stability.

Lead (Pb)–zinc (Zn) slags contain large amounts of Pb, causing irreversible damage to the environment. Therefore, developing an effective strategy to extract Pb from Pb–Zn slags and convert them into a renewable high-value catalyst not only solves the energy crisis but also reduces environmental pollution. Herein, we present a viable strategy to recycle Pb and iron (Fe) from Pb–Zn slags for the fabrication of efficient methylammonium lead tri-iodide (r-MAPbI₃) piezocatalysts with single-atom Fe–N₄ sites. Intriguingly, atomically dispersed Fe sites from Pb–Zn slags, which coordinated with N in the neighboring four CH₃NH₃ to form the FeN₄ configuration, were detected in the as-obtained r-MAPbI₃ by synchrotron X-ray absorption spectroscopy. The introduction of Fe single atoms amplified the polarization of MAPbI₃ and upshifted the d-band center of MAPbI₃. This not only enhanced the piezoelectric response of MAPbI₃ but also promoted the proton transfer during the hydrogen evolution process. Due to the decoration of Fe single atoms, r-MAPbI₃ showed a pronounced H₂ yield of 322.4 μmol g⁻¹ h⁻¹, which was 2.52 times that of MAPbI₃ synthesized using commercially available reagents. This simple yet robust strategy to manufacture MAPbI₃ piezocatalysts paves a novel way to the large-scale and value-added consumption of Pb-containing waste residues.

Copper complexes inspired by O₂-activating enzymes have been widely investigated as molecular water oxidation catalysts, capable of facile and reversible O─O bond formation and cleavage under mild conditions. In this study, two copper phenanthroline complexes, namely, Cu(phen) and Cu(dophen), exhibit high turnover frequencies (TOFs) of 74 ± 13 and (5.66 ± 0.29) × 10³ s⁻¹ for water oxidation, respectively. Moreover, amino acid-functionalized carbon dots (CDs) were used to support the adhesion of the [Cu] complexes onto the electrode, significantly enhancing the TOFs of (2.80 ± 0.12) × 10³ and (4.11 ± 0.24) × 10⁴ s⁻¹, respectively, exceeding the activity of photosystem II in nature. Remarkably, the amino acid-functionalized CDs provide a secondary sphere that mimics the catalytic microenvironment of the copper centre, which promotes proton-coupled electron transfer and O─O bond formation. Finally, the photovoltaic-electrolysis (PVE) system was established using CDs-supported Cu catalysts and commercial silicon solar panels, achieving a high solar-to-hydrogen efficiency of 11.59% under the illumination of AM 1.5 G. This represents the most efficient solar-driven water splitting system based on copper-based catalysts to date, introducing the biomimetic secondary sphere to a “proton-rocking” process for water oxidation catalysis and application of the PVE system.

Back cover image: The rational design of transition metal incorporated electrocatalyst for hydrogen evolution reaction is an effective way to produce economical hydrogen. However, the practical application of data-driven methodology is limited due to the complexity of electrochemical systems. In article number cey2.70006, Kim and Sim et al. present the machine learning based facile strategy to optimize the catalyst and experimental conditions. The trained model accurately predicts experimental variables, which are validated by proton exchange membrane-based water electrolysis system. This work provides insight into the simplified approach for the design optimization of machine learning-assisted catalysts and systems.

Development of high-efficiency bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts is vital for the widespread application of zinc–air batteries (ZABs). However, it still remains a great challenge to avoid the inhomogeneous distribution and aggregation of metal single-atomic active centers in the construction of bifunctional electrocatalysts with atomically dispersed multimetallic sites because of the common calcination method. Herein, we report a novel catalyst with phthalocyanine-assembled Fe-Co-Ni single-atomic triple sites dispersed on sulfur-doped graphene using a simple ultrasonic procedure without calcination, and X-ray absorption fine structure (XAFS), aberration-corrected scanning transmission electron microscopy (AC-STEM), and other detailed characterizations are performed to demonstrate the successful synthesis. The novel catalyst shows extraordinary bifunctional ORR/OER activities with a fairly low potential difference (ΔE = 0.621 V) between the OER overpotential (E_j10 = 315 mV at 10 mA cm⁻²) and the ORR half-wave potential (E_half-wave = 0.924 V). Moreover, the above catalyst shows excellent ZAB performance, with an outstanding specific capacity (786 mAh g⁻¹), noteworthy maximum power density (139 mW cm⁻²), and extraordinary rechargeability (discharged and charged at 5 mA cm⁻² for more than 1000 h). Theoretical calculations reveal the vital importance of the preferable synergetic coupling effect between adjacent active sites in the Fe-Co-Ni trimetallic single-atomic sites during the ORR/OER processes. This study provides a new avenue for the investigation of bifunctional electrocatalysts with atomically dispersed trimetallic sites, which is intended for enhancing the ORR/OER performance in ZABs.

Front cover image: The cost-effective fabrication of silicon-carbon (Si/C) anode materials is crucial for their industrial application. However, challenges such as high raw material costs, difficult morphology control, and low product yield persist. In article number cey2.70004, Shen et al. develop a binder-regulated spray granulation strategy to convert photovoltaic silicon waste into high-yield, cost-effective Si/C materials for lithium-ion battery anodes, offering a new pathway for the value-added utilization of silicon waste and its industrial-scale application.

Developing low-cost and efficient catalysts for sustainable hydrogen (H₂) production to the reliance on precious metal is an important trend in the future development of catalysts. Herein, a simple in-situ one-step hydrothermal strategy is employed to modify the outer layer of Ni₃S₂ crystals with amorphous MoS₂ to construct core-shell heterostructures and heterogeneous interfaces, which promotes the chemisorption of intermediates, including hydrogen and oxygen, and realizes the coupling enhancement of hydrogen-evolution reaction (HER) and oxygen-evolution reaction (OER) in alkaline water electrolysis process. In 1.0 M KOH electrolyte, the overpotentials of the electrodes are 78 mV (HER) and 245 mV (OER) at a current density of 10 mA cm⁻², respectively. At the same time, the electrode has excellent stability for more than 100 h at a current density of 100 mA cm⁻², due to the amorphous structure. In addition, when used as an anode and cathode to form an electrolyzer, a cell voltage of only 1.5 V is required to produce a current density of 10 mA cm⁻². This study demonstrates that the constructed amorphous heterostructured interface synergistically promotes the dissociation of water and the adsorption of intermediates, providing a deep insight on how to accelerate the development of efficient catalysts.

Photoelectrochemical (PEC) water splitting holds significant promise for sustainable energy harvesting that enables efficient conversion of solar energy into green hydrogen. Nevertheless, achievement of high performance is often limited by charge carrier recombination, resulting in unsatisfactory saturation current densities. To address this challenge, we present a novel strategy for achieving ultrahigh current density by incorporating a bridge layer between the Si substrate and the NiOOH cocatalyst in this paper. The optimal photoanode (TCO/n–p–Si/TCO/Ni) shows a remarkably low onset potential of 0.92 V vs. a reversible hydrogen electrode and a high saturation current density of 39.6 mA·cm⁻², which is about 92.7% of the theoretical maximum (42.7 mA·cm⁻²). In addition, the photoanode demonstrates stable operation for 60 h. Our systematic characterizations and calculations demonstrate that the bridge layer facilitates charge transfer, enhances catalytic performance, and provides corrosion protection to the underlying substrate. Notably, the integration of this photoanode into a PEC device for overall water splitting leads to a reduction of the onset potential. These findings provide a viable pathway for fabricating high-performance industrial photoelectrodes by integrating a substrate and a cocatalyst via a transparent and conductive bridge layer.

All-solid-state batteries (ASSBs) have garnered significant interest as the next-generation in battery technology, praised for their superior safety and high energy density. However, a conductive agent accelerates the undesirable side reactions of sulfide-based solid electrolytes, resulting in poor electrochemical properties with increased interfacial resistance. Here, we propose a wet chemical method rationally designed to achieve a conformal coating of lithium–indium chloride (Li₃InCl₆) onto vapor-grown carbon fibers (VGCFs) as conductive agents. First, with the advantage of the Li₃InCl₆ protective layer, use of VGCF@Li₃InCl₆ leads to enhanced interfacial stability and improved electrochemical properties, including stable cycle performance. These results indicate that the Li₃InCl₆ protective layer suppresses the unwanted reaction between Li₆PS₅Cl and VGCF. Second, VGCF@Li₃InCl₆ effectively promotes polytetrafluoroethylene fibrillization, leading to a homogeneous electrode microstructure. The uniform distribution of the cathode active material in the electrode results in reduced charge-transfer resistance and enhanced Li-ion kinetics. As a result, a full cell with the LiNi_xMn_yCo_zO₂/VGCF@Li₃InCl₆ electrode shows an areal capacity of 7.7 mAh cm⁻² at 0.05 C and long-term cycle stability of 77.9% over 400 cycles at 0.2 C. This study offers a strategy for utilizing stable carbon-based conductive agents in sulfide-based ASSBs to enhance their electrochemical performance.