Carbon Energy最新文献

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.

All-solid-state batteries (ASSBs) are a promising next-generation energy storage solution due to their high energy density and enhanced safety. To achieve this, specialized electrode designs are required to efficiently enhance interparticle lithium-ion transport between solid components. In particular, for active materials with high specific capacity, such as silicon, their volume expansion and shrinkage must be carefully controlled to maintain mechanical interface stability, which is crucial for effective lithium-ion transport in ASSBs. Herein, we propose a mechanical stress-tolerant all-solid-state graphite/silicon electrode design to ensure stable lithium-ion diffusion at the interface through morphology control of active material particles. Plate-type graphite with a high surface-area-to-volume ratio is used to maximize the dispersion of silicon within the electrode. The carefully designed electrode can accommodate the volume changes of silicon, ensuring stable capacity retention over cycles. Additionally, spherical graphite is shown to contribute to improved rate performance by providing an efficient lithium-ion diffusion pathway within the electrode. Therefore, the synergistic effect of our electrode structure offers balanced electrochemical performance, providing practical insights into the mechano–electrochemical interactions essential for designing high-performance all-solid-state electrodes.

The recovery and utilization of ubiquitous low-grade heat are crucial for mitigating the fossil energy crisis. However, uncontrolled spontaneous heat dissipation limits its practical application. Inspired by skeletal muscle thermogenesis, we develop a compressible wood phase change gel with mechano-controlled heat release by infiltrating xylitol gel into wood aerogel. The xylitol gel can store recovered low-grade heat for at least 1 month by leveraging its inherent energy barrier. The hierarchically aligned lamellar structure of wood aerogel facilitates mechanical adaptation, hydrogen bond formation, and energy dissipation between the wood aerogel and the xylitol gel, increasing the compressive strength and toughness of wood phase change gel fivefold compared to xylitol gel. This enhancement effect enables repetitive contact-separation motions between the wood phase change gel and the substrate during radial compression, overcoming the energy barrier and releasing approximately 178.6 J g⁻¹ of heat. As a proof-of-concept, the wood phase change gel serves as the hot side in a thermoelectric generator, providing about 2.13 W m⁻² of clean electricity by the controlled utilization of recovered solar heat. This study presents a sustainable method to achieve off-grid electricity generation through the controlled utilization of recovered low-grade heat.

The use of conjugated microporous polymers (CMPs) in photocatalytic CO₂ reduction (CO₂RR), leveraging solar energy and water to generate carbon-based products, is attracting considerable attention. However, the amorphous nature of most CMPs poses challenges for effective charge carrier separation, limiting their application in CO₂RR. In this study, we introduce an innovative approach utilizing donor π-skeleton engineering to enhance skeleton coplanarity, thereby achieving highly crystalline CMPs. Advanced femtosecond transient absorption and temperature-dependent photoluminescence analyses reveal efficient exciton dissociation into free charge carriers that actively engage in surface reactions. Complementary theoretical calculations demonstrate that our highly crystalline CMP (Py-TDO) not only greatly improves the separation and transfer of photoexcited charge carriers but also introduces additional charge transport pathways via intermolecular π–π stacking. Py-TDO exhibits outstanding photocatalytic CO₂ reduction capabilities, achieving a remarkable CO generation rate of 223.97 μmol g⁻¹ h⁻¹ without the addition of chemical scavengers. This work lays pioneering groundwork for the development of novel highly crystalline materials, advancing the field of solar-driven energy conversion.