Carbon Energy最新文献

Advanced oxygen carrier plays a pivotal role in various chemical looping processes, such as CO₂ splitting. However, oxygen carriers have been restricted by deactivation and inferior oxygen transferability at low temperatures. Herein, we design an Fe–O_v–Ce–triggered phase-reversible CeO_2−x·Fe·CaO ↔ CeO₂·Ca₂Fe₂O₅ oxygen carrier with strong electron-donating ability, which activates CO₂ at low temperatures and promotes oxygen transformation. Results reveal that the maximum CO₂ conversion and CO yield obtained with 50 mol% CeO_2−x·Fe·CaO are, respectively, 426% and 53.6 times higher than those of Fe·CaO at 700°C. This unique multiphase material also retains exceptional redox durability, with no obvious deactivation after 100 splitting cycles. The addition of Ce promotes the formation of the Fe–O_v–Ce structure, which acts as an activator, triggers CO₂ splitting, and lowers the energy barrier of C═O dissociation. The metallic Fe plays a role in consuming O²⁻_lattice transformed from Fe–O_v–Ce, whereas CaO acts as a structure promoter that enables phase-reversible Fe⁰ ↔ Fe³⁺ looping.

Layered manganese dioxide (δ-MnO₂) is a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to its high theoretical capacity, high operating voltage, and low cost. However, its practical application faces challenges, such as low electronic conductivity, sluggish diffusion kinetics, and severe dissolution of Mn²⁺. In this study, we developed a δ-MnO₂ coated with a 2-methylimidazole (δ-MnO₂@2-ML) hybrid cathode. Density functional theory (DFT) calculations indicate that 2-ML can be integrated into δ-MnO₂ through both pre-intercalation and surface coating, with thermodynamically favorable outcomes. This modification expands the interlayer spacing of δ-MnO₂ and generates Mn–N bonds on the surface, enhancing Zn²⁺ accommodation and diffusion kinetics as well as stabilizing surface Mn sites. The experimentally prepared δ-MnO₂@2-ML cathode, as predicted by DFT, features both 2-ML pre-intercalation and surface coating, providing more zinc-ion insertion sites and improved structural stability. Furthermore, X-ray diffraction shows the expanded interlayer spacing, which effectively buffers local electrostatic interactions, leading to an enhanced Zn²⁺ diffusion rate. Consequently, the optimized cathode (δ-MnO₂@2-ML) presents improved electrochemical performance and stability, and the fabricated AZIBs exhibit a high specific capacity (309.5 mAh/g at 0.1 A/g), superior multiplicative performance (137.6 mAh/g at 1 A/g), and impressive capacity retention (80% after 1350 cycles at 1 A/g). These results surpass the performance of most manganese-based and vanadium-based cathode materials reported to date. This dual-modulation strategy, combining interlayer engineering and interface optimization, offers a straightforward and scalable approach, potentially advancing the commercial viability of low-cost, high-performance AZIBs.

Front cover image: The development of lignin-based photocatalyst has become a cutting-edge strategy towards the high-value H₂O₂ production. However, the enhanced catalytic efficiency and stable environmental adaptability are crucial for the establishment of comprehensive photocatalytic H₂O₂ production system. In article number cey2.666, Xiao et al. propose a new-type lignin-based photocatalyst assisted by graphene oxide and delve into the pathways and mechanisms of the optimized photocatalytic process, providing scientific guidance for the development of a green, low-carbon, and circular economy.

Silicon–air (Si–air) batteries have received significant attention owing to their high theoretical energy density and safety profile. However, the actual energy density of the Si–air battery remains significantly lower than the theoretical value, primarily due to corrosion issues and passivation. This study used various metal–organic framework (MOF) materials, such as MIL-53(Al), MIL-88(Fe), and MIL-101(Cr), to modify Si anodes. The MOFs were fabricated to have different morphologies, particle sizes, and pore sizes by altering their central metal nodes and ligands. This approach aimed to modulate the adsorption behavior of H₂O, SiO₂, and OH⁻, thereby mitigating corrosion and passivation reactions. Under a constant current of 150 μA, Si–air batteries with MIL-53(Al)@Si, MIL-88(Fe)@Si, and MIL-101(Cr)@Si as anodes demonstrated lifetimes of 293, 412, and 336 h, respectively, surpassing the 276 h observed with pristine silicon anodes. Among these composite anodes, MIL-88(Fe)@Si displayed the best performance due to its superior hydrophobicity and optimal pore size, which enhance OH⁻ migration. This study offers a promising strategy for enhancing Si–air battery performance by developing an anodic protective layer with selective screening properties.

Back cover image: Fuel cells are electrochemical energy conversion devices that promise clean routes of generating energy for enabling carbon neutrality. The electrolyte membrane medium sandwiched between two electrodes plays a vital role in improving their conversion efficiency and the durability. In the article number cey2.695, Yang et al. provide a comprehensive overview on recent advances in nanofiber-based polyelectrolyte membranes for fuel cells. Emerging strategies for the use of electrospun nanofibers and natural nanofibers as proton-exchange membranes and anion-exchange membranes are carefully outlined, respectively. The key challenges and potential solutions in such fields are finally presented.

The exsolution method has garnered significant attention owing to its high efficacy in developing highly efficient and stable metal nanocatalysts. Herein, a versatile exsolution approach is developed to embed size-tunable metal nanocatalysts within a conductive metal pnictogenide matrix. The gas-phase reaction of Ru-substituted Ni–Fe-layered-double-hydroxide (Ni₂Fe_1−xRu_x-LDH) with pnictogenation reagents leads to the exsolution of Ru metal nanocatalysts and a phase transformation into metal pnictogenide. The variation in reactivity of pnictogenation reagents allows for control over the size of the exsolved metal nanocatalysts (i.e., nanoclusters for nitridation and single atoms for phosphidation), underscoring the effectiveness of the pnictogenation-driven exsolution strategy in stabilizing size-tunable metal nanocatalysts. The Ru-exsolved nickel–iron nitride/phosphide demonstrates outstanding electrocatalyst activity for the hydrogen evolution reaction, exhibiting a smaller overpotential and higher stability than Ru-deposited homologs. The high efficacy of pnictogenation-assisted exsolution in optimizing the performance and stability of Ru metal nanocatalysts is ascribed to the efficient interfacial electronic interaction between Ru metals and nitride/phosphide ions assisted by the inner sphere mechanism. In situ spectroscopic analyses highlight that exsolved Ru single atoms facilitate more efficient electron transfer to the reactants than the exsolved Ru nanoclusters, which is primarily responsible for the superior impact of the phosphidation-driven exsolution approach.

While silicon/carbon (Si/C) is considered one of the most promising anode materials for the next generation of high-energy lithium-ion batteries (LIBs), the industrialization of Si/C anodes is hampered by high-cost and low product yield. Herein, a high-yield strategy is developed in which photovoltaic waste silicon is converted to cost-effective graphitic Si/C composites (G-Si@C) for LIBs. The introduction of a binder improves the dispersion and compatibility of silicon and graphite, enhances particle sphericity, and significantly reduces the loss rate of the spray prilling process (from about 25% to 5%). As an LIB anode, the fabricated G-Si@C composites exhibit a capacity of 605 mAh g⁻¹ after 1200 cycles. The cost of manufacturing Si/C anode materials has been reduced to approximately $7.47 kg⁻¹, which is close to that of commercial graphite anode materials ($5.0 kg⁻¹), and significantly lower than commercial Si/C materials (ca. $20.74 kg⁻¹). Moreover, the G-Si@C material provides approximately 81.0 Ah/$ of capacity, which exceeds the current best commercial graphite anodes (70.0 Ah/$) and Si/C anodes (48.2 Ah/$). The successful implementation of this pathway will significantly promote the industrialization of high-energy-density Si/C anode materials.

Zinc-ion batteries (ZIBs) have significant potential for advancements in energy storage systems owing to their high level of safety and theoretical capacity. However, ZIBs face several challenges, such as cathode capacity degradation and short cycle life. Ordinary metal–organic frameworks (MOFs) are characterized by high specific surface areas, large pore channels, and controllable structures and functions, making them suitable for use in ZIB cathodes with good performance. However, the insulating properties of MOFs hinder their further development. In contrast, electronic conductive MOFs (EC-MOFs) show high electronic conductivity, which facilitates rapid electron transport and ameliorates the charging and discharging efficiency of ZIBs. This paper introduces the unique conduction mechanism of EC-MOFs and elaborates various strategies for constructing EC-MOFs with high conductivity and stability. Additionally, the synthesis methods of EC-MOF-based cathode materials and their properties in ZIBs are elucidated. Finally, this paper presents a summary and outlook on the advancements of EC-MOFs for ZIB cathodes. This review provides guidance for designing and applying EC-MOFs in ZIBs and other energy storage devices.

The controversies about the mechanism of sodium storage in hard carbon (HC) hinder its rational structural design. A series of porous HC materials using coal tar pitch show a reversible capacity of 377 mAh g⁻¹ and an initial Coulombic efficiency (ICE) of 87% as well as excellent cycling performance. More attention is paid to exploration of the relationships between the sodium status on various storage sites at different sodiation states and the ICE by solid-state ²³Na nuclear magnetic resonance spectroscopy. The adsorbed Na ions contribute the most to the irreversible capacity. The de-solvated Na ions entering the closed pores are reduced to Na atoms and aggregated to Na clusters. Also, this process contributes the most to the reversible capacity and is characteristic of a long plateau in the voltage profile. Intercalation is partially reversible; it is the main source of capacity for slope-type HCs but plays a minor role in the reversible capacity of plateau-type HCs. Therefore, increasing the content of the closed pores can improve the reversible plateau capacity and reducing the open mesopores of HC increases the ICE. These findings provide insights into the structural design and cost-efficient preparation of high-performance HC anode materials for advanced sodium-ion batteries.

Metallene has been widely considered as an advanced electrocatalytic material due to its large specific surface area and highly active reaction sites. Herein, we design and synthesize ultrathin rhodium metallene (Rh ML) with abundant wrinkles to supply surface-strained Rh sites for driving acetonitrile electroreduction to ethylamine (AER). The electrochemical tests indicate that Rh ML shows an ethylamine yield rate of 137.1 mmol g_cat⁻¹ h⁻¹ in an acidic solution, with stability lasting up to 200 h. Theoretical calculations reveal that Rh ML with wrinkle-induced compressive strain not only shows a lower energy barrier in the rate-determining step but also facilitates the ethylamine desorption process compared to wrinkle-free Rh ML and commercial Rh black. The assembled electrolyzer with bifunctional Rh ML shows an electrolysis voltage of 0.41 V at 10 mA cm⁻², enabling simultaneous ethylamine production and hydrazine waste treatment. Furthermore, the voltage of an assembled hybrid zinc–acetonitrile battery can effectively drive this electrolyzer to achieve the dual AER process. This study provides guidance for improving the catalytic efficiency of surface atoms in two-dimensional materials, as well as the electrochemical synthesis technology for series-connected battery–electrolyzer systems.