Carbon Energy最新文献

Front cover image: Oxygen carriers play pivotal roles in various chemical looping processes, such as CO₂ splitting. Nevertheless, they have been restricted by deactivation and inferior oxygen transferability at low temperatures, and in article number e70011, Sun et al. design a Fe–O_v–Ce-triggered phase-reversible CeO_2−x·Fe·CaO oxygen carrier with strong electron-donating ability, which activates CO₂ at low temperatures and promotes oxygen transformation.

Gel polymer electrolytes (GPEs) with high flame-retardant concentration can remarkably reduce the thermal runaway risk of lithium metal batteries (LMBs). However, higher flame-retardant content in GPEs always leads to increased leakage of active component and severe lithium corrosion, which greatly hinders the service life of LMBs. Herein, GPEs with high-loading triphenyl phosphate (TPP) are originally fabricated by coaxial electrospinning and stabilized by dual confinement effects, including chemisorption of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and physical encapsulation of polyacrylonitrile (PAN)/PVDF-HFP. These effects arise from the strong polar interactions between the −CF₃ group in PVDF-HFP and P=O group in TPP, as well as the superior anti-swelling property of PAN. To mitigate TPP-induced corrosion during cycling, the optimized Li anode is armored with LiF-rich solid electrolyte interphase (SEI) layer through immersing it in fluoroethylene carbonate-containing electrolyte. As expected, the corresponding Li||Li symmetric cells deliver long-term stable cycling behavior over 2400 h at 0.5 mA cm⁻², and the LiFePO₄||Li batteries hold a high-capacity retention ratio of 81.7% after 6000 cycles at 10 C with excellent flame retardancy. These findings offer new insight into designing the SEI layer for lithium metal in flame-retardant electrolytes, thus promoting the development and application of high-security LMBs.

Photoelectrochemistry is a promising method for the direct conversion of sunlight into valuable chemicals by combining the functions of solar panels and electrolyzers in one technology. In most studies, semiconductor/catalyst photoelectrode assemblies are used to achieve reasonable efficiencies. At the same time, unlike in dark electrochemical processes, the role of the catalyst is not straightforward in photoelectrochemistry, where the onset potential of the redox process should be mostly determined by the flatband potential of the semiconductor. In addition, the energy of holes (i.e., the surface potential) is independent of the applied bias; it is defined by the valence band (VB) position. In this study, we compared PdAu, Au, and Ni on Si photoanodes in the photoelectrochemical (PEC) oxidation of glycerol at record high current densities (> 180 mA cm^‒2), coupled to H₂ evolution at the cathode. We successfully decreased the energy requirement (i.e., the cell voltage) of the paired conversion of glycerol and water by 0.7 V by exchanging the widely studied Ni catalyst with PdAu. The catalyst choice also dictates the product distribution, resulting mainly in C3 products on PdAu, glycolate (C2 product) on Au, and formate (C1 product) on Ni, without complete mineralization of glycerol (CO₂ formation) that is difficult to rule out in dark electrochemical processes (as demonstrated by comparative measurements). Finally, we achieved a bias-free (standalone) operation with PdAu/Si and Au/Si photoanodes by combining the PEC oxidation of glycerol with oxygen reduction reaction (ORR).

The design of efficient and cost-effective bifunctional catalysts, which are capable of driving both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is of paramount importance for advancing overall water splitting. Here, we developed an innovative heterogeneous interface engineering strategy to boost the electrocatalytic performance of overall water splitting. This approach involves the synergistic integration of ultra-fine CoMoP nanocrystals coupled with three-dimensional (3D) porous C₃N₄/N-doped carbon (NC) architectures, constructing a distinctive CoMoP/C₃N₄/NC heterogeneous interface. The CoMoP/C₃N₄/NC exhibits distinguished overall water splitting performance. To drive the overall water splitting current of 10 mA cm⁻², the CoMoP/C₃N₄/NC||CoMoP/C₃N₄/NC electrolysis cell only needs an ultralow cell voltage of 1.496 V. The electronic properties and localized coordination environments characterizations, and density functional theory (DFT) calculations elucidate that the improved catalytic activities of CoMoP/C₃N₄/NC are primarily attributed to the synergistic interfacial coupling between CoMoP/C₃N₄/NC heterogeneous interface. A novel multi-site synergistic catalytic mechanism was revealed by the DFT calculations, in which the optimum H* adsorption site on CoMoP/C₃N₄/NC for HER is on the cobalt atoms in CoMoP with the ultralow Gibbs free energy of hydrogen bonding (ΔG_H*) of 0.018 eV, while for the OER, the optimum intermediates adsorption site of the CoMoP/C₃N₄/NC is on the carbon atoms in C₃N₄/NC. Besides, the intricately engineered 3D hierarchical porous framework of the CoMoP/C₃N₄/NC can facilitate the ion and electron transport and improve mass transfer, which gives rise to enhanced water splitting performance.

The practical application of lithium (Li) metal batteries (LMBs) faces challenges due to the irreversible Li deposition/dissolution process, which promotes Li dendrite growth with severe parasitic reactions during cycling. To address these issues, achieving uniform Li-ion flux and improving Li-ion conductivity of the separator are the top priorities. Herein, a separator (PCELS) with enhanced Li-ion conductivity, composed of polymer, ceramic, and electrically conductive carbon, is proposed to facilitate fast Li-ion transport kinetics and increase Li deposition uniformity of the LMBs. The PCELS immobilizes PF₆^– anions with high adsorption energies, leading to a high Li-ion transference number. Simultaneously, the PCELS shows excellent electrolyte wettability on both its sides, promoting rapid ion transport. Moreover, the electrically conductive carbon within the PCELS provides additional electron transport channels, enabling efficient charge transfer and uniform Li-ion flux. With these advantages, the PCELS achieves rapid Li-ion transport kinetics and uniform Li deposition, demonstrating excellent cycling stability over 100 cycles at a high current density of 12.0 mA cm^–2. Furthermore, the PCELS shows stable cycling performances in Li–S cell tests and delivers an excellent capacity retention of 95.45% in the Li|LiFePO₄ full-cell test with a high areal capacity of over 5.5 mAh cm^–2.

High-nickel cathode, LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811), and sulfide-solid electrolyte are a promising combination for all-solid-state lithium batteries (ASSLBs). However, this combination faces the issue of interfacial instability between the cathode and electrolyte. Given the surface alkalinity of NCM811, we propose a strategy to construct a solid–polymer–electrolyte (SPE) interphase on NCM811 surface by leveraging the surface alkaline residues to nucleophilically initiate the in-situ ring-opening polymerization of cyclic organic molecules. As a proof-of-concept, this study demonstrates that the ring-opening copolymerization of 1,3-dioxolane and maleic anhydride produces a homogeneous, compact, and conformal SPE layer on NCM811 surface to prevent the cathode from contact and reaction with Li₆PS₅Cl solid-state electrolyte. Consequently, the SPE-modified-NCM811 in ASSLBs exhibits high capacities of 193.5 mA h g^–1 at 0.2 C, 160.9 mA h g^–1 at 2.0 C and 112.3 mA h g^–1 at 10 C, and particularly, excellent long-term cycling stabilities over 11000 cycles with a 71.95% capacity retention at 10 C at 25°C, as well as a remained capacity of 117.9 mA h g^–1 after 8000 cycles at 30 C at 60°C, showing a great application prospect. This study provides a new route for creating electrochemically and structurally stable solid–solid interfaces for ASSLBs.

Silicon-based anode materials have garnered considerable attention in lithium-ion batteries (LIBs) due to their exceptionally high theoretical capacity and energy density. However, intrinsic challenges, such as significant volumetric expansion and the consequent degradation in cycling stability, severely hinder their practical application. As a result, development of silicon anodes that can effectively mitigate volumetric expansions, enhance cycling durability, and improve rate performance has emerged as a critical research focus. However, due to neglect of “size effects”, the modification strategy of silicon-based electrodes lacks systematic, scientific, and comprehensive guidance. Herein, this review starts from the “size effect” of silicon-based materials, and reveals in depth the different failure mechanisms of nano-silicon (Si NPs) and micro-silicon (μSi). Furthermore, this review provides targeted classification of modification strategies for Si NPs and μSi, and reviews comprehensively, in detail, and in depth the latest research progress on silicon-based materials. In addition, the review also comprehensively summarizes the cutting-edge dynamics of matching silicon-based electrodes with solid electrolytes to construct high-energy LIBs. It is hoped that this review can provide comprehensive and systematic scientific guidance for modification strategies of silicon-based electrodes, which is of great significance for promoting the industrialization process of silicon-based electrodes in high-energy LIBs.

Seawater electrolysis is promising for green hydrogen production, while its application is inhibited by sluggish anodic oxygen evolution reaction (OER) and rapid chloride corrosion-induced electrode deactivation. Herein, we report a conductive and ion-selective OER electrocatalyst with a CoFe alloy core and microporous metal-doped carbon shell. Co/Fe-N₄-C active sites in the shell optimize the adsorption strength of intermediates and synergize with the metal core to endow the catalyst with high OER activity and selectivity, while the rich ultra-micropores in the shell demonstrate a significant sieving effect to hinder Cl⁻ transfer, thus protecting the inner Co/Fe-N₄-C active sites and metal core from Cl⁻ corrosion. The catalyst is assembled in an alkaline seawater electrolyzer with an electrode geometric area of 254 cm² and delivers a current density of 3000 A m⁻² at 1.85 V for 330 h. Such catalysts can be synthesized in a large batch (100 g), providing sound opportunities for industrial seawater splitting.

Electrides, in which anionic electrons are trapped in structural cavities, have garnered significant attention for exceptional functionalities based on their low work function. In low-dimensional electrides, a strong quantum confinement of anionic electrons leads to many interesting phenomena, but a severe chemical instability due to their open structures is one of the major disadvantages for practical applications. Here we report that one-dimensional (1D) dititanium sulfide electride exhibits an extraordinary stability originating from the surface self-passivation and consequent durability in bifunctional electrocatalytic activity. Theoretical calculations identify the uniqueness of the 1D [Ti₂S]²⁺·2e⁻ electride, where multiple cavities form two distinct channel structures of anionic electrons. Combined surface structure analysis and in-situ work function measurement indicate that the natural formation of amorphous titanium oxide surface layer in air is responsible for the remarkable inertness in water and pH-varied solutions. This makes the [Ti₂S]²⁺·2e⁻ electride an ideal support for a heterogenous metal-electride hybrid catalyst, demonstrating the enhanced efficiency and superior durability in both the hydrogen evolution and oxygen reduction reactions compared to commercial Pt/C catalysts. This study will stimulate further exploratory research for developing a chemically stable electride in reactive conditions, evoking a strategy for a practical electrocatalyst for industrial energy conversions.

Enhancing the energy density of all-solid-state batteries (ASSBs) with lithium metal anodes is crucial, but lithium dendrite-induced short circuits limit fast-charging capability. This study presents a high-power ASSB employing a novel, robust solid electrolyte (SE) with exceptionally high stability at the lithium metal/SE interface, achieved via site-specific Nb doping in the argyrodite structure. Pentavalent Nb incorporation into Wyckoff 48h sites enhances structural stability, as confirmed by neutron diffraction, X-ray absorption spectroscopy, magic angle spinning nuclear magnetic resonance, and density functional theory calculations. While Nb doping slightly reduces ionic conductivity, it significantly improves interfacial stability, suppressing dendrite formation and enabling a full cell capable of charging in just 6 min (10-C rate, 16 mA cm⁻²). This study highlights, for the first time, that electrochemical stability, rather than ionic conductivity, is key to achieving high-power performance, advancing the commercialization of lithium metal-based ASSBs.