Carbon Energy最新文献

As the cyclable sodium ions' primary suppliers, O3-type layer-structured manganese-based oxides are recognized as one of the most competitive cathode candidates for sodium-ion batteries. Suffering from complex structural transformations and transition metal migration during the sodium intercalation/deintercalation process, particularly at high voltage, the energy density and lifespan cannot satisfy the increasing demand. The orbital and electronic structure of the octahedral center metal element plays an important role in maintaining the octahedral structural integrity and improving the Na⁺ diffusivity by the introduced heterogeneous [Me–O] (Me: transition metals) chemical bonding. Herein, inspired by the 4f and 5d orbital bonding possibility from the abundant configuration of extranuclear electrons and large ion radius, O3-type Na[La_0.01Ni_0.3Mn_0.54Cu_0.1Ti_0.05]O₂ was synthesized with a nearly single crystal structure. Based on the experimental and computational results, the introduced heterogeneous [La–O] chemical bond with larger bond strength can not only ensure the stability of the lattice oxygen framework and the reversibility of oxygen redox but also optimize the oxygen local electronic structure resulting from La 5d and O 2p orbital mixing due to O 2p → La 5d charge transfer. It delivers an optimal electrochemical performance with a high energy density and cycling lifespan.

The low-energy electrochemical production of hydrogen peroxide (H₂O₂) has garnered significant attention as a viable alternative to traditional industrial routes, with the goal of achieving carbon neutrality. For their H₂O₂ selectivity in the two-electron oxygen reduction reaction (ORR), the coordination environment of tungsten (W)-based materials is critical. In this study, atomically dispersed W single atoms were immobilized on N-doped carbon substrates by a facile pyrolysis method to obtain a W single-atom catalyst (W-SAC). The coordination environment of an isolated W single atom with a tetra-coordinated porphyrin-like structure in W-SAC was determined by X-ray photoelectron spectroscopy and X-ray absorption spectroscopy analysis. Notably, the as-prepared W-SAC showed superior two-electron ORR activity in 0.1 M KOH solution, including high onset potential (0.89 V), high H₂O₂ selectivity (82.5%), and excellent stability. By using differential phase contrast-scanning transmission electron microscopy and density functional theory calculations, it is revealed that the charge symmetry-breaking of W atoms changes the adsorption behavior of the intermediates, leading to enhanced reactivity and selectivity for two-electron ORR. This work broadens the avenue for understanding the charge transfer of W-based electrocatalytic materials and the in-depth reaction mechanism of SACs in two-electron ORR.

Lithium metal shows a great advantage as the most promising anode for its unparalleled theoretical specific capacity and extremely low electrochemical potential. However, uncontrolled lithium dendrite growth and severe side reactions of the reactive intermediates and organic electrolytes still limit the broad application of lithium metal batteries. Herein, we propose 4-nitrobenzenesulfonyl fluoride (NBSF) as an electrolyte additive for forming a stable organic–inorganic hybrid solid electrolyte interphase (SEI) layer on the lithium surface. The abundance of lithium fluoride and lithium nitride can guarantee the SEI layer's toughness and high ionic conductivity, achieving dendrite-free lithium deposition. Meanwhile, the phenyl group of NBSF significantly contributes to both the chemical stability of the SEI layer and the good adaptation to volume changes of the lithium anode. The lithium–oxygen batteries with NBSF exhibit prolonged cycle lives and excellent cycling stability. This simple approach is hoped to improve the development of the organic–inorganic SEI layer to stabilize the lithium anodes for lithium–oxygen batteries.

Back cover image: BiVO₄ is a promising photoanode material for photoelectrocatalytic water decomposition. However, it still suffers from insufficient photoelectrocatalytic efficiency. Liang et al. introduced Fe-doped carbon nitride to increase the light absorption capacity of BIVO₄ photoanode and double electrode stacking to boost the light utilization rate. This work is beneficial to the design, preparation, and large-scale application of the next generation of high-performance photoanodes.

Front cover image: Solar-driven CO₂ conversion to solar fuels via semiconductor-photocatalysis is promising, however, it suffers from low selectivity and efficiency due to the lack of desired functionalities of the photocatalyst, and in article number cey2420, Xuezhong Gong et al. demonstrated the selective photoreduction of CO₂ to CO using elaborately fabricated ultrathin Bi₁₂O₁₇Cl₂ nanosheets, identify the functions of bismuth clusters and oxygen vacancies, elucidate synergetic effect, and provide new research approach for preparing smart multi-functional photocatalysts.

Diamond possesses excellent thermal conductivity and tunable bandgap. Currently, the high-pressure, high-temperature, and chemical vapor deposition methods are the most promising strategies for the commercial-scale production of synthetic diamond. Although diamond has been extensively employed in jewelry and cutting/grinding tasks, the realization of its high-end applications through microstructure engineering has long been sought. Herein, we discuss the microstructures encountered in diamond and further concentrate on cutting-edge investigations utilizing electron microscopy techniques to illuminate the transition mechanism between graphite and diamond during the synthesis and device constructions. The impacts of distinct microstructures on the electrical applications of diamond, especially the photoelectrical, electrical, and thermal properties, are elaborated. The recently reported elastic and plastic deformations revealed through in situ microscopy techniques are also summarized. Finally, the limitations, perspectives, and corresponding solutions are proposed.

Rational design and construction of oxygen reduction reaction (ORR) electrocatalysts with high activity, good stability, and low price are essential for the practical applications of renewable energy conversion devices, such as metal-air batteries. Electronic modification through constructing metal/semiconductor Schottky heterointerface represents a powerful strategy to enhance the electrochemical performance. Herein, we demonstrate a concept of Schottky electrocatalyst composed of uniform Co nanoparticles in situ anchored on the carbon nanotubes aligned on the carbon nanosheets (denoted as Co@N-CNTs/NSs hereafter) toward ORR. Both experimental findings and theoretical simulation testify that the rectifying contact could impel the voluntary electron flow from Co to N-CNTs/NSs and create an internal electric field, thereby boosting the electron transfer rate and improving the intrinsic activity. As a consequence, the Co@N-CNTs/NSs deliver outstanding ORR activity, impressive long-term durability, excellent methanol tolerance, and good performance as the air-cathode in the Zn-air batteries. The design concept of Schottky contact may provide the innovational inspirations for the synthesis of advanced catalysts in sustainable energy conversion fields.

Potassium-ion batteries (PIBs) offer a cost-effective and resource-abundant solution for large-scale energy storage. However, the progress of PIBs is impeded by the lack of high-capacity, long-life, and fast-kinetics anode electrode materials. Here, we propose a dual synergic optimization strategy to enhance the K⁺ storage stability and reaction kinetics of Bi₂S₃ through two-dimensional compositing and cation doping. Externally, Bi₂S₃ nanoparticles are loaded onto the surface of three-dimensional interconnected Ti₃C₂T_x nanosheets to stabilize the electrode structure. Internally, Cu²⁺ doping acts as active sites to accelerate K⁺ storage kinetics. Various theoretical simulations and ex situ techniques are used to elucidate the external–internal dual synergism. During discharge, Ti₃C₂T_x and Cu²⁺ collaboratively facilitate K⁺ intercalation. Subsequently, Cu²⁺ doping primarily promotes the fracture of Bi₂S₃ bonds, facilitating a conversion reaction. Throughout cycling, the Ti₃C₂T_x composite structure and Cu²⁺ doping sustain functionality. The resulting Cu²⁺-doped Bi₂S₃ anchored on Ti₃C₂T_x (C-BT) shows excellent rate capability (600 mAh g^–1 at 0.1 A g^–1; 105 mAh g^–1 at 5.0 A g^–1) and cycling performance (91 mAh g^–1 at 5.0 A g^–1 after 1000 cycles) in half cells and a high energy density (179 Wh kg^–1) in full cells.

Hydrogen (H₂) has been regarded as a promising alternative to fossil-fuel energy. Green H₂ produced via water electrolysis (WE) powered by renewable energy could achieve a zero-carbon footprint. Considerable attention has been focused on developing highly active catalysts to facilitate the reaction kinetics and improve the energy efficiency of WE. However, the stability of the electrocatalysts hampers the commercial viability of WE. Few studies have elucidated the origin of catalyst degradation. In this review, we first discuss the WE mechanism, including anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER). Then, we provide strategies used to enhance the stability of electrocatalysts. After that, the deactivation mechanisms of the typical commercialized HER and OER catalysts, including Pt, Ni, RuO₂, and IrO₂, are summarized. Finally, the influence of fluctuating energy on catalyst degradation is highlighted and in situ characterization methodologies for understanding the dynamic deactivation processes are described.

Layered composite oxide materials with O3/P2 biphasic crystallographic structure typically demonstrate a combination of high capacities of the O3 phase and high operation voltages of the P2 phase. However, their practical applications are seriously obstructed by difficulties in thermodynamic phase regulation, complicated electrochemical phase transition, and unsatisfactory cycling life. Herein, we propose an efficient structural evolution strategy from biphase to monophase of Na_0.766+xLi_xNi_0.33−xMn_0.5Fe_0.1Ti_0.07O₂ through Li⁺ substitution. The role of Li⁺ substitution not only simplifies the unfavorable phase transition by altering the local coordination of transition metal (TM) cations but also stabilizes the cathode–electrolyte interphase to prevent the degradation of TM cations during battery cycling. As a result, the thermodynamically robust O3-Na_0.826Li_0.06Ni_0.27Mn_0.5Fe_0.1Ti_0.07O₂ cathode delivers a high capacity of 139.4 mAh g⁻¹ at 0.1 C and shows prolonged cycling life at high rates, with capacity retention of 81.6% at 5 C over 500 cycles. This work establishes a solid relationship between the thermodynamic structure evolution and electrochemistry of layered cathode materials, contributing to the development of long-life sodium-ion batteries.