Energy & Environmental Materials最新文献

Solar irradiation can efficiently promote the kinetics of the oxygen evolution reaction (OER) during water splitting, where heterojunction catalysts exhibit excellent photoresponsive properties. However, insights into the origins of photoassisted OER catalysis remain unclear, especially the interfaced promotion under convergent solar irradiation (CSI). Herein, novel allotropic Co_5.47N/CoN heterojunctions were synthesized, and corresponding OER mechanisms under CSI were comprehensively uncovered from physical and chemical aspects using the in situ Raman technique and electrochemical cyclic voltammetry method. Our results provide a unique mechanism where high-energy UV light promotes the Co^3+/4+ conversion process in addition to the ordinary photoelectric effect excitation of the Co²⁺ material. Importantly, visible light under CSI can produce a photothermal effect for Co²⁺ excitation and Co^3+/4+ conversion, which promotes the OER significantly more than the usual photoelectric effect. As a result, Co_5.47N/CoN (containing 28% CoN) obtained 317.9% OER enhancement, which provides a pathway for constructing excellent OER catalysts.

Lithium–sulfur batteries (LSBs) are widely regarded as promising next-generation batteries due to their high theoretical specific capacity and low material cost. However, the practical applications of LSBs are limited by the shuttle effect of lithium polysulfides (LiPSs), electronic insulation of charge and discharge products, and slow LiPSs conversion reaction kinetics. Accordingly, the introduction of catalysts into LSBs is one of the effective strategy to solve the issues of the sluggished LiPS conversion. Because of their nearly 100% atom utilization and high electrocatalytic activity, single-atom catalysts (SACs) have been widely used as reaction mediators for LSBs' reactions. Excitingly, the SACs with asymmetric coordination structures have exhibited intriguing electronic structures and superior catalytic activities when compared to the traditional M–N₄ active sites. In this review, we systematically describe the recent advancements in the installation of asymmetrically coordinated single-atom structure as reactions catalysts in LSBs, including asymmetrically nitrogen coordinated SACs, heteroatom coordinated SACs, support effective asymmetrically coordinated SACs, and bimetallic coordinated SACs. Particularly noteworthy is the discussion of the catalytic conversion mechanism of LiPSs spanning asymmetrically coordinated SACs. Finally, a perspective on the future developments of asymmetrically coordinated SACs in LSB applications is provided.

Traditional heat conductive epoxy composites often fall short in meeting the escalating heat dissipation demands of large-power, high-frequency, and high-voltage insulating packaging applications, due to the challenge of achieving high thermal conductivity (k), desirable dielectric performance, and robust thermomechanical properties simultaneously. Liquid crystal epoxy (LCE) emerges as a unique epoxy, exhibiting inherently high k achieved through the self-assembly of mesogenic units into ordered structures. This characteristic enables liquid crystal epoxy to retain all the beneficial physical properties of pristine epoxy, while demonstrating a prominently enhanced k. As such, liquid crystal epoxy materials represent a promising solution for thermal management, with potential to tackle the critical issues and technical bottlenecks impeding the increasing miniaturization of microelectronic devices and electrical equipment. This article provides a comprehensive review on recent advances in liquid crystal epoxy, emphasizing the correlation between liquid crystal epoxy's microscopic arrangement, organized mesoscopic domain, k, and relevant physical properties. The impacts of LC units and curing agents on the development of ordered structure are discussed, alongside the consequent effects on the k, dielectric, thermal, and other properties. External processing factors such as temperature and pressure and their influence on the formation and organization of structured domains are also evaluated. Finally, potential applications that could benefit from the emergence of liquid crystal epoxy are reviewed.

High-temperature CO₂ electrolysis via solid oxide electrolysis cells (CO₂–SOECs) has drawn special attention due to the high energy convention efficiency, fast electrode kinetics, and great potential in carbon cycling. However, the development of cathode materials with high catalytic activity and chemical stability for pure CO₂ electrolysis is still a great challenge. In this work, A-site cation deficient dual-phase material, namely (Pr_0.4Ca_0.6)_xFe_0.8Ni_0.2O_3−δ (PCFN, x = 1, 0.95, and 0.9), has been designed as the fuel electrode for a pure CO₂–SOEC, which presents superior electrochemical performance. Among all these compositions, (Pr_0.4Ca_0.6)_0.95Fe_0.8Ni_0.2O_3−δ (PCFN95) exhibited the lowest polarization resistance of 0.458 Ω cm² at open-circuit voltage and 800 °C. The application of PCFN95 as the cathode in a single cell yields an impressive electrolysis current density of 1.76 A cm⁻² at 1.5 V and 800 °C, which is 76% higher than that of single cells with stoichiometric Pr_0.4Ca_0.6Fe_0.8Ni_0.2O_3−δ (PCFN100) cathode. The effects of A-site deficiency on materials' phase structure and physicochemical properties are also systematically investigated. Such an enhancement in electrochemical performance is attributed to the promotion of effective CO₂ adsorption, as well as the improved electrode kinetics resulting from the A-site deficiency.

Rechargeable lithium–sulfur (Li–S) batteries, featuring high energy density, low cost, and environmental friendliness, have been dubbed as one of the most promising candidates to replace current commercial rechargeable Li-ion batteries. However, their practical deployment has long been plagued by the infamous “shuttle effect” of soluble Li polysulfides (LiPSs) and the rampant growth of Li dendrites. Therefore, it is important to specifically elucidate the solvation structure in the Li–S system and systematically summarize the feasibility strategies that can simultaneously suppress the shuttle effect and the growth of Li dendrites for practical applications. This review attempts to achieve this goal. In this review, we first introduce the importance of developing Li–S batteries and highlight the key challenges. Then, we revisit the working principles of Li–S batteries and underscore the fundamental understanding of LiPSs. Next, we summarize some representative characterization techniques and theoretical calculations applied to characterize the solvation structure of LiPSs. Afterward, we overview feasible designing strategies that can simultaneously suppress the shuttle effect of soluble LiPSs and the growth of Li dendrites. Finally, we conclude and propose personal insights and perspectives on the future development of Li–S batteries. We envisage that this timely review can provide some inspiration to build better Li–S batteries for promoting practical applications.

Growing energy demand drives the rapid development of clean and reliable energy sources. In the past years, the exploration of novel materials with considerable efficiency and durability has drawn attention in the area of electrochemical energy conversion. Transition metal macrocyclic metallophthalocyanines (MPcs)-based catalysts with a peculiar 2D constitution have emerged with a promising future account of their highly structural tailorability and molecular functionality which greatly extend their functionalities as electrocatalytic materials for energy conversion. This review summarizes the systematic engineering of synthesis of MPcs and their analogs in detail, and mostly pays attention to the frontier research of MPc-based high-performance catalysts toward different electrocatalytic processes concerning hydrogen, oxygen, water, carbon dioxide, and nitrogen, with a particular focus on discussing the interrelationship between the electrocatalytic activity and component/structure, as well as functional applications of MPcs. Finally, we give the gaps that need to be addressed after much thought.

Since 2019, research into MXene derivatives has seen a dramatic rise; further progress requires a rational design for specific functionality. Herein, through a molecular design by selecting suitable functional groups in the MXene coating, we have implemented the dual N doping of the derivatives, nitrogen-doped TiO₂@nitrogen-doped carbon nanosheets (N-TiO₂@NC), to strike a balance between the active anatase TiO₂ at low temperatures, and carbon activation at high temperatures. The NH₃ reduction environment generated at 400 °C as evidenced by the in situ pyrolysis SVUV-PIMS process is crucial for concurrent phase engineering. With both electrical conductivity and surface Na⁺ availability, the N-TiO₂@NC achieves higher interface capacitive-like sodium storage with long-term stability. More than 100 mAh g⁻¹ is achieved at 2 A g⁻¹ after 5000 cycles. The proposed design may be extended to other MXenes and solidify the growing family of MXene derivatives for energy storage.

Grain boundaries (GBs) in perovskite polycrystalline films are the most sensitive place for the formation of the defect states and the accumulation of impurities. Thus, abundant works have been carried out to explore their properties and then try to solve the induced problems. Currently, two important issues remain. First, the role of GBs in charge carrier dynamics is unclear due to their component complexity/defect tolerance nature and the insufficiency in testing accuracy. Some works conclude that GBs are benign, while others consider GBs as carrier recombination centers. Things for sure are the deterioration in ion transport and perovskite decomposition. Second, to solve the known hazards of GBs, a lot of additives have been added to anchoring ions and passivate defects. But in most of those works, GBs and perovskite surfaces are treated in the same manner ignoring the fact that GB is essentially a homogeneous junction in a narrow and slender space, while surface is a heterogeneous junction with a stratified structure. In this review, we focus on works insight into GBs and additives for them. Additionally, we also discuss the prospects of the maturity of GB exploration toward upscaling the manufacture of perovskite photovoltaic and related optoelectronic devices.

Wearable triboelectric nanogenerators (TENGs) have attracted attention owing to their ability to harvest energy from the surrounding environment without maintenance. Herein, polyetherimide–Al₂O₃ (PAl) and polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP, PH) nanofiber membranes were used as tribo-positive and tribo-negative materials, respectively. Phytic acid-doped polyaniline (PANI)/cotton fabric (PPCF) and ethylenediamine (EDA)-crosslinked PAl (EPAl) nanofiber membranes were used as triboelectrode and triboencapsulation materials, respectively. The result showed that when the PAl–PH-based TENG was shaped as a circle with a radius of 1 cm, under the pressure of 50 N, and the frequency of 0.5 Hz, the open-circuit voltage (V_oc) and short-circuit current (I_sc) reached the highest value of 66.6 V and −93.4 to 110.1 nA, respectively. Moreover, the PH-based TENG could be used as a fabric sensor to detect fabric composition and as a sensor-inductive switch for light bulbs or beeping warning devices. When the PAl–PH-based TENG was shaped as a 5 × 5 cm² rectangle, a 33 μF capacitor could be charged to 15 V in 28 s. Interestingly, compared to PAl nanofiber membranes, EPAl nanofiber membranes exhibited good dyeing properties and excellent solvent resistance. The PPCF exhibited <5% resistance change after washing, bending, and stretching.

Calcium-ion batteries have been considered attractive candidates for large-scale energy storage applications due to their natural abundance and low redox potential of Ca²⁺/Ca. However, current calcium ion technology is still hampered by the lack of high-capacity and long-life electrode materials to accommodate the large Ca²⁺ (1.00 Å). Herein, an amorphous vanadium structure induced by Mo doping and in-situ electrochemical activation is reported as a high-rate anode material for calcium ion batteries. The doping of Mo could destroy the lattice stability of VS₄ material, enhancing the flexibility of the structure. The following electrochemical activation further converted the material into sulfide and oxides co-dominated composite (defined as MoVSO), which serves as an active material for the storage of Ca²⁺ during cycling. Consequently, this amorphous vanadium structure exhibits excellent rate capability, achieving discharge capacities of 306.7 and 149.2 mAh g⁻¹ at 5 and 50 A g⁻¹ and an ultra-long cycle life of 2000 cycles with 91.2% capacity retention. These values represent the highest level to date reported for calcium ion batteries. The mechanism studies show that the material undergoes a partial phase transition process to derive MoVSO. This work unveiled the calcium storage mechanism of vanadium sulfide in aqueous electrolytes and accelerated the development of high-performance aqueous calcium ion batteries.