Energy & Environmental Materials最新文献

The purpose of this study is to develop novel P-Mo-V heteropoly compound catalysts for the oxidation of methacrolein to methacrylic acid. The introduction of Cu, as a modifying element, was employed to enhance the catalytic performance. Experimental results show that the addition of Cu significantly improved the catalyst performance, increasing the conversion rate of methacrolein from 17.2% to 84.2%, while the yield of methacrylic acid was boosted from 5.5% to 51.7%. A series of characterization results showed that both P-Mo-V and Cu-P-Mo-V catalysts primarily exhibited the crystal phase of [PMo₁₂O₄₀]³⁻, with a small amount of [PMo₁₁VO₄₀]³⁻ phase. However, the Cu-P-Mo-V catalyst exhibited much better oxidation–reduction ability compared to the P-Mo-V catalyst. Isolated Cu atoms were found to exist in a highly decentralized tetrahedral coordination structure, bridged by oxygen atoms within the heteropoly compound framework. The addition of Cu resulted in notable alterations in the modulation of the surface electronic structure, enhancement of oxidation–reduction ability, and optimization of the reaction pathway, thereby improving the overall catalytic activity of the catalyst. This study not only provides new insights into the modification of P-Mo-V heteropoly compound catalysts but also lays a foundation for understanding their catalytic mechanisms in organic synthesis reactions, demonstrating the potential of modifying elements in improving catalyst performance.

The LiNi_xCo_yMn_1-x-yO₂ (NCM) cathode materials have emerged as critical components in lithium-ion batteries due to their high energy and power densities. The co-precipitation method is widely used in laboratory and industry settings to optimize the crystallinity, grain morphology, particle size, and sphericity of precursor materials, directly affecting NCM battery performance. This review addresses the nucleation mechanism and the thermodynamic and kinetic reaction processes of co-precipitation. The comprehensive effects of key parameters on precursor physicochemical properties are also systematically interpreted. Notably, precursor characterization and physicochemical properties, including impurity levels and tolerance limits relevant to production, are highlighted. Finally, optimization strategies for developing high-quality precursor materials toward commercialization are proposed. This systematic review provides a deeper understanding of precursor optimization and advances relevant theories for the development of NCM cathode materials.

Selective extraction of precious metals from urban mines plays a crucial role in mitigating the risk of depletion of precious metal resources and reducing waste pollution. However, a major obstacle in precious metal extraction lies in the difficulty of distinguishing the subtle differences in the physicochemical characteristics between them, especially gold and palladium. Herein, a proton-driven separation system was presented for cascade recovery of gold and palladium from waste-printed circuit boards (W-PCBs) leachate using poly(amidoxime) (PAO) hydrogel. This exhibits an ultra-high capacity, extra-fast rate, and excellent selectivity for the extraction of Au(III) and Pd(II). Notably, the separation of Au(III) and Pd(II) can be achieved with high selectivity at pH = 0, resulting in a remarkable separation factor of k_{Au(III)/Pd(II)} = 36.5. This was demonstrated to originate from the differential mechanism of PAO hydrogel for the capture of Au(III) and Pd(II) under proton-mediated conditions. Drawing inspiration from the mechanism, the proton-driven cascade recovery system demonstrates remarkable efficiency in sequentially recovering 99.92% of gold and 99.05% of palladium from W-PCBs acid leachate. This research opens up a strategy to precisely separate and recover precious metals from e-waste of urban mines.

Solid-state lithium batteries are considered one of the most promising next-generation energy storage technologies owing to their safety and high energy density. The key to solid-state lithium battery advancement lies in the design and optimization of suitable solid-state electrolytes. Among various solid-state electrolytes, solid-state composite polymer electrolytes offer the combined benefits of solid inorganic electrolytes and solid polymer electrolytes. In particular, Li_1 + xAl_xTi_2 − x(PO₄)₃ (LATP)/polymer composite polymer electrolytes exhibit high ionic conductivity due to LATP and improved flexibility from the polymer matrix. These systems also demonstrate robust mechanical properties and excellent electrode contact. While recent reviews have primarily focused on the performance of LATP/polymer composite polymer electrolytes and the general effects of composite polymer electrolyte modifications for solid-state lithium battery applications, this review provides a concise overview of the Li⁺ transport mechanisms in LATP/polymer composite polymer electrolytes and strategies to enhance ionic conductivity. It highlights several modification approaches, including the use of fillers, additives, and LATP coatings, which markedly influence the performance of composite polymer electrolytes across different polymer matrices. Finally, the review addresses the challenges of LATP/polymer composite polymer electrolytes and outlines key research directions for developing advanced composite polymer electrolytes for high-performance solid-state lithium batteries.

Redox-active covalent organic polymers (COPs) have emerged as appealing renewable electrode materials for next-generation Li-ion batteries, but their performance is limited by insufficient redox sites and inadequate Li-ion diffusion. Here, we develop a novel class of mesoporous covalent organic polymer (namely TF-Azo-COP) bearing multiple redox sites and explore its first use as efficient 18-electron-redox anodes for superior Li-ion storage in both coin-type and fiber-type batteries. The newly produced TF-Azo-COP involves three types of active sites including C=N in triazines and imines, N=N in azo, and C₆-ring aromatics to enable 18-Li-ion storage on one repeatable segment, while affording extended π-conjugation for fast electron transfer and a pore size of ~2.5 nm for facilitated ion diffusion with a high coefficient up to ~10⁻¹⁰ cm² s⁻¹—superior to some reported organic electrodes. Meriting from the above, pairing TF-Azo-COP with metal Li endows a coin cell with good cycling stability and a large reversible capacity of 795.4 mAh g⁻¹ at 0.1 A g⁻¹—representing one of the best performances among reported organic electrodes. When coupled with fiber-shaped LiFePO₄ cathodes, the assembled fiber cell delivers an excellent combination of linear capacity (0.23 mAh cm⁻¹), energy density (0.55 mWh cm⁻¹), cycling stability (250 cycles), and good flexibility.

Carbon coatings for silicon (Si)-based anode materials are essential for designing high-performance Li-ion batteries (LIBs). The coatings prevent direct contact with the electrolyte and enhance anode performance. However, conventional carbon coatings are limited by their volume expansion and structural degradation, which lead to capacity fading and reduced durability. This study introduces a scalable and practical one-step carbon-coating strategy for directly coating silicon suboxide (SiO_x)-based materials using aqueous quasi-defect-free reduced graphene oxide (QrGO) without post-treatment, unlike conventional graphene oxide (GO)-based coating methods. This simple process enables uniform encapsulation with QrGO for a highly adhesive and conductive coating. The QrGO-based composite anode material has several advantages, including reduced cracking due to volume expansion and enhanced charge carrier transport, as well as an increased Si content of 20 wt.% compared to the 5 wt.% in typical commercial Si-based active materials. In particular, the capacity retention of the QrGO-coated Si electrodes dramatically increases at high C-rate. The full cell exhibited long-term stability and capacity that were twice that of commercial SiO_x-based cells. Therefore, the QrGO-based one-step coating process represents a scalable, transformative, and commercially viable strategy for developing high-performance LIBs.

Covalent organic frameworks have emerged as a hot spot in the field of photocatalysis due to their excellent structural tunability, high specific surface area, high porosity, and good chemical stability. Specifically, they exhibit distinctive optoelectronic features by integrating different molecular building blocks with appropriate links, constructing an π-conjugated system, or introducing electron donor–acceptor units into the conjugated framework. The reasonably adjusted band structure yields excellent photocatalytic activity of covalent organic framework materials. In this review, we comprehensively focus on applications of covalent organic framework materials as effective photocatalysts within the realm of hydrogen production, CO₂ reduction, pollutant degradation, organic conversion and other aspects. The discussion encompasses synthesis methods and reaction types of covalent organic frameworks. This review also discusses the state-of-the-art research progress, performance optimization strategies and the diverse manifestations of covalent organic framework materials used in photocatalysis. Finally, the main challenges and prospects aimed at further improving the photocatalytic performance of covalent organic frameworks are briefly proposed. By giving us a thorough understanding of the structural complexities of covalent organic frameworks and their essential role in photocatalytic processes, this effort advances our understanding and serves as a guide for the future design and development of novel covalent organic frameworks.

This work explores the potential of La_1-xPr_xNiO_4+δ thin films fabricated by Pulsed Injection Metal–Organic Chemical Vapor Deposition as oxygen electrodes for low-temperature solid oxide cells. La_1-xPr_xNiO_4+δ materials offer promising mixed ionic and electronic conductivity and high oxygen reduction reaction kinetics. In this study, we focus on the microstructural and electrochemical properties of LaPrNiO_4+δ thin films deposited at various temperatures (600–650 °C), revealing that a two-temperature deposition process yields nano-architectured films with a dense bottom film and a porous nano-columnar top layer of the same material. Electrochemical impedance spectroscopy and electrical conductivity relaxation experiments demonstrate enhanced surface exchange coefficients compared to bulk LaPrNiO_4+δ and La₂NiO_4+δ and high performance, with polarization resistances as low as 0.10 Ω cm² at 600 °C and 1.00 at 500 °C. To better understand the electrochemical behavior of these electrodes, we investigated the limiting mechanisms of oxygen reduction by analyzing the kinetic response to varying oxygen partial pressures and performing detailed impedance analyses. These nano-columnar LaPrNiO_4+δ oxygen electrodes were also deposited on commercial half-cells, enabling the resulting full cells to operate successfully in both reversible solid oxide fuel cell and electrolysis cell modes, reaching a performance of 0.34 W cm⁻² at 600 °C in reversible solid oxide fuel cell mode. This work underscores the promise of LaPrNiO_4+δ thin films for efficient low-temperature-solid oxide cells while addressing challenges in durability and stability.

A versatile spectroelectrochemical measurement method of surface-enhanced Raman scattering spectroscopy is developed, and its capability is assessed in an actual electrochemical system. The spectroelectrochemical cell consists of a plasmonic sensor with metal nanoparticles and a wire-type working electrode. The advantages of this method over conventional surface-enhanced Raman scattering methods are as follows: 1) surface-enhanced Raman scattering for electrode materials that show little plasmon resonance; and 2) measurement without undesirable influences on the physical and chemical states of the electrode surface and transport phenomena of reaction species. During the measurement, the sensor contacts the working electrode wire at a single point, allowing the surface-enhanced Raman scattering signal to be obtained from the interfacial area of the working electrode surface without significantly disturbing the mass transfer of the reaction species. As plasmon-active metal nanoparticles are modified on the sensor surface in advance, destructive and complicated pretreatment processes on the working electrode are not required. The method is applied to the in situ analysis of electrolyte decomposition reactions in a Li metal battery to reveal the potential of each decomposition product of an organic solvent containing Li. The obtained surface-enhanced Raman scattering spectrum corresponding to the voltammogram reveals the pathway for obtaining decomposition products, such as Li₂CO₃. In particular, Li₂C₂ was clearly detected with our setup. It is also revealed from the setup that the Ni electrode surface, in contrast to the Cu, does not hold a stable Li-containing composite layer. Such in situ chemical information will contribute to the effective interfacial design of high-performance batteries.

The exceptional resistive switching characteristics and neuromorphic computational potential of memristors are crucial for advancing information processing in both traditional and non-traditional computing paradigms. However, the non-ideal resistive switching behavior of conventional oxide-based memristors hardly meets the performance requirements for neuromorphic computing applications. Besides, the two-terminal memristors are restricted by their configuration limitations toward multi-field/multi-functional modulation. Herein, this article presents a 2D GaSe/MoS₂ heterojunction thin-film transistor with four-terminal (4-T) tuning capability and flexible programming/erasing operations for non-volatile storage. The heterojunction transistor demonstrates an exceptional resistance switching ratio exceeding 10⁷, an ultra-wide modulation range of 10–10⁶, highly reliable stability, and cyclic durability. The in situ Kelvin probe force microscope and dynamic characterization reveal the conduction mediated by defect-induced space charge limitations, as well as the tuning filling process of trap states within the channel by dual-gate terminals. This device functions as a 4-T artificial synapse, capable of achieving basic optoelectronic synaptic operations. The self-denoising and pattern recognition capabilities exhibited by artificial neural networks based on this device serve as excellent examples for developing efficient and energy-saving neuromorphic computing architectures.