Energy & Environmental Materials最新文献

Cobalt pentlandite (Co₉S₈) is a promising non-precious catalyst due to its superior oxygen reduction reaction activity and excellent stability. However, its oxygen reduction reaction catalytic activity has traditionally been limited to the four-electron pathway because of strong *OOH intermediate adsorption. In this study, we synthesized electron-deficient Co₉S₈ nanocrystals with an increased number of Co³⁺ states compared to conventional Co₉S₈. This was achieved by incorporating a high density of surface ligands in small-sized Co₉S₈ nanocrystals, which enabled the transition of the electrochemical reduction pathway from four-electron oxygen reduction reaction to two-electron oxygen reduction reaction by decreasing *OOH adsorption strength. As a result, the Co³⁺-enriched Co₉S₈ nanocrystals exhibited a high onset potential of 0.64 V (vs RHE) for two-electron oxygen reduction reaction, achieving H₂O₂ selectivity of 70–80% over the potential range from 0.05 to 0.6 V. Additionally, these nanocrystals demonstrated a stable H₂O₂ electrosynthesis at a rate of 459.12 mmol g⁻¹ h⁻¹ with a H₂O₂ Faradaic efficiency over 90% under alkaline conditions. This study provides insights into nanoscale catalyst design for modulating electrochemical reactions.

High-temperature performance of energy storage dielectric polymers is desired for many electronics and electrical applications, but the trade-off between energy density and temperature stability remains fundamentally challenging. Here, we report a general material design strategy to enhance energy storage performance at high temperatures by crosslinking a polar polymer and a high glass-transition temperature polymer as a crosslinked binary blend. Such crosslinked binary polymers display a temperature-insensitive and high energy density behavior of about 6.2 ~ 8.5 J cm⁻³ up to 110 °C, showing a significant enhancement in thermal resistant properties and consequently outperforming most of the other ferroelectric polymers. Further microstructural investigations reveal that the improved thermal stability stems from the confinement effect on conformational motion of the crosslinking network, which is evidenced by the increased rigid amorphous fraction and steady intermolecular distance of amorphous regions from temperature-dependent X-ray diffraction results. Our findings provide a general and straightforward strategy to attain temperature-stable, high-energy-density polymer-based dielectrics for energy storage capacitors.

Alpha-voltaic cell is a type of micro nuclear battery that provides several decades of reliable power in the nanowatt to microwatt range, supplying for special applications where traditional chemical batteries or solar cells are difficult to operate. However, the power conversion efficiency of the alpha-voltaic cells reported are still far behind the theoretical limit, making the development of alpha-voltaic cell challenging. Developing advanced semiconductor transducers with higher efficiency in converting the energy of alpha particles into electric energy is proving to be necessary for realizing high-power conversion efficiency. Herein, we propose an alpha-voltaic cell based on SiC PIN transducer that includes a sensitive region with an area of 1 cm², a width of 51.2 μm, and a charge collection efficiency of 95.6% at 0 V bias. We find that optimizing the unintentional doping concentration and crystal quality of the SiC epitaxial layer can significantly increase the absorption and utilization of the energy of alpha particles, resulting in a 2.4-fold enhancement in power conversion efficiency compared with that of the previous study. Electrical properties of the SiC alpha-voltaic cell are measured using an He-ion accelerator as the equivalent α-radioisotopes, with the best power conversion efficiency of 2.10% and maximum output power density of 406.66 nW cm⁻² is obtained. Our research makes a big leap in SiC alpha-voltaic cell, bridging the gap between micro nuclear batteries and practical applications in micro-electromechanical systems, micro aerial vehicles, and tiny satellites.

Nanofiltration (NF) membranes with exceptional ion selectivity and permeability are needed for the recovery of lithium from waste lithium-ion batteries. Herein, inspired by the homogeneous microchannels in the skeletal structure of glass sponges, an innovative biomimetic sponge-like sub-nanostructured NF membrane was designed using an alkali-induced MXene (AMXene)-ethyl formate (EF)-induced bulk/interfacial diffusion decoupling strategy to simultaneously improve Li⁺/Co²⁺ selectivity and membrane permeability. The Li⁺/Co²⁺ separation factor (S_Li,Co = 24) of the engineered membrane was improved by an order of magnitude compared to that of an NF270 membrane (S_Li,Co = 2). The selectivity of Mg²⁺/Na⁺ ($�B_{\text{NaCl}}�/�B_{{\text{MgCl}}_2}$ = 286) and $��{\mathrm{SO}}_4^{�2�-�}�$/Cl⁻ ($�B_{\text{NaCl}}�/�B_{{\text{NaSO}}_4}$ = 941) increased by 3 ~ 12 times, and the permeability (25.8 L m⁻² h⁻¹ bar⁻¹) remained at a desirable level, beyond the current upper bound of the other cutting-edge membranes. The superior performance was attributed to the limited release of amine in bulk phase and the boosted interfacial diffusion by reducing interfacial energy barrier during the interfacial polymerization reaction, which were realized via the synergetic effects of AMXene and EF. This approach yielded a biomimetic sponge-like sub-nanostructured NF membrane with controlled homogeneous pore radii (0.202 nm) and a thickness as small as 16.08 nm, which led to high ion selectivity and permeability. The engineered membrane was capable of efficient separation and recovery of Li⁺/metal ions.

Metal dichalcogenide-based 2D materials, gained considerable attention recently as a hydrogen evolution reaction (HER) electrocatalyst. In this work, we synthesized MoSe₂-based electrocatalyst via hydrothermal route with varying phase contents (1T/2H) and respective HER performances were evaluated under the acidic media (0.5 m H₂SO₄), where best HER performance was obtained from the sample consisting of mixed 1T/2H phases, which was directly grown on a carbon paper (167 mV at 10 mA cm⁻²) Furthermore, HER performance of electrocatalyst was further improved by in-situ electrodeposition of Pt nanoparticles (0.15 wt%) on the MoSe₂ surface, which lead to significant enhancement in the HER performances (133 mV at 10 mA cm⁻²). Finally, we conducted density functional theory calculations to reveal the origin of such enhanced performances when the mixed 1T/2H phases were present, where phase boundary region (1T/2H heterojunction) act as a low energy pathway for H₂ adsorption and desorption via electron accumulation effect. Moreover, presence of the Pt nanoparticles tunes the electronic states of the MoSe₂ based catalyst, resulting in the enhanced HER activity at heterointerface of 1T/2H MoSe₂ while facilitating the hydrogen adsorption and desorption process providing a low energy pathway for HER. These results provide new insight on atomic level understanding of the MoSe₂ based catalyst for HER application.

With the pressing concern of the climate change, hydrogen will undoubtedly play an essential role in the future to accelerate the way out from fossil fuel-based economy. In this case, the role of membrane-based separation cannot be neglected since, compared with other conventional process, membrane-based process is more effective and consumes less energy. Regarding this, metal-based membranes, particularly palladium, are usually employed for hydrogen separation because of its high selectivity. However, with the advancement of various microporous materials, the status quo of the metal-based membranes could be challenged since, compared with the metal-based membranes, they could offer better hydrogen separation performance and could also be cheaper to be produced. In this article, the advancement of membranes fabricated from five main microporous materials, namely silica-based membranes, zeolite membranes, carbon-based membranes, metal organic frameworks/covalent organic frameworks (MOF/COF) membranes and microporous polymeric membranes, for hydrogen separation from light gases are extensively discussed. Their performances are then summarized to give further insights regarding the pathway that should be taken to direct the research direction in the future.

This study demonstrates the fabrication of mesoporous tungsten trioxide (WO₃)-decorated flexible polyimide (PI) electrodes for the highly sensitive detection of catechol (CC) and hydroquinone (HQ), two environmental pollutants. Organic–inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly (EISA) and electrospray methods. The EISA process is induced by a temperature gradient during electrospray, and the heated substrate partially decomposes the organic parts etched by O₂ plasma, creating mesoporous structures. Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response. Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO₃ surfaces. The proposed sensor shows high sensitivity, a wide linear range, and a low detection limit for both individual and simultaneous determination of CC and HQ. Real sample analysis on river water confirms practical applicability. The WO₃-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants, contributing to environmental safety measures.

Hydrophobic nanofiber composite membranes comprising polyimide and metal–organic frameworks are developed for desalination via direct contact membrane distillation (DCMD). Our study demonstrates the synthesis of hydrophobic polyimides with trifluoromethyl groups, along with superhydrophobic UiO-66 (hMOF) prepared by phenylsilane modification on the metal-oxo nodes. These components are then combined to create nanofiber membranes with improved hydrophobicity, ensuring long-term stability while preserving a high water flux. Integration of hMOF into the polymer matrix further increases membrane hydrophobic properties and provides additional pathways for vapor transport during MD. The resulting nanofiber composite membranes containing 20 wt% of hMOFs (PI-1-hMOF-20) were able to desalinate hypersaline feed solution of up to 17 wt% NaCl solution, conditions that are beyond the capability of reverse osmosis systems. These membranes demonstrated a water flux of 68.1 kg m⁻² h⁻¹ with a rejection rate of 99.98% for a simulated seawater solution of 3.5 wt% NaCl at 70 °C, while maintaining consistent desalination performance for 250 h.

The intricate sulfur redox chemistry involves multiple electron transfers and complicated phase changes. Catalysts have been previously explored to overcome the kinetic barrier in lithium–sulfur batteries (LSBs). This work contributes to closing the knowledge gap and examines electrocatalysis for enhancing LSB kinetics. With a strong chemical affinity for polysulfides, the electrocatalyst enables efficient adsorption and accelerated electron transfer reactions. Resulting cells with catalyzed cathodes exhibit improved rate capability and excellent stability over 500 cycles with 91.9% capacity retention at C/3. In addition, cells were shown to perform at high rates up to 2C and at high sulfur loadings up to 6 mg cm⁻². Various electrochemical, spectroscopic, and microscopic analyses provide insights into the mechanism for retaining high activity, coulombic efficiency, and capacity. This work delves into crucial processes identifying pivotal reaction steps during the cycling process at commercially relevant areal capacities and rates.

The development of lithium-ion batteries with high-energy densities is substantially hampered by the graphite anode's low theoretical capacity (372 mAh g⁻¹). There is an urgent need to explore novel anode materials for lithium-ion batteries. Silicon (Si), the second-largest element outside of Earth, has an exceptionally high specific capacity (3579 mAh g⁻¹), regarded as an excellent choice for the anode material in high-capacity lithium-ion batteries. However, it is low intrinsic conductivity and volume amplification during service status, prevented it from developing further. These difficulties can be successfully overcome by incorporating carbon into pure Si systems to form a composite anode and constructing a buffer structure. This review looks at the diffusion mechanism, various silicon-based anode material configurations (including sandwich, core-shell, yolk-shell, and other 3D mesh/porous structures), as well as the appropriate binders and electrolytes. Finally, a summary and viewpoints are offered on the characteristics and structural layout of various structures, metal/non-metal doping, and the compatibility and application of various binders and electrolytes for silicon-based anodes. This review aims to provide valuable insights into the research and development of silicon-based carbon anodes for high-performance lithium-ion batteries, as well as their integration with binders and electrolyte.