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A dual-channel superstructured Ni single-atom catalyst with a unique axial oxygen coordination configuration was controllably constructed and affords a preeminent performance for convergent paired electrosynthesis of dimethyl carbonate from CO2.

Hydrogen transfer (H-transfer) is an important elementary reaction in chemistry and bioscience. It is often facilitated by the hydrogen bonds between the H-donor and acceptor. Here, at room temperature and high pressure, we found that solid 2-butyne experienced a concerted two-in-two-out intermolecular CH···π H-transfer, which initiated the subsequent polymerization. Such double H-transfer goes through an aromatic Hückel six-membered ring intermediate state via intermolecular CH···π interactions enhanced by external pressure. Our work shows that H-transfer can occur via the CH···π route in appropriate conformations under high pressure, which gives important insights into the H-transfer in solid-state hydrocarbons.

Solid-state batteries have fascinated the research community over the past decade, largely due to their improved safety properties and potential for high-energy density. Searching for fast ion conductors with sufficient electrochemical and chemical stabilities is at the heart of solid-state battery research and applications. Recently, significant progress has been made in solid-state electrolyte development. Sulfide-, oxide-, and halide-based electrolytes have been able to achieve high ionic conductivities of more than 10

In this work, we combined red phosphorus and hierarchically porous carbon networks by the evaporation–condensation method to obtain a red phosphorus/porous carbon composite with outstanding performance for potassium storage.

Zirconium-based metal-organic frameworks (Zr-MOFs) have shown tremendous prospects as highly efficient adsorbents against toxic chemicals under ambient conditions. Here, we report for the first time the enhanced toxic chemical adsorption and mass transfer properties of hierarchically porous Zr-MOF nanoarchitectures. A general and scalable sol-gel-based strategy combined with facile ambient pressure drying (APD) was utilized to construct MOF-808, MOF-808-NH2, and UiO-66-NH2 xerogel monoliths, denoted as G808, G808-NH2, and G66-NH2, respectively. The resulting Zr-MOF xerogels demonstrated 3D porous networks assembled by nanocrystal aggregates, with substantially higher mesoporosities than the precipitate analogues. Microbreakthrough tests on powders and tube breakthrough experiments on engineered granules were conducted at different relative humidities to comprehensively evaluate the NO2 adsorption capabilities. The Zr-MOF xerogels showed considerably better NO2 removal abilities than the precipitates, whether intrinsically or under simulated respirator canister/protection filter environment conditions. Multiple physicochemical characterizations were conducted to illuminate the NO2 filtration mechanisms. Analysis on adsorption kinetics and mass transfer patterns in Zr-MOF xerogels was further performed to visualize the underlying structure-activity relationship using the gravimetric uptake and zero length column methods with cyclohexane and acetaldehyde as probes. The results revealed that the synergy of hierarchical porosities and nanosized crystals could effectively expedite the intracrystalline diffusion for the G66-NH2 xerogel as well as alleviate the surface resistance for the G808-NH2 xerogel, which led to accelerated overall adsorption uptake and thus enhanced performance toward toxic chemical removal.

Phase change materials (PCMs) have been extensively explored for latent heat thermal energy storage in advanced energy-efficient systems. Flexible PCMs are an emerging class of materials that can withstand certain deformation and are capable of making compact contact with objects, thus offering substantial potential in a wide range of smart applications. To realize the flexibility, the energy storage capacity of flexible PCMs is partially reduced by the presence of thermally inactive flexible supports. Considering this tradeoff, several versatile methodologies have been proposed to develop flexible PCMs with optimal energy storage capacity and device-level flexibility. In this article, we systematically reviewed these strategies including (1) confinement of rigid PCM into flexible porous scaffolds, (2) encapsulation of PCM into elastic shells, and (3) development of intrinsically flexible PCM based on molecularly engineered structures. Besides, the applications of flexible PCMs in diverse fields including thermal management of electronic devices, thermal therapy of the human body, and flexible sensors have been presented. Finally, the major problems associated with the development of flexible PCMs and their prospective solutions are provided in detail.

Cryo-electron microscopy (cryo-EM) has emerged as a vital tool to reveal the native structure of beam-sensitive biomolecules and materials. Yet high-resolution cryo-EM analysis is still limited by the poorly controlled specimen preparation and urgently demands a robust supporting film material to prepare desirable samples. Here, we developed a bilayer Janus graphene membrane with the top-layer graphene being functionalized to interact with target molecules on the surface, while the bottom layer being kept intact to reinforce its mechanical steadiness. The ultraclean and atomically thin bilayer Janus membrane prepared by our protocol on one hand generates almost no extra noise and on the other hand reduces the specimen motion during cryo-EM imaging, thus allowing the atomic-resolution characterization of surface functional groups. Using such Janus membranes in cryo-EM specimen preparation, we were able to directly image the lithium dendrite and reconstruct macromolecules at near-atomic resolution. Our results demonstrate the bilayer Janus design as a promising supporting material for high-resolution cryo-EM and EM imaging.

Summary Lithium-sulfur (Li-S) batteries promise high energy density for next-generation energy storage systems, yet many challenges remain. Li-S batteries follow a conversion chemistry, which radically differs from intercalation-based lithium-ion batteries. Recently, it has become clear that the chemistry of electrolyte solutions and their ability to stabilize polysulfide Li2Sx species formed by sulfur reduction have a critical effect on energy density and cycling performance. This review evaluates the key role of solution properties and polysulfide solvation. Factors that determine the solvation are discussed, including the solvent, salt, concentration, and interaction with Li-polysulfide species. Three fundamental types of electrolyte solution—moderately (conventional), sparingly, and highly solvating—are presented along with a multi-dimensional analysis of solution chemistry, polysulfide solubility, sulfur reaction pathway, Li2S deposition, and solution quantity. The stability of lithium metal anodes with these solutions is discussed with respect to side reactions, protective surface film formation, and dendritic Li deposition. Emphasis is placed on options to reduce the electrolyte solution/sulfur ratio and prolong battery cycle life. The advantages and disadvantages of the three systems are compared in accordance with the multifaceted requirements. In conclusion, we offer our perspective for future development of Li-S batteries.

Amine-functionalized metal-organic framework (MOF) material is a promising CO

Highlights Hard-carbon anode dominated with ultra-micropores ( The ultra-micropores dominated carbon anode displays an enhanced capacity, which originates from the extra sodium-ion storage sites of the designed ultra-micropores. The thick electrode (~ 19 mg cm−2) with a high areal capacity of 6.14 mAh cm−2 displays an ultrahigh cycling stability and an outstanding low-temperature performance. Abstract Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries (SIBs). Ultra-micropores (+ but allow the entrance of naked Na+ into the pores, which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics. Herein, a molten diffusion–carbonization method is proposed to transform the micropores (> 1 nm) inside carbon into ultra-micropores (−1 at 30 mA g−1 with a high ICE value of ~ 80.6% and most of the capacity (~ 90%) is below 1 V. Moreover, the high-loading electrode (~ 19 mg cm−2) exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm−2 at 25 °C and 5.32 mAh cm−2 at − 20 °C. Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results, the designed ultra-micropores provide the extra Na+ storage sites, which mainly contributes to the enhanced capacity. This proposed strategy shows a good potential for the development of high-performance SIBs.

Solid-state electrolytes (SSEs) with high ionic conductivities are crucial for the development of all-solid-state lithium batteries (ASSLBs), and there is a strong correlation between the ionic conductivities and underlying lattice structures of SSEs. Here, we report a novel lattice manipulation method of replacing 6OH>+ octahedral clusters with potassium ions in antiperovskite SSEs (Li2OH)0.99K0.01Cl, which leads to its ionic conductivity at room temperature two orders of magnitude higher than that of Li2OHCl. The mechanisms analysis indicates that the novel lattice manipulation method leads to the stabilization of cubic phase and lattice contraction for antiperovskite, and causes significant changes in Li-ion transport paths and migration barriers. Also, the Li | Li symmetric cell and LiFePO4 | Li ASSLB employing (Li2OH)0.99K0.01Cl electrolyte exhibit long-term stable cycling performance, which indicates the application prospects of antiperovskite electrolyte in ASSLBs.

Metal-organic frameworks (MOFs), featuring porous crystalline structures with coordinated metal nodes and organic linkers, have recently found increasing interest in diverse applications. By virtue of their versatile and highly tunable compositions and structures, constructing hollow architectures will further endow MOFs with enhanced properties and designability, exceeding the molecular scale. MOFs could be considered as promising building units to fabricate complex hollow nanocomposites with faster mass transport, multiple active components, more exposed active sites, and better compatibility than bulk MOFs. To construct a promising blueprint for hollow pristine MOFs, this review provides a comprehensive overview for structural design strategies and applications of hollow pristine MOFs. We will highlight the merits, challenges and future potential by structuring and applying MOFs in sensing, separation, storage, catalysis, environmental remediation, photochemical and electrochemical energy conversion. This review might pave a new avenue for future development of novel pristine hollow MOFs.

The excessive depletion of fossil fuels and consequent energy crisis combined with environmental issues call for inexhaustible, clean and renewable energy sources and environmentally friendly energy technologies, such as solar energy and novel electrochemical energy conversion and storage devices. Developing supporting platforms for energy conversion and storage ameliorating mass transfer and electron transfer has stepped into the center of the energy research arena. Covalent organic frameworks (COFs) are emerging crystalline porous materials linked via covalent bonding possessing flexible molecular design and synthetic strategies, high conjugated and modifiable structures, large surface area and porosity. Due to these merits, COFs have shown promising perspectives in energy applications including photocatalysis, electrocatalysis, supercapacitors, metal-ion/sulfur batteries, etc. This critical review imparts a comprehensive summary of the fast-developing COF field in terms of molecular design and subsequent synthetic strategies to prepare COFs with highly conjugated and modifiable structures and their applications in energy conversion and storage. Furthermore, challenges and perspectives according to previous contributions are also discussed for developing more efficient energy conversion and storage COF materials. It is anticipated that this review could boost further research enthusiasm for COF-based materials in energy applications.

Transition metal nitrides (TMNs) are predicted to be highly promising electrocatalysts for the nitrogen reduction reaction (NRR) by theoretical calculations. TMNs follow a special Mars-van Krevelen (MvK) mechanism during the NRR, involving surface lattice nitrogen exchange and regeneration. It is hence essential to identify the source of nitrogen, especially taking the stability of lattice nitrogen into consideration. Herein, we investigated the deactivation process of a benchmark CrN nanoparticle catalyst (CrN NPs) with a phase-pure cubic rocksalt (RS) structure for the electrochemical NRR. The current work identifies two possible deactivation pathways for CrN: (i) potential-induced structural collapse of the catalyst including both lattice N leaching and metal dissolution and (ii) ammonia poisoning due to the accumulation and strong chemical bonding of the produced ammonia on the CrN surface. This work provides new perspectives for understanding the structural evolution of nitrogen-containing electrocatalysts for NRR research.

The suppression of irreversible phase change in battery-type materials during electrochemical process, leading to high-performance asymmetric supercapacitors (ASCs), remains one of the crucial challenges for the new generation of electrochemical energy storage devices. Herein, we propose a pre-activation strategy to address the corresponding problem based on an in-depth study of the failure mechanism of nickel–manganese layered double hydroxide (LDH), which is the inhibition of the exfoliation and deactivation of lattice Mn during the cycling process. The modified NiMn-LDH shows enhanced electrochemistry performance compared to pristine NiMn-LDH, with an increase in specific capacity from 855 to 1082 C g−1 and a doubling of stability after 3000 cycles. Furthermore, the assembled ASC device achieves a high specific energy density of 48.9 W h kg−1 at a power density of 810 W kg−1. The anchored, activated lattice Mn provided by hydrogen peroxide in the pre-activation strategy is proved to play a vital role in achieving high-performance ASCs. This work paves a new avenue to solve the long-standing significant challenge of battery-type materials for asymmetric supercapacitors.

Thermal energy plays an indispensable role in the sustainable development of modern societies. Being a key component in various domestic and industrial processes as well as in power generation systems, the storage of thermal energy ensures system reliability, power dispatchability, and economic profitability. Among the numerous methods of thermal energy storage (TES), latent heat TES technology based on phase change materials has gained renewed attention in recent years owing to its high thermal storage capacity, operational simplicity, and transformative industrial potential. Here, we review the broad and critical role of latent heat TES in recent, state-of-the-art sustainable energy developments. The energy storage systems are categorized into the following categories: solar-thermal storage; electro-thermal storage; waste heat storage; and thermal regulation. The fundamental technology underpinning these systems and materials as well as system design towards efficient latent heat utilization are briefly described. Finally, the exciting research opportunities available to further improve the overall energy efficiency of integrated TES systems are discussed.

[EN] Supercapacitors (SCs), showing excellent power density, long service life, and high reversibility, have received great attention because of the increasing demand for energy storage devices. To further improve their performance, it is essential to develop advanced electrode materials. One group of materials, porous crystalline solids referred to as metal-organic frameworks (MOFs), have proved to be excellent templates for synthesizing functional materials to be employed in the preparation of electrodes for SCs. In comparison to monometallic MOFs, bimetallic MOFs and their derivatives offer a number of advantages, including tunable electrochemical activity, high charge capacity, and improved electrical conductivity. This review focuses on the use of MOF-derived bimetallic materials in SCs, the origin of the improved performance, and the latest developments in the field. Furthermore, the challenges and perspectives in this research area are discussed., This work was supported by Tarbiat Modares University and College of Engineering, Peking University. Financial support by the Spanish Ministry of Science and Innovation (Severo Ochoa and RTI2018-98237-CO2-1) and Generalitat Valenciana (Prometeo 2017-083) is gratefully acknowledged.