A weakly coordinating-intervention strategy for modulating Na solvation sheathes and constructing robust interphase in sodium-metal batteries.

Constructing powerful anode/cathode interphases by modulate ion solvation structure is the principle of electrolyte design. However, the methodological and theoretical design principles of electrolyte/solvation structure and their effect on electrochemical performance are still vague. Here, we propose a cationic weakly coordinating-intervention strategy for modulating the Na solvation sheathes and constructing robust anode/cathode interphases in sodium-metal batteries.

Design Principles of Quinone Redox Systems for Advanced Sulfide Solid-State Organic Lithium Metal Batteries.

The emergence of solid-state battery technology presents a potential solution to the dissolution challenges of high-capacity small molecule quinone redox systems. Nonetheless, the successful integration of argyrodite-type LiPSCl, the most promising solid-state electrolyte system, and quinone redox systems remains elusive due to their inherent reactivity. Here, a library of quinone derivatives is selected as model electrode materials to ascertain the critical descriptors governing the (electro)chemical compatibility and subsequently the performances of LiPSCl-based solid-state organic lithium metal batteries (LMBs).

Constructing an Interlaced Catalytic Surface via Fluorine-Doped Bimetallic Oxides for Oxygen Electrode Processes in Li-O Batteries.

Lithium-oxygen (Li-O) batteries, renowned for their high theoretical energy density, have garnered significant interest as prime candidates for future electric device development. However, their actual capacity is often unsatisfactory due to the passivation of active sites by solid-phase discharge products. Optimizing the growth and storage of these products is a crucial step in advancing Li-O batteries.

A Hybrid-Salt Strategy for Modulating the Li Solvation Sheathes and Constructing Robust SEI in Non-Flammable Electrolyte Lithium Metal Batteries.

The electrode interface determines the performance of an electrochemical energy storage system. Using traditional electrolyte organic additives and high-concentration electrolyte emerging recently are two generally strategies for improving the electrode interface. Here, a hybrid-salt electrolyte strategy is proposed for constructing the stable electrode interface.

An Endogenous Prompting Mechanism for Sulfur Conversions Via Coupling with Polysulfides in Li-S Batteries.

The sluggish kinetics process and shuttling of soluble intermediates present in complex conversion between sulfur and lithium sulfide severely limit the practical application of lithium-sulfur batteries. Herein, by introducing a designated functional organic molecule to couple with polysulfide intermediators, an endogenous prompting mechanism of sulfur conversions has thus been created leading to an alternative sulfur-electrode process, in another words, to build a fast "internal cycle" of promotors that can promote the slow "external cycle" of sulfur conversions. The coupling-intermediators between the functional organic molecule and polysulfides, organophosphorus polysulfides, to be the "promotors" for sulfur conversions, are not only insoluble in the electrolyte but also with higher redox-activity.

Regulating SEI Components of Sodium Anode via Capturing Organic-Molecule Intermediates in Ester-Based Electrolyte.

Highly reversible sodium metal anodes are still regarded as a stubborn hurdle in ester-based electrolytes due to the issue of uncontrollable dendrites and incredibly unstable interphase. Evidently, a strong protective film on sodium is decisive, while the quality of the protective film is mainly determined by its components. However, it is challenging to actively adjust the expected components.

Ultrafast and Ultralarge Lithium-Ion Storage Enabled by Fluorine-Nitrogen Co-Implanted Carbon Tubes.

As a holy grail in electrochemistry, both high-power and high-energy electrochemical energy storage system (EES) has always been a pursued dream. To simultaneously achieve the "both-high" EES, a rational design of structure and composition for storage materials with characteristics of battery-type and capacitor-type storage is crucial. Herein, fluorine-nitrogen co-implanted carbon tubes (FNCT) have been designed, in which plentiful active sites and expanded interlayer space have been created benefiting from the heteroatom engineering and the fluorine-nitrogen synergistic effect, thus the above two-type storage mechanism can get an optimal balance in the FNCT.

An Organic Redox Mediator with a Defense-Donor for Lithium Anode in Lithium-Oxygen Batteries.

Lithium-oxygen batteries (LOBs) suffer from large charge overpotential and unstable Li metal interface, which can be attributed to the inefficient charge transport at the insulating Li O /cathode interface and the severe oxygen corrosion issue on the Li anode surface. The use of soluble redox mediators (RMs) can effectively enhance the charge transport between Li O and cathode, thus greatly reducing the charge overpotential. However, oxidized RMs will also shuttle to the anode side and react with the Li metal, which not only results in the loss of both the RMs and the electrical energy efficiency but also exacerbates the Li anode corrosion.

An Encapsulation-Based Sodium Storage via Zn-Single-Atom Implanted Carbon Nanotubes.

The properties of high theoretical capacity, low cost, and large potential of metallic sodium (Na) has strongly promoted the development of rechargeable sodium-based batteries. However, the issues of infinite volume variation, unstable solid electrolyte interphase (SEI), and dendritic sodium causes a rapid decline in performance and notorious safety hazards. Herein, a highly reversible encapsulation-based sodium storage by designing a functional hollow carbon nanotube with Zn single atom sites embedded in the carbon shell (Zn -HCNT) is achieved.

Single-dispersed polyoxometalate clusters embedded on multilayer graphene as a bifunctional electrocatalyst for efficient Li-S batteries.

The redox reactions occurring in the Li-S battery positive electrode conceal various and critical electrocatalytic processes, which strongly influence the performances of this electrochemical energy storage system. Here, we report the development of a single-dispersed molecular cluster catalyst composite comprising of a polyoxometalate framework ([Co(PWO)]) and multilayer reduced graphene oxide. Due to the interfacial charge transfer and exposure of unsaturated cobalt sites, the composite demonstrates efficient polysulfides adsorption and reduced activation energy for polysulfides conversion, thus serving as a bifunctional electrocatalyst.

POM Anolyte for All-Anion Redox Flow Batteries with High Capacity Retention and Coulombic Efficiency at Mild pH.

A highly soluble Li BW O cluster delivers 2 e redox reaction with fast electron transfer rates (2.5 × 10  cm s ) and high diffusion coefficients (≈2.08 × 10 cm s ) at mild pH ranging from 3 to 8.

The Intrinsic Charge Carrier Behaviors and Applications of Polyoxometalate Clusters Based Materials.

Polyoxometalates (POMs) are a series of molecular metal oxide clusters, which span the two domains of solutes and solid metal oxides. The unique characters of POMs in structure, geometry, and adjustable redox properties have attracted widespread attention in functional material synthesis, catalysis, electronic devices, and electrochemical energy storage and conversion. This review is focused on the links between the intrinsic charge carrier behaviors of POMs from a chemistry-oriented view and their recent ground-breaking developments in related areas.

Geminal Dicationic Ionic Liquid-Based Freestanding Ion Membrane for High-Safety Lithium Batteries.

A freestanding ion membrane with high ionic conductivity, electrochemical compatibility, satisfactory strength, and safety is a goal pursued for advanced energy storage. Geminal dicationic ionic liquids (GDILs) are expected to be designed and synthesized as a basic building block for the target ionic conductors. Herein, we fabricated a GDIL-based flexible ion conductive material, which appears and behaves as a freestanding film, an ion membrane actually, denoted as iMembrane.

Turning Soluble Polysulfide Intermediates Back into Solid State by a Molecule Binder in Li-S Batteries.

The shuttle effect of dissolved polysulfides produced during the operation of lithium-sulfur batteries is the most serious and fundamental problem among many challenges. We propose a strategy formation of a functionalized molecule with a dual-terminal coupling function to bind the dissolved polysulfide intermediates, thus turning them back into solid-state organopolysulfide complexes by molecule binding, and then the polysulfides can be pinned on the cathode firmly. The dual-terminal coupling functional molecule binder (MB), which is formed by reaction between quinhydrone (QH) and lithium, can not only bind polysulfides by reversible chemical coordination but also promote the conversion of polysulfides during cycling synchronously.

Tuning Redox Active Polyoxometalates for Efficient Electron-Coupled Proton-Buffer-Mediated Water Splitting.

We present strategies to tune the redox properties of polyoxometalate clusters to enhance the electron-coupled proton-buffer-mediated water splitting process, in which the evolution of hydrogen and oxygen can occur in different forms and is separated in time and space. By substituting the heteroatom template in the Keggin-type polyoxometalate cluster, H ZnW O , it is possible to double the number of electrons and protonation in the redox reactions (from two to four). This increase can be achieved with better matching of the energy levels as indicated by the redox potentials, compared to the ones of well-studied H PW O and H SiW O .

Enhanced Adsorptions to Polysulfides on Graphene-Supported BN Nanosheets with Excellent Li-S Battery Performance in a Wide Temperature Range.

For Li-S batteries, the catalysis for S redox reaction is indispensable. A lot of multifunctional sulfur electrode support materials with have been investigated widely. However, most of these studies were carried out at room temperature, and the interaction between different components in the matrix is not often paid enough attention.

Mechanisms of CO Incorporation into Propargylic Amine Catalyzed by Ag(I)/Amine Catalysts.

Density functional theory calculations are carried out to explore the detail mechanisms of CO incorporation into propargylic amine catalyzed by Ag(I)/amine catalysts. Our calculations reveal that the whole reaction involves Lewis acid catalysis and Lewis base catalysis stages, and the outcomes of this reaction critically depend on the basicity of amine. A weaker base (i.

A Honeycomb-like Co@N-C Composite for Ultrahigh Sulfur Loading Li-S Batteries.

Because of the high theoretical capacity of 1675 mAh g and high energy density of 2600 Wh kg, respectively, lithium-sulfur batteries are attracting intense interest. However, it remains an enormous challenge to realize high utilizations and loadings of sulfur in cathodes for the practical applications of Li-S batteries. Herein, we design a quasi-2D Co@N-C composite with honeycomb architecture as a multifunctional sulfur host via a simple sacrificial templates method.

How the Coordinated Structures of Ag(I) Catalysts Affect the Outcomes of Carbon Dioxide Incorporation into Propargylic Amine: A DFT Study.

Density functional theory calculations have been carried out to explore the detailed mechanisms for carbon dioxide incorporation of N-unsubstituted propargylic amine catalyzed by Ag(I) catalysts. We show that the reaction undergoes substrate adsorption or displacement, isomerization from amine-coordinated species to the alkyne-coordinated species, CO attack, and proton transfer, giving the carbamate intermediate. Subsequently, the reaction would bifurcate at the intermolecular ring-closing step, which produces five-membered ring (5MR) and six-membered ring (6MR) products at the same time, thus raising a regioselectivity issue.

Mechanistic Insight into the Copper-Catalyzed Regiodivergent Silacarboxylation of Allenes with CO2.

DFT calculations were performed to investigate the detailed reaction mechanisms in the copper-catalyzed regiodivergent silacarboxylation of allenes. According to our calculations, the catalysis would bifurcate at the allene silylcupration step, followed by CO2 insertion, eventually leading to the carboxylated vinylsilane or allylsilane products. The gaps between the two silylcupration barriers were predicted to be -2.

Brønsted-NH(4)(+) mechanism versus nitrite mechanism: new insight into the selective catalytic reduction of NO by NH(3).

The selective catalytic reduction (SCR) of NO by NH(3) over V(2)O(5)-based catalysts is used worldwide to control NO(x) emission. Understanding the mechanisms involved is vital for the rational design of more effective catalysts. Here, we have performed a systematic density functional theory (DFT) study of a SCR reaction by using cluster models.