Amorphous-Carbon-Coated 3D Solid Electrolyte for an Electro-Chemomechanically Stable Lithium Metal Anode in Solid-State Batteries.

The use of solid-state electrolyte may be necessary to enable safe, high-energy-density Li metal anodes for next-generation energy storage systems. However, the inhomogeneous local current densities during long-term cycling result in instability and detachment of the Li anode from the electrolyte, which greatly hinders practical application. In this study, we report a new approach to maintain a stable Li metal | electrolyte interface by depositing an amorphous carbon nanocoating on garnet-type solid-state electrolyte. The carbon nanocoating provides both electron and ion conducting capability, which helps to homogenize the lithium metal stripping and plating processes. After coating, we find the Li metal/garnet interface displays stable cycling at 3 mA/cm2 for more than 500 h, demonstrating the interface's outstanding electro-chemomechanical stability. This work suggests amorphous carbon coatings may be a promising strategy for achieving stable Li metal | electrolyte interfaces and reliable Li metal batteries.

Regio- and Stereoselective Alkylboration of Endocyclic Olefins Enabled by Nickel Catalysis.

Whereas there is a significant interest in the rapid construction of diversely substituted saturated heterocycles, direct and modular access is currently limited to the mono-, 2,3-, or 3,4-substitution pattern. This Communication describes the straightforward and modular construction of 2,4-substituted saturated heterocycles from readily available materials in a highly stereo- and regioselective manner, which sets the stage for numerous readily accessible drug motifs. The strategy relies on chain walking catalysis.

Achieving High-Performance Lithium-Sulfur Batteries by Modulating Li+ Desolvation Barrier with Liquid Crystal Polymers.

Lithium-sulfur (Li-S) batteries offer high theoretical capacity but are hindered by poor rate capability and cycling stability due to sluggish Li2S precipitation kinetics. Here a sulfonate-group-rich liquid crystal polymer (poly-2,2'-disulfonyl-4,4'-benzidine terephthalamide, PBDT) is designed and fabricated to accelerate Li2S precipitation by promoting the desolvation of Li+ from electrolyte. PBDT-modified separators are employed to assemble Li-S batteries, which deliver a remarkable rate capacity (761 mAh g-1 at 4 C) and cycling stability (500 cycles with an average decay rate of 0.088% per cycle at 0.5 C). A PBDT-based pouch cell even delivers an exceptional capacity of ≈1400 mAh g-1 and an areal capacity of ≈11 mAh cm-2 under lean-electrolyte and high-sulfur-loading condition, demonstrating promise for practical applications. Results of Raman spectra, molecular dynamic (MD) and density functional theory (DFT) calculations reveal that the abundant anionic sulfonate groups of PBDT aid in Li+ desolvation by attenuating Li+-solvent interactions and lowering the desolvation energy barrier. Plus, the polysulfide adsorption/catalysis is also excluded via electrostatic repulsion. This work elucidates the critical impact of Li+ desolvation on Li-S batteries and provides a new design direction for advanced Li-S batteries.

Ligand-modulated nickel-catalyzed regioselective silylalkylation of alkenes.

Organosilicon compounds have shown tremendous potential in drug discovery and their synthesis stimulates wide interest. Multicomponent cross-coupling of alkenes with silicon reagents is used to yield complex silicon-containing compounds from readily accessible feedstock chemicals but the reaction with simple alkenes remains challenging. Here, we report a regioselective silylalkylation of simple alkenes, which is enabled by using a stable Ni(II) salt and an inexpensive trans-1,2-diaminocyclohexane ligand as a catalyst. Remarkably, this reaction can tolerate a broad range of olefins bearing various functional groups, including alcohol, ester, amides and ethers, thus it allows for the efficient and selective assembly of a diverse range of bifunctional organosilicon building blocks from terminal alkenes, alkyl halides and the Suginome reagent. Moreover, an expedient synthetic route toward alpha-Lipoic acid has been developed by this methodology.

Microstructure Manipulation for Enhancing the Resistance of Garnet-Type Solid Electrolytes to "Short Circuit" by Li Metal Anodes.

Al-contained Li7- xLa3Zr2- xTa xO12 ( xTa-LLZO) powder was synthesized via solid-state reaction, where increasing the Ta doping level was found to reduce the average particle size and facilitate a higher relative density in the sintered pellet. 0.8Ta-LLZO pellets sintered at 1150 °C achieved a relative density of 96.2 ± 0.2% and survived the Li striping/plating test under a unidirectional current polarization of 0.5 mA/cm2 for more than 8 h without short-circuiting. In contrast, other xTa-LLZO sintered pellets with lower Ta doping levels were short-circuited by lithium dendrites after polarization for much shorter time periods. The microstructure of the sintered body played a more essential role in lithium dendrite prevention compared to relative density alone. By characterizing the microstructure of xTa-LLZO sintered pellets, we proposed a formation mechanism of the pathways for lithium dendrite growth.

Structural characteristics, biological, rheological and thermal properties of the polysaccharide and the degraded polysaccharide from raspberry fruits.

A native polysaccharide (RCPI) with sugar content of 79.94 ±â€¯0.57% was isolated from raspberry fruits. A degraded polysaccharide (DRCPI) with sugar content of 83.82 ±â€¯0.71% was obtained from the crude polysaccharides after degradation by Fe2+-H2O2 treatment. The molecular weights of RCPI and DRCPI were determined to be 411,000 and 8010 Da, respectively. GC analysis revealed that both RCPI and DRCPI were composed of the same monosaccharides (rhamnose, arabinose, xylose, mannose, glucose, galactose, and galacturonic acid) in different molar ratios. IR and NMR spectroscopy confirmed that RCPI and DRCPI possessed similar structural characteristics, although DRCPI displayed higher antioxidant activities and greater thermal stability. Furthermore, DRCPI exhibited excellent rheological properties. These data provide evidence to support the application of raspberry-derived polysaccharides in functional foods.