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The key bottleneck troubling the application of solid electrolyte is the contradictory requirements from Li-metal and cathode, which need high modulus to block Li-dendrite penetration and flexibility to enable low interface resistance, respectively. This study describes a thin asymmetrical design of solid electrolyte to address these shortcomings. In this architecture, a rigid ceramic-layer modified with an ultrathin polymer is toward Limetal to accomplish dendrite-suppression of Li-anode, and a soft polymer-layer spreads over the exterior and interior of cathode to endow connected interface simultaneously. This ingenious arrangement endows solid Li-metal batteries with extremely high Coulombic efficiency and cyclability. This work will open up one avenue for realizing safe and long-life energy storage systems. [ABSTRACT FROM AUTHOR]

Copper (Cu), with the advantage of producing a deep reduction product, is a unique catalyst for the electrochemical reduction of CO 2 (CO 2 RR). Designing a Cu-based catalyst to trigger CO 2 RR to a multicarbon product and understanding the accurate structure-activity relationship for elucidating reaction mechanisms still remain a challenge. Herein, we demonstrate a rational design of a core-shell structured silica-copper catalyst (p-Cu@m-SiO 2 ) through Cu-Si direct bonding for efficient and selective CO 2 RR. The Cu-Si interface fulfills the inversion in CO 2 RR product selectivity. The product ratio of C 2 H 4 /CH 4 changes from 0.6 to 14.4 after silica modification, and the current density reaches a high of up to 450 mA cm -2 . The kinetic isotopic effect, in situ attenuated total reflection Fourier-transform infrared spectra, and density functional theory were applied to elucidate the reaction mechanism. The SiO 2 shell stabilizes the *H intermediate by forming Si-O-H and inhibits the hydrogen evolution reaction effectively. Moreover, the direct-bonded Cu-Si interface makes bare Cu sites with larger charge density. Such bare Cu sites and Si-O-H sites stabilized the *CHO and activated the *CO, promoting the coupling of *CHO and *CO intermediates to form C 2 H 4 . This work provides a promising strategy for designing Cu-based catalysts with high C 2 H 4 catalytic activity.

Introducing an external visible-light field would be a promising strategy to improve the activity of the electrocatalytic CO 2 reduction reaction (CO 2 RR), but it still remains a challenge due to the short excited-state lifetime of active sites. Herein, Ru(bpy) 3 Cl 2 struts as powerful photosensitive donors were immobilized into the backbones of Co-porphyrin-based covalent organic frameworks (named Co-Bpy-COF-Ru x , x is the molar ratio of Ru and Co species, x = 1/2 and 2/3) via coordination bonds, for the photo-coupled CO 2 RR to produce CO. The optimal Co-Bpy-COF-Ru 1/2 displays a high CO Faradaic efficiency of 96.7% at -0.7 V vs reversible hydrogen electrode (RHE) and a CO partial current density of 16.27 mA cm -2 at -1.1 V vs RHE under the assistance of light, both of which were far surpassing the values observed in the dark. The significantly enhanced activity is mainly attributed to the incorporation of a Ru(bpy) 3 Cl 2 donor with long excited-state lifetime and concomitantly giant built-in electric field in Co-Bpy-COF-Ru 1/2 , which efficiently accelerate the photo-induced electron transfer from Ru(bpy) 3 Cl 2 to the cobalt-porphyrin under the external light. Thus, the cobalt-porphyrin active sites have a longer excited-state lifetime to lower the rate-determining steps' energy occurring during the actual photo-coupled electrocatalytic CO 2 RR process. This is the first work of porphyrin-based COFs for photo-coupled CO 2 RR, opening a new frontier for the construction of efficient photo-coupled electrocatalysts.

The photocatalytic conversion of CO 2 into C 2+ products such as ethylene is a promising path toward the carbon neutral goal but remains a big challenge due to the high activation barrier for CO 2 and similar reduction potentials of many possible multi-electron-transfer products. Herein, an effective tandem photocatalysis strategy has been developed to support conversion of CO 2 to ethylene by construction of the synergistic dual sites in rhenium-(I) bipyridine fac -[Re I (bpy)(CO) 3 Cl] (Re-bpy) and copper-porphyrinic triazine framework [PTF(Cu)]. With these two catalysts, a large amount of ethylene can be produced at a rate of 73.2 μmol g -1 h -1 under visible light irradiation. However, ethylene cannot be obtained from CO 2 by use of either component of the Re-bpy or PTF(Cu) catalysts alone; with a single catalyst, only monocarbon product CO is produced under similar conditions. In the tandem photocatalytic system, the CO generated at the Re-bpy sites is adsorbed by the nearby Cu single sites in PTF(Cu), and this is followed by a synergistic C-C coupling process which ultimately produces ethylene. Density functional theory calculations demonstrate that the coupling process between PTF(Cu)-*CO and Re-bpy-*CO to form the key intermediate Re-bpy-*CO-*CO-PTF(Cu) is vital to the C 2 H 4 production. This work provides a new pathway for the design of efficient photocatalysts for photoconversion of CO 2 to C 2 products via a tandem process driven by visible light under mild conditions.

Li + -conductive ceramic oxide electrolytes, such as garnet-structured Li 7 La 3 Zr 2 O 12, have been considered as promising candidates for realizing the next-generation solid-state Li-metal batteries with high energy density. Practically, the ceramic pellets sintered at elevated temperatures are often provided with high stiffness yet low fracture toughness, making them too brittle for the manufacture of thin-film electrolytes and strain-involved operation of solid-state batteries. The ceramic powder, though provided with ductility, does not yield satisfactorily high Li + conductivity due to poor ion conduction at the boundaries of ceramic particles. Here we show, with solid-state nuclear magnetic resonance, that a uniform conjugated polymer nanocoating formed on the surface of ceramic oxide particles builds pathways for Li + conduction between adjacent particles in the unsintered ceramics. A tape-casted thin-film electrolyte (thickness: <10 μm), prepared from the polymer-coated ceramic particles, exhibits sufficient ionic conductivity, a high Li + transference number, and a broad electrochemical window to enable stable cycling of symmetric Li/Li cells and all-solid-state rechargeable Li-metal cells.