The rational tailoring and molecular-level engineering of stable cathode-electrolyte interphases (CEIs) is paramount to advancing the performance of next-generation high-energy, layered nickel-rich oxide-based lithium...
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The rational tailoring and molecular-level engineering of stable cathode-electrolyte interphases (CEIs) is paramount to advancing the performance of next-generation high-energy, layered nickel-rich oxide-based lithium metal batteries. However, developing well-tailored electrolyte additives with rationally controlled interfacial chemistry remains highly challenging. Here, two lithium borates: lithium (2-methoxy-15-crown-5)trifluoroborate (C-LiMCFB) and lithium (15-methoxy-2,5,8,11,14-pentaoxahexadecan)trifluoroborate (L-LiMCFB), incorporating cyclic 15-crown-5 (15C5) and linear pentaethylene glycol monomethyl ether (PEGME) as respective host groups tethered to the boron center are designed and synthesized. In C-LiMCFB, the supramolecular polydentate chelation/de-chelation of the 15C5 with Li + can sequentially deactivate/activate the anodic decomposition of the C─O bonds, therefore leading to the controlled cleavage pathway of B─O and C─O bonds. The controlled interfacial chemistry leads to the formation of a uniform CEI layer, rich in lithium boron–oxygen clusters interwoven with LiF, on the NCM811 surface. This novel CEI configuration demonstrates an exceptional balance of mechanical robustness, adhesiveness, and toughness, providing highly desirable protection for the NCM811 cathode. The discovery of these novel supramolecular boron-based lithium salts not only unlocks supramolecular chemistry for rational electrolyte tuning but also provides a deeper understanding of the CEI formation mechanism in high-energy lithium metal batteries.
A facile and eco-friendly biosynthetic route for preparing Pd truncated octahedrons (PdTOs) using firmiana simplex leaf extract was reported without any chemical reducing agents. The information of reducing components...
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A facile and eco-friendly biosynthetic route for preparing Pd truncated octahedrons (PdTOs) using firmiana simplex leaf extract was reported without any chemical reducing agents. The information of reducing components, reduction process and time were obtained by ATR-FTIR imaging, FTIR and UV-Vis spectroscopy, respectively. TEM image revealed that more than 75% of PdNPs were composed of PdTOs with an average diameter of 9.2 nm. HR-TEM analysis demonstrated that a single PdTO consisted of the mix of {100} and {111} crystal planes. SAED and XRD pattern confirmed the well crystalline nature of fcc structured PdTOs. The model reactions of electro-oxidation of methanol and reduction of p-nitrophenol (p-NP) were adopted to explore the effects of structure and size of PdNPs on the catalytic properties. In the electro-oxidation of methanol, the forward-scan peak current density (If) of PdTOs was 10.05 mA cm-2, 6.3 times and 1.9 times of PdNPs-0 and PdNPs-4:1, illustrating its superior electro-catalytic property to that of spherical PdNPs. In the p-NP reduction reaction, the apparent rate constant (Ka) over PdTOs was 0.358 min-1, higher than spherical PdNPs-0 (0.08 min-1) with the similar particle size and lower than the same spherical PdNPs-4:1 (0.562 min-1) and commercial Pd/C (0.415 min-1), which all about half the size of PdTOs. It has been demonstrated that electro-chemical oxidation of methanol was a structure-sensitive reaction, while the reduction of p-NP was mainly dependent on the particle size of PdNPs.
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