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931.
Li‐Peng Hou Xue‐Qiang Zhang Bo‐Quan Li Qiang Zhang 《Angewandte Chemie (International ed. in English)》2020,59(35):15109-15113
Stable operation at elevated temperature is necessary for lithium metal anode. However, Li metal anode generally has poor performance and safety concerns at high temperature (>55 °C) owing to the thermal instability of the electrolyte and solid electrolyte interphase in a routine liquid electrolyte. Herein a Li metal anode working at an elevated temperature (90 °C) is demonstrated in a thermotolerant electrolyte. In a Li|LiFePO4 battery working at 90 °C, the anode undergoes 100 cycles compared with 10 cycles in a practical carbonate electrolyte. During the formation of the solid electrolyte interphase, independent and incomplete decomposition of Li salts and solvents aggravate. Some unstable intermediates emerge at 90 °C, degenerating the uniformity of Li deposition. This work not only demonstrates a working Li metal anode at 90 °C, but also provides fundamental understanding of solid electrolyte interphase and Li deposition at elevated temperature for rechargeable batteries. 相似文献
932.
Fu‐Peng Wu Yang Yuan Claas Schünemann Paul C. J. Kamer Xiao‐Feng Wu 《Angewandte Chemie (International ed. in English)》2020,59(26):10451-10455
The borocarbonylative coupling of unactivated alkenes with alkyl halides remains a challenge. In this communication, a Cu‐catalyzed borocarbonylative coupling of unactivated alkenes with alkyl halides for the synthesis of β‐boryl ketones has been developed. A broad range of β‐boryl ketone derivatives was prepared in moderate to excellent yields with complete regioselectivity. 相似文献
933.
Xin Chang Pei‐Long Ma Hong‐Chao Chen Chuan‐Ying Li Peng Wang 《Angewandte Chemie (International ed. in English)》2020,59(23):8937-8940
Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh‐catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh‐catalyzed hydrogenation and a Pd‐catalyzed intramolecular carboamination. 相似文献
934.
Hui Duan Wan‐Ping Chen Min Fan Wen‐Peng Wang Le Yu Shuang‐Jie Tan Xiang Chen Qiang Zhang Sen Xin Li‐Jun Wan Yu‐Guo Guo 《Angewandte Chemie (International ed. in English)》2020,59(29):12069-12075
Garnet‐type electrolytes suffer from unstable chemistry against air exposure, which generates contaminants on electrolyte surface and accounts for poor interfacial contact with the Li metal. Thermal treatment of the garnet at >700 °C could remove the surface contaminants, yet it regenerates the contaminants in the air, and aggravates the Li dendrite issue as more electron‐conducting defective sites are exposed. In a departure from the removal approach, here we report a new surface chemistry that converts the contaminants into a fluorinated interface at moderate temperature <180 °C. The modified interface shows a high electron tunneling barrier and a low energy barrier for Li+ surface diffusion, so that it enables dendrite‐proof Li plating/stripping at a high critical current density of 1.4 mA cm?2. Moreover, the modified interface exhibits high chemical and electrochemical stability against air exposure, which prevents regeneration of contaminants and keeps high critical current density of 1.1 mA cm?2. The new chemistry presents a practical solution for realization of high‐energy solid‐state Li metal batteries. 相似文献
935.
Rongrong Li Hongjie Peng Qingping Wu Xuejun Zhou Jiang He Hangjia Shen Minghui Yang Chilin Li 《Angewandte Chemie (International ed. in English)》2020,59(29):12129-12138
Herein, we propose the construction of a sandwich‐structured host filled with continuous 2D catalysis–conduction interfaces. This MoN‐C‐MoN trilayer architecture causes the strong conformal adsorption of S/Li2Sx and its high‐efficiency conversion on the two‐sided nitride polar surfaces, which are supplied with high‐flux electron transfer from the buried carbon interlayer. The 3D self‐assembly of these 2D sandwich structures further reinforces the interconnection of conductive and catalytic networks. The maximized exposure of adsorptive/catalytic planes endows the MoN‐C@S electrode with excellent cycling stability and high rate performance even under high S loading and low host surface area. The high conductivity of this trilayer texture does not compromise the capacity retention after the S content is increased. Such a job‐synergistic mode between catalytic and conductive functions guarantees the homogeneous deposition of S/Li2Sx, and avoids thick and devitalized accumulation (electrode passivation) even after high‐rate and long‐term cycling. 相似文献
936.
Principles of Surface Potential Estimation in Mixed Electrolyte Solutions:Taking into Account Dielectric Saturation 下载免费PDF全文
The dielectric properties between in-particle/water interface and bulk solution are significantly different, which are ignored in the theories of surface potential estimation. The analytical expressions of surface potential considering the dielectric saturation were derived in mixed electrolytes based on the nonlinear Poisson-Boltzmann equation. The surface potentials calculated from the approximate analytical and exact numerical solutions agreed with each other for a wide range of surface charge densities and ion concentrations. The effects of dielectric saturation became important for surface charge densities larger than 0.30 C/m\begin{document}$ ^2 $\end{document} . The analytical models of surface potential in different mixed electrolytes were valid based on original Poisson-Boltzmann equation for surface charge densities smaller than 0.30 C/m\begin{document}$ ^2 $\end{document} . The analytical model of surface potential considering the dielectric saturation for low surface charge density can return to the result of classical Poisson-Boltzmann theory. The obtained surface potential in this study can correctly predict the adsorption selectivity between monovalent and bivalent counterions. 相似文献
937.
Kaikai Wen Lifen Wu Xiaoxi Wu Ying Lu Tao Duan Han Ma Aidong Peng Qinqin Shi Hui Huang 《Angewandte Chemie (International ed. in English)》2020,59(31):12756-12761
Cancer possesses normoxic and hypoxia microenvironments with different levels of oxygen, needing different efficacies of photothermal and photodynamic therapies. It is important to precisely tune the photothermal and photodynamic effects of phototherapy nano‐agents for efficient cancer treatment. Now, a series of copolymeric nanoparticles (PPy‐Te NPs) were synthesized in situ by controlled oxidative copolymerization with different ratios of pyrrole to tellurophene by FeCl3. The photothermal and photodynamic effects of semiconducting nano‐agents under the first near‐infrared (NIR) irradiation were precisely and systematically tuned upon simply varying the molar ratio of the pyrrole to tellurophene. The PPy‐Te NPs were used for cancer treatment in mice, exhibiting excellent biocompatibility and therapeutic effect. This work presents a simple method to tune photothermal and photodynamic therapies effect in semiconducting nano‐agents for cancer treatment. 相似文献
938.
Mohammad Yasir Peng Liu Jens C. Markwart Oksana Suraeva Frederik R. Wurm Jansie Smart Marco Lattuada Andreas F. M. Kilbinger 《Angewandte Chemie (International ed. in English)》2020,59(32):13597-13601
Using a one‐step synthetic route for block copolymers avoids the repeated addition of monomers to the polymerization mixture, which can easily lead to contamination and, therefore, to the unwanted termination of chain growth. For this purpose, monomers ( M1 – M5 ) with different steric hindrances and different propagation rates are explored. Copolymerization of M1 (propagating rapidly) with M2 (propagating slowly), M1 with M3 (propagating extremely slowly) and M4 (propagating rapidly) with M5 (propagating slowly) yielded diblock‐like copolymers using Grubbs’ first ( G1 ) or third generation catalyst ( G3 ). The monomer consumption was followed by 1H NMR spectroscopy, which revealed vastly different reactivity ratios for M1 and M2 . In the case of M1 and M3 , we observed the highest difference in reactivity ratios (r1=324 and r2=0.003) ever reported for a copolymerization method. A triblock‐like copolymer was also synthesized using G3 by first allowing the consumption of the mixture of M1 and M2 and then adding M1 again. In addition, in order to measure the fast reaction rates of the G3 catalyst with M1 , we report a novel retardation technique based on an unusual reversible G3 Fischer‐carbene to G3 benzylidene/alkylidene transformation. 相似文献
939.
Zhantao Peng Bin Di Wentao Li Dan Liu Xiaojie Wen Hao Zhu Huanjun Song Yajie Zhang Cen Yin Xiong Zhou Kai Wu 《Angewandte Chemie (International ed. in English)》2020,59(34):14321-14325
Potassium (K) cations are spontaneously formed upon thermal deposition of low‐coverage K onto an ultrathin CuO monolayer grown on Cu(110) and they were explored by low‐temperature scanning tunneling microscopy (STM) and X‐ray photoemission spectroscopy. The formed K cations are highly immobile and thermally stable. The local work function around an individual K cation decreases by 1.5±0.3 eV, and a charging zone underneath it is established within about 1.0 nm. The cationic and neutral states of the K atom are switchable upon application of an STM bias voltage pulse, which is simultaneously accompanied by an adsorption site relocation. 相似文献
940.
Pin Xu Peng‐Yu Chen Hai‐Chao Xu 《Angewandte Chemie (International ed. in English)》2020,59(34):14275-14280
Heteroarenes are structural motifs found in many bioactive compounds and functional materials. Dehydrogenative cross‐coupling of heteroarenes with aliphatic C?H bonds provides straightforward access to functionalized heteroarenes from readily available materials. Established methods employ stoichiometric chemical oxidants under conditions of heating or light irradiation. By merging electrochemistry and photochemistry, we have achieved efficient photoelectrochemical dehydrogenative cross‐coupling of heteroarenes and C(sp3)?H donors through H2 evolution, without the addition of metal catalysts or chemical oxidants. Mechanistically, the C(sp3)?H donor is converted to a nucleophilic carbon radical through H‐atom transfer with chlorine atom, which is produced by light irradiation of anodically generated Cl2 from Cl?. The carbon radical then undergoes radical substitution to the heteroarene to afford alkylated heteroarene products. 相似文献