Chemical prelithiation is regarded as a crucial method for improving the initial Coulombic efficiency(ICE)of Li-storage anodes.Herein,a substituent-engineered Li-cyanonaphthalene chemical prelithiation system is desig...Chemical prelithiation is regarded as a crucial method for improving the initial Coulombic efficiency(ICE)of Li-storage anodes.Herein,a substituent-engineered Li-cyanonaphthalene chemical prelithiation system is designed to simultaneously enhance the ICE and construct a multifunctional interfacial film for SiO electrodes.X-ray photoelectron spectroscopy(XPS),electron energy-loss spectroscopy(EELS),nuclear magnetic resonance(NMR)spectroscopy and atomic force microscopy(AFM)prove that the Licyanonaphthalene prelithiation reagent facilitates the formation of a rectified solid electrolyte interface(SEI)film in two ways:(1)generation of a gradient SEI film with an organic outer layer(dense Ncontaining organics,ROCO_(2)Li)and an inorganic LiF-enriched inner layer;(2)homogenization of the horizontal distribution of the composition,mechanical properties and surface potential.As a result,the prelithiated SiO electrode exhibits an ICE above 100%,enhanced CEs during cycling,better cycle stability and inhibition of lithium dendrite formation in the overcharged state.Notably,the prelithiated hard carbon/SiO(9:1)‖LHCoO_(2) cell displays an enhancement in the energy density of 62.3%.展开更多
Cellulose acetates with low degree of substituent(DS) were homogeneously synthesized in an ionic liquid,1-allyl-3-methyl-imidazolium chloride(AmimC1).Under mild reaction conditions,cellulose monoacetates(CMA) with the...Cellulose acetates with low degree of substituent(DS) were homogeneously synthesized in an ionic liquid,1-allyl-3-methyl-imidazolium chloride(AmimC1).Under mild reaction conditions,cellulose monoacetates(CMA) with the DS in a range from 0.34 to 1.60 were obtained.NMR analysis shows that the distribution of acetyl moieties among the three OH groups of anhydroglucose unit is C6■C3>C2 for the synthesized CMA.The water solubility measurement shows that the CMA samples with the DS ranging from 0.65 to 1.06 are readily dissolved in water.The relationship between the structure and water solubility of CMA was briefly discussed.展开更多
Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has b...Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has been determined. Further-morel experimental equation K = 2.71× 10^(-2)(DS)^(-1.2) reflecting the relationship betweenK and the degree of substitution (DS) is correlated and used to describe chemical mi-crostructure uniformity of the distribution of substituents along chains effectively. Chainstructure parameters of enzymatic degradation products of CMC-the number of chainbreaks and the percentage of glucose released have been also measured. Average length ofsubstituted and unsubstituted chain segments are calculated simultaneously. Through thestudy of static and dynamic procedures of enzymatic degradation, the method to charac-terize the distribution of substituents of CMC along the chain has been improved.展开更多
基金supported by the National Key Research and Development Program of China(2017YFA0206703)the National Natural Science Foundation of China(21701163,21671181,21831006,22075268)Ningbo Veken Battery Co.,Ltd.(2018B10043)。
文摘Chemical prelithiation is regarded as a crucial method for improving the initial Coulombic efficiency(ICE)of Li-storage anodes.Herein,a substituent-engineered Li-cyanonaphthalene chemical prelithiation system is designed to simultaneously enhance the ICE and construct a multifunctional interfacial film for SiO electrodes.X-ray photoelectron spectroscopy(XPS),electron energy-loss spectroscopy(EELS),nuclear magnetic resonance(NMR)spectroscopy and atomic force microscopy(AFM)prove that the Licyanonaphthalene prelithiation reagent facilitates the formation of a rectified solid electrolyte interface(SEI)film in two ways:(1)generation of a gradient SEI film with an organic outer layer(dense Ncontaining organics,ROCO_(2)Li)and an inorganic LiF-enriched inner layer;(2)homogenization of the horizontal distribution of the composition,mechanical properties and surface potential.As a result,the prelithiated SiO electrode exhibits an ICE above 100%,enhanced CEs during cycling,better cycle stability and inhibition of lithium dendrite formation in the overcharged state.Notably,the prelithiated hard carbon/SiO(9:1)‖LHCoO_(2) cell displays an enhancement in the energy density of 62.3%.
文摘Cellulose acetates with low degree of substituent(DS) were homogeneously synthesized in an ionic liquid,1-allyl-3-methyl-imidazolium chloride(AmimC1).Under mild reaction conditions,cellulose monoacetates(CMA) with the DS in a range from 0.34 to 1.60 were obtained.NMR analysis shows that the distribution of acetyl moieties among the three OH groups of anhydroglucose unit is C6■C3>C2 for the synthesized CMA.The water solubility measurement shows that the CMA samples with the DS ranging from 0.65 to 1.06 are readily dissolved in water.The relationship between the structure and water solubility of CMA was briefly discussed.
文摘Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has been determined. Further-morel experimental equation K = 2.71× 10^(-2)(DS)^(-1.2) reflecting the relationship betweenK and the degree of substitution (DS) is correlated and used to describe chemical mi-crostructure uniformity of the distribution of substituents along chains effectively. Chainstructure parameters of enzymatic degradation products of CMC-the number of chainbreaks and the percentage of glucose released have been also measured. Average length ofsubstituted and unsubstituted chain segments are calculated simultaneously. Through thestudy of static and dynamic procedures of enzymatic degradation, the method to charac-terize the distribution of substituents of CMC along the chain has been improved.
