Lignin is the world's greatest renewable aromatic biofeedstock,and it has promising applications in high value-added chemical products.Herein,N-Co/ATP-CZO was used as a catalyst for the depolymerization of alkali ...Lignin is the world's greatest renewable aromatic biofeedstock,and it has promising applications in high value-added chemical products.Herein,N-Co/ATP-CZO was used as a catalyst for the depolymerization of alkali lignin in ethanol and isopropanol systems,and explored the effects of formic acid(FA)amount,reaction time,reaction temperature and other factors on the depolymerization of alkali lignin.Among them,formic acid serves as both catalytic and in situ-hydrogen donor.Ultimately,the highest yield of bio-oil(59.28%(mass)),including 30.05%(mass)of monomer,was obtained after a reaction of FA to alkali lignin mass ratio of 4 and 240°C for 8 h.Among the monomers,the yield of Guaiacol was the highest(5.94%(mass)),followed by 2-methoxy-4-methylphenol(5.74%(mass)).This study,the modification of attapulgite was carried out to reduce the acidity while enhancing the catalytic activity for depolymerization,and the selection of hydrogen donor was investigated.A feasible pathway for lignin depolymerization research was opened.展开更多
Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) is a promising solid-state electrolyte for Li-ion batteries,but Li-dendrite's formation greatly limits the applications.In this paper,we systematically investigate the st...Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) is a promising solid-state electrolyte for Li-ion batteries,but Li-dendrite's formation greatly limits the applications.In this paper,we systematically investigate the stability,electronic properties,and Li-ion mobility of the LLZO surface by the ifrst-principles calculations.We consider the(110) and(001) slab structures with different terminations in the t-and c-LLZO.Our results indicate that both(110) and(001) surfaces prefer to form Li-rich termination due to their low surface energies for either t-or c-LLZO.Moreover,with the decrease of Li contents the stability of Li-rich surfaces is improved initially and degrades later.Unfortunately,the localized surface states at the Fermi level can induce the formation of metallic Li on the Li-rich surfaces.In comparison,Li/La-termination has a relatively low metallic Li formation tendency due to its rather low diffusion barrier.In fact,Li-ion can spontaneously migrate along path II(Li3→Li2) on the Li/La-T(001) surface.In contrast,it is more difficult for Li-ion diffusion on the Li-T(001) surface,which has a minimum diffusion barrier of 0.50 eV.Interestingly,the minimum diffusion barrier decreases to 0.34 eV when removing four Li-ions from the Li-T(001) surface.Thus,our study suggests that by varying Li contents,the stability and Li-ion diffusion barrier of LLZO surfaces can be altered favorably.These advantages can inhibit the formation of metallic Li on the LLZO surfaces.展开更多
Solid-state batteries(SSBs)have been considered the most promising technology because of their superior energy density and safety.Among all the solid-state electrolytes(SEs),Li_(7) La_(3) Zr_(2) O_(12)(LLZO)with high ...Solid-state batteries(SSBs)have been considered the most promising technology because of their superior energy density and safety.Among all the solid-state electrolytes(SEs),Li_(7) La_(3) Zr_(2) O_(12)(LLZO)with high ionic conductivity(3×10^(−4) S/cm)has been widely investigated.However,its large-scale production in ambient air faces a challenge.After air exposure,the generated Li_(2)CO_(3) layer deteriorates the ionic conductivity and interfacial wettability,thus greatly compromising the electrochemical performance of SSBs.Many works aim to eliminate this layer to recover the pristine LLZO surface.Unfor-tunately,few articles have emphasized the merits of Li_(2)CO_(3).In this review,we focus on the two-sidedness of Li_(2)CO_(3).We discuss the various characteristics of Li_(2)CO_(3) that can be used and recapitulate the strategies that utilize Li_(2)CO_(3).Insulating Li_(2)CO_(3) is no longer an obstacle but an opportunity for realizing intimate interfacial contact,high air stability,and outstand-ing electrochemical performance.This review aims to off er insightful guidelines for treating air-induced Li_(2)CO_(3) and lead to developing the enhanced air stability and electrochemical performance of LLZO.展开更多
基金financially supported by National Natural Science Foundation of China (21774059)。
文摘Lignin is the world's greatest renewable aromatic biofeedstock,and it has promising applications in high value-added chemical products.Herein,N-Co/ATP-CZO was used as a catalyst for the depolymerization of alkali lignin in ethanol and isopropanol systems,and explored the effects of formic acid(FA)amount,reaction time,reaction temperature and other factors on the depolymerization of alkali lignin.Among them,formic acid serves as both catalytic and in situ-hydrogen donor.Ultimately,the highest yield of bio-oil(59.28%(mass)),including 30.05%(mass)of monomer,was obtained after a reaction of FA to alkali lignin mass ratio of 4 and 240°C for 8 h.Among the monomers,the yield of Guaiacol was the highest(5.94%(mass)),followed by 2-methoxy-4-methylphenol(5.74%(mass)).This study,the modification of attapulgite was carried out to reduce the acidity while enhancing the catalytic activity for depolymerization,and the selection of hydrogen donor was investigated.A feasible pathway for lignin depolymerization research was opened.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12064015 and 12064014)。
文摘Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) is a promising solid-state electrolyte for Li-ion batteries,but Li-dendrite's formation greatly limits the applications.In this paper,we systematically investigate the stability,electronic properties,and Li-ion mobility of the LLZO surface by the ifrst-principles calculations.We consider the(110) and(001) slab structures with different terminations in the t-and c-LLZO.Our results indicate that both(110) and(001) surfaces prefer to form Li-rich termination due to their low surface energies for either t-or c-LLZO.Moreover,with the decrease of Li contents the stability of Li-rich surfaces is improved initially and degrades later.Unfortunately,the localized surface states at the Fermi level can induce the formation of metallic Li on the Li-rich surfaces.In comparison,Li/La-termination has a relatively low metallic Li formation tendency due to its rather low diffusion barrier.In fact,Li-ion can spontaneously migrate along path II(Li3→Li2) on the Li/La-T(001) surface.In contrast,it is more difficult for Li-ion diffusion on the Li-T(001) surface,which has a minimum diffusion barrier of 0.50 eV.Interestingly,the minimum diffusion barrier decreases to 0.34 eV when removing four Li-ions from the Li-T(001) surface.Thus,our study suggests that by varying Li contents,the stability and Li-ion diffusion barrier of LLZO surfaces can be altered favorably.These advantages can inhibit the formation of metallic Li on the LLZO surfaces.
基金the support from the National Natural Science Foundation of China (Nos.U2001220 and 51902223)the Haihe Laboratory of Sustainable Chemical Transformations+2 种基金the Fundamental Research Funds for the Central Universitiesthe National Key Research and Development Program of China (Nos.2021YFF0500600 and 2019YFE0118800)the Natural Science Foundation of Tianjin (No.20JCYBJC00850)
文摘Solid-state batteries(SSBs)have been considered the most promising technology because of their superior energy density and safety.Among all the solid-state electrolytes(SEs),Li_(7) La_(3) Zr_(2) O_(12)(LLZO)with high ionic conductivity(3×10^(−4) S/cm)has been widely investigated.However,its large-scale production in ambient air faces a challenge.After air exposure,the generated Li_(2)CO_(3) layer deteriorates the ionic conductivity and interfacial wettability,thus greatly compromising the electrochemical performance of SSBs.Many works aim to eliminate this layer to recover the pristine LLZO surface.Unfor-tunately,few articles have emphasized the merits of Li_(2)CO_(3).In this review,we focus on the two-sidedness of Li_(2)CO_(3).We discuss the various characteristics of Li_(2)CO_(3) that can be used and recapitulate the strategies that utilize Li_(2)CO_(3).Insulating Li_(2)CO_(3) is no longer an obstacle but an opportunity for realizing intimate interfacial contact,high air stability,and outstand-ing electrochemical performance.This review aims to off er insightful guidelines for treating air-induced Li_(2)CO_(3) and lead to developing the enhanced air stability and electrochemical performance of LLZO.
