Li metal batteries using high-voltage layered oxides cathodes are of particular interest due to their high energy density.However,they suffer from short lifespan and extreme safety concerns,which are attributed to the...Li metal batteries using high-voltage layered oxides cathodes are of particular interest due to their high energy density.However,they suffer from short lifespan and extreme safety concerns,which are attributed to the degradation of layered oxides and the decomposition of electrolyte at high voltage,as well as the high reactivity of metallic Li.The key is the development of stable electrolytes against both highvoltage cathodes and Li with the formation of robust interphase films on the surfaces.Herein,we report a highly fluorinated ether,1,1,1-trifluoro-2-[(2,2,2-trifluoroethoxy)methoxy]ethane(TTME),as a cosolvent,which not only functions as a diluent forming a localized high concentration electrolyte(LHCE),but also participates in the construction of the inner solvation structure.The TTME-based electrolyte is stable itself at high voltage and induces the formation of a unique double-layer solid electrolyte interphase(SEI)film,which is embodied as one layer rich in crystalline structural components for enhanced mechanical strength and another amorphous layer with a higher concentration of organic components for enhanced flexibility.The Li||Cu cells display a noticeably high Coulombic efficiency of 99.28%after 300 cycles and Li symmetric cells maintain stable cycling more than 3200 h at 0.5 mA/cm^(2) and 1.0m Ah/cm^(2).In addition,lithium metal cells using LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) and Li CoO_(2) cathodes(both loadings~3.0 m Ah/cm^(2))realize capacity retentions of>85%over 240 cycles with a charge cut-off voltage of 4.4 V and 90%for 170 cycles with a charge cut-off voltage of 4.5 V,respectively.This study offers a bifunctional ether-based electrolyte solvent beneficial for high-voltage Li metal batteries.展开更多
Luminescence is one of the most important properties for metal nanoclusters;however,clearly revealing its origin remains challenging.The different luminescence properties of the two prototypical 8e nanoclusters Au_(11...Luminescence is one of the most important properties for metal nanoclusters;however,clearly revealing its origin remains challenging.The different luminescence properties of the two prototypical 8e nanoclusters Au_(11)and Au_(13)remain elusive—Au_(11)is always nonluminescent,whereas Au_(13)is luminescent.In this work,by using a designed unique aromatic ligand(quinoline-2-thiol),we obtained new atomically precise phosphine-thiolate-protected neutral Au_(11)-SH and cationic Au_(13)-SH.In comparison with the classic phosphine-halide-protected Au_(11)-Cl and Au_(13)-Cl,the Cl-to-thiol alteration triggered room-temperature luminescence of the Au_(11)core and dramatically modulated that of the Au_(13)core.Ultrafast ultraviolet/infrared(UV/IR)spectroscopy,which is sensitive to organic aromatic groups,together with ultrafast transient absorption(TA)spectroscopy unprecedently revealed a relaxation process from the ligand to core state affecting the dynamics in excited states and some critical intermediate states favouring efficient room-temperature emission of these nanoclusters.This work provides some new insights into the origin of photoluminescence of metal nanoclusters and opens an avenue to modulate the dynamics of their excited states using aromatic ligands,which would have direct applications in lighting,light harvesting,and photocatalysis.展开更多
基金the financial supports from the KeyArea Research and Development Program of Guangdong Province (2020B090919001)the National Natural Science Foundation of China (22078144)the Guangdong Natural Science Foundation for Basic and Applied Basic Research (2021A1515010138 and 2023A1515010686)。
文摘Li metal batteries using high-voltage layered oxides cathodes are of particular interest due to their high energy density.However,they suffer from short lifespan and extreme safety concerns,which are attributed to the degradation of layered oxides and the decomposition of electrolyte at high voltage,as well as the high reactivity of metallic Li.The key is the development of stable electrolytes against both highvoltage cathodes and Li with the formation of robust interphase films on the surfaces.Herein,we report a highly fluorinated ether,1,1,1-trifluoro-2-[(2,2,2-trifluoroethoxy)methoxy]ethane(TTME),as a cosolvent,which not only functions as a diluent forming a localized high concentration electrolyte(LHCE),but also participates in the construction of the inner solvation structure.The TTME-based electrolyte is stable itself at high voltage and induces the formation of a unique double-layer solid electrolyte interphase(SEI)film,which is embodied as one layer rich in crystalline structural components for enhanced mechanical strength and another amorphous layer with a higher concentration of organic components for enhanced flexibility.The Li||Cu cells display a noticeably high Coulombic efficiency of 99.28%after 300 cycles and Li symmetric cells maintain stable cycling more than 3200 h at 0.5 mA/cm^(2) and 1.0m Ah/cm^(2).In addition,lithium metal cells using LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) and Li CoO_(2) cathodes(both loadings~3.0 m Ah/cm^(2))realize capacity retentions of>85%over 240 cycles with a charge cut-off voltage of 4.4 V and 90%for 170 cycles with a charge cut-off voltage of 4.5 V,respectively.This study offers a bifunctional ether-based electrolyte solvent beneficial for high-voltage Li metal batteries.
基金supported by the National Natural Science Foundation of China(Nos.U21A20277,92061201,21825106,21975065,12174012,22203006,and 22103072)Zhengzhou University.
文摘Luminescence is one of the most important properties for metal nanoclusters;however,clearly revealing its origin remains challenging.The different luminescence properties of the two prototypical 8e nanoclusters Au_(11)and Au_(13)remain elusive—Au_(11)is always nonluminescent,whereas Au_(13)is luminescent.In this work,by using a designed unique aromatic ligand(quinoline-2-thiol),we obtained new atomically precise phosphine-thiolate-protected neutral Au_(11)-SH and cationic Au_(13)-SH.In comparison with the classic phosphine-halide-protected Au_(11)-Cl and Au_(13)-Cl,the Cl-to-thiol alteration triggered room-temperature luminescence of the Au_(11)core and dramatically modulated that of the Au_(13)core.Ultrafast ultraviolet/infrared(UV/IR)spectroscopy,which is sensitive to organic aromatic groups,together with ultrafast transient absorption(TA)spectroscopy unprecedently revealed a relaxation process from the ligand to core state affecting the dynamics in excited states and some critical intermediate states favouring efficient room-temperature emission of these nanoclusters.This work provides some new insights into the origin of photoluminescence of metal nanoclusters and opens an avenue to modulate the dynamics of their excited states using aromatic ligands,which would have direct applications in lighting,light harvesting,and photocatalysis.
