Lithium-halogen batteries(LHBs),including lithium iodide(Li-I_(2))and lithium bromide(Li-Br_(2))batteries,are receiving more attention for offering high energy density and excellent kinetic performance.However,LHBs co...Lithium-halogen batteries(LHBs),including lithium iodide(Li-I_(2))and lithium bromide(Li-Br_(2))batteries,are receiving more attention for offering high energy density and excellent kinetic performance.However,LHBs commercialization is seriously hindered by the high solubility of halides,causing lower capacity and poor cyclability.This research covers the fabrication of a highly stable cathode of amorphous carbon coated CMK-3/LiI/LiBr nanocomposite for metal lithium batteries.The nanopores and coated layer can physically trap the dissolution of active materials.The amorphous carbon generated from polyacrylonitrile carries abundant nitrogen heteroatoms for the stable anchorage of halogens and halides via strong chemical adsorption.In addition,iodine can act as a complexing agent with bromine to reduce solvation energy.Consequently,the as-prepared CMK-3/LiI/LiBr/carbon(CIBP)nanocomposite cathode demonstrates an ultra-high reversible capacity of 407.4 mAh/g at the current density of 1.0 C performing up to 300 stable cycles.展开更多
Spinel LiMn2O4-xYx （Y=F, Cl, Br） compounds were prepared by solid-state reaction and the electrochemically galvanostatic charge-discharge cycles were performed using as-prepared compounds as cathode material. The in...Spinel LiMn2O4-xYx （Y=F, Cl, Br） compounds were prepared by solid-state reaction and the electrochemically galvanostatic charge-discharge cycles were performed using as-prepared compounds as cathode material. The influence of halogens on their lattice constants and the relation of electrochemical properties and their lattice constants were investigated. It is concluded that when the lattice constants are smaller than that of LiMn2O4, the reversible capacity fade is suppressed and the initial capacity sacrifice is observed. When the content of fluorine is （0.05,） the lattice constant of LiMn2O3.95F0.05 is larger than that of LiMn2O4, the initial capacity is improved. An efficient method was found to control the lattice constants of LiMn2O4 through the addition of halogen, and to improve the electrochemical performance of LiMn2O4. The LiMn2O3.95F0.05 shows excellent electrochemical charge-discharge performance, with high initial capacity of 143 mAh/g and nearly no capacity loss after 116 cycles.展开更多
Organic electron acceptor materials play an important role in organic electronics.Recently,many organic electron acceptors have been developed,in which aromatic fused-imides have proved to be a promising family of exc...Organic electron acceptor materials play an important role in organic electronics.Recently,many organic electron acceptors have been developed,in which aromatic fused-imides have proved to be a promising family of excellent electron acceptors.We report the first synthesis of a novel aromatic fused-imide,acenaphtho[1,2-k]fluoranthene diimide derivative(AFI),using lithium-halogen exchange and Diels-Alder reactions.The construction of a large conjugated plane and the introduction of electron-withdrawing imide groups endow AFI with a low lowest unoccupied molecular orbital(LUMO)level of 3.80 e V.AFI exhibits a regular molecular arrangement and strong - interactions in the single-crystal structure,which indicates its potential application in organic electronic devices.Solar cell devices that were fabricated using AFI as the electron acceptor and P3HT as the electron donor achieved an energy conversion efficiency of 0.33%.展开更多
The characteristics and structures of single-electron halogen bond complexes H3C…Br-Y(Y = H,CCH,CN,NC,C2H3) have been investigated by theoretical calculation methods.The geometries were optimized and frequencies calc...The characteristics and structures of single-electron halogen bond complexes H3C…Br-Y(Y = H,CCH,CN,NC,C2H3) have been investigated by theoretical calculation methods.The geometries were optimized and frequencies calculated at the B3LYP/6-311++G level.The interaction energies were corrected for basis set superposition error(BSSE) and the wavefunctions obtained by the natural bond orbital(NBO) and atom in molecule(AIM) analyses at the MP2/6-311++G level.For each H3C…Br-Y complex,a single-electron Br bond is formed between the unpaired electron of the CH3(electron donor) radical and the Br atom of Br-Y(electron acceptor);this kind of single-electron bromine bond also possesses the character of a"three-electron bond".Due to the formation of the single-electron Br bond,the C-H bonds of the CH3 radical bend away from the Br-Y moiety and the Br-Y bond elongates,giving red-shifted single-electron Br bond complexes.The effects of substituents,hybridization of the carbon atom,and solvent on the properties of the complexes have been investigated.The strengths of single-electron hydrogen bonds,single-electron halogen bonds and single-electron lithium bonds have been compared.In addition,the single-electron halogen bond system is discussed in the light of the first three criteria for hydrogen bonding proposed by Popelier.展开更多
基金the financial support by the Research Foundation of Hunan Education Committee of China(No.21B0067)Natural National Science Foundation of China(No.22278197).
文摘Lithium-halogen batteries(LHBs),including lithium iodide(Li-I_(2))and lithium bromide(Li-Br_(2))batteries,are receiving more attention for offering high energy density and excellent kinetic performance.However,LHBs commercialization is seriously hindered by the high solubility of halides,causing lower capacity and poor cyclability.This research covers the fabrication of a highly stable cathode of amorphous carbon coated CMK-3/LiI/LiBr nanocomposite for metal lithium batteries.The nanopores and coated layer can physically trap the dissolution of active materials.The amorphous carbon generated from polyacrylonitrile carries abundant nitrogen heteroatoms for the stable anchorage of halogens and halides via strong chemical adsorption.In addition,iodine can act as a complexing agent with bromine to reduce solvation energy.Consequently,the as-prepared CMK-3/LiI/LiBr/carbon(CIBP)nanocomposite cathode demonstrates an ultra-high reversible capacity of 407.4 mAh/g at the current density of 1.0 C performing up to 300 stable cycles.
文摘Spinel LiMn2O4-xYx （Y=F, Cl, Br） compounds were prepared by solid-state reaction and the electrochemically galvanostatic charge-discharge cycles were performed using as-prepared compounds as cathode material. The influence of halogens on their lattice constants and the relation of electrochemical properties and their lattice constants were investigated. It is concluded that when the lattice constants are smaller than that of LiMn2O4, the reversible capacity fade is suppressed and the initial capacity sacrifice is observed. When the content of fluorine is （0.05,） the lattice constant of LiMn2O3.95F0.05 is larger than that of LiMn2O4, the initial capacity is improved. An efficient method was found to control the lattice constants of LiMn2O4 through the addition of halogen, and to improve the electrochemical performance of LiMn2O4. The LiMn2O3.95F0.05 shows excellent electrochemical charge-discharge performance, with high initial capacity of 143 mAh/g and nearly no capacity loss after 116 cycles.
基金financially supported by the National Basic Research Program of China(2013CB933501)the National Natural Science Foundation of Chinasupported by a General Financial Grant(2013M530135)from the China Postdoctoral Science Foundation
文摘Organic electron acceptor materials play an important role in organic electronics.Recently,many organic electron acceptors have been developed,in which aromatic fused-imides have proved to be a promising family of excellent electron acceptors.We report the first synthesis of a novel aromatic fused-imide,acenaphtho[1,2-k]fluoranthene diimide derivative(AFI),using lithium-halogen exchange and Diels-Alder reactions.The construction of a large conjugated plane and the introduction of electron-withdrawing imide groups endow AFI with a low lowest unoccupied molecular orbital(LUMO)level of 3.80 e V.AFI exhibits a regular molecular arrangement and strong - interactions in the single-crystal structure,which indicates its potential application in organic electronic devices.Solar cell devices that were fabricated using AFI as the electron acceptor and P3HT as the electron donor achieved an energy conversion efficiency of 0.33%.
基金supported by the Foundation of the Education Committee of Gansu Province (Grant No. 0708-11)"Qinglan" Talent Engineering Funds of Tianshui Normal University
文摘The characteristics and structures of single-electron halogen bond complexes H3C…Br-Y(Y = H,CCH,CN,NC,C2H3) have been investigated by theoretical calculation methods.The geometries were optimized and frequencies calculated at the B3LYP/6-311++G level.The interaction energies were corrected for basis set superposition error(BSSE) and the wavefunctions obtained by the natural bond orbital(NBO) and atom in molecule(AIM) analyses at the MP2/6-311++G level.For each H3C…Br-Y complex,a single-electron Br bond is formed between the unpaired electron of the CH3(electron donor) radical and the Br atom of Br-Y(electron acceptor);this kind of single-electron bromine bond also possesses the character of a"three-electron bond".Due to the formation of the single-electron Br bond,the C-H bonds of the CH3 radical bend away from the Br-Y moiety and the Br-Y bond elongates,giving red-shifted single-electron Br bond complexes.The effects of substituents,hybridization of the carbon atom,and solvent on the properties of the complexes have been investigated.The strengths of single-electron hydrogen bonds,single-electron halogen bonds and single-electron lithium bonds have been compared.In addition,the single-electron halogen bond system is discussed in the light of the first three criteria for hydrogen bonding proposed by Popelier.
