A one-step overall strategy from surface to bulk was proposed to simultaneously synthesize the Nb-doped and LiNbO_(3)-coated LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2) cathode materials.The incorporation of LiNbO_(3) coating ...A one-step overall strategy from surface to bulk was proposed to simultaneously synthesize the Nb-doped and LiNbO_(3)-coated LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2) cathode materials.The incorporation of LiNbO_(3) coating can regulate the interface and facilitate the diffusion of Li-ions.Simultaneously,the stronger Nb—O bond can effectively suppress Li^(+)/Ni^(2+) cation mixing and strengthen the stability of crystal structure,which helps to mitigate the anisotropic variations of lattice parameters during Li^(+) de/intercalation.The results showed that the dual-modified materials exhibited good structural stability and distinguished electrochemical performance.The optimal NCM-Nb2 sample showed an excellent capacity retention of 90.78%after 100 cycles at 1C rate between 2.7 and 4.3 V,while only 67.90%for the pristine one.Meanwhile,it displayed a superior rate capability of 149.1 mA·h/g at the 10C rate.These results highlight the feasibility of one-step dual modification strategy to synchronously improve the electrochemical performance of Ni-rich layered oxide cathodes.展开更多
Chemical stability and reactivity of organic pollutants is dependent to their formation enthalpies. The main objective of this study is to provide simple straightforward strategy for prediction of the formation enthal...Chemical stability and reactivity of organic pollutants is dependent to their formation enthalpies. The main objective of this study is to provide simple straightforward strategy for prediction of the formation enthalpies of wide range organic pollutants only from their structural functional groups. Using such an extended dataset cornprising 1694 organic chemicals from 77 diverse material classes benefits the generalizability and reliability of the study. The new suggested collection of 12 functional groups and a simple linear regression lead to promising statis- tics of R2= 0.958, Q2 =0.956, and AEE= 57 kJ.mo1-1 for the whole dataset. Moreover, unknown experimental formation enthalpies for 27 organic pollutants are estimated by the presented approach. The resultant model needs no technical software/calculations, and thus can be easily applied by a non-specialist user.展开更多
Using the particle swarm optimization algorithm on crystal structure prediction,we first predict that Mg Y alloy undergoes a first-order phase transition from Cs Cl phase to P4/NMM phase at about 55 GPa with a small v...Using the particle swarm optimization algorithm on crystal structure prediction,we first predict that Mg Y alloy undergoes a first-order phase transition from Cs Cl phase to P4/NMM phase at about 55 GPa with a small volume collapse of 2.63%.The dynamical stability of P4/NMM phase at 55 GPa is evaluated by the phonon spectrum calculation and the electronic structure is discussed.The elastic constants are calculated,after which the bulk moduli,shear moduli,Young's modui,and Debye temperature are derived.The brittleness/ductile behavior,and anisotropy of two phases under pressure are discussed in details.Our results show that external pressure can change the brittle behavior to ductile at10 GPa for Cs Cl phase and improve the ductility of Mg Y alloy.As pressure increases,the elastic anisotropy in shear of Cs Cl phase decreases,while that of P4/NMM phase remains nearly constant.The elastic anisotropic constructions of the directional dependences of reciprocals of bulk modulus and Young's modulus are also calculated and discussed.展开更多
基金the Regional Innovation and Development Joint Fund of National Natural Science Foundation of China(No.U19A2018)the National Natural Science Foundation of China(No.21703191)+2 种基金Project of Innovation Team of the Ministry of Education,China(No.IRT_17R90)Hunan Provincial Natural Scientific Foundation of China(No.2019JJ50600)Outstanding Youth Project of Hunan Provincial Education Department,China(No.18B076).
文摘A one-step overall strategy from surface to bulk was proposed to simultaneously synthesize the Nb-doped and LiNbO_(3)-coated LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2) cathode materials.The incorporation of LiNbO_(3) coating can regulate the interface and facilitate the diffusion of Li-ions.Simultaneously,the stronger Nb—O bond can effectively suppress Li^(+)/Ni^(2+) cation mixing and strengthen the stability of crystal structure,which helps to mitigate the anisotropic variations of lattice parameters during Li^(+) de/intercalation.The results showed that the dual-modified materials exhibited good structural stability and distinguished electrochemical performance.The optimal NCM-Nb2 sample showed an excellent capacity retention of 90.78%after 100 cycles at 1C rate between 2.7 and 4.3 V,while only 67.90%for the pristine one.Meanwhile,it displayed a superior rate capability of 149.1 mA·h/g at the 10C rate.These results highlight the feasibility of one-step dual modification strategy to synchronously improve the electrochemical performance of Ni-rich layered oxide cathodes.
基金Supported by the "Tehran Naftoon Arya Eng. Co." research committee of Iran
文摘Chemical stability and reactivity of organic pollutants is dependent to their formation enthalpies. The main objective of this study is to provide simple straightforward strategy for prediction of the formation enthalpies of wide range organic pollutants only from their structural functional groups. Using such an extended dataset cornprising 1694 organic chemicals from 77 diverse material classes benefits the generalizability and reliability of the study. The new suggested collection of 12 functional groups and a simple linear regression lead to promising statis- tics of R2= 0.958, Q2 =0.956, and AEE= 57 kJ.mo1-1 for the whole dataset. Moreover, unknown experimental formation enthalpies for 27 organic pollutants are estimated by the presented approach. The resultant model needs no technical software/calculations, and thus can be easily applied by a non-specialist user.
基金Supported by the Henan Joint Funds of the National Natural Science Foundation of China under Grant Nos.U1304612,U1404608the National Natural Science Foundation of China under Grant Nos.51501093,51374132+2 种基金the Special Fund of the Theoretical Physics of China under Grant No.11247222Postdoctoral Science Foundation of China under Grant No.2015M581767Young Core Instructor Foundation of Henan Province under Grant No.2015GGJS-122
文摘Using the particle swarm optimization algorithm on crystal structure prediction,we first predict that Mg Y alloy undergoes a first-order phase transition from Cs Cl phase to P4/NMM phase at about 55 GPa with a small volume collapse of 2.63%.The dynamical stability of P4/NMM phase at 55 GPa is evaluated by the phonon spectrum calculation and the electronic structure is discussed.The elastic constants are calculated,after which the bulk moduli,shear moduli,Young's modui,and Debye temperature are derived.The brittleness/ductile behavior,and anisotropy of two phases under pressure are discussed in details.Our results show that external pressure can change the brittle behavior to ductile at10 GPa for Cs Cl phase and improve the ductility of Mg Y alloy.As pressure increases,the elastic anisotropy in shear of Cs Cl phase decreases,while that of P4/NMM phase remains nearly constant.The elastic anisotropic constructions of the directional dependences of reciprocals of bulk modulus and Young's modulus are also calculated and discussed.
