Doping of ceria with trivalent lanthanides and pentavalent ions is known to influence its catalytic activity,optical properties and ionic conductivity.In this study,(Nb,Eu)-codoped CeO_(2)has been synthesized by hydro...Doping of ceria with trivalent lanthanides and pentavalent ions is known to influence its catalytic activity,optical properties and ionic conductivity.In this study,(Nb,Eu)-codoped CeO_(2)has been synthesized by hydroxide precipitation to study the synergistic effect of(Nb,Eu)codoping on the defect evolution and optical properties of CeO_(2).展开更多
Li-rich cathode materials(LLO)exhibit a high specific capacity,but their application is impeded by their poor cycling stability and rate performance which arises from the irreversible anionic redox reaction and their ...Li-rich cathode materials(LLO)exhibit a high specific capacity,but their application is impeded by their poor cycling stability and rate performance which arises from the irreversible anionic redox reaction and their poor electrical conductivity.In this regard,a simple phytic acid surface treatment technique was employed to form an integrated surface structure comprising Li_(3)PO_(4)and oxygen vacancies(Vos)on the surface of LLO materials.In particular,the effect of the Li_(3)PO_(4)layer on the defect structure and their synergistic effect on the electrochemical performances of LLO were researched through experimental and theoretical calculations.The results prove that the existence of Li_(3)PO_(4)can improve the Vo content obviously.The coating layer and the synchronously formed Vo can also facilitate Li+diffusion,improve the electrical conductivity,and inhibit the irreversible O_(2)release effectively,thus increasing the cycling stability and rate performance of LLO.Consequently,the initial coulombic efficiency(ICE)increases from 62.8%to 72%.After 200 cycles at 0.5C,the capacity retention has improved significantly from 78%to 92.3%,accompanied by a minimal voltage fading value of 108.8 mV.The discharge specific capacity still reaches 125 mA h g^(−1)even at a current density of 5C.This work proves the effect of the Li_(3)PO_(4)coating layer on the defect structure and electrochemical properties of the LLO material and provides an effective clue to improve its performance.展开更多
Earth-abundant molybdenum disulfide(MoS_(2))shows a high application potential in thermoelectric(TE)field owing to its high Seebeck coefficient.However,the main obstacle to achieve high TE performance for the MoS_(2)m...Earth-abundant molybdenum disulfide(MoS_(2))shows a high application potential in thermoelectric(TE)field owing to its high Seebeck coefficient.However,the main obstacle to achieve high TE performance for the MoS_(2)material is its poor electrical conductivity.In this work,the flexible MoS_(2)/single-walled carbon nanotube(SWCNT)films with enhanced TE performance were fabricated via hydrothermal reaction,solution mixing,and subsequent vacuum filtration.The strong S-πinteraction and the energy filtering effect at the MoS_(2)/SWCNT interface produced an impressive power factor value of 107.99±4.98μW·m^(-1)·K^(-2)for the MoS_(2)/SWCNT composite films.In addition,the TE performance had high stability on bending deformation.Finally,at a temperature difference of 50 K,the assembled TE device of MoS_(2)/SWCNT films exhibited good output performance.This work provides a feasible reference to optimize the TE performance of MoS_(2)materials and demonstrates a high potential of flexible MoS_(2)-based composites in TE applications.展开更多
文摘Doping of ceria with trivalent lanthanides and pentavalent ions is known to influence its catalytic activity,optical properties and ionic conductivity.In this study,(Nb,Eu)-codoped CeO_(2)has been synthesized by hydroxide precipitation to study the synergistic effect of(Nb,Eu)codoping on the defect evolution and optical properties of CeO_(2).
文摘Li-rich cathode materials(LLO)exhibit a high specific capacity,but their application is impeded by their poor cycling stability and rate performance which arises from the irreversible anionic redox reaction and their poor electrical conductivity.In this regard,a simple phytic acid surface treatment technique was employed to form an integrated surface structure comprising Li_(3)PO_(4)and oxygen vacancies(Vos)on the surface of LLO materials.In particular,the effect of the Li_(3)PO_(4)layer on the defect structure and their synergistic effect on the electrochemical performances of LLO were researched through experimental and theoretical calculations.The results prove that the existence of Li_(3)PO_(4)can improve the Vo content obviously.The coating layer and the synchronously formed Vo can also facilitate Li+diffusion,improve the electrical conductivity,and inhibit the irreversible O_(2)release effectively,thus increasing the cycling stability and rate performance of LLO.Consequently,the initial coulombic efficiency(ICE)increases from 62.8%to 72%.After 200 cycles at 0.5C,the capacity retention has improved significantly from 78%to 92.3%,accompanied by a minimal voltage fading value of 108.8 mV.The discharge specific capacity still reaches 125 mA h g^(−1)even at a current density of 5C.This work proves the effect of the Li_(3)PO_(4)coating layer on the defect structure and electrochemical properties of the LLO material and provides an effective clue to improve its performance.
基金financial support from the Natural Science Foundation of Chongqing,China(No.CSTB2023NSCQ-MSX0602)Fundamental Research Funds for the Central Universities(No.SWU-KR22041 and SWU-XDJH202314)+2 种基金the Science and Technology Innovation and Venture Capital Special Projects of TIANDI Science Technology Co.Ltd(No.2023-TD-ZD014-004 and 2023-TD-QN012)CCTEG Chongqing Research Institute(No.2023ZDYF19)Xinjiang Uygur Autonomous Region Colleges and Universities Basic Scientific Research Operating Expenses Scientific Research Projects(No.XJEDU2023P113).
文摘Earth-abundant molybdenum disulfide(MoS_(2))shows a high application potential in thermoelectric(TE)field owing to its high Seebeck coefficient.However,the main obstacle to achieve high TE performance for the MoS_(2)material is its poor electrical conductivity.In this work,the flexible MoS_(2)/single-walled carbon nanotube(SWCNT)films with enhanced TE performance were fabricated via hydrothermal reaction,solution mixing,and subsequent vacuum filtration.The strong S-πinteraction and the energy filtering effect at the MoS_(2)/SWCNT interface produced an impressive power factor value of 107.99±4.98μW·m^(-1)·K^(-2)for the MoS_(2)/SWCNT composite films.In addition,the TE performance had high stability on bending deformation.Finally,at a temperature difference of 50 K,the assembled TE device of MoS_(2)/SWCNT films exhibited good output performance.This work provides a feasible reference to optimize the TE performance of MoS_(2)materials and demonstrates a high potential of flexible MoS_(2)-based composites in TE applications.
