The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_...The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were characterized thoroughly by means of X-ray diffractometer,scanning electron microscope and electrochemical charge/discharge instruments.Moreover,a thin layer of Al_(2)O_(3),which was formed on the surface of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2),can enhance the storage performance by preventing the formation of Na_(2)CO_(3)·H_(2)O,which is believed to enhance the electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials.This facile surface modification method may pave a way to synthesize advanced cathode materials for sodium-ion batteries.展开更多
Two helical one-dimensional complexes [Mnn（MeOH）4][MnlV（L）2]·2MeOH （1） and [Mnm（salen）][Mnm（L）2] （2） （H2L = HON=C（Ph）N=NC6HaCO2H） contain the noninnocent ligand [Mn（L）2]2- and innocent low-spin ...Two helical one-dimensional complexes [Mnn（MeOH）4][MnlV（L）2]·2MeOH （1） and [Mnm（salen）][Mnm（L）2] （2） （H2L = HON=C（Ph）N=NC6HaCO2H） contain the noninnocent ligand [Mn（L）2]2- and innocent low-spin [Mn（L）2]-. Intrachain anti- ferromagnetic interaction between adjacent manganese syn-anti and anti-anti carboxylate bridges have been high-spin and low-spin Mn（llI） ions in complex 2. ions via the syn-anti carboxylate bridges in complex 1. Alternate found to transmit ferro- and antiferromagnetic coupling between展开更多
Atomistic simulation has been performed to investigate the dynamical and defect properties of multiferroic hexagonal YMnO3 with newly developed interaction potentials. Dynamical calculation reveals that phonon vibrati...Atomistic simulation has been performed to investigate the dynamical and defect properties of multiferroic hexagonal YMnO3 with newly developed interaction potentials. Dynamical calculation reveals that phonon vibrations of hexagonal YMnO3 are quite different from those of orthorhombic YMnO3. Defect calculation finds that O Frenkel is the most probable intrinsic disorder, and Mn antisite defect is favorable to exist, especially for Mn ions entering the Y2 sites. It is also found that holes prefer to localize at O2sites rather than at Mn3+ sites, while the electron can be localized at the Mn3+ site. The disproportionation of Mn3+ ions is unlikely to occur in hexagonal YMnO3.展开更多
基金financially supported by the Natural Science Foundation of Hunan Province,China(No.2020JJ5755)the National Natural Science Foundation of China(Nos.51804344,51704332,51874360)the Innovation and Entrepreneurship Project of Hunan Province,China(No.2018GK5026)。
文摘The P2-type Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method.The structures,morphologies and electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials were characterized thoroughly by means of X-ray diffractometer,scanning electron microscope and electrochemical charge/discharge instruments.Moreover,a thin layer of Al_(2)O_(3),which was formed on the surface of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2),can enhance the storage performance by preventing the formation of Na_(2)CO_(3)·H_(2)O,which is believed to enhance the electrochemical performances of Na_(2/3)Fe_(1/2)Mn_(1/2)O_(2)materials.This facile surface modification method may pave a way to synthesize advanced cathode materials for sodium-ion batteries.
基金supported by the National Natural Science Foundation of China (21171103, 20921001)
文摘Two helical one-dimensional complexes [Mnn（MeOH）4][MnlV（L）2]·2MeOH （1） and [Mnm（salen）][Mnm（L）2] （2） （H2L = HON=C（Ph）N=NC6HaCO2H） contain the noninnocent ligand [Mn（L）2]2- and innocent low-spin [Mn（L）2]-. Intrachain anti- ferromagnetic interaction between adjacent manganese syn-anti and anti-anti carboxylate bridges have been high-spin and low-spin Mn（llI） ions in complex 2. ions via the syn-anti carboxylate bridges in complex 1. Alternate found to transmit ferro- and antiferromagnetic coupling between
基金supported by the National Natural Science Foundation of China (Grant Nos. U0734001 and 50772054)the Ministry of Science and Technology of China (Grant No. 2009CB929202)
文摘Atomistic simulation has been performed to investigate the dynamical and defect properties of multiferroic hexagonal YMnO3 with newly developed interaction potentials. Dynamical calculation reveals that phonon vibrations of hexagonal YMnO3 are quite different from those of orthorhombic YMnO3. Defect calculation finds that O Frenkel is the most probable intrinsic disorder, and Mn antisite defect is favorable to exist, especially for Mn ions entering the Y2 sites. It is also found that holes prefer to localize at O2sites rather than at Mn3+ sites, while the electron can be localized at the Mn3+ site. The disproportionation of Mn3+ ions is unlikely to occur in hexagonal YMnO3.
