Birnessite M_(x)MnO_(2)(M=Na^(+),K^(+),etc.)has emerged as a promising alternative to the classical MnO_(2)material owing to its improved pseudocapacitive performance for energy storage.Understanding their structure–...Birnessite M_(x)MnO_(2)(M=Na^(+),K^(+),etc.)has emerged as a promising alternative to the classical MnO_(2)material owing to its improved pseudocapacitive performance for energy storage.Understanding their structure–property correlation is essential for the development and application of advanced supercapacitors.Herein,we adopt the crystal field theory and density functional simulation to reveal the structural dependence of the pseudocapacitive property of M_(x)MnO_(2).Attributing to the Jahn–Teller effect of Mn^(3+),the bandgap of Kx MnO_(2)can be tuned by changing the x value(i.e.,the Mn(III)/Mn(IV)ratio).Then,we design a narrow-bandgap K 0.25 MnO_(2)(0.84 eV),which affords a high capacitance of 415 F g^(-1)at 1 A g^(-1)and a desirable rate capability of 293 F g^(-1)at 20 A g^(-1).Operando Raman spectroscopy confirms that the Jahn–Teller induced structure evolution of[MnO_(6)]octahedron accounts for the superior pseudocapacitive behavior of K_(0.25)MnO_(2).This finding offers theoretical guidance to the design and application of birnessite materials for pseudocapacitors.展开更多
Rechargeable aqueous zinc ion batteries(AZIBs)based on manganese dioxide(MnO_(2))have received much attention for large-scale energy storage applications,however,their energy density is mainly limited by the one-elect...Rechargeable aqueous zinc ion batteries(AZIBs)based on manganese dioxide(MnO_(2))have received much attention for large-scale energy storage applications,however,their energy density is mainly limited by the one-electron reaction of Mn4+/Mn3+redox.Herein,Mo dopedδ-MnO_(2)(Mo-MnO_(2))is prepared and used as a high-performance cathode for AZIBs,which delivers an⇌⇌ultrahigh specific capacity of 652 mAh·g^(−1)at 0.2 A·g^(−1)based on the two-step two-electron redox reaction of Mn^(4+)Mn^(3+)Mn^(2+).Ex-situ structural analysis and density functional theory calculation reveal that the Mo^(5+)dopant plays an important role in enhancing the electronic conductivity of Mo-MnO_(2)and promoting Jahn–Teller distortion of octahedral[MnO_(6)]in ZnMn_(2)O_(4),which facilitates the second step redox reaction of Mn^(3+)/Mn_(2+).This work provides a novel cathode materials design with multi-electron redox chemistry to achieve high energy density in AZIBs.展开更多
Oxygen anion redox chemistry in layered oxide cathodes for sodium-ion batteries has attracted great interest.However,the release of lattice oxygen caused by the irreversible anionic redox and Jahn–Teller effect accel...Oxygen anion redox chemistry in layered oxide cathodes for sodium-ion batteries has attracted great interest.However,the release of lattice oxygen caused by the irreversible anionic redox and Jahn–Teller effect accelerates the structural distortion and electrochemical degradation.Herein,we rationally construct a stable crystal lattice to enhance the reactivity and reversibility of oxygen redox and inhibit the Jahn–Teller effect by Sn doping.The stronger binding energy of Sn–O enhances the structural stability of the cathode,which is favorable to suppress the oxygen release and Jahn–Teller effect.Thus,the reversibility of oxygen redox and the stability of the layered structure are enhanced.The expansion of the interlayer spacing decreases the energy barriers for Na+ion intercalation,improving the rate performance of the electrode.Benefitting from the rational design,the electrode delivers an enhanced rate performance and cycling stability.This work offers some insights into tuning the oxygen anion redox chemistry as well as suppressing the Jahn–Teller effect by lattice modulation.展开更多
The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that there are conflicts of interests among the authors. The scientific community takes a ...The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that there are conflicts of interests among the authors. The scientific community takes a very strong view on this matter, and the Advances in Materials Physics and Chemistry treats all unethical behaviors seriously. This paper published in Vol. 4 No. 4 61-74, 2014 has been removed from this site. Title: Jahn–Teller Effect, Crystal Structure and High Temperature Raman Spectroscopy Studies of Ba2-xSrxCuWO6 (0 ≤ x≤ 2) Double Perovskite Oxide. Authors: Amine Ezzahi, Abdellah展开更多
基金supported by Ministry of Science and Technology of China(2016YFA0201904)National Natural Science Foundation of China(21631002,52172219,51872192)+3 种基金Projects of International Cooperation and Exchanges NSFC(22120102004)Beijing National Laboratory for Molecular Sciences(BNLMS-CXTD-202001)the Jiangsu Natural Science Foundation(No.BK20180002)Fundamental Research Program of Shanxi Province(202103021223019).
文摘Birnessite M_(x)MnO_(2)(M=Na^(+),K^(+),etc.)has emerged as a promising alternative to the classical MnO_(2)material owing to its improved pseudocapacitive performance for energy storage.Understanding their structure–property correlation is essential for the development and application of advanced supercapacitors.Herein,we adopt the crystal field theory and density functional simulation to reveal the structural dependence of the pseudocapacitive property of M_(x)MnO_(2).Attributing to the Jahn–Teller effect of Mn^(3+),the bandgap of Kx MnO_(2)can be tuned by changing the x value(i.e.,the Mn(III)/Mn(IV)ratio).Then,we design a narrow-bandgap K 0.25 MnO_(2)(0.84 eV),which affords a high capacitance of 415 F g^(-1)at 1 A g^(-1)and a desirable rate capability of 293 F g^(-1)at 20 A g^(-1).Operando Raman spectroscopy confirms that the Jahn–Teller induced structure evolution of[MnO_(6)]octahedron accounts for the superior pseudocapacitive behavior of K_(0.25)MnO_(2).This finding offers theoretical guidance to the design and application of birnessite materials for pseudocapacitors.
基金supported by the National Natural Science Foundation of China(Nos.21935001 and 22101015)the National Key Research and Development Program of China(No.2018YFA0702002)the Program for Changjiang Scholars and Innovation Research Team in the University(No.IRT1205).
文摘Rechargeable aqueous zinc ion batteries(AZIBs)based on manganese dioxide(MnO_(2))have received much attention for large-scale energy storage applications,however,their energy density is mainly limited by the one-electron reaction of Mn4+/Mn3+redox.Herein,Mo dopedδ-MnO_(2)(Mo-MnO_(2))is prepared and used as a high-performance cathode for AZIBs,which delivers an⇌⇌ultrahigh specific capacity of 652 mAh·g^(−1)at 0.2 A·g^(−1)based on the two-step two-electron redox reaction of Mn^(4+)Mn^(3+)Mn^(2+).Ex-situ structural analysis and density functional theory calculation reveal that the Mo^(5+)dopant plays an important role in enhancing the electronic conductivity of Mo-MnO_(2)and promoting Jahn–Teller distortion of octahedral[MnO_(6)]in ZnMn_(2)O_(4),which facilitates the second step redox reaction of Mn^(3+)/Mn_(2+).This work provides a novel cathode materials design with multi-electron redox chemistry to achieve high energy density in AZIBs.
基金the National Natural Science Foundation of China(grant nos.11975238 and 11575192)the Chinese Academy of Sciences(grant nos.ZDKYYQ20170001,211211KYSB20170060,and 211211KYSB20180020)the Natural Science Foundation of Beijing Municipality(grant no.2182082).
文摘Oxygen anion redox chemistry in layered oxide cathodes for sodium-ion batteries has attracted great interest.However,the release of lattice oxygen caused by the irreversible anionic redox and Jahn–Teller effect accelerates the structural distortion and electrochemical degradation.Herein,we rationally construct a stable crystal lattice to enhance the reactivity and reversibility of oxygen redox and inhibit the Jahn–Teller effect by Sn doping.The stronger binding energy of Sn–O enhances the structural stability of the cathode,which is favorable to suppress the oxygen release and Jahn–Teller effect.Thus,the reversibility of oxygen redox and the stability of the layered structure are enhanced.The expansion of the interlayer spacing decreases the energy barriers for Na+ion intercalation,improving the rate performance of the electrode.Benefitting from the rational design,the electrode delivers an enhanced rate performance and cycling stability.This work offers some insights into tuning the oxygen anion redox chemistry as well as suppressing the Jahn–Teller effect by lattice modulation.
文摘The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that there are conflicts of interests among the authors. The scientific community takes a very strong view on this matter, and the Advances in Materials Physics and Chemistry treats all unethical behaviors seriously. This paper published in Vol. 4 No. 4 61-74, 2014 has been removed from this site. Title: Jahn–Teller Effect, Crystal Structure and High Temperature Raman Spectroscopy Studies of Ba2-xSrxCuWO6 (0 ≤ x≤ 2) Double Perovskite Oxide. Authors: Amine Ezzahi, Abdellah
