Jahn-Teller Effect Directed Bandgap Tuning of Birnessite for Pseudocapacitive Application  

作　　者：Sheng Zhu Yuechao Wang Jinshu Zhang Jian Sheng Feng Yang Meng Wang Jiangfeng Ni Hong Jiang Yan Li 

机构地区：[1]Beijing National Laboratory for Molecular Sciences,Key Laboratory for the Physics and Chemistry of Nanodevices,State Key Laboratory of Rare Earth Materials Chemistry and Applications,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China [2]Institute of Molecular Science,Key Laboratory of Chemical Biology and Molecular Engineering of Education Ministry,Shanxi University,Taiyuan 030006,China [3]Beijing National Laboratory for Molecular Sciences,Institute of Theoretical and Computational Chemistry,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China [4]School of Physical Science and Technology,Center for Energy Conversion Materials&Physics(CECMP),Jiangsu Key Laboratory of Thin Films,Soochow University,Suzhou 215006,China

出　　处：《Energy & Environmental Materials》2023年第3期222-228,共7页能源与环境材料（英文）

基　　金：supported by Ministry of Science and Technology of China(2016YFA0201904);National Natural Science Foundation of China(21631002,52172219,51872192);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).

摘　　要：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.

关 键 词：BIRNESSITE charge storage Jahn–Teller effect manganese dioxide SUPERCAPACITOR 

分 类 号：TB34[一般工业技术—材料科学与工程] TM53[电气工程—电器]