TY - JOUR
T1 - Atomic-level tunnel engineering of todorokite MnO2 for precise evaluation of lithium storage mechanisms by in situ transmission electron microscopy
AU - Cai, Ran
AU - Guo, Shiying
AU - Meng, Qingping
AU - Yang, Shize
AU - Xin, Huolin L.
AU - Hu, Xiaobing
AU - Li, Mingqiang
AU - Sun, Yuanwei
AU - Gao, Peng
AU - Zhang, Shengli
AU - Dong, Hui
AU - Lei, Shuangying
AU - Kim, Kisslinger
AU - Zeng, Haibo
AU - Sun, Litao
AU - Xu, Feng
AU - Zhu, Yimei
N1 - Funding Information:
Dr. Haibo Zeng received his Ph.D. from the Institute of Solid State Physics, Chinese Academy of Sciences, in 2006. He worked with Prof. Claus Klingshirn in 2007 at the University of Karlsruhe, Germany. In 2008, he joined Prof. Yoshio Bando's group at the National Institute for Materials Science, Japan, under the support of JSPS. In 2011, he returned to Nanjing University of Aeronautics and Astronautics as a full professor, and then moved to Nanjing University of Science and Technology in 2013 as a director of the Institute of Optoelectronics & Nanomaterials. His current research interest includes 2D materials and QDs.
Funding Information:
This work was supported by the National Natural Science Foundation of China (Grant Nos. 11774051 , 61574034 , 11525415 , 51420105003 , 11774052 ), the 973 Program (Grant No. 2015CB352106 ), the National Key R&D Program of China (Grant Nos. 2016YFA0300804 , 2016YFA0300903 ), National Equipment Program of China ( ZDYZ2015-1 ), China Postdoctoral Science Foundation Funded Project ( 2014M550259 , 2015T80480 ), Jiangsu Planned Projects for Postdoctoral Research Funds ( 1401006A ), and the Fundamental Research Funds for the Central Universities ( 2242018K41020 ). The authors acknowledge the Electron Microscopy Laboratory in Peking University for the use of in situ TEM platform.
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/9
Y1 - 2019/9
N2 - Todorokite-type manganese oxide (τ-MnO2) with p × 3 tunneled structure is especially captivating as charge storage material for rechargeable batteries, since the enlarged tunnel dimensions enable rapid electrode kinetics and superior rate performance. However, its congenitally rich polytypism associated with tunnel heterogeneity impedes our precise understanding of structure-property relationship in this polytypic material. In this regard, this work has taken substantial effort to preliminarily achieve uniform 4 × 3 tunnel-structured τ-MnO2 nanorods, as corroborated via atomically resolved imaging. Afterwards, the (de)lithiation mechanisms of the tunnel-specific phase are investigated via in situ transmission electron microscopy including electron diffraction, high-resolution imaging, and electron energy loss spectroscopy, coupled with density functional theory calculations and phase field simulations. Upon initial lithiation, the intercalation reaction region β (less than 1.43 Li insertion) is observed as result of rapid lithium-ion diffusion through the tunnels with slightly increased lattice constants. By tracing the full lithiation procedure, the evolution of intermediate Mn2O3 phase and the development of final Mn and Li2O phases are identified in the conversion reaction region α (more than 1.43 Li insertion). These results indicate that τ-MnO2 can be applied to a cathode by intercalation reaction and to an anode by conversion reaction in corresponding to voltage ranges in a lithium-based battery. Upon delithiation, we observe an unusual reciprocating-motion reaction front (different from one-way lithiation reaction front), for which the driven dynamics are delineated based on a phase field model. Impressively, a reversible and symmetric conversion reaction between Mn2O3 phase and Mn + Li2O phases is established upon subsequent (de)lithiation cycles. This work can be regarded as a stepping-stone arousing the appetite of a comprehensive understanding of the highly polytypic material with other tunnel-specific phases.
AB - Todorokite-type manganese oxide (τ-MnO2) with p × 3 tunneled structure is especially captivating as charge storage material for rechargeable batteries, since the enlarged tunnel dimensions enable rapid electrode kinetics and superior rate performance. However, its congenitally rich polytypism associated with tunnel heterogeneity impedes our precise understanding of structure-property relationship in this polytypic material. In this regard, this work has taken substantial effort to preliminarily achieve uniform 4 × 3 tunnel-structured τ-MnO2 nanorods, as corroborated via atomically resolved imaging. Afterwards, the (de)lithiation mechanisms of the tunnel-specific phase are investigated via in situ transmission electron microscopy including electron diffraction, high-resolution imaging, and electron energy loss spectroscopy, coupled with density functional theory calculations and phase field simulations. Upon initial lithiation, the intercalation reaction region β (less than 1.43 Li insertion) is observed as result of rapid lithium-ion diffusion through the tunnels with slightly increased lattice constants. By tracing the full lithiation procedure, the evolution of intermediate Mn2O3 phase and the development of final Mn and Li2O phases are identified in the conversion reaction region α (more than 1.43 Li insertion). These results indicate that τ-MnO2 can be applied to a cathode by intercalation reaction and to an anode by conversion reaction in corresponding to voltage ranges in a lithium-based battery. Upon delithiation, we observe an unusual reciprocating-motion reaction front (different from one-way lithiation reaction front), for which the driven dynamics are delineated based on a phase field model. Impressively, a reversible and symmetric conversion reaction between Mn2O3 phase and Mn + Li2O phases is established upon subsequent (de)lithiation cycles. This work can be regarded as a stepping-stone arousing the appetite of a comprehensive understanding of the highly polytypic material with other tunnel-specific phases.
KW - Atomic-precise structure engineering
KW - In situ transmission electron microscopy
KW - Lithiation mechanism
KW - Reciprocating-motion reaction front
KW - Todorokite MnO
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U2 - 10.1016/j.nanoen.2019.06.036
DO - 10.1016/j.nanoen.2019.06.036
M3 - Article
AN - SCOPUS:85067882206
SN - 2211-2855
VL - 63
JO - Nano Energy
JF - Nano Energy
M1 - 103840
ER -
