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Title: Mechanism of Na-Ion Storage in Hard Carbon Anodes Revealed by Heteroatom Doping

Abstract

Hard carbon is the candidate anode material for the commercialization of Na-ion batteries the batteries that by virtue of being constructed from inexpensive and abundant components open the door for massive scale up of battery-based storage of electrical energy. Holding back the development of these batteries is that a complete understanding of the mechanism of Na-ion storage in hard carbon has remained elusive. Although as an amorphous carbon, hard carbon possesses a subtle and complex structure composed of domains of layered rumpled sheets that have local order resembling graphene within each layer but complete disorder along the c-axis between layers. Here, we present two key discoveries: first that characteristics of hard carbon s structure can be modified systematically by heteroatom doping, and second, that these changes greatly affect Na-ion storage properties, which reveal the mechanisms for Na storage in hard carbon. Specifically, P, S and B doping was used to engineer the density of local defects in graphenic layers, and to modify the spacing between the layers. While opening the interlayer spacing through P or S doping extends the low-voltage capacity plateau, and increasing the defect concentration with P or B doping high first sodiation capacity is achieved. Furthermore, wemore » observe that the highly defective B-doped hard carbon suffers a tremendous irreversible capacity in the first desodiation cycle. Our combined first principles calculations and experimental studies revealed a new trapping mechanism, showing that the high binding energies between B-doping induced defects and Na-ions are responsible for the irreversible capacity. The understanding generated in this work provides a totally new set of guiding principles for materials engineers working to optimize hard carbon for Na-ion battery applications.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [2];  [3];  [1];  [4];  [1]
  1. Oregon State Univ., Corvallis, OR (United States). Dept. of Chemistry
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical and Engineering Materials Division
  3. Hewlett Packard Labs., Palo Alto, CA (United States)
  4. Univ. of California, Riverside, CA (United States). Materials Science and Engineering
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF)
OSTI Identifier:
1361320
Alternate Identifier(s):
OSTI ID: 1393301
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Advanced Energy Materials
Additional Journal Information:
Journal Volume: 7; Journal Issue: 18; Journal ID: ISSN 1614-6832
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 25 ENERGY STORAGE; hard carbon anodes; heteroatom doping; local structures; mechanisms; Na-ion batteries

Citation Formats

Li, Zhifei, Bommier, Clement, Chong, Zhi Sen, Jian, Zelang, Surta, Todd Wesley, Wang, Xingfeng, Xing, Zhenyu, Neuefeind, Joerg C., Stickle, William F., Dolgos, Michelle, Greaney, P. Alex, and Ji, Xiulei. Mechanism of Na-Ion Storage in Hard Carbon Anodes Revealed by Heteroatom Doping. United States: N. p., 2017. Web. doi:10.1002/aenm.201602894.
Li, Zhifei, Bommier, Clement, Chong, Zhi Sen, Jian, Zelang, Surta, Todd Wesley, Wang, Xingfeng, Xing, Zhenyu, Neuefeind, Joerg C., Stickle, William F., Dolgos, Michelle, Greaney, P. Alex, & Ji, Xiulei. Mechanism of Na-Ion Storage in Hard Carbon Anodes Revealed by Heteroatom Doping. United States. doi:10.1002/aenm.201602894.
Li, Zhifei, Bommier, Clement, Chong, Zhi Sen, Jian, Zelang, Surta, Todd Wesley, Wang, Xingfeng, Xing, Zhenyu, Neuefeind, Joerg C., Stickle, William F., Dolgos, Michelle, Greaney, P. Alex, and Ji, Xiulei. Tue . "Mechanism of Na-Ion Storage in Hard Carbon Anodes Revealed by Heteroatom Doping". United States. doi:10.1002/aenm.201602894.
@article{osti_1361320,
title = {Mechanism of Na-Ion Storage in Hard Carbon Anodes Revealed by Heteroatom Doping},
author = {Li, Zhifei and Bommier, Clement and Chong, Zhi Sen and Jian, Zelang and Surta, Todd Wesley and Wang, Xingfeng and Xing, Zhenyu and Neuefeind, Joerg C. and Stickle, William F. and Dolgos, Michelle and Greaney, P. Alex and Ji, Xiulei},
abstractNote = {Hard carbon is the candidate anode material for the commercialization of Na-ion batteries the batteries that by virtue of being constructed from inexpensive and abundant components open the door for massive scale up of battery-based storage of electrical energy. Holding back the development of these batteries is that a complete understanding of the mechanism of Na-ion storage in hard carbon has remained elusive. Although as an amorphous carbon, hard carbon possesses a subtle and complex structure composed of domains of layered rumpled sheets that have local order resembling graphene within each layer but complete disorder along the c-axis between layers. Here, we present two key discoveries: first that characteristics of hard carbon s structure can be modified systematically by heteroatom doping, and second, that these changes greatly affect Na-ion storage properties, which reveal the mechanisms for Na storage in hard carbon. Specifically, P, S and B doping was used to engineer the density of local defects in graphenic layers, and to modify the spacing between the layers. While opening the interlayer spacing through P or S doping extends the low-voltage capacity plateau, and increasing the defect concentration with P or B doping high first sodiation capacity is achieved. Furthermore, we observe that the highly defective B-doped hard carbon suffers a tremendous irreversible capacity in the first desodiation cycle. Our combined first principles calculations and experimental studies revealed a new trapping mechanism, showing that the high binding energies between B-doping induced defects and Na-ions are responsible for the irreversible capacity. The understanding generated in this work provides a totally new set of guiding principles for materials engineers working to optimize hard carbon for Na-ion battery applications.},
doi = {10.1002/aenm.201602894},
journal = {Advanced Energy Materials},
number = 18,
volume = 7,
place = {United States},
year = {Tue May 23 00:00:00 EDT 2017},
month = {Tue May 23 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 7works
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  • Cited by 7
  • The capacity of hard carbon anodes in Na-ion batteries 2.5 rarely reaches values beyond 300 mAh/g. We report that doping POx into local structures of hard carbon increases its reversible capacity from 283 to 359 mAh/g. We confirm that the doped POx is redox inactive by X-ray adsorption near edge structure measurements, thus not contributing to the higher capacity. We observe two significant changes of hard carbon's local structures caused by doping. First, the (002) d-spacing inside the turbostratic nanodomains is increased, revealed by both laboratory and synchrotron X-ray diffraction. Second, doping turns turbostratic nanodomains more defective along ab planes,more » indicated by neutron total scattering and the associated pair distribution function studies. The local structural changes of hard carbon are correlated to the higher capacity, where both the plateau and slope regions in the potential profiles are enhanced. Our study demonstrates that Na-ion storage in hard carbon heavily depends on carbon local structures, where such structures, despite being disordered, can be tuned toward unusually high capacities.« less
  • Solid-electrolyte interphase (SEI) films with controllable properties are highly desirable for improving battery performance. In this paper, a combined experimental and theoretical approach is used to study SEI films formed on hard carbon in Li- and Na-ion batteries. It is shown that a stable SEI layer can be designed by precycling an electrode in a desired Li- or Na-based electrolyte, and that ionic transport can be kinetically controlled. Selective Li- and Na-based SEI membranes are produced using Li- or Na-based electrolytes, respectively. The Na-based SEI allows easy transport of Li ions, while the Li-based SEI shuts off Na-ion transport. Na-ionmore » storage can be manipulated by tuning the SEI layer with film-forming electrolyte additives, or by preforming an SEI layer on the electrode surface. The Na specific capacity can be controlled to < 25 mAh g(-1); approximate to 1/10 of the normal capacity (250 mAh g(-1)). Unusual selective/ preferential transport of Li ions is demonstrated by preforming an SEI layer on the electrode surface and corroborated with a mixed electrolyte. This work may provide new guidance for preparing good ion-selective conductors using electrochemical approaches.« less
  • Solid-electrolyte interphase (SEI) with controllable properties are highly desirable to improve battery performance. In this paper, we use a combined experimental and simulation approach to study the SEI formation on hard carbon in Li and Na-ion batteries. We show that with proper additives, stable SEI can be formed on hard carbon by pre-cycling the electrode materials in Li or Na-ion electrolyte. Detailed mechanistic studies suggest that the ion transport in the SEI layer is kinetically controlled and can be tuned by the applied voltage. Selective Na and Li-ion SEI membranes are produced using the Na or Li-ion based electrolytes respectively.more » The large Na ion SEI allows easy transport of Li ions, while the small Li ion SEI shuts off the Na-ion transport. Na-ion storage can be manipulated by tuning the SEI with film-forming electrolyte additives or preforming a SEI on the electrodes’ surface. The Na specific capacity can be controlled to <25 mAh/g, ~1/10 of the normal capacity (250 mAh/g). Unusual selective/preferential transport of Li-ion is demonstrated by preforming a SEI on the electrode’s surface and corroborated with a mixed electrolyte. This work may provide new guidance for preparing good ion selective conductors using electrochemical approaches in the future.« less