Journal Article

FZJ-2018-01936

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Nanostructured Na 2 Ti 9 O 19 for Hybrid Sodium-Ion Capacitors with Excellent Rate Capability

Bhat, S. S. M. ; Babu, B. ; Feygenson, M.FZJ* ; Neuefeind, J. C. ; Shaijumon, M. M. (Corresponding author)

2018
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/acsami.7b13300

Abstract: Herein, we report a new Na-insertion electrode material, Na2Ti9O19, as a potential candidate for Na-ion hybrid capacitors. We study the structural properties of nanostructured Na2Ti9O19, synthesized by a hydrothermal technique, upon electrochemical cycling vs Na. Average and local structures of Na2Ti9O19 are elucidated from neutron Rietveld refinement and pair distribution function (PDF), respectively, to investigate the initial discharge and charge events. Rietveld refinement reveals electrochemical cycling of Na2Ti9O19 is driven by single-phase solid solution reaction during (de)sodiation without any major structural deterioration, keeping the average structure intact. Unit cell volume and lattice evolution on discharge process is inherently related to TiO6 distortion and Na ion perturbations, while the PDF reveals the deviation in the local structure after sodiation. Raman spectroscopy and X-ray photoelectron spectroscopy studies further corroborate the average and local structural behavior derived from neutron diffraction measurements. Also, Na2Ti9O19 shows excellent Na-ion kinetics with a capacitve nature of 86% at 1.0 mV s–1, indicating that the material is a good anode candidate for a sodium-ion hybrid capacitor. A full cell hybrid Na-ion capacitor is fabricated by using Na2Ti9O19 as anode and activated porous carbon as cathode, which exhibits excellent electrochemical properties, with a maximum energy density of 54 Wh kg–1 and a maximum power density of 5 kW kg–1. Both structural insights and electrochemical investigation suggest that Na2Ti9O19 is a promising negative electrode for sodium-ion batteries and hybrid capacitors.

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Contributing Institute(s):

1. Neutronenstreuung (ICS-1)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)
3. JCNS-ESS (JCNS-ESS)

Research Program(s):

1. 551 - Functional Macromolecules and Complexes (POF3-551) (POF3-551)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)
3. 6215 - Soft Matter, Health and Life Sciences (POF3-621) (POF3-621)

Appears in the scientific report 2018

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Database coverage:
; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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