McColl, K;
Griffith, KJ;
Dally, RL;
Li, R;
Douglas, JE;
Poeppelmeier, KR;
Cora, F;
... Butala, MM; + view all
(2021)
Energy storage mechanisms in vacancy-ordered Wadsley-Roth layered niobates.
Journal of Materials Chemistry A
10.1039/d1ta02992d.
(In press).
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Abstract
Wadsley–Roth (WR) crystallographic shear structures demonstrate high energy and power densities as Li-ion battery anode materials. We report the (de)lithiation behavior of two WR-derived layered niobates: NaNb_{3}O_{8} and KNb_{3}O_{8}. Both demonstrate multi-electron (Nb5+/Nb3+) redox on the first discharge, reacting with ≈5 mol Li per mol ANb_{3}O_{8}. Li intercalation in NaNb_{3}O_{8} is dominated by Li-diffusion kinetics and evolution of the interlayer structure, with Li initially filling octahedral sites near the interlayer space to draw the layers together to form a (2 × 2)_{∞} WR structure. This average structure change pushes Na ions into the square channels, blocking fast Li diffusion down the square channels that provide the fast Li-ion conduction in most WR materials. Upon charge, Li ions incorporated into the octahedral WR sites (ordered vacancies in the layered structure) are extracted, revealing a new, reversible Li site for additional capacity in WR-like materials. The behavior of KNb_{3}O_{8} is similar, but has additional hysteresis associated with its larger counter-cation. While neither layered niobate matches the demonstrated performance of WR materials, by studying them, we identify a route for increased capacity in WR-like frameworks. Additionally, we identify the important role of Li diffusion kinetics and counter-cations in the cycling behavior of WR-derived structures.
| Type: | Article |
|---|---|
| Title: | Energy storage mechanisms in vacancy-ordered Wadsley-Roth layered niobates |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1039/d1ta02992d |
| Publisher version: | https://doi.org/10.1039/d1ta02992d |
| Language: | English |
| Additional information: | © Royal Society of Chemistry 2021. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (http://creativecommons.org/licenses/by/3.0/). |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10133129 |
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