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Exfoliation of layered Na-ion anode material Na 2 Ti 3 O 7 for enhanced capacity and cyclability

DOI: 10.1021/acs.chemmater.7b03753 DOI Help

Authors: Maria A. Tsiamtsouri (University of Cambridge) , Phoebe K. Allan (University of Cambridge; Diamond Light Source) , Andrew J. Pell (University of Cambridge) , Joshua M. Stratford (University of Cambridge) , Gunwoo Kim (University of Cambridge) , Rachel N. Kerber (University of Cambridge) , Pieter M. Magusin (University of Cambridge) , David A. Jefferson (University of Cambridge) , Clare P. Grey (University of Cambridge)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemistry Of Materials

State: Published (Approved)
Published: February 2018
Diamond Proposal Number(s): 14177

Abstract: We report the exfoliation of layered Na2Ti3O7, a promising anode material for Na-ion batteries, and restacking using HNO3 and NaOH to form H-[Ti3O7] and Na(x)-[Ti3O7] compositions, respectively. The materials were characterised by a range of techniques (SEM, TEM, solid state NMR, XRD, PDF). Although the formation of aggregated nanoparticles is favoured under acidic restacking conditions, control over the adherence between the exfoliated layers can be achieved in basic conditions. Pair distribution function (PDF) analysis confirms that the local TiO6 connectivity of the pristine material is maintained. The lowest sodium-containing Na(1)-[Ti3O7] phase, which is the stable product upon Na+ leaching after consecutive washing steps, displays the best performance among the compositions studied, affording a stable reversible capacity of about 200 mAh.g-1 for 20 cycles at a C/20 rate. Washing removes the excess of ‘free/reactive’ Na+, which otherwise forms inactive Na2CO3 in the insufficiently-washed compositions.

Subject Areas: Materials, Chemistry

Instruments: I15-Extreme Conditions

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