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Evolution of Reduced Graphene Oxide-SnS2 Hybrid Nanoparticle Electrodes in Li-Ion Batteries

Accepted version
Peer-reviewed

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Type

Article

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Authors

Modarres, MH 
Lim, JHW 
George, C 

Abstract

Hybrid nanomaterials where active battery nanoparticles are synthesized directly onto conductive additives such as graphene hold the promise of improving the cyclability and energy density of conversion and alloying type Li-ion battery electrodes. Here we investigate the evolution of hybrid reduced graphene oxide–tin sulfide (rGO-SnS2) electrodes during battery cycling. These hybrid nanoparticles are synthesized by a one-step solvothermal microwave reaction which allows for simultaneous synthesis of the SnS2 nanocrystals and reduction of GO. Despite the hybrid architecture of these electrodes, electrochemical impedance spectroscopy shows that the impedance doubles in about 25 cycles and subsequently gradually increases, which may be caused by an irreversible surface passivation of rGO by sulfur enriched conversion products. This surface passivation is further confirmed by post-mortem Raman spectroscopy of the electrodes, which no longer detects rGO peaks after 100 cycles. Moreover, galvanostatic intermittent titration analysis during the 1st and 100th cycles shows a drop in Li-ion diffusion coefficient of over an order of magnitude. Despite reports of excellent cycling performance of hybrid nanomaterials, our work indicates that in certain electrode systems, it is still critical to further address passivation and charge transport issues between the active phase and the conductive additive in order to retain high energy density and cycling performance.

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Keywords

1007 Nanotechnology, 0306 Physical Chemistry (incl. Structural)

Journal Title

Journal of Physical Chemistry C

Conference Name

Journal ISSN

1932-7447
1932-7455

Volume Title

121

Publisher

American Chemical Society
Sponsorship
European Research Council (337739)
EPSRC (1361022)
Engineering and Physical Sciences Research Council (EP/G037221/1)
M.H.M acknowledges the support from EPSRC Cambridge NanoDTC, EP/G037221/1. C.G and M.D.V acknowledge the support from ERC starting grant HIENA-337739.