Polyaniline-intercalated layered vanadium oxide nanocomposites—One-pot hydrothermal synthesis and application in lithium battery

Downloaded on 02 December 2010Published on 08 September 2010 on | doi:10.1039/C0NR00246A

Fig.8XRDpatternsoftheas-preparedsamplesobtainedatdifferentreactiontemperatures(pH¼3,t¼24h).(a)80 C,(b)100 C,(c)120 C,(d)140 C,(e)160 C,(d)180

C.

Fig.10XRDpatternsoftheas-preparedsamplesobtainedat120 Cfordifferentreactiontimes(pH¼3).(a)15min,(b)30min,(c)1h,(d)15

h.

Fig.9SEMimagesoftheas-preparedsamplesobtainedatdifferentreactiontemperatures(pH¼3,t¼24h).(a)120 C,(b)140 C,(c)160 C,(d)180

C.

Fig.11SEMimagesoftheas-preparedsamplesobtainedat120 Cfordifferentreactiontimes(pH¼3).(a)15min,(b)30min,(c)1h,(d)15h.

self-assembledfromthenanosheets,whilethesamplesynthesizedat140 Chasthemorphologyofshaleself-assembledfromthenanosheets.Asthetemperatureisincreasedto160 C,theXRDpattern(Fig.8e)revealsthattheobtainedsampleiscomposedoftwodifferentphases,yeredphaseofthepolyaniline-inter-calatedvanadiumoxidenanocompositeandmonocliniccrys-tallinephaseofVO2(JCPDS81-2392),andtheSEMimage(Fig.9c)showsithasamixedmorphologyofnanosheetsandnanobelts.Whenthetemperatureisfurtherincreasedto180 C,allthediffractionpeaksoftheresultingsamplecanbeindexedtothemonocliniccrystallinephaseofVO2(seeFig.8f)andthesampleshowsthemorphologyofuniformnanobelts(Fig.9d).Theseresultssuggestthatanappropriatereactiontemperatureiscrucialfortheformationofthepolyaniline-intercalatedlayeredvanadiumoxidenanocomposite.

Fig.10showstheXRDpatternsoftheas-preparedsamplessynthesizedat120 Cfordifferentreactiontimes.Thesamplesynthesizedat120 Cfor15mincanbeindexedtothepureorthorhombiccrystallinephaseofV2O5(Fig.10a),andthelayeredphaseofthepolyaniline-intercalatedvanadiumoxidenanocompositeappearedinthesampleobtainedafter30min(Fig.10b).AsshowninFig.10cand10d,whenthereactiontime

isfurtherincreasedto1handthereafter,alltheBraggpeaksoftheobtainedsamplesareconsistentwiththoseofthepolyaniline-intercalatedvanadiumoxidenanocomposite.Itrevealsthatthepolyaniline-intercalatedvanadiumoxidehybridmaterialcanbesynthesizedwithin1h.Fig.11showsthecorrespondingSEMimagesoftheas-preparedsamplesobtainedatdifferentreactiontimes.AsshowninFig.11a,thesampleobtainedatareactiontemperatureof120 Cfor15minhasthemorphologyofnano-plates,similarwiththeprecursorV2O5butwithadecreasedthickness.Asthereactiontimeisincreasedto30min,theobtainedsamplehasamixedmorphologyofnanoplatesandnanosheets(Fig.11b).Withprolongingthereactiontime,thesampleobtainedat60minpresentsahomogeneousmorphologyofnanosheets(Fig.11c).Thesampleobtainedafter15hhasthemorphologyofnanosheetsandthenanosheetsbecomemoreuniformandordered(Fig.11d).

Fig.12andFig.13showXRDpatternsandcorrespondingSEMimagesoftheresultingsamplessynthesizedinthepresenceofdifferentamountsofanilineat120 Cfor24h.AsshowninFig.12,allthesamplescanbeindexedtothelayeredphaseofthepolyaniline-intercalatedvanadiumoxidenanocomposite.InFig.13,itcanbefoundthattheresultingsamplespresentthemorphologyofnanosheetsandthethicknessofthenanosheets

is