.

1Maria Rita Mancini, Recupero di componenti da batterie al litio-ione esauste: processo eco-sostenibile e innovativo, Report RdS/PAR2014/184.

Graphite is an industrially important material used in steel industries, foundries, batteries, etc.. Furthermore, graphite-based composites reveal to be promising candidates for the manufacture of high-performance coatings against corrosion and for UV shielding. Natural graphite powders are mainly produced in China, which holds a 70% share of total world production, followed by Latin America with 20%. Europe production of natural graphite powders is less than 1% and therefore graphite was recently listed among the critical raw materials for EU.In this work, we describe an eco-friendly method for recovering graphite powders from anodes of end of life Li-ion batteries. Recovered graphite powders were used as starting material for the sustainable synthesis of graphene, graphene oxide, and reduced graphene oxide. High purity graphene solution was obtained by mild sonication, in ecofriendly solvents, of recovered graphite powders, while graphene oxide was synthetized by modified Hummers’ methods starting from same recovered graphite powders. Reduced graphene oxide (rGO) was obtained by chemical reduction by means of glucose and by thermal treatment in a reducing atmosphere of H2 and Ar at temperatures in the range of 400-900 °C.The proposed synthesis methodologies have been validated applying them to commercial graphite powders. Graphene and graphene oxide films were deposited on fused silica, silicon and yttria stabilized zirconia substrates by spin coating and drop casting techniques, starting from water dispersion of exfoliated graphite and water solution graphene oxide. Thermogravimetical analysis (TGA/DTA), UV-Vis-NIR and FTIR spectrophotometry, XRD, Raman and electron microscope (FE-SEM) measurements were used to investigate solutions, powders and films characteristics.

M.R. Mancini1*, M. L. Grilli1*, L. Pilloni1, M. Falconieri1, A. Mancini2, L. Petrucci1, S. Stendardo1

1ENEA Casaccia Research Centre, Via Anguillarese 301, 00123 Rome, Italy

2ENEA, Frascati Research Centre, Via Enrico Fermi 45, 00044 Frascati (Rome), Italy

corresponding authors: rita.mancini@enea.it, marialuisa.grilli@enea.it

Sustainable syntheses of graphene and graphene oxide from graphite powders recovered

by anodes of end of life Li-ion batteries

ACKNOWLEDGMENTS

The activity was supported by the Italian Ministry of Economic Development in the framework of the Operating Agreement with ENEA for the Research on the Electric System.

UV-Vis absorption spectra of graphene obtained by sonication

of commercial graphite

GRAPHENE SYNTHESIS: via SONICATION

assisted Liquid-Phase Exfoliation (LPE) in H2O

CONCLUSIONS

RECOVERY OF GRAPHITE FROM END OF LIFE Li-ION ANODES

Graphene and Graphene oxide were successfully grown by sustainable synthesis starting from commercial and recovered graphite powders. Graphite recovery was carried out from end of life Li-ion batteries with a sustainable and ecofriendly method. This method allows the separation and recovery of all components in the LIBs1. Graphene was obtained by sonication of graphite powders in water and/or alcohol. Graphene oxide was prepared by different synthesis based on the modified Hummers’ method. Reduced H2SO4 and KMnO4 weigth percentage with respect to graphite were used with the aim of speeding up GO purification. Moreover, a new step consisting in the sonication process of the solution before the oxidation, was introduced to promote the exfoliation process. Graphene oxide films were obtained by spin coating and drop casting techniques starting from graphene oxide in water solution. Powders and films were characterized by different techniques and resulted in high quality materials.

Graphene H2O DISPERSION

GRAPHENE OXIDE SYNTHESIS: Modified Hummers’ method:

Graphite (commercial and recovered); H2SO4; KMnO4; H2O2; H2O

Sonicators Centrifuge

a) Graphite soution with H2SO4 and KMnO4

b) GO in water solution after several washes and

centrifugations

c) Dried GO and GO solution

d) Spin coater for the deposition of GO films on

fused silica and Si substrates.

SEM micrograph of graphene oxide film

deposited by spin coating

2000 1800 1600 1400 1200 1000900

950

1000

1050

1100

1150

1200

Co

un

ts

Raman shift (cm-1)

D-band

G-band

Raman spectrum of graphene oxide film deposited by spin coating

UV-Vis absorption spectra of graphene obtained by sonication

of recovered graphite ANODE

GRAPHENE CHARACTERIZATION GRAPHENE OXIDE CHARACTERIZATION

Recovery of LIBs components were pursued by a simple and eco-friendly process1. Graphite, Li and Co are listed among the critical raw materials. Recovered graphite was used for the

synthesis of graphene and graphene oxide.

Sonochemical process

Spent lithium ion batteries

Dissasembling to cells

Separation of Graphite ANODE from Cu Collector

Graphite Flakes

a

b

c

d

SEM micrograph of graphene oxide flakes

UV-vis absorption spectrum of GO solution obtained from recovered graphite ANODE

SEM micrograph of graphene oxide from recovered graphite ANODE

UV-vis absorbance spectrum of GO solution

RAMAN spectra of graphite flakes, dried GO and rGO

XRD spectra of Grafite flakes and dried GO

1000 1250 1500 1750 2000 2250 2500 2750 3000

Counts

(a.u

.)

Raman Shift (cm-1)

Graphite Flakes

Graphene Oxide

Reduced Graphene Oxide

D-band

G-band

2D-band

250 300 350 400 450 500 550 600

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Ab

so

rba

nce

(nm)

C=C

n-C

A B

Separator tape

Flash

*Steel *Plastic

Cathodic tape Catodico

Anodic tape

Anodico

Spent LIBs

Discharging

CO2

Recovered Electrolyte

Degassing

Separating CO2

Supercritical

Dismanting and separating

Electrolyte extraction

Solvents + PVDF

Recovered active Materials

Recovered collectors PVDF dissolution

Solvents

Recovered PVDF

Recuperato

PVDF dissolution

SONICATION

Filtration/

purification

AGENZIA NAZIONALE PER LE NUOVE TECNOLOGIE,

L’ENERGIA E LO SVILUPPO ECONOMICO SOSTENIBILE

Recovered Graphite

Separation of tape: Anode, Cathode and

Separator

Recovery of LIBs components

250 300 350 400 450 500 550 6000.15

0.20

0.25

0.30

Sonication 60min

90min

Ab

sorb

ance

Wavelength (nm)

268nm

Recovered Graphite Anode from

Lithium ion batteries (LIBs)

5 10 15 20 25 30 35 40 45 50 55 60

Inte

nsity (

a.u

.)

2

Graphite Flakes

Graphene Oxide

200 250 300 350 4000.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Ab

so

rba

nce

Wavelenght (nm)

Graphite Sonication 10 min

15 min

268 nm