Supplementary Information
Cu/Li4Ti5O12 scaffold as superior anode for lithium-ion batteries
Xi Wang,1,2 Dequan Liu,1,2 Qunhong Weng,1 Jiangwei Liu,1 Qifeng Liang3 and Chao
Zhang1
E-mail: wangxicas@gmail.com or qfliang@usx.edu.cn
Synthetic process of 3D nanoporous Cu/LTO scaffold electrode:
Etching
1) Growth
2) Annealing
under Ar/H2
AlCu alloys
Nanoporous Cu scaffolds (NPCu)
Ti3+
Cu/LTO scaffold hybrids
Ti3+
Hydrogenation
Al
Cu
Li4Ti5O12 (LTO NPs) nanoparticles
Figure S1. Schematic illustration of the fabrication process for nanoporous Cu/Li4Ti5O12
hybrid materials by de-alloying Cu50Al50 (at%) using NaOH and then directly growing
Li4Ti5O12 (purple) onto nanoporous Cu, followed by annealing treatment under Ar/H2.
Note that hydrogenation effect in presence of H2 could cause the reduction of partial Ti4+
to Ti3+ ions in the formation process of LTO, and thereby further enhance the electronic
conductivity.
*
*
Cu
Rutile TiO2
(440)
(331)
(531)
*
(333)
(400)
(311)
(111)
Intensity (a.u.)
Cu/LTO scaffolds
Li4Ti5O12
Cu
10
20
30
40
50
60
70
2(degree)
Figure S2. XRD pattern: XRD pattern of as-synthesized Cu/LTO in the 2θ range of
10-70°
500 nm
Figure S3. Large-scale SEM image of Copper scaffold template.
a)
c)
Cu : (111) plane: 0.21 nm
b)
LTO: (111) plane: 0. 47 nm
d)
LTO (111)
Cu (111)
Figure S4. DFT calculations of surface energies of LTO and Cu and the relaxed
interfacial structure: a) The cubic structure of Copper (space group Fm3̅m), where the
pink color plane indicates the (111) plane of Cu. b) The spinel structure of Li4Ti5O12
(space group Fd3̅m), where the yellow color plane corresponds to the (111) plane of LTO.
c) The calculated surface energy of Copper on the different exposed planes. d) The
relaxed interfacial structure between LTO (111) and Cu (111) simulated by DFT
calculations.
Capacity (mAh/g)
300
200
100
Charge
Discharge
0
0
25
Cycles (n)
Figure S5. The cycling performance of Cu/LTO at 0.1C.
50
b)
a)
3+
Ti
468
Intensity (a.u.)
Intensity (a.u.)
LTO nanoparticles
Cu/LTO scaffolds
e-
466
Ti3+
Ti3+
464
462
460
3+
Ti
e-
458
Binding Energy (eV)
456
454
468
466
464
462
460
458
456
454
Binding Energy (eV)
Figure S6. a) The normalized XPS Ti2p overlay spectra of as-made Cu/LTO and LTO
nanoparticles (NPs), b) The difference in their spectra (“Cu/LTO” minus “LTO NPs”
shown in Figure S6a). Compared with the XPS spectrum of Ti 2p of LTO NPs, a small
negative shift can be observed in the XPS spectrum of hydrogenated Cu/LTO,
demonstrating that treatment with hydrogen caused a change of surface bonding of LTO
NPs.
Voltage (V vs. Li+/Li)
3
LTO (111)
2
1
0
-1
4
5
6
7
8
9
x in LixTi5O12
Figure S7. The calculated voltage profile based on DFT1: The calculated voltage profile
for LTO (111) in the Li4Ti5O12-LixTi5O12 system. The blue dash corresponds to the total
number of the inserted Li ion when the LTO discharges to 1V and 0 V.
1. S. Ganapathy, et al. ACS Nano 2012, 6, 8702.
(111)
stepped
Figure S8. STEM-HAADF image of the edge of Cu/LTO, which has the highly exposed
(111) facets with atomic kinks. Scale bar: 1 nm.