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Stabilizing an amorphous V2O5/carbon nanotube paper electrode with conformal TiO2 coating by atomic layer deposition for lithium ion batteriesElectronic supplementary information (ESI) available. See DOI: 10.1039/c5ta01949d
Amorphous V 2 O 5 (a-V 2 O 5 ) thin films were conformally coated onto the surface of hydroxyl (-OH) functionalized multi-walled carbon nanotubes (CNTs) and carbon nanotube (CNT) paper using atomic layer deposition (ALD). In order to achieve 3 Li + intercalation (442 mA h g −1 ) and prevent V 2 O 5...
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| Main Authors: | , , , , , , |
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| Format: | Article |
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| Summary: | Amorphous V
2
O
5
(a-V
2
O
5
) thin films were conformally coated onto the surface of hydroxyl (-OH) functionalized multi-walled carbon nanotubes (CNTs) and carbon nanotube (CNT) paper using atomic layer deposition (ALD). In order to achieve 3 Li
+
intercalation (442 mA h g
−1
) and prevent V
2
O
5
dissolution at 1.5 V, a conformal TiO
2
protective layer is coated on the surface of V
2
O
5
/CNT. A free-standing paper electrode can be made by vacuum filtration or coating pre-fabricated CNT paper directly. The electrochemical characteristics of the TiO
2
/V
2
O
5
/CNT paper electrode were then determined using cyclic voltammetry and galvanostatic charge/discharge curves. Because the TiO
2
and V
2
O
5
ALD films were ultrathin, the poor electrical conductivity and low ionic diffusivity of V
2
O
5
did not limit the ability of the V
2
O
5
ALD films to display high specific capacity and high rate capability. A high discharge capacity of ∼400 mA h g
−1
is obtained for 15 cycle ALD TiO
2
coated 50 cycle ALD V
2
O
5
/CNT samples by depositing pre-fabricated CNT paper. We believe that this is the highest capacity for V
2
O
5
cathodes reported in the literature. The capacities of the a-V
2
O
5
/CNT nanocomposites are higher than the bulk theoretical values. The extra capacity is attributed to additional interfacial charge storage resulting from the high surface area of the a-V
2
O
5
/CNT nanocomposites. These results demonstrate that metal oxide ALD on high surface-area conducting carbon substrates can be used to fabricate high power and high capacity electrode materials for lithium ion batteries. In addition, ultrathin and conformal TiO
2
ALD coating can be used to mitigate the dissolution and capacity fading of the cathode.
Amorphous V
2
O
5
(a-V
2
O
5
) thin films were conformally coated onto the surface of hydroxyl (-OH) functionalized multi-walled carbon nanotubes (CNTs) and carbon nanotube (CNT) paper using atomic layer deposition (ALD). |
|---|---|
| ISSN: | 2050-7488 2050-7496 |
| DOI: | 10.1039/c5ta01949d |