Development of an efficient CVD technique to prepare TiO/porous-carbon nanocomposites for high rate lithium-ion capacitors

• Published in: RSC advances Vol. 1; no. 63; pp. 38196 - 3824
• Main Authors: Iwamura, Shinichiroh, Motohashi, Shota, Mukai, Shin R
• Format: Journal Article
• Language: English
• Published: 16-10-2020
• ISSN: 2046-2069
• DOI: 10.1039/d0ra07590f

Titanium dioxide is a promising electrode material for lithium-ion capacitors. When using TiO
2
as an electrode material, it is necessary to combine it with carbon at the nanometer level to improve its low electrical conductivity and low reactivity with Li
+
. However, preparation methods of reported TiO
2
/porous-carbon nanocomposites are generally not cost-effective, and their productivities are low. In this study, the vacuum liquid-pulse chemical vapor deposition (VLP-CVD) technique was developed to easily prepare TiO
2
/porous-carbon nanocomposites, where TiO
2
nanoparticles with a diameter of ∼4 nm could be homogeneously deposited inside the pores of meso- or macroporous carbons. Because the deposited TiO
2
nanoparticles had access to effective electrically conductive paths formed by the porous-carbon substrate, they showed a high discharge capacity of ∼200 mA h g
−1
-TiO
2
(based on TiO
2
weight). In particular, the composite prepared from macroporous carbon showed an extremely high rate performance, where 50% of the discharge capacity was retained at a current density of 15 000 mA g
−1
when compared to that measured at 50 mA g
−1
. In addition, the composite also showed very high cyclability, where 80% of the discharge capacity was retained at the 10 000
th
cycle. Because the VLP-CVD technique can be performed using simple apparatus and commercially available starting materials, it can be expected to boost industrial production of TiO
2
/porous-carbon for lithium-ion capacitors.
TiO
2
nanoparticles with a diameter of around 5 nm were homogeneously deposited inside the pores of meso-macroporous carbons.