136
6 Nanomaterials for Batteries
electronic and ionic conductivity of LTO. Therefore, the electrochemical property
and the cycling stability of LTO anode material can be enormously enhanced. Despite
LTO anode has a lot of advantages, LTO still has many challenges in some energy
storage systems.
Firstly, how to enhance the power property is a challenge in the electric vehicles (EVs) field. As everyone knows, the low electrical conductivity and the
low lithium diffusion coefficient limit the rate capacity of LTO anode material. The excellent rate property of LTO relies on the lithium diffusion and
the phase transformation mechanism. Li
+ is transferred between the tetrahedral
8a sites (spinel [Li 3 ]
8a [Li 1 Ti 5 ]
16d [O 12 ]
32e ) and the octahedral 16c sites (rocksalt [Li 6 ]
16c [Li 1 Ti 5 ]
16d [O 12 ]
32e ) upon the phase transition, in the meantime, the
stable voltage plateau is 1.55 V
[10] . The cell structure hardly changes during
charge/discharge progress. Compared with the other active material such as olivine
LiFePO 4 , there are a little of papers to study the insertion/deinsertion processes mechanisms of LTO due to the similar lattice constant (Li 4 Ti 5 O 12 and Li 7 Ti 5 O 12 ). Therefore, Li 4 Ti 5 O 12 and Li 7 Ti 5 O 12 materials are difficult confirmed by the conventional
characterization technique. However, recently, the in situ characterization methods
can provide more evidences about the mechanism of Li
+ insertion/deinsertion for
LTO, which also can provide a method to enhance high capacity of LTO.
Secondly, how to control the charge/discharge cycles and the emission of gas
(CO 2 , H 2 , and CO) of LTO electrodes is another challenge of LIBs, because the
gas can further cause the safety issues. Therefore, many researchers look for the
cause of the gas. The lack of solid electrolyte interface (SEI), the decomposition
of electrolyte, and the special electrochemical potential will cause safety issues.
However, there are still some methods to control the emission of gas such as online
in situ gas analysis approaches, which are available to the large-scale applications of
LTO storage batteries in the future.
Li 3 V O 4 Material
The anode material plays a vital role in the property of LIBs. In 2013, Li 3 VO 4 was
considered as a very promising candidate material. Li 3 VO 4 materials have some
advantages compared with other anode material. Firstly, the Li 3 VO 4 lattice consists
of the corner-sharing VO 4 and the tetrahedra LiO 4 . The Li 3 VO 4 structure is very
similar to Li 3 PO 4 . Hence, Li 3 VO 4 is used as an ionic-conductor, which facilitates the
transfer of Li
+ . Secondly, Li 3 VO 4 anode materials have a small volume change upon
cycling processes. Therefore, Li 3 VO 4 anode materials can display excellent cycling
stability. Thirdly, Li 3 VO 4 materials have the lower Li
+ intercalation voltage (from
0.5 to 1.0 V vs. Li
+ /Li) and the higher discharge/charge capacity (about 590 mAhg
−1 )
compared to LTO. In addition, since the voltage range of Li 3 VO 4 exceeds than other
the graphite anode material, the Li 3 VO 4 can effectively avoid the growth of lithium
dendrites. However, Li 3 VO 4 material has low electronic conductivity, which limits its
wide application of in LIBs. Recently, some researchers try to adopt series methods
to enhance conductivity and rate performance of Li 3 VO 4 material, such as the carbon
coating or the forming composite or doping with metal ions.
6 Nanomaterials for Batteries
electronic and ionic conductivity of LTO. Therefore, the electrochemical property
and the cycling stability of LTO anode material can be enormously enhanced. Despite
LTO anode has a lot of advantages, LTO still has many challenges in some energy
storage systems.
Firstly, how to enhance the power property is a challenge in the electric vehicles (EVs) field. As everyone knows, the low electrical conductivity and the
low lithium diffusion coefficient limit the rate capacity of LTO anode material. The excellent rate property of LTO relies on the lithium diffusion and
the phase transformation mechanism. Li
+ is transferred between the tetrahedral
8a sites (spinel [Li 3 ]
8a [Li 1 Ti 5 ]
16d [O 12 ]
32e ) and the octahedral 16c sites (rocksalt [Li 6 ]
16c [Li 1 Ti 5 ]
16d [O 12 ]
32e ) upon the phase transition, in the meantime, the
stable voltage plateau is 1.55 V
[10] . The cell structure hardly changes during
charge/discharge progress. Compared with the other active material such as olivine
LiFePO 4 , there are a little of papers to study the insertion/deinsertion processes mechanisms of LTO due to the similar lattice constant (Li 4 Ti 5 O 12 and Li 7 Ti 5 O 12 ). Therefore, Li 4 Ti 5 O 12 and Li 7 Ti 5 O 12 materials are difficult confirmed by the conventional
characterization technique. However, recently, the in situ characterization methods
can provide more evidences about the mechanism of Li
+ insertion/deinsertion for
LTO, which also can provide a method to enhance high capacity of LTO.
Secondly, how to control the charge/discharge cycles and the emission of gas
(CO 2 , H 2 , and CO) of LTO electrodes is another challenge of LIBs, because the
gas can further cause the safety issues. Therefore, many researchers look for the
cause of the gas. The lack of solid electrolyte interface (SEI), the decomposition
of electrolyte, and the special electrochemical potential will cause safety issues.
However, there are still some methods to control the emission of gas such as online
in situ gas analysis approaches, which are available to the large-scale applications of
LTO storage batteries in the future.
Li 3 V O 4 Material
The anode material plays a vital role in the property of LIBs. In 2013, Li 3 VO 4 was
considered as a very promising candidate material. Li 3 VO 4 materials have some
advantages compared with other anode material. Firstly, the Li 3 VO 4 lattice consists
of the corner-sharing VO 4 and the tetrahedra LiO 4 . The Li 3 VO 4 structure is very
similar to Li 3 PO 4 . Hence, Li 3 VO 4 is used as an ionic-conductor, which facilitates the
transfer of Li
+ . Secondly, Li 3 VO 4 anode materials have a small volume change upon
cycling processes. Therefore, Li 3 VO 4 anode materials can display excellent cycling
stability. Thirdly, Li 3 VO 4 materials have the lower Li
+ intercalation voltage (from
0.5 to 1.0 V vs. Li
+ /Li) and the higher discharge/charge capacity (about 590 mAhg
−1 )
compared to LTO. In addition, since the voltage range of Li 3 VO 4 exceeds than other
the graphite anode material, the Li 3 VO 4 can effectively avoid the growth of lithium
dendrites. However, Li 3 VO 4 material has low electronic conductivity, which limits its
wide application of in LIBs. Recently, some researchers try to adopt series methods
to enhance conductivity and rate performance of Li 3 VO 4 material, such as the carbon
coating or the forming composite or doping with metal ions.