Versatile 1-D Nanostructures for Green Energy Conversion …
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anodes. It is similar to the nanorod or nanotube but coated with thin shell of another
efficient material.
Core–shell nanorod arrays of Ti@Si on Ti foil via hydrothermal method and
carbon-free core–shell α-iron oxide (α-Fe 2 O 3 ) @ spinel lithium titanate (Li 4 Ti 5 O 12 ,
LTO via facile hydrothermal process when used as electrodes of Li ion battery demonstrated reversible capacity of 1125 mAh g
−1 and 249.3 mAh g
−1 respectively (Chen
et al. 2014; Meng and Deng 2015).
Yu and Thomas have reported CuO@AuPd@MnO 2 core shell NWs as electrode
for supercapacitor. It can drop the surface energy of the active material, reduce the
aggregation possibility and relive the electrode electrolyte side reaction. It gives good
results and show specific capacitance ~1400 F/g @ 5 mV/s (Yu and Thomas 2014).
PANI/CNTs combine the large pseudocapacitance of the conducting polymers with
the fast charging/discharging double-layer capacitance with CNTs and give specific
capacitance ~260 F/g @ 50 mV/s (de Riccardis et al. 2012). In another process,
MnO 2 /PEDOT coaxial nanowires synthesized by a one-step co-electrodeposition
method in a porous alumina template showed specific capacitance values of MnO 2
films of 190–240 F/g (Liu and Sang 2008). Also, hierarchical heterostructure comprising Fe 3 O 4 @Fe 2 O 3 core/shell nanorod arrays (NRAs) exhibited a high capacitive
performance, compared to the bare Fe 2 O 3 and Fe 3 O 4 NRAs electrodes and delivered
specific capacitance 1206 F/cm
3 with a mass loading of 1.25 mg/cm
2 (Tang et al.
2015).
4.5 Hierarchical Nanostructures for ESS
In this type of structures, pseudocapacitive and electric double-layered capacitor
(EDLC) materials are combined, leading to an enhancement in charge storage, as
both charge storage mechanisms (EDLC and pseudo-capacitive) reinforced in the
same structure. The combinations can be carried out for different materials and
different 1-D nanostructures (like 1-D branched heterostructures) by easy methods.
Electronically conductive and interconnected porous metal oxide fiber composites
(Ni/NiO/MnO x /carbon nanofiber) offer several advantages over isolated nanowire
and nanotube-based Li-ion battery electrode. It has the highest discharge capacity
of 1360 mAh g
−1 after 200 cycles on the basis of active material for the mesoporous Ni66–Mn33/C fiber anode and also exhibits good cycling stability and low
impedance (238 ) (Bhaway et al. 2016). In another process, using low-cost NH 4 VO 3
as the starting materials, a cost-saving method was developed to synthesize ultra-long
hierarchical vanadium oxide nanowires constructed from attached vanadium oxide
nanorods for lithium-ion batteries cathode electrode. The NH 4 VO 3 nanorods growth
on the surface of electrospun NH 4 VO 3 /PVA composite nanowires exhibited a high
performance for lithium-ion batteries, which delivered high discharge capacity of
390 mAh/g and improved cycling stability (Mai et al. 2010).
Lee Yu and co-workers constructed hierarchical NiCo 2 O 4 @MnO 2 core/shell heterostructured NW array for supercapacitor electrode on nickel foam and delivered
347
anodes. It is similar to the nanorod or nanotube but coated with thin shell of another
efficient material.
Core–shell nanorod arrays of Ti@Si on Ti foil via hydrothermal method and
carbon-free core–shell α-iron oxide (α-Fe 2 O 3 ) @ spinel lithium titanate (Li 4 Ti 5 O 12 ,
LTO via facile hydrothermal process when used as electrodes of Li ion battery demonstrated reversible capacity of 1125 mAh g
−1 and 249.3 mAh g
−1 respectively (Chen
et al. 2014; Meng and Deng 2015).
Yu and Thomas have reported CuO@AuPd@MnO 2 core shell NWs as electrode
for supercapacitor. It can drop the surface energy of the active material, reduce the
aggregation possibility and relive the electrode electrolyte side reaction. It gives good
results and show specific capacitance ~1400 F/g @ 5 mV/s (Yu and Thomas 2014).
PANI/CNTs combine the large pseudocapacitance of the conducting polymers with
the fast charging/discharging double-layer capacitance with CNTs and give specific
capacitance ~260 F/g @ 50 mV/s (de Riccardis et al. 2012). In another process,
MnO 2 /PEDOT coaxial nanowires synthesized by a one-step co-electrodeposition
method in a porous alumina template showed specific capacitance values of MnO 2
films of 190–240 F/g (Liu and Sang 2008). Also, hierarchical heterostructure comprising Fe 3 O 4 @Fe 2 O 3 core/shell nanorod arrays (NRAs) exhibited a high capacitive
performance, compared to the bare Fe 2 O 3 and Fe 3 O 4 NRAs electrodes and delivered
specific capacitance 1206 F/cm
3 with a mass loading of 1.25 mg/cm
2 (Tang et al.
2015).
4.5 Hierarchical Nanostructures for ESS
In this type of structures, pseudocapacitive and electric double-layered capacitor
(EDLC) materials are combined, leading to an enhancement in charge storage, as
both charge storage mechanisms (EDLC and pseudo-capacitive) reinforced in the
same structure. The combinations can be carried out for different materials and
different 1-D nanostructures (like 1-D branched heterostructures) by easy methods.
Electronically conductive and interconnected porous metal oxide fiber composites
(Ni/NiO/MnO x /carbon nanofiber) offer several advantages over isolated nanowire
and nanotube-based Li-ion battery electrode. It has the highest discharge capacity
of 1360 mAh g
−1 after 200 cycles on the basis of active material for the mesoporous Ni66–Mn33/C fiber anode and also exhibits good cycling stability and low
impedance (238 ) (Bhaway et al. 2016). In another process, using low-cost NH 4 VO 3
as the starting materials, a cost-saving method was developed to synthesize ultra-long
hierarchical vanadium oxide nanowires constructed from attached vanadium oxide
nanorods for lithium-ion batteries cathode electrode. The NH 4 VO 3 nanorods growth
on the surface of electrospun NH 4 VO 3 /PVA composite nanowires exhibited a high
performance for lithium-ion batteries, which delivered high discharge capacity of
390 mAh/g and improved cycling stability (Mai et al. 2010).
Lee Yu and co-workers constructed hierarchical NiCo 2 O 4 @MnO 2 core/shell heterostructured NW array for supercapacitor electrode on nickel foam and delivered