6.2 Metal–Carbon Nanocomposites as Anode Materials …
83
is considered that the nanocomposite can be produced in large scales. By increasing the amount of Si content of the nanocomposite to 91 wt%, the reversible stable
capacity increased to 2217 mA h g
−1 , demonstrating the capability of the molten salt
method to correlate the cost and electrochemical performance of the graphene–silicon nanocomposite product (Fig. 6.4c). This finding is interesting since it proposes
a sustainable approach for the large-scale preparation of high-performance anode
materials using commercially available graphite and Si feed materials [4].
6.3 Supercapacitors
As exhibited in Fig. 6.5a, the molten salt process was adapted to produce an interconnected graphene nanostructure comprising of nanosheets and nanoscrolls. As
shown in Fig. 6.5b, the morphology of the nanostructured carbon material produced
could be characterized by the presence of graphene nanosheets interconnected by
carbon nanotubes, enhancing the overall conductivity and integrity of the carbon
material. The electrochemical properties of the nanostructured material were investigated using a CR2032 coin cell at room temperature. The graphene electrodes were
prepared using a slurry composed of 90 wt% of the prepared carbon active material
and 10 wt% of polyvinylidene fluoride (PVDF; Aldrich) as the binder dissolved in
N-methylpyrrolidone (NMP). Notably, no additional conducting agent was used in
the electrode because the interconnected carbon nanostructure with a high surface
area had sufficiently high conductivity to act as both the conductor and the active
material. The slurry was uniformly cast on an etched aluminum foil using a doctor
blade and then dried in a vacuum oven at 100 °C for 24 h. The 2032 coin cell, a symmetrical two-electrode unit cell, was assembled using graphene electrodes with an
area of 1.13 cm
2 and a microporous polyethylene film (Celgard 2400) separator in an
Ar-filled glove box. The electrolyte was 1 M TEABF 4 dissolved in ACN. Electrodes
fabricated exhibited a reversible specific capacitance with the value of 213 F g
−1 at
1 A g
−1 , and excellent capacitance retention of 84.5% of the initial specific capacitance at 50 A g
−1 , as well as a reasonable cyclability of about 98% after 10,000
cycles (Fig. 6.5c). In fact, the high conductivity and the reasonably high surface area
of the carbon product were responsible for its performance. These properties are also
highly desirable for ultracapacitor applications [5].
6.4 Ceramic-Based Composites
As an important industrially used material, aluminum oxide (Al 2 O 3 ) serves as the
raw material for a broad range of advanced ceramic products due to the combination
of desirable properties including its high melting point, hardness, strength, stiffness,
wear resistance, chemical inertness and biocompatibility. Therefore, alumina is one
of the prime choices for a large variety of applications, including in high-temperature
83
is considered that the nanocomposite can be produced in large scales. By increasing the amount of Si content of the nanocomposite to 91 wt%, the reversible stable
capacity increased to 2217 mA h g
−1 , demonstrating the capability of the molten salt
method to correlate the cost and electrochemical performance of the graphene–silicon nanocomposite product (Fig. 6.4c). This finding is interesting since it proposes
a sustainable approach for the large-scale preparation of high-performance anode
materials using commercially available graphite and Si feed materials [4].
6.3 Supercapacitors
As exhibited in Fig. 6.5a, the molten salt process was adapted to produce an interconnected graphene nanostructure comprising of nanosheets and nanoscrolls. As
shown in Fig. 6.5b, the morphology of the nanostructured carbon material produced
could be characterized by the presence of graphene nanosheets interconnected by
carbon nanotubes, enhancing the overall conductivity and integrity of the carbon
material. The electrochemical properties of the nanostructured material were investigated using a CR2032 coin cell at room temperature. The graphene electrodes were
prepared using a slurry composed of 90 wt% of the prepared carbon active material
and 10 wt% of polyvinylidene fluoride (PVDF; Aldrich) as the binder dissolved in
N-methylpyrrolidone (NMP). Notably, no additional conducting agent was used in
the electrode because the interconnected carbon nanostructure with a high surface
area had sufficiently high conductivity to act as both the conductor and the active
material. The slurry was uniformly cast on an etched aluminum foil using a doctor
blade and then dried in a vacuum oven at 100 °C for 24 h. The 2032 coin cell, a symmetrical two-electrode unit cell, was assembled using graphene electrodes with an
area of 1.13 cm
2 and a microporous polyethylene film (Celgard 2400) separator in an
Ar-filled glove box. The electrolyte was 1 M TEABF 4 dissolved in ACN. Electrodes
fabricated exhibited a reversible specific capacitance with the value of 213 F g
−1 at
1 A g
−1 , and excellent capacitance retention of 84.5% of the initial specific capacitance at 50 A g
−1 , as well as a reasonable cyclability of about 98% after 10,000
cycles (Fig. 6.5c). In fact, the high conductivity and the reasonably high surface area
of the carbon product were responsible for its performance. These properties are also
highly desirable for ultracapacitor applications [5].
6.4 Ceramic-Based Composites
As an important industrially used material, aluminum oxide (Al 2 O 3 ) serves as the
raw material for a broad range of advanced ceramic products due to the combination
of desirable properties including its high melting point, hardness, strength, stiffness,
wear resistance, chemical inertness and biocompatibility. Therefore, alumina is one
of the prime choices for a large variety of applications, including in high-temperature