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Fabrication and Characterization of SnO 2 /Graphene Composites as High Capacity Anodes for Li-Ion Batteries

View Article: PubMed Central - PubMed

ABSTRACT

Tin-oxide and graphene (TG) composites were fabricated using the Electrostatic Spray Deposition (ESD) technique, and tested as anode materials for Li-ion batteries. The electrochemical performance of the as-deposited TG composites were compared to heat-treated TG composites along with pure tin-oxide films. The heat-treated composites exhibited superior specific capacity and energy density than both the as-deposited TG composites and tin oxide samples. At the 70th cycle, the specific capacities of the as-deposited and post heat-treated samples were 534 and 737 mA·h/g, respectively, and the corresponding energy densities of the as-deposited and heat-treated composites were 1240 and 1760 W·h/kg, respectively. This improvement in the electrochemical performance of the TG composite anodes as compared to the pure tin oxide samples is attributed to the synergy between tin oxide and graphene, which increases the electrical conductivity of tin oxide and helps alleviate volumetric changes in tin-oxide during cycling.

No MeSH data available.


Charge-discharge profiles of (a) TG composites at 195 °C (as deposited); and (b) TG composites at 280 °C (post-heat treated).
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nanomaterials-03-00606-f003: Charge-discharge profiles of (a) TG composites at 195 °C (as deposited); and (b) TG composites at 280 °C (post-heat treated).

Mentions: The charge-discharge profiles of the as-deposited and heat-treated TG composites (Figure 3) were obtained using cyclic charge-discharge at a constant current density of 0.2 C between 0.01 and 3.0 V. The profiles show three voltage plateaus corresponding to the decomposition reaction (~1.25 V), lithium alloy formation with tin (~0.5 V) and graphene (~0.1 V) during discharge. During charging, the lithium de-alloys from tin around ~0.75 V and lithium de-intercalates from graphene layers around 0.3 V. There is no imperceptible difference in the voltage plateaus for the as-deposited composites and post-treat heated samples. The first cycle discharge capacity of the as-deposited TG composite was 1360 mA·h/g whereas the charge capacity was 940 mA·h/g, resulting in a Columbic efficiency of 69%. For the second cycle, the charge capacity was 915 mA·h/g, however the discharge capacity reduced to 964 mA·h/g, resulting in an increased columbic efficiency of 95%. The capacity loss between the first and second discharge cycles was ~396 mA·h/g. For the heat-treated TG composite, the first and second cycle discharge capacities were 1423 and 1110 mA·h/g, making a discharge capacity loss of ~313 mA·h/g. The charge capacities were 1124 mA·h/g and 1065 mA·h/g for the first and second cycles and the corresponding columbic efficiencies were 79% and 96%. The increase in the columbic efficiency suggests that the number of Li+ ions that were trapped or the ones undergoing side reactions reduced considerably after the first cycle.


Fabrication and Characterization of SnO 2 /Graphene Composites as High Capacity Anodes for Li-Ion Batteries
Charge-discharge profiles of (a) TG composites at 195 °C (as deposited); and (b) TG composites at 280 °C (post-heat treated).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5304589&req=5

nanomaterials-03-00606-f003: Charge-discharge profiles of (a) TG composites at 195 °C (as deposited); and (b) TG composites at 280 °C (post-heat treated).
Mentions: The charge-discharge profiles of the as-deposited and heat-treated TG composites (Figure 3) were obtained using cyclic charge-discharge at a constant current density of 0.2 C between 0.01 and 3.0 V. The profiles show three voltage plateaus corresponding to the decomposition reaction (~1.25 V), lithium alloy formation with tin (~0.5 V) and graphene (~0.1 V) during discharge. During charging, the lithium de-alloys from tin around ~0.75 V and lithium de-intercalates from graphene layers around 0.3 V. There is no imperceptible difference in the voltage plateaus for the as-deposited composites and post-treat heated samples. The first cycle discharge capacity of the as-deposited TG composite was 1360 mA·h/g whereas the charge capacity was 940 mA·h/g, resulting in a Columbic efficiency of 69%. For the second cycle, the charge capacity was 915 mA·h/g, however the discharge capacity reduced to 964 mA·h/g, resulting in an increased columbic efficiency of 95%. The capacity loss between the first and second discharge cycles was ~396 mA·h/g. For the heat-treated TG composite, the first and second cycle discharge capacities were 1423 and 1110 mA·h/g, making a discharge capacity loss of ~313 mA·h/g. The charge capacities were 1124 mA·h/g and 1065 mA·h/g for the first and second cycles and the corresponding columbic efficiencies were 79% and 96%. The increase in the columbic efficiency suggests that the number of Li+ ions that were trapped or the ones undergoing side reactions reduced considerably after the first cycle.

View Article: PubMed Central - PubMed

ABSTRACT

Tin-oxide and graphene (TG) composites were fabricated using the Electrostatic Spray Deposition (ESD) technique, and tested as anode materials for Li-ion batteries. The electrochemical performance of the as-deposited TG composites were compared to heat-treated TG composites along with pure tin-oxide films. The heat-treated composites exhibited superior specific capacity and energy density than both the as-deposited TG composites and tin oxide samples. At the 70th cycle, the specific capacities of the as-deposited and post heat-treated samples were 534 and 737 mA·h/g, respectively, and the corresponding energy densities of the as-deposited and heat-treated composites were 1240 and 1760 W·h/kg, respectively. This improvement in the electrochemical performance of the TG composite anodes as compared to the pure tin oxide samples is attributed to the synergy between tin oxide and graphene, which increases the electrical conductivity of tin oxide and helps alleviate volumetric changes in tin-oxide during cycling.

No MeSH data available.