Graphene
Graphene based Supercapacitors with Improved Specific Capacitance and Fast Charging
Time at High Current Density
Santhakumar Kannappana, Karthikeyan Kaliyappanb,c, Rajesh Kumar Maniand, Amaresh
Samuthira Pandianb, Hao Yange , Yun Sung Leeb, Jae-Hyung Janga,f and Wu Lua,e*
a) Department of Nanobio Materials and Electronics, Gwangju Institute of Science and
Technology, Gwangju 500-712, Republic of Korea.
b) Faculty of Applied Chemical Engineering, Chonnam National University, Gwangju, 500757, Republic of Korea.
c) Department of Mechanical and Materials Engineering, The University of Western
Ontario, London, Ontario, N6A 5B9, Canada
d) Department of Chemistry, Institute of Basic Science, Chonnam National University,
Gwangju, 500-757, Republic of Korea
e) Department of Electrical and Computer Engineering, The Ohio State University,
Columbus, OH 43210, USA.
f) School of Information and Communications, Gwangju Institute of Science and
Technology, Gwangju 500-712, Republic of Korea.
*To whom all correspondence should be addressed. E-mail address: lu@ece.osu.edu
Graphene is a promising material for energy storage, especially for high performance supercapacitors. For real time high power applications, it is critical to have high specific capacitance with fast charging time at high current density. Using a modified Hummer’s method and tip sonication for graphene synthesis, here we show graphene-based supercapacitors with high stability and significantly-improved electrical double layer capacitance and energy density with fast charging and discharging time at a high current density, due to enhanced ionic electrolyte accessibility in deeper regions. The discharge capacitance and energy density values,
195 Fg-1 and 83.4 Whkg-1, are achieved at a current density of 2.5 Ag-1. The time required to discharge 64.18 Whkg-1 at 5 A/g is around 25 sec. At 7.5 Ag-1 current density, the cell can deliver a specific capacitance of about 137 Fg-1 and maintain
Time at High Current Density
Santhakumar Kannappana, Karthikeyan Kaliyappanb,c, Rajesh Kumar Maniand, Amaresh
Samuthira Pandianb, Hao Yange , Yun Sung Leeb, Jae-Hyung Janga,f and Wu Lua,e*
a) Department of Nanobio Materials and Electronics, Gwangju Institute of Science and
Technology, Gwangju 500-712, Republic of Korea.
b) Faculty of Applied Chemical Engineering, Chonnam National University, Gwangju, 500757, Republic of Korea.
c) Department of Mechanical and Materials Engineering, The University of Western
Ontario, London, Ontario, N6A 5B9, Canada
d) Department of Chemistry, Institute of Basic Science, Chonnam National University,
Gwangju, 500-757, Republic of Korea
e) Department of Electrical and Computer Engineering, The Ohio State University,
Columbus, OH 43210, USA.
f) School of Information and Communications, Gwangju Institute of Science and
Technology, Gwangju 500-712, Republic of Korea.
*To whom all correspondence should be addressed. E-mail address: lu@ece.osu.edu
Graphene is a promising material for energy storage, especially for high performance supercapacitors. For real time high power applications, it is critical to have high specific capacitance with fast charging time at high current density. Using a modified Hummer’s method and tip sonication for graphene synthesis, here we show graphene-based supercapacitors with high stability and significantly-improved electrical double layer capacitance and energy density with fast charging and discharging time at a high current density, due to enhanced ionic electrolyte accessibility in deeper regions. The discharge capacitance and energy density values,
195 Fg-1 and 83.4 Whkg-1, are achieved at a current density of 2.5 Ag-1. The time required to discharge 64.18 Whkg-1 at 5 A/g is around 25 sec. At 7.5 Ag-1 current density, the cell can deliver a specific capacitance of about 137 Fg-1 and maintain
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