Highly Oriented Graphene Sponge Electrode for Ultra High Energy Density Lithium Ion Hybrid Capacitors.
Highly oriented rGO sponge (HOG) can be easily synthesized as an effective anode for application in high-capacity lithium ion hybrid capacitors. X-ray diffraction and morphological analyses show that successfully exfoliated rGO sponge on average consists of 4.2 graphene sheets, maintaining its three-dimensional structure with highly oriented morphology even after the thermal reduction procedure. Lithium-ion hybrid capacitors (LIC) are fabricated in this study based on a unique cell configuration which completely eliminates the predoping process of lithium ions. The full-cell LIC consisting of AC/HOG-Li configuration has resulted in remarkably high energy densities of 231.7 and 131.9 Wh kg(-1) obtained at 57 W kg(-1) and 2.8 kW kg(-1). This excellent performance is attributed to the lithium ion diffusivity related to the intercalation reaction of AC/HOG-Li which is 3.6 times higher that of AC/CG-Li. This unique cell design and configuration of LIC presented in this study using HOG as an effective anode is an unprecedented example of performance enhancement and improved energy density of LIC through successful increase in cell operation voltage window.
Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, N2L3G1 Ontario, Canada.
Wook
W
Ahn
Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, N2L3G1 Ontario, Canada.
Dong Un
DU
Lee
Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, N2L3G1 Ontario, Canada.
Ge
G
Li
Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, N2L3G1 Ontario, Canada.
Kun
K
Feng
Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, N2L3G1 Ontario, Canada.
Xiaolei
X
Wang
Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, N2L3G1 Ontario, Canada.
Aiping
A
Yu
Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, N2L3G1 Ontario, Canada.
Gregory
G
Lui
Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, N2L3G1 Ontario, Canada.
Zhongwei
Z
Chen
graphene electrode; graphene sponge; high energy density lithium ion capacitor; lithium ion predoping; oriented graphene