TY - JOUR
T1 - Ultrafine Ni(OH)2 nanoplatelets grown on 3D graphene hydrogel fabricated by electrochemical exfoliation for high-performance battery-type asymmetric supercapacitor applications
AU - Huang, Yang
AU - Buffa, Andrea
AU - Deng, Haiqiang
AU - Sarkar, Sujoy
AU - Ouyang, Yu
AU - Jiao, Xinyan
AU - Hao, Qingli
AU - Mandler, Daniel
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/11/1
Y1 - 2019/11/1
N2 - Rechargeable energy storage systems with merits of durable, powerful, and inexpensive are urgently desired along with the rapid development in portable electronics and electric vehicles. Herein, a facile electrochemical method is employed to prepare a free-standing exfoliated graphite (EG) electrode with significantly enhanced surface area and pore volume. Then a binder-free composite electrode is fabricated by a double-phase (DP) electrochemical deposition of vertical arrays of Ni(OH)2 throughout the EG hydrogel electrode in an organic electrolyte. The obtained composite, Ni(OH)2@EG-DP, exhibits battery-type capacitive behavior and much higher capacity than its counterparts fabricated either by single-phase electrochemical deposition or with non-exfoliated graphite foil. Ni(OH)2@EG-DP also exhibits remarkable rate capability and cycling stability, due to the well-dispersed ultrathin Ni(OH)2 nanoplatelets and the graphene-like expanded gallery of EG, enabling the efficient transportation of both electrons and ions. When coupling with an active carbon anode, the assembled asymmetric supercapacitor shows 84.5% capacity retention after 20000 cycles at 8 A g−1, and a high energy density of 34.7 Wh kg−1 at the power density of 15 kW kg−1. This work opens an avenue towards the efficient construction of free-standing three-dimensional (3D) conductive substrates and high-performance 3D hybrid electrodes using electrochemistry.
AB - Rechargeable energy storage systems with merits of durable, powerful, and inexpensive are urgently desired along with the rapid development in portable electronics and electric vehicles. Herein, a facile electrochemical method is employed to prepare a free-standing exfoliated graphite (EG) electrode with significantly enhanced surface area and pore volume. Then a binder-free composite electrode is fabricated by a double-phase (DP) electrochemical deposition of vertical arrays of Ni(OH)2 throughout the EG hydrogel electrode in an organic electrolyte. The obtained composite, Ni(OH)2@EG-DP, exhibits battery-type capacitive behavior and much higher capacity than its counterparts fabricated either by single-phase electrochemical deposition or with non-exfoliated graphite foil. Ni(OH)2@EG-DP also exhibits remarkable rate capability and cycling stability, due to the well-dispersed ultrathin Ni(OH)2 nanoplatelets and the graphene-like expanded gallery of EG, enabling the efficient transportation of both electrons and ions. When coupling with an active carbon anode, the assembled asymmetric supercapacitor shows 84.5% capacity retention after 20000 cycles at 8 A g−1, and a high energy density of 34.7 Wh kg−1 at the power density of 15 kW kg−1. This work opens an avenue towards the efficient construction of free-standing three-dimensional (3D) conductive substrates and high-performance 3D hybrid electrodes using electrochemistry.
KW - 3D electrode
KW - Asymmetric supercapacitor
KW - Double-phase electrochemical deposition
KW - Exfoliated graphite
KW - Graphene hydrogel
UR - http://www.scopus.com/inward/record.url?scp=85071725642&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2019.227046
DO - 10.1016/j.jpowsour.2019.227046
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AN - SCOPUS:85071725642
SN - 0378-7753
VL - 439
JO - Journal of Power Sources
JF - Journal of Power Sources
M1 - 227046
ER -
