Wednesday, 16 May 2018: 08:50
Room 607 (Washington State Convention Center)
Nickel hydroxide is considered to be a potential electrode material for supercapacitors owing to its high theoretical capacity. However, its poor inherent electrical conductivity results in severe capacity fading and inferior cycling stability during the continuous charge/discharge process. Herein, we propose an approach to fabricate a compact, robust, and integrated chemical vapor deposition (CVD) graphene (G)/Ni(OH)2/nickel foam (NF) electrode using an inner-constructed growth strategy in which Ni(OH)2 nanosheets were grown on NF by a hydrothermal reaction via the fractures on CVD graphene intentionally created through ultrasonication. The resultant G/Ni(OH)2/NF enables Ni(OH)2 to possess high electrical conductivity for efficient electron transport and suppresses the structural deformation of Ni(OH)2 nanosheet arrays. The unique architecture boosts the electrochemical performance of Ni(OH)2 to its theoretical limit with a high specific capacity of 991 C g−1 at a current density of 1 A g−1, good rate capability, and excellent cycling stability, retaining 95.4% of the initial capacity after 5000 cycles. Moreover, an asymmetrical supercapacitor (ASC) was fabricated using G/Ni(OH)2/NF and activated carbon (AC) coated on NF as the positive and negative electrodes, respectively. The ASC device operating at a cell voltage of 1.45 V delivered an energy density of 50.3 W h kg−1 at a power density of 725 W kg−1 in addition to achieving good cycling stability with a capacitance retention of 84.3% after 10000 cycles at a current density of 10 A g−1.