In situ growth of hydrophilic nickel-cobalt layered double hydroxides nanosheets on biomass waste-derived porous carbon for high-performance hybrid supercapacitors

Rational design and cost-effective fabrication of layered double hydroxides(LDHs)nanosheets with extraordinary electrochemical performance is a key challenge for hybrid supercapacitors(HSCs).Herein,we report a facile in situ growth methodology to eco-friendly synthesize hydrophilic Ni Co-LDHs nanosheets on biomass waste-derived porous carbon(BC)for robust high-performance HSC cathode.The in situ growth process under ultrasonication realizes the rational arrangement of Ni Co-LDHs nanosheets on the surface of BC,which effectively increases the specific surface area,promotes the electronic conductivity and enhances the wettability of Ni Co-LDHs nanosheets without affecting their thickness values.With the beneficial effects of ultrathin thickness of LDHs nanosheets(6.20 nm),large specific surface area(2324.1 m^(2)g^(-1)),low charge transfer resistance(1.65Ω),and high wettability with electrolyte(34°–35°),the obtained Ni2Co1-LDHs/BC50 electrode possesses an ultra-high specific capacitance of 2390 F g^(-1)(956 C g^(-1))at 1 A g^(-1),which is superior to most reported values.Furthermore,an assembled Ni_(2)Co_(1)-LDHs/BC50//YP-80F HSC delivers a maximum specific energy of 52.47 Wh kg^(-1)at375 W kg^(-1),and maintains a high capacitance retention of 75.9%even after 4000 cycles.This work provides a facile approach to fabricate LDHs nanosheets based cathode materials for high-performance HSCs.