Sheet-like NiCo-layered double hydroxide anchored on N self-doped hierarchical porous carbon aerogel from chitosan for high-performance supercapacitors

Smart use of renewable and biodegradable biomass materials to partially replace other synthetic materials can bring huge economic benefit and environmental improvement. Herein, a highly graphitized N self-doped hierarchical porous carbon aerogel (HPCA) conductive frame is prepared using biomass chitosan particle as the precursor. Subsequently, nickel-cobalt layered double hydroxide (NiCo-LDH) nanosheets with desired pseudocapacitance properties are uniformly anchored on HPCA. Generally, a porous carbon skeleton with high conductivity and a large surface area brings a lot of active sites and channels for rapid electron and ion transport, and can control the growth morphology of NiCo-LDH nanosheets. As a result, compared with NiCo-LDH/HPCA-10, NiCo-LDH/HPCA-50 and pure NiCo-LDH, the optimized NiCo-LDH/HPCA-30 composite exhibits a large specific capacitance (1504 F g −1 at 1 A g −1 ) and excellent capacitance retention rate (85.9% after 5000 cycles) in a three-electrode system. In addition, the assembled NiCo-LDH/HPCA-30//AC asymmetric supercapacitor can bring a high energy density (33.33 Wh kg −1 ) and an outstanding cycle retention rate (90.76% after 3000 cycles). Therefore, the new NiCo-LDH/HPCA-30 composite with excellent electrochemical properties is expected to give full play to the application advantages of high-performance energy storage devices. The composite material of NiCo-LDH ultra-thin nanosheets uniformly grown on highly graphitized N self-doped HPCA conductive substrate shows outstanding electrochemical storage performance. • Chitosan (Cs) is biomass material which is biodegradable, resource-rich and low-cost. • HPCA has a high specific surface area and can control the even dispersion and growth of NiCo-LDH nanosheets. • The NiCo-LDH/HPCA-30 electrode shows excellent supercapacitor characteristics.