Flower-like NiMn-layered double hydroxide microspheres coated on biomass-derived 3D honeycomb porous carbon for high-energy hybrid supercapacitors

Abstract

The efficient utilization of composites derived from the renewable biomass resources could provide a cost-effective alternative for supercapacitor applications. Herein, the honeycomb-like porous carbon conductive scaffold was prepared with biomass Chingma Abutilon seeds as the precursor. Subsequently, NiMn-layered double hydroxide (NiMn LDH) microspheres with pseudocapacitive properties were uniformly supported on the as-prepared carbon nanomaterials in the form of nanosheets. Typically, the highly conductive porous carbon skeleton provided more active sites for fast electron transport and might regulate the growth of the nanosheets. Indeed, the optimal CAS30@NiMn LDH material exhibited a large specific capacity of 1719 F g−1 (1 A g−1) and superior rate stability in the three-electrode configuration, which were relatively higher than the values of pure NiMn-LDH. Moreover, the as-assembled hybrid supercapacitor with CAS30@NiMn LDH composite could deliver a high energy density of 95.29 Wh kg−1 and impressive cycle performance (87 % retention after 5000 cycles).