Engineered NiCo-LDH nanosheets- and ZnFe2O4 nanocubes-decorated carbon nanofiber bonded mats for high-rate asymmetric supercapacitors

In this work, we have prepared the hierarchically nanostructured core-shell NiCo layered double hydroxide (NiCo-LDH) nanosheets- and ZnFe2O4 nanocubes-decorated polyacrylonitrile (PAN)/pitch-based carbon nanofibers (PPCNs) webs (NiCo-LDH@PPCNs as cathode and ZnFe2O4@PPCNs as anode materials) with the bonded network structure by a facile and scalable hydrothemal method. Herein, the low-cost pitch with lower softening point (similar to 90 degrees C) as co-precursor was utilized to produce the PAN/pitch-based carbon nanofibers (PPCNs) with enhanced electrical conductivity. The obtained PPCNs with pitch content of 30% (PP30CNs) electrode material delivered higher specific capacitance (similar to 67 F g(-1)) than that (similar to 48 F g(-1)) of the PAN-based carbon nanofibers (PCNs) at 1 A g(-1), due to the increased electrical conductivity and lower interfacial charge transfer resistance (RCT) of similar to 0.16 Omega. Further, the NiCo-LDH-decorated PP30CNs (NiCoLDH@PP30CNs) as cathode material showed superior specific capacitance of 1162 F g(-1) at 1.0 A g(-1) and ultra-high retention rate of 91.56% at 10 A g(-1). The ZnFe2O4@PP30CNs as anode material also showed higher specific capacitance of 282 F g(-1) at 1 A g(-1) and good rate capability with capacitance retention of 56.73% at 10 A g(-1). The as-fabricated asymmetric NiCo-LDH@PP30CNs//ZnFe2O4@PP30CNs hybrid supercapacitor device delivered a specific capacitance of similar to 98 F g(-1) at 1 A g(-1) and excellent capacitance retention of similar to 88% after 5000 chargedischarge cycles. (c) 2021 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

In this study, hierarchically nanostructured core-shell NiCo layered double hydroxide (NiCo-LDH) nanosheets and ZnFe2O4 nanocubes-decorated polyacrylonitrile (PAN)/pitch-based carbon nanofibers (PPCNs) webs were prepared. The resulting materials exhibited high specific capacitance, enhanced electrical conductivity, and good rate capability, making them promising for hybrid supercapacitor applications. The asymmetric NiCo-LDH@PPCNs//ZnFe2O4@PPCNs hybrid supercapacitor device showed excellent energy storage performance and cycling stability.