Metal–Organic Framework-Derived Bi2O3/C and NiCo2S4 Hollow Nanofibers for Asymmetric Supercapacitors

Asymmetric supercapacitors (ASCs) are regarded as promising energy storage devices due to their excellent electrochemical properties, especially favorable power density. In this work, both the high-performance positive electrode and negative electrode materials are designed and prepared using the electrospinning technique and a metal–organic framework (MOF)-derived strategy. The obtained Bi-MOF-derived Bi2O3/C hollow nanofibers have an outstanding specific capacity (1420 F g–1 at 1 A g–1) and show an excellent cycling performance (92.21% retention after 4000 cycles) as negative electrodes, while the NiCo-MOF-derived NiCo2S4 hollow nanofibers as positive electrodes also have an excellent specific capacity (2656 F g–1 at 1 A g–1), and their capacity retention is 92.11% after 4000 charge–discharge cycles. The assembled ASC device with these two electrodes displays a high energy density of 85.38 W h kg–1 and excellent cycling performance with 80% retention after 10,000 cycles. Therefore, this work not only experimentally demonstrates MOF-derived Bi2O3/C and NiCo2S4 as fascinating candidate electrode materials for ASCs but also affords a method to rationally design and fabricate other electrode materials with unique hollow nanofiber structures for energy storage.