Highly enhanced electrochemical cycling stabilities of hierarchical partially-embedded MnO/carbon nanofiber composites as supercapacitor electrodes

Post-grown hierarchical pseudocapacitive nanostructures often suffer from their bad long-term cycling stability. In this work, a type of hierarchical partially-embedded MnO nanocube/electrospun carbon nanofiber composites (pe-MnO/ECNFs) was designed. Results show the MnO nanocubes are partially embedded into the ECNFs skeletons, showing a strong joint between them. The pe-MnO/ECNFs electrodes exhibit a high specific capacitance of 146 F g(-1) (to the whole electrode mass) at scan rate of 5 mV s(-1), and an ultralow decay rate of 0.004 parts per thousand per cycle for 20,000 cycles at 10 A g(-1), which is much better than those of the MnO2/ECNF ones (96 F g(-1), decay rate of 0.015 parts per thousand per cycle). Furthermore, the assembled flexible symmetric supercapacitors show an high energy density of 6.8 W h kg(-1), a high dynamic bending stability, and a robust long cycling stability (low decay rate of 0.003 parts per thousand per cycle for 6000 cycles at 1 A g(-1)).