Templated synthesis of spinel cobaltite MCo₂O₄ (M=Ni, Co and Mn) hierarchical nanofibers for high performance supercapacitors

Rational construction of transitional metal oxides electrode materials with suitable structure and composition is an effective strategy of improving their electrochemical performance. Herein, novel MCo₂O₄ hierarchical nanofibers (H-MCo₂O₄NFs, M = Ni, Co and Mn) were fabricated by a multi-step self-templating method using electrospun nanofibers as precursors. Benefiting from the unique structure, such as numerous of vertically interlinked nanosheets on the surface and 1D interwoven nanofibers networks, the obtained H[sbnd]NiCo₂O₄NFs electrode exhibits a high specific capacitance of 1750 F g⁻¹ (At a current density of 0.5 A g⁻¹), good rate capability (Capacitance retention of 70% at 20 A g⁻¹), and outstanding cycling stability (Capacitance retention of 92% after 6000 cycles). Moreover, the solid-state hybrid supercapacitor assembled by H[sbnd]NiCo₂O₄NFs and activated carbon (AC), delivers a high energy density of 38.4 Wh kg⁻¹ at a power density of 800 W kg⁻¹, and excellent cycling stability. Thus, the H[sbnd]NiCo₂O₄NFs is a promising candidate material for supercapacitors electrode and this self-templating method in this work also provides a new path for the preparation of one-dimensional hierarchical metallic oxides.