Phosphate Ions and Oxygen Defects Modulated Nickel Cobaltite Nanowires: A Bifunctional Cathode for Flexible Hybrid Supercapacitors and Microbial Fuel Cells

The exploration of efficient and cost-effective cathode for flexible hybrid supercapacitors (HSCs) and microbial fuel cells (MFCs) is highly desirable but challenging. Benefiting from the strong points of abundant source, low price and respectable theoretical capacity, Nickel cobaltite (NCO) has a wider applicable prospect as a cathode for flexible HSCs and MFCs. Nevertheless, the capacity, rate capability and oxygen reduction reaction (ORR) activity of the NCO are far from satisfaction due to its intrinsic weak conductivity. Herein, a feasible and valid method is employed to adjust NCO nanowires (NWs) to a high performance cathode for flexible HSCs and MFCs via introducing phosphate ions and oxygen defects. Due to the larger surface, more active sites and faster charge transfer, the as-assembled flexible HSCs device delivers a high energy density of 211 Wh Kg−1, and the MFCs device achieves a power density of 3276.1 mW cm−2. This work may shed light on the modulation of phosphate ions and oxygen defects in enhancing electrochemical performance of metal oxide electrodes, holding great potential for future flexible multifunctional electrodes.