Preparation and electrochemical performance of Co Prussian blue analogue/ multi-walled carbon nanotubes nanocomposite for supercapacitors

Co Prussian blue analogue (CoPBA) has attracted much attentions as a promising anode material of supercapacitors due to its high capacity and long cycle life. But CoPBA suffers from poor electrical conductivity, leading to unsatisfied rate performance. A nanocomposite of Co Prussian blue analogue/multi-walled carbon nano-tubes (CoPBA/MWCNT) composite was synthesized using ZIF-67 as a precursor. The structure and morphology of CoPBA/MWCNT were characterized by XRD, SEM and TEM. In a three-electrode system, the specific capacitance of the CoPBA/MWCNT electrode reaches up to 312 F·g⁻¹ at a current density of 1 A·g⁻¹. The fabrication of CoPBA/MWCNT is beneficial for improving electronic conductivity and mechanical stability, resulting in high electrochemical performance. An asymmetric supercapacitor cell is assembled with CoPBA/MWCNT as cathode and activated carbon (AC) as anode. Its capacity retention rate is 83.1% after 5000 cycles, exhibiting excellent cycling stability.