Ultrathin Mn Doped Ni-MOF Nanosheet Array for Highly Capacitive and Stable Asymmetric Supercapacitor.

In this study, we demonstrate that an Mn-doped ultrathin Ni-MOF nanosheet array on nickel foam (Mn0.1 -Ni-MOF/NF) serves as a highly capacitive and stable supercapacitor positive electrode. The Mn0.1 -Ni-MOF/NF shows an areal capacity of 6.48 C cm-2 (specific capacity C: 1178 C g-1 ) at 2 mA cm-2 in 6.0 m KOH, outperforming most reported MOF-based materials. More importantly, it possesses excellent cycle stability to maintain 80.6 % capacity after 5000 cycles. An asymmetric supercapacitor device utilizing Mn0.1 -Ni-MOF/NF as the positive electrode and activated carbon as the negative electrode attains a high energy density of 39.6 Wh kg-1 at 143.8 Wkg-1 power density with a capacitance retention of 83.6 % after 5000 cycles.