“One-for-two” strategy: The construction of high performance positive and negative electrode materials via one Co-based metal organic framework precursor for boosted hybrid supercapacitor energy density

In this work, using a Co-based metal organic framework (Co-MOF) array as precursor, the high performance supercapacitor positive electrode (CNVS: Ni/V-doped Co3S2@Co/Ni-doped VS2 hetero-structure) and negative electrode (CNFS: Fe/V-doped Co3S2@Co/Fe-doped VS2 hetero-structure) are successfully constructed by a “one-for-two” synthesis strategy. Benefiting from their unique hollow triangular arrays, rich mesoporous structure constructed by M3S2/MS2 heterogeneous interface, abundant active centers originating from the defect of elements doping, the optimized CNVS and CNFS can improve the transfer ratio of electrons and electrolytes for fast kinetics, and provide more electroactive sites for deeply redox reaction. Therefore, an outstanding specific capacitance of 6556 mF cm−2 (910.56 μA h cm−2) is achieved by CNVS electrode under 0–0.5 V (vs. Hg/HgO) at 2 mA cm−2, and the CFVS electrode displays a high specific capacitance of 6195 mF cm−2 (1720 μA h cm−2) under −0.1 to −1.1 V range (vs. Hg/HgO) at 5 mA cm−2. Furthermore, a high-performance hybrid supercapacitor (HSC) is assembled with CNVS as the positive electrode, and CFVS as the negative electrode, which presents an ultrahigh energy density of 0.83 mWh cm−2 at a power density of 4.56 mW cm−2, and excellent cycle performance of maintaining 79.6% initial capacity after 5000 cycles.