Electrodeposited molybdenum-doped Co3O4 nanosheet arrays for high-performance and stable hybrid supercapacitors.

Long-cycle stability and high-energy density are big challenges for developing high-performance hybrid supercapacitor (HSC) electrode materials. In this work, molybdenum-doped Co3O4 nanosheets arrays on nickel foam (noted as MoxCo1.5−xO/NF) are successfully prepared via facile one-step electrodeposition followed by annealing for hybrid supercapacitors. The experimental and calculated results indicate that the band gap modification and conductivity enhancement of MoxCo1.5−xO lead to excellent capacitive performance due to the doping of Mo into Co3O4. The as-prepared Mo0.25Co1.25/NF electrode demonstrates a high specific capacity of 128.2 mAh g−1 (923 F g−1) at 1 A g−1 (60% higher than the undoped Co3O4) and superior cycle stability with 95.2% capacity retention after 10,000 cycles at 10 A g−1. The assembled HSC delivers high-energy density of 64.3 Wh kg−1 at the power density of 794.1 W kg−1 and with 87.7% capacity retention after 10,000 cycles. This work can present a new strategy to fabricate the three-dimensional high-performance integrated electrode materials by a facile electrodeposition for heteroatom-doped transition metal oxide for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]