Rational design of tubular-like NiMoO4·xH2O microspheres and ZIF-67 derived Bi2S3/C for asymmetric supercapacitor

The tubular microsphere structure is an effective structure for asymmetric supercapacitors due to its high specific surface area and porosity. It can slow down the volume shrinkage caused by redox process. In this paper, tubular-like NiMoO4·xH2O microspheres were designed to reach a high specific capacity. The NiMoO4·xH2O was prepared by hydrothermal method and subsequent annealing treatment showed a tubular microsphere structure with many particles uniformly distributed. And its specific capacity is 943 F g−1 at 1 A·g−1 and capacity retention is 73.4 % after 3000 cycles. The Bi2S3/C was selected as negative material to build an asymmetric supercapacitor (battery-type device). It exhibited an impressive specific capacity (419 F g−1 at 1 A g−1). It was worth noting that the battery-type devices built with NiMoO4·xH2O and Bi2S3/C can achieve a specific energy of 27.1 Wh kg−1 at 2456.9 W kg−1 and capacity retention of 69.2 % after 5000 cycles. It was shown that NiMoO4-xH2O and Bi2S3/C as electrode materials have great potential and can enhance the energy storage application of supercapacitors.