Supercapacitors have attracted considerable attention due to the fast charge-discharge ability, excellent rate capability and long-time stability. Transition metal sulfides possess multiple oxidation states that enable rich redox reactions for pseudocapacitance, which have been investigated as promising electrode materials for high performance supercapacitors. Here, NiMoS4 is successfully synthesized by a facile chemical co-precipitation method and further heating in Ar atmosphere. The as-prepared NiMoS4 is firstly studied in a three-electrode system, it exhibits a specific capacitance of 707 F g-1 at a current density of 1 A g-1. Moreover, an asymmetric supercapacitor is fabricated using the NiMoS4 electrode as positive electrode and activated carbon (AC) as negative electrode. The asymmetric supercapacitor demonstrates high rate capability and good cycling stability. The operation voltage could expand to 1.6 V, at which the energy density can reach 35 Wh kg-1 with a power density at 400 W kg-1. The capacitance maintains around 82.4% after 10000 cycles at a current density of 5 A g-1. These high performances indicate NiMoS4 electrode is promising for applications in renewable energy storage in the future.
Fig. 1 Cycling performances of the asymmetric supercapacitor for 10000 cycles at 5 A g-1.
 Stoller, M. D. & Ruoff, R. S. Best practice methods for determining an electrode material's performance for ultracapacitors. Energy & Environmental Science 3. (2010) 1294-1301.
 Guan, B. Y., Yu, L., Wang, X., Song, S., & Lou, X. W. D. Formation of Onion‐Like NiCo2S4 Particles via Sequential Ion‐Exchange for Hybrid Supercapacitors. Advanced Materials 29 (2017) 1605051.
 Dongwei Du, Rong Lan, Wei Xu, Richard Beanland, Huanting Wang and Shanwen Tao, Preparation of a hybrid Cu2O/CuMoO4 nanosheet electrode for high-performance asymmetric supercapacitors, Journal of Materials Chemistry A, 4 (2016) 17749–17756.