**4. Conclusions**

Direct NiMoO4 nanostructure growth on SS substrates was achieved via a facile, single-step hydrothermal method, and the resultant electrode electrochemical characteristics were investigated with respect to growth times of 9, 18, and 27 h. The NMO-18 electrode exhibited the maximum supercapacitance value of 619, 500, 458, and 390 F/g at 1, 3, 5, and 10 A/g, respectively. All the electrodes showed good stability over 3000 charge-discharge cycles. The available active surface area for all the samples were estimated from ECSA analysis. The highest capacitance observed in NMO-18 could be attributed to the observed maximum ECSA value of the sample. Along with excellent capacitive characteristics, NiMoO4 showed appreciable energy and power density values. We propose that the direct growth of nanostructured NiMoO4 on SS substrate through a one-step hydrothermal method offers a promising electrode material for supercapacitor applications.

**Author Contributions:** V.K. did the experiment and prepared the manuscript. H.-J.K. helped with analysis and discussion. H.-C.P. helped in performing the discussion and revising the manuscript. H.-S.K. planned and supervised the project. All of the authors have discussed the results and approved the submitted version.

**Funding:** This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20174030201520), and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2017R1D1A1A09000823).

**Conflicts of Interest:** There are no conflicts of interest to declare.
