Recently, sulfurization and phosphorylation protocols are employed in porous nano-materials preparation beneficial to improve energy density and power density of pseudocapacitors. Due to well-defined redox activity and higher theoretical capacitance, manganese sulfide electrode is used in super-capacitor application. In present work, MnCO3 microcubes are converted into MnS2 nanoparticles using cost-effective high diffusion rate sulfurization method. Reducing size of material from microcubes to nanoparticles has facilitated rate capability in the material along with improved capacitance. MnS2 nanoparticles exhibit 713 Fg(-1) specific capacitance at 5 mVs(-1) scan rate compared with 407 Fg(-1) obtained for MnCO3 microcubes. The impedance study analyzes improvement in interfacial conductivity for MnS2 nanoparticles observed form 1.83 Omega cm(-2) equivalent series resistance in comparison with 2.35 cm(-2) for MnCO3 microcubes. Fabricated solid state MnS2//MoS2 asymmetric supercapacitor exhibits 41.7 Whkg(-1) energy density, and 450 Wkg(-1) power density with the respectable 88 % capacitance retention for the continuous 2000 CV cycles charging and discharging at 100 mVs(-1) scan rate. (C) 2019 Elsevier Ltd. All rights reserved.