Our present work deals with the hydrothermal synthesis of Platelet β Co(OH)2 using cobalt(II) acetate as the metal precursor and ammonia solution as the hydrolyzing agent. Electrochemical capacitive performance was studied through cyclic voltammetry (CV), galvanostatic charge discharge (CCD), and electrochemical impedance spectroscopy (EIS) analyses with 6 M KOH as supporting electrolyte. The Electrochemical characterizations of the β Co(OH)2 in 6M KOH exhibited a maximum specific capacitance of 251 F/g at 2 mV/s scan rate and 228 F/g at 2 A/g constant current density accompanied with high cycle stability. Calcination of the β Co(OH)2 at 330°C leads to the formation of spinal Co3O4 exhibiting an increased specific capacitance of 270 F/g at 2mV/s scan rate and 238 F/g at 2A/g constant current density. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1059–1064, 2014