Here we demonstrate the fabrication,electrochemical performance and application of an asymmetric supercapacitor (AS) device constructed with β-Ni(OH)2/MWCNTs as positive electrode and KOH activated honeycomb-like porous carbon (K-PC) derived from banana fibers as negative electrode.Initially,the electrochemical performance of hydrothermally synthesizedβ-Ni(OH)2/MWCNTs nanocomposite and K-PC was studied in a three-electrode system using 1 M KOH.These materials exhibited a specific ca pacitance (Cs) of 1327 F/g and 324 F/g respectively at a scan rate of 10 mV/s.Further,the AS device i.e.,β-Ni(OH)2/MWCNTs// K-PC in 1 M KOH solution,demonstrated a Cs of 156 F/g at scan rate of 10 mV/s in a broad cell voltage of 0-2.2 V.The device demonstrated a good rate capability by maintaining a Cs of 59 F/g even at high current density (25 A/g).The device also offered high energy density of 63 Wh/kg with maximum power density of 5.2 kW/kg.The AS device exhibited excellent cycle life with 100％ capac itance retention at 5000th cycle at a high current density of 25 A/g.Two AS devices connected in series were employed for powering a pair of LEDs of different colors and also a mini fan.