High‐Performance Lithium‐ion Supercapatteries Constructed Using Li ₃ V ₂ (PO ₄ ) ₃ /C Mesoporous Nanosheets

Abstract

Abstract To construct “non‐consumable electrolyte type” or “internal serial hybrid type” lithium‐ion supercapatteries with both high power and energy densities, carbon‐coated lithium vanadium phosphate composite (Li 3 V 2 (PO 4 ) 3 /C) is utilized as the cathode. This cathode with a high specific area is synthesized by a hydrothermal method assisted by delayed sol‐gel method and using the surfactant of myristyltrimethylammonium bromide as the carbon source. It is self‐assembled and mesoporous. This cathode has a high specific surface area of 40.92 m 2 g −1 , a pore volume of 0.095 cm 3 g −1 , a considerably high initial discharge capacity of 166 mAh g −1 at 0.2 C‐rate. Even at 20 C‐rate, the high discharge capacity of 90 mAh g −1 is maintained. The lithium‐ion supercapattery assembled using this cathode, the anode of activated carbon as exhibits a discharge time of as long as 1369.24 s, a maximum energy density of 53.22 Wh kg −1 , and a maximum power density of 3.01 kW kg −1 . Such lithium‐ion supercapatteries thus overcome the disadvantages of rapid energy density attenuation under high power density of existed lithium‐ion supercapatteries.