Polyoxovanadate-Activated Carbon-Based Hybrid Materials for High-Performance Electrochemical Capacitors

Two different polyoxovanadates derivatives, K 5 Mn IV V 11 O 32 .10 H 2 O (MnV 11 ) and K 7 Mn IV V 13 O 38 .18 H 2 O (MnV 13 ), have been studied to evaluate their electrochemical performance. These polyoxovanadates were deposited on activated carbon (AC) to prepare AC-MnV 11 and AC-MnV 13 composites. The electrochemical performance of the AC- MnV 11 electrode exhibits the remarkable specific capacitance of 479.73 F g −1 at a current density of 0.6 A g −1 , along with incredible specific power and energy of 960 W kg −1 . Likewise, the AC-MnV 13 exhibits a specific capacitance of 357.33 F g −1 at the current density of 0.6 A g −1 with a specific energy of 71.46 Wh kg −1 . Interestingly, the AC- MnV 11 could light up the red and yellow color LED bulbs for a duration of 80 and 60 s, respectively, indicating a considerable specific power of the material. The AC-MnV 13 electrode shows significantly less lighting up during the 65 and 30 s period with red and yellow LED bulbs.