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

Two different polyoxovanadates derivatives K 5 Mn IV V 11 O 33 .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 0.4 A g -1 , along with incredible power and energy density. Likewise, the AC-MnV 13 exhibits a specific capacitance of 357.33 F g -1 at the same current density of 0.4 A g -1 with an energy density 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 seconds, respectively, indicating a considerable power density of the material. The AC-MnV 13 electrode shows significantly less lighting up the 65 and 30 seconds period with red and yellow LED bulbs.