Polyoxovanadate-activated carbon-based hybrid materials for high-performance electrochemical capacitors

Abstract

Two different polyoxovanadates derivatives K<inf>5</inf>MnIVV<inf>11</inf>O<inf>33</inf>.10 H<inf>2</inf>O (MnV<inf>11</inf>) and K<inf>7</inf>MnIVV<inf>13</inf>O<inf>38</inf>.18 H<inf>2</inf>O (MnV<inf>13</inf>), have been studied to evluate their electrochemical performance. These polyoxovanadates were deposited on activated carbon (AC) to prepare AC-MnV<inf>11</inf> and AC-MnV<inf>13</inf> composites. The electrochemical performance of the AC- MnV<inf>11</inf> 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 specific power and energy of 960 W kg-1. Likewise, the AC-MnV<inf>13</inf> exhibits a specific capacitance of 357.33 F g-1 at the same current density of 0.4 A g-1 with a specific energy of 71.46 Wh kg-1. Interestingly, the AC- MnV<inf>11</inf> could light up the red and yellow color LED bulbs for a duration of 80 and 60 seconds, respectively, indicating a considerable specific power of the material. The AC-MnV<inf>13</inf> electrode shows significantly less lighting up the 65 and 30 seconds period with red and yellow LED bulbs. © The Electrochemical Society