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Supercapacitors are playing a very relevant role in many applications due to their capability to supply high power density and long durability. However, there is a growing demand to increase their energy density, in gravimetric and volumetric basis. There are different strategies to increase supercapacitor performance by improving the active materials used in the electrodes, the type of electrolyte used or even the configuration employed in the cell. In this work, a combination of these strategies is presented with the use of different active materials, electrolytes, and symmetric vs. asymmetric configuration. The supercapacitor with asymmetric configuration using the graphene‐doped carbon xerogel in the negative electrode and the manganese oxide in the positive electrode, along with the use of Na+‐form Aquivion electrolyte membrane as solid electrolyte, seems to be a promising combination to obtain a substantial enhancement of both gravimetric and volumetric capacitance. Furthermore, the device presents great stability in a wide operational voltage window from 0 to 1.8 V and with a neutral pH polymer electrolyte which contributes to improve the performance, safety, and long cycle life of the device. [ABSTRACT FROM AUTHOR]

For the development and optimization of solid-state symmetrical supercapacitors, herein, we propose using carbon-based electrodes and sodium- and lithium-form Aquivion electrolyte membranes, which serve as the separator and electrolyte. Carbon xerogels, synthesized using microwave-assisted sol-gel methodology, with designed and controlled properties were obtained as electrode materials. Commercial activated carbon (YP-50F, "Kuraray Europe" GmbH) was used as the active material for comparison. Notably, the developed solid-state symmetrical supercapacitors provide sufficiently high specific capacitances of 105–110 F g−1 at 0.2 A g−1, along with an energy density of 4.5 Wh kg−1 at 300 W kg−1, and a voltage window of 0–1.2 V in aqueous environments, also demonstrating an excellent cycling stability for up to 10,000 charge/discharge cycles. These results can demonstrate the potential applications of carbon xerogel as the active electrode material and cation exchange membrane as the electrolyte in the development of solid-state supercapacitor devices. [ABSTRACT FROM AUTHOR]

Mesoporous carbons can contribute to the development of high energy and high-power density energy storage devices due to their tunable pore structures, high surface area and excellent electrical conductivity. The well-known mesoporous carbon CMK-3 with a hierarchical nanoporous structure can be promising candidate as electrode materials for supercapacitors to achieve high performance. Herein, we have produced a series of well-ordered mesoporous carbon materials with nano-sized structural units adopting two methods of synthesis: i) standard method and ii) ultrasonication assisted synthesis. Mesoporous carbons with hierarchical porous features and high surface area were obtained by both methods, and symmetrical supercapacitors containing these carbons and using an Aquivion membrane as polymer electrolyte were subsequently fabricated. Specific capacitance values of 66 and 78 F g−1 at 0.2 A g−1 were found for sonication assisted synthesised carbon (USC) and standard method derived carbon (SMC), respectively. Furthermore, the fabricated SMC//MnO 2 supercapacitor with asymmetric configuration delivers a capacitance performance of 95 F g−1 and presents a low self-discharge rate if charged for 3 h at 1.6 V. This asymmetric supercapacitor device, as-assembled, also demonstrates a long-term durability of more than 10,000 galvanostatic charge and discharge cycles and 150 h under floating conditions at 1.6 V, which is among the best asymmetric supercapacitors developed. [Display omitted] • Mesoporous carbons with hierarchical porous structure and high surface area were synthesized. • Asymmetric SMC//MnO 2 supercapacitor with CMK-3 was developed using Na+ Aquivion membrane. • High capacitance performance of 95 F g−1 at 0. 5 Ag−1 in voltage window of 0–1.6 V were achieved. • Very low self-discharge with voltage retention 88 % after 15 h was achieved from the supercapacitor. • Asymmetric supercapacitor can withstand 10,000 cycles without degradation of materials. [ABSTRACT FROM AUTHOR]