Graphene Doped Carbon‐Gels and MnO2 for Next Generation of Solid‐State Asymmetric Supercapacitors

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. Solid‐state asymmetric supercapacitors: The supercapacitor with asymmetric configuration with 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, presents great stability in a wide operational voltage window and a very low self‐discharge rate.