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

Abstract

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.

Potential of Carbon Aerogels in Energy: Design, Characteristics, and Applications

“…Raap et al synthesized and compared graphene–doped carbon xerogel (GAG) and nitrogen–doped carbon xerogel (NAG), which exhibit analogous textural properties, with surface areas of approximately 1200 m 2 g −1 and micropore volumes of approximately 0.50 cm 3 g −1 [ 67 ]. GAG demonstrated a higher mesopore volume (0.48 cm 3 g −1 ) compared to NAG (0.29 cm 3 g −1 ).…”

“…It appears that the higher electrical conductivity of GAG contributes to its favorable performance, despite the increased wettability of the electrolyte due to nitrogen doping in NAG. The combination of higher electrical conductivity and a larger volume of mesopores facilitates ion mobility (such as Na + , OH − , and SO 4 2− ) during the charge storage process, thus favoring enhanced performance [ 67 ].…”

“…The ZHCs demonstrated a specific capacity of 299.5 F g −1 (133.1 mAh g −1 ) at a current density of 0.1 A g −1 , yielding an energy density of 80 W kg −1 and exhibiting 86.3% capacity retention over 10,000 cycles at 2 A g −1 [63]. Raap et al synthesized and compared graphene-doped carbon xerogel (GAG) and nitrogen-doped carbon xerogel (NAG), which exhibit analogous textural properties, with surface areas of approximately 1200 m 2 g⁻ 1 and micropore volumes of approximately 0.50 cm 3 g⁻ 1 [67]. GAG demonstrated a higher mesopore volume (0.48 cm 3 g⁻ 1 ) compared to NAG (0.29 cm 3 g⁻ 1 ).…”

“…These materials were investigated for their application in supercapacitors. In a symmetric supercapacitor configuration, GAG -/GAG + exhibited an improved specific capacitance of 19 F g -1 for the cell and 74 F g -1 for one electrode, along with an Raap et al synthesized and compared graphene-doped carbon xerogel (GAG) and nitrogen-doped carbon xerogel (NAG), which exhibit analogous textural properties, with surface areas of approximately 1200 m 2 g −1 and micropore volumes of approximately 0.50 cm 3 g −1 [67]. GAG demonstrated a higher mesopore volume (0.48 cm 3 g −1 ) compared to NAG (0.29 cm 3 g −1 ).…”