Template-Assisted Low Temperature Synthesis of Functionalized Graphene for Ultrahigh Volumetric Performance Supercapacitors

Abstract

We demonstrated the fabrication of functionalized graphene nanosheets via low temperature (300 °C) treatment of graphite oxide with a slow heating rate using Mg(OH)2 nanosheets as template. Because of its dented sheet with high surface area, a certain amount of oxygen-containing groups, and low pore volume, the as-obtained graphene delivers both ultrahigh specific gravimetric and volumetric capacitances of 456 F g(-1) and 470 F cm(-3), almost 3.7 times and 3.3 times higher than hydrazine reduced graphene, respectively. Especially, the obtained volumetric capacitance is the highest value so far reported for carbon materials in aqueous electrolytes. More importantly, the assembled supercapacitor exhibits an ultrahigh volumetric energy density of 27.2 Wh L(-1), which is among the highest values for carbon materials in aqueous electrolytes, as well as excellent cycling stability with 134% of its initial capacitance after 10,000 cycles. Therefore, the present work holds a great promise for future design and large-scale production of high performance graphene electrodes for portable energy storage devices.

All-MXene (2D titanium carbide) solid-state microsupercapacitors for on-chip energy storage

“…45 MXenes could be potential candidate materials for highperformance MSCs due to the following merits: 1) MXenes show high gravimetric capacitances comparable to graphene, while have a much larger packing density (~4.0 g cm -3 ), 29,36,45 which helps to improve the volumetric characteristics. For instance, stable specific volumetric capacitance close to 1000 F cm -3 was reported for Ti3C2Tx MXenes in a conventional 3-electrode configuration, 36 exceeding all of the carbon-based supercapacitors [46][47][48] . 2) Most MXenes are metallic conductors with an electrical conductivity up to 6500 S cm -1 , 49 this enables the fast transfer of electrons and eliminates the need for noble metal current collectors.…”

N-doped microporous carbon microspheres for high volumetric performance supercapacitors

“…Therefore, the fabrication of porous carbon materials with a high gravimetric and volumetric performance is still an important challenge to be overcome [15]. In recent literature, several attempts to fabricate materials with a high volumetric energy density can be found, most of them based on the use of carbon nanotubes or graphene materials as substrates [16][17][18][19][20].…”

Holey graphene frameworks for highly efficient capacitive energy storage

“…Although gravimetric capacitance was traditionally used as the figure-of-merit to evaluate an EC electrode, the volumetric performance is becoming an increasingly important metric to consider for many practical applications with limited space such as portable electronic products [14][15][16][17][18][19][20] . However, there is usually a trade-off relationship between the gravimetric and volumetric capacitances for most electrode design.…”