Pseudocapacitive performance of phenothiazine functionalized graphene aerogel

Understanding and Optimizing Capacitance Performance in Reduced Graphene‐Oxide Based Supercapacitors

“…Notably, for instance, as-synthesized GO has been subjected to prolonged ultrasonication to achieve an exfoliated GO suspension; then, further processed by hydro-/solvo-thermal curing, vacuum filtration or cast into templates of mesostructured foams followed by reduction either with chemical and/or thermal routes (see details in Table S1, Supporting Information). Nevertheless, the high capacitance values of 280±20 to 340±10 F g −1 at 0.5 A g −1 in EG samples in this work are higher than most of the RGO based structures in the literature and superior to direct solidstate thermal-/microwave-shock exfoliated and plasma reduced graphene counterparts, [28,29,51,[57][58][59][60][61][62][63][64][65][66][67] which typically show capacitance of <250 F g −1 (Figure S9, Supporting Information). Such an improvement of up to 40% suggests that despite using similar techniques, our optimized synthesis and processing conditions can lead to significant enhancement in their final device performance.…”

“…Here, the high capacitance values in Figure 1 can be linked to a lower reduction with a C:O ratio of less than 6.0 (e.g., hydrothermally reduced/etched RGO structures) and/or heteroatom dopants and micro-porosity (e.g., in RGO films with ultra-small/slit-like pores to micro-pores) in the RGO samples, and such factors induce a significant amount of pseudo-capacitance. [13,[19][20][21][22][23][24][25]29,43,56] These combined properties actively enhance EDLC and pseudo-capacitance significantly and contribute to boosting the total capacitance. In this context, it is worth noting that in many cases, porous graphene structures in the literature have been developed with an extended postsynthesis chemical manipulation of as-synthesized GO.…”

“…This area of research is extremely active and many different approaches have generated a huge range of conducting graphene networks with exceptionally varied porosity from ultra-small/slit-like pores to micro-porosity and high in meso-and macro-porosity that can potentially host high charge storage and ion transfer to form extensive electrical doublelayers. [9][10][11][12][13][14][21][22][23][24][25][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] Thus, RGO-based graphene networks are demonstrating attractive energy storage capacities in SCs. However, progress is held back by a lack of understanding of how to optimize these structures (and how they are processed) for the most efficient performances.…”

“…Some variation in capacitance is expected due to differing degrees of oxidation/reduction of the GO/RGO structures (Figure 1a,b) that result in disproportional conductive, nonconductive, and oxygenated or other heteroatom functionalized graphene sp 2 /sp 3 carbon components, and accessible porosity of the graphenic framework for facilitating charge storage and its dynamics. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][44][45][46][47][48][49][50][51][52][53] Other factors (Figure 1c; Table S1, Supporting Information) that can affect the overall capacitance performance include electrode preparation routes resulting in different mass-loadings and thicknesses (ultra-low mass loadings or ultrathin layers of active materials often show high capacities over thicker counterparts due to enhanced charge and mass transfer). [53,…”

Biomass-based graphene aerogel for the removal of emerging pollutants from wastewater

“…For example, Lee et al demonstrated the functionalization of graphene aerogels with phenothiazine to enhance the electrochemical active surface area and diffusion behavior by a one-step approach. 36 The polylysine This journal is © The Royal Society of Chemistry 2024 functionalization was found to enhance the adsorption capacity of graphene aerogel towards the contaminants present in wastewater. 37 Overall, recent trends are driving advancements in the field and expanding the ability of biomass-derived graphene aerogels for various environmental and technological applications.…”