Bioinspired Highly Crumpled Porous Carbons with Multidirectional Porosity for High Rate Performance Electrochemical Supercapacitors

Abstract

Rational design and facile synthesis of porous carbon materials with optimized porosity are necessary to boost electrochemical performance for energy storage and conversion devices. In this work, we report the fabrication of three-dimensional (3D) highly crumpled porous carbons (HCPCs) inspired by the crumpled structure and functionality of renewable Moringa oleifera leaves by a facile postactivation-free method. The as-resulted HCPCs deliver an interconnected framework, abundant active interfaces, rich heteroatom content, and notably multidirectional porosity for fast ion transport and efficient charge storage. Employed as electrode materials for supercapacitors, the HCPCs exhibit ultrahigh rate capability of capacitance retention over 90% when increasing the current density from 1.0 to 50 A g–1 as well as outstanding cycling stability over 20 000 charge/discharge cycles. Furthermore, the HCPC-based symmetric supercapacitor manifests a high specific energy of 21.6 Wh kg–1, along with excellent structural and electrochemical stability after 20 000 cycles in aqueous medium. This work provides an appealing model of carbon material engineering inspired by the unique structure of natural leaves for fast and high-rate supercapacitors, as well as guidance for rational structural design in extended energy storage and conversion systems.

Sustainable Biomass Activated Carbons as Electrodes for Battery and Supercapacitors—A Mini-Review

“…Thus, to enhance Li-storage capacity, efforts have been made to reach the application of porous ACs from biomasses for electrodes fabrication [66][67][68][69][70][71][72]. Many kinds of research have been devoted to the feasibility of preparation of CEs from biomasses, mainly due to the significant existence of micro-, meso-, and macropores that have huge effects on their electronic structure and electrochemical performance, such as reduced diffusion length for Li + ions and electrons and improved reversible capacity (RC).…”

“…In terms of physical features of the CE, the combination of macro-, meso-, and micropores might enhance the CE performances in terms of i) electrode wettability and electrolyte accessibility which are mainly facilitated by the presence of macro-and mesopores [61,65], although the hydrophobicity of the CE also influences the wettability process [65,66] ii) ion diffusion rate, and iii) charge transport kinetics at the CE/electrolyte interphase which is mainly potentialised by the presence of the micropores [60]. Therefore, together with the high specific surface area, the simultaneous presence of various types of pore sizes into the CE allows for the enhancement of their electrochemical performances in energy storage devices [60,[65][66][67][68][69][70][71][72][73].…”

“…Moreover, a large amount of ordered mesoporous in the AC structure can serve as Li + deposit and also potential pathways for diffusion of electrolyte which speedy the kinetic process of ions diffusion in CE surfaces and structures, leading to better electrochemical performance metrics (as illustrated in Figure 4). The effect of carbon structure was studied and highlighted by Peng et al [68] using Moringa oleifera leaves as a precursor to produce highly porous AC (HCPC) with multidirectional porosity that was used as CE for efficient DLCs (see Figure 5). Figure 5a shows conventional AC with dominant microporous structures with single-directional ion channels, which provides more reduced accessibility for electrode ions to transfer into the internal pore structure and thus resulting in poor electrochemical performances.…”

“…The effect of carbon structure was studied and highlighted by Peng et al [ 68 ] using Moringa oleifera leaves as a precursor to produce highly porous AC (HCPC) with multidirectional porosity that was used as CE for efficient DLCs (see Figure 5 ).…”

3D N,O-Codoped Egg-Box-Like Carbons with Tuned Channels for High Areal Capacitance Supercapacitors

“…The properties of SC largely depend on the electrode materials, e.g., carbonaceous materials (CMs) [6,7], metal oxides [8], conductive polymers [9], and their composites [10][11][12]. CMs have become the prime choice of electrode materials for SCs due to their excellent electrical conductivity, versatile porosity and high surface area [13][14][15]. A substantial number of strategies have been reported for the preparation of porous CMs [16][17][18].…”