Hierarchical Carbide‐Derived Carbon Foams with Advanced Mesostructure as a Versatile Electrochemical Energy‐Storage Material

Abstract

Highly porous carbide-derived carbon (CDC) mesofoams (DUT-70) are prepared by nanocasting of mesocellular silica foams with a polycarbosilane precursor. Ceramic conversion followed by silica removal and high-temperature chlorine treatment yields CDCs with a hierarchical micro-mesopore arrangement. This new type of polymer-based CDC is characterized by specifi c surface areas as high as 2700 m 2 g −1 , coupled with ultrahigh microand mesopore volumes up to 2.6 cm 3 g −1 . The relationship between synthesis conditions and the properties of the resulting carbon materials is described in detail, allowing precise control of the properties of DUT-70. Since the hierarchical pore system ensures both effi cient mass transfer and high capacities, the novel CDC shows outstanding performance as an electrode material in electrochemical double-layer capacitors (EDLCs) with specifi c capacities above 240 F g −1 when measured in a symmetrical two-electrode confi guration. Remarkable capacities of 175 F g −1 can be retained even at high current densities of 20 A g −1 as a result of the enhanced ion-transport pathways provided by the cellular mesostructure. Moreover, DUT-70 can be infi ltrated with sulfur and host the active material in lithium-sulfur battery cathodes. Reversible capacities of 790 mAh g −1 are achieved at a current rate of C/10 after 100 cycles, which renders DUT-70 an ideal support material for electrochemical energy-storage applications.

Nitrogen Codoped Unique Carbon with 0.4 nm Ultra‐Micropores for Ultrahigh Areal Capacitance Supercapacitors

“…Moreover, when the ultra‐micropore total volume of the carbon microspheres increased from 0.006 to 0.016 cm 3 g −1 , the gravimetric capacitance increased from 147 to 294 F g −1 . More importantly, due to the narrow size distribution of ultra‐microporous carbon than typical carbon‐based electrodes, the area capacitance of obtained sample reaches the value of 330 µF cm −2 , significantly higher than that of previously reported electrode materials . This work provides a better understanding of the correlation between ultra‐microporous structures and their capacitance.…”

“…For such pore diameter, a slightly increasing coverage of the inner ultra‐micropore is more suitable to the ion coming in and out from the pore channel. And due to the ultra‐microporous carbon possesses a much lower surface area than other typical carbon‐based electrodes (1500–2000 m 2 g −1 ), the area‐normalized capacitance ( C a , µF cm −2 ) of the CM‐D electrode is up to 330 µF cm −2 at 0.1 A g −1 , significantly higher than those from carbon‐based electrodes, such as activated carbons (10–25 µF cm −2 ), carbide‐derived carbons (5–22 µF cm −2 ), MXene‐derived carbons (24 µF cm −2 ), nitrogen‐enriched carbon materials (73.4 µF cm −2 ), and functionalized graphene sheets (54.1 µF cm −2 ) …”

Mesoporous materials for energy conversion and storage devices

“…The ordered mesopore channels in these materials serve as ion highways and allow for very fast ionic transport into the bulk of the carbon particles. In a different approach, it may be possible to combine the benefits of micro-, meso-and macropores in a hierarchical porous carbon material to further enhance the electrochemical performance 168 . Although much effort in the past decade has been devoted to optimizing the structure of mesostructured carbon materials -more specifically, the surface area, pore size and pore geometry -the capacity achieved to date (~200 F g −1 ) remains too low for commercial application in high-energy-density supercapacitors.…”

Zinc-salt templating of hierarchical porous carbons for low electrolyte high energy lithium-sulfur batteries (LE-LiS)

“…Up to date many preparation strategies of porous carbons with tunable pore sizes have been reported [8,9]. On the one hand the most often applied silica hard templating approach allows tuning a wide range of pore sizes but low carbon yields as well as an undesirable expansive and time consuming purification steps are disadvantageous [8,[10][11]. More favorable, evaporation induced self-assembly (EISA) approaches (soft templating), developed by Zhao and co-workers [12] allow more efficient processing and upscaling.…”