Facile Synthesis of Two-Dimensional (2D) Boron Carbonitride and 2D Porous Boron Carbonitride for Excellent Energy Storage and Gas Adsorption Applications

Abstract

The development of two-dimensional (2D) carbon nanosheets and microporous 2D carbon nanosheets with high specific surface area (SSA), large pore volume, and high conductivity is important for energy storage and gas storage applications. Traditional microporous carbon materials have several disadvantages such as low accessibility of active sites and poor mass transport due to large diffusion pathways. The nanometer-thick 2D microporous carbon nanosheets permit easy mass/heat transport, leading to overcoming the drawbacks of bulk porous materials. Herein, we demonstrate a facile synthesis of 2D boron carbonitride (BCN) and 2D porous BCN for energy and gas storage applications. The 2D BCN sample showed excellent supercapacitor (SC) applications with a specific capacitance (C s) of 273 F g–1 under 1 A g–1. Most importantly, 2D porous BCN (p-BCN) was prepared by KOH activation at high temperatures. The optimized 2D porous BCN with highly concentrated micropores and a considerable amount of mesopores provides a high SSA (3310.4 m2 g–1) and pore volume of 1.75 cc g–1. The combined effect of unique porous nanosheets and optimum doping of heteroatoms allows easy electrolyte/ion diffusion, electron conduction, faradic reactions, and so forth. The p-BCN-800 electrode showed superior C s of 406 and 355 F g–1 under 1 A g–1 in H2SO4 and KOH electrolytes, respectively. Moreover, the symmetric p-BCN-800//p-BCN-800 device showed high energy and power densities (17 W h Kg–1 and 4000 W kg–1) with high cycling stability. The 2D porous BCN showed excellent H2 and CO2 adsorption capacity. The H2 uptake of 2D porous BCN is 2.91 wt % at 77 K under 1 bar pressure, whereas the CO2 uptake is 3.96 and 2.39 mmol g–1 at 0 and 25 °C, respectively. This work demonstrates an efficient way to produce 2D BCN and 2D porous BCN for energy storage and gas uptake applications.

Borocarbonitride‐Based Emerging Materials for Supercapacitor Applications: Recent Advances, Challenges, and Future Perspectives

“…This can be ascribed to its time effectiveness, large‐scale production, high crystallinity, large surface area, and plentiful active sites. [ 120 ]…”

“…However, their working potential is limited to near 1.2 V. In studies done by Panda et al, they already demonstrated that redox-active N─ and O─ -functional groups make BCN better candidates for supercapacitor applications. [120] The electron deficiency in the boron atom can attract more OH − ions, producing good supercapacitive performance in aqueous and alkaline electrolytes. Their studies demonstrated that compared to 6.0 M potassium hydroxide (KOH), the KOH-activated BCN performs better in acidic electrolytes such as 1 M sulfuric acid (H 2 SO 4 ) Smaller cations such as (H + ) have acidic electrolytes than larger (K + ) ions having VA-BCNNTAs Ni-Fe-coated SiO 2 /Si substrate Vertically aligned 321.0 F g −1 95% after 1000 cycles.…”

“…iii) The substitution of boron with carbon results in a downward shift in the Fermi level, thereby enhancing charge transfer and storage within this structure. [120] The possible redox reactions in the KOH medium of this porous BCN are given in Figure 14e. Among the various approaches used for synthesizing BCN doping, in situ approaches, including direct carbonization, provide better performance.…”

“…Figure 14. a,b) HRTEM images of porous BCN produced at 800 o C by KOH activation, specific capacitance versus current density graph before, c) KOH activation,and d) after KOH activation, e) possible charge-storage mechanism in KOH, (Reproduced with permission [120]. 2023, American chemical Society).…”

A Review on Recent Progress Achieved in Boron Carbon Nitride Nanomaterials for Supercapacitor Applications

“…Pore/defect engineering and introducing a complementary high-performance 2D counterpart material can improve the surface area and alleviate the stability issue of both 2D materials, respectively, providing enhanced synergistic interplayed energy storage opportunities [113]. Panda et al obtained hierarchal porous BCNNs (p-BCN) with extremely high SSA (3310.4 m 2 g −1 ) by KOH activation at high temperatures [114]. It was found that the assembled symmetric p-BCN device possessed high energy and power densities (17 W h Kg −1 and 4000 W kg −1 ) with high cycling stability.…”