Microwave-plasma induced one-step synthesis of Ni(PO₃)₂ nanosphere-loaded bio-waste derived N, P co-doped carbon for an asymmetric supercapacitor with prolonged life

Abstract

Ni(PO3)2 nanospheres and bio-waste derived N, P co-doped carbon composites as asymmetric supercapacitor with long cycle life to run an oximeter and 28 LEDs demonstrating a strong practical application prospect.

Mechanochemically Assisted Microwave-Induced Plasma Synthesis of a N-Doped Graphitic Porous Carbon-Based Aqueous Symmetric Supercapacitor with Ultrahigh Volumetric Capacitance and Energy Density

“…Therefore, the optical microscopic images and FTIR study confirm that ball milling not only reduced the agglomeration and particle sizes but also created more oxygenated dipoles like −C−O, −C�O, and −OH to influence the microwave absorption of MAP 2 through the dipolar polarization mechanism. 30 Smaller particle sizes and low agglomerations may also help to boost the surface area of MAP 2, which can eventually increase its contact area with microwave-irradiated radiation 31 for better microwave absorption.…”

“…However, the process of ionizing N 2 gas to generate N 2 plasma through microwave irradiation has been previously explored in one of our recent publications. 30 Interestingly, it is seen that the kinetics of plasma formation vary significantly during the preparation of NGC and HP-NGC. In the process videos (Movies S1 and S2), it was observed that plasma formation started immediately (within ∼2−5 s) during the preparation of HP-NGC, whereas for NGC, the plasma state appeared almost 5 times slower (after ∼25 s).…”

“…35,36 Additionally, a few small peaks are also observed, which might have appeared due to the presence of an insignificant amount of residual ash in the developed NGC and HP-NGC from coffee grounds. 30,37 After confirming the formation of the carbon structure, it is important to understand the nature of graphitization in the developed HP-NGC and NGC via Raman spectroscopy, as shown in Figure 2b. Both NGC and HP-NGC contain D (∼1350 cm −1 ), G (∼1590 cm −1 ), and 2D (∼2886 cm −1 ) peaks at almost the same position but with different intensities, suggesting that both are graphitic in nature but with different levels of defects.…”

“…The high-resolution spectra of N 1s for HP-NGC (Figure 2d) show four fitted peaks to confirm the presence of N−H, pyridinic-N, pyrrolic-N, and graphitic-N corresponding to the binding energies of 398.1, 399.1, 399.9, and 400.9 eV, respectively. 24,30,31 Pyridinic-N and pyrrolic-N are known for contributing PC, while graphitic-N enhances conductivity by introducing positive charges. 41 Consequently, the high-resolution C 1s spectrum (Figure 2e) shows four distinct fitted peaks centered at the binding energies of 283.9, 284.…”

“…According to the “Saha ionization energy” relation of plasma ionization (given in eq ), ionization probability increases with the increase in temperature, which indicates that plasma formation becomes faster at higher temperatures; this might be the case with MAP 2, where higher microwave absorption propagates higher temperatures to ease the ionization of N 2 gas to form N 2 plasma. P normali normalo normaln ∝ e − ( E i o n / k B T ) Here, P ion is the probability of ionization, E ion is the ionization energy of the atom, and k B is the Boltzmann constant. However, the process of ionizing N 2 gas to generate N 2 plasma through microwave irradiation has been previously explored in one of our recent publications . Interestingly, it is seen that the kinetics of plasma formation vary significantly during the preparation of NGC and HP-NGC.…”