Studies on the electrochemical intercalation/de-intercalation mechanism of NiMn₂O₄ for high stable pseudocapacitor electrodes

Abstract

Sub-micron sized polyhedral shaped NiMn 2 O 4 particles were successfully prepared by a glycine assisted solution combustion method. The phase purity and the presence of functional groups in NiMn 2 O 4 were revealed through X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), respectively. The formation of polyhedral shaped particles was inferred by field emission scanning electron microscopy (FE-SEM). The negative temperature coefficient of resistance (NTCR) behaviour of NiMn 2 O 4 was observed using a solid state impedance analyser in the measured temperature range between 30 and 180 C. Further, electrochemical studies revealed that NiMn 2 O 4 stores the charge through intercalation rather than by a capacitive mechanism. The electrode stores 91% of the specific capacitance by intercalation and 9% by a capacitive mechanism. Also, NiMn 2 O 4 possesses a specific capacitance of 202 F g À1 at 0.5 mA cm À2 in 1 M Na 2 SO 4 electrolyte and exhibits excellent cyclic stability over 15 000 cycles. Similarly, the fabricated asymmetric device (FeVO 4 kNiMn 2 O 4 ) also delivers good specific capacitance (50 F g À1 at 1 mV s À1 ) and cyclic stability.

Enhanced activity of highly conformal and layered tin sulfide (SnSx) prepared by atomic layer deposition (ALD) on 3D metal scaffold towards high performance supercapacitor electrode

“…Furthermore, the amount of areal capacity contribution from the inner and outer surface of the optimized electrode (SnS x @NF-160, 500 ALD cycles) is calculated another method using Trasatti analysis. According to Trasatti theory, the maximum total capacitance can be determined as the sum of the capacitance provided by the inner and outer surface of the electrode materials, which can be expressed using the following equation 66 ,…”

Comparison of Charge Storage Properties of Prussian Blue Analogues Containing Cobalt and Copper

“…Representative examples of this analysis are shown in Figure S4, confirming that the charge storage kinetics for these samples is the result of mixed capacitive and diffusional behavior. Both an intermediate value of b in power-law fits and mixed kinetic behavior from Trasatti fits have been observed in a variety of intercalation charge storage systems [38][39][40][41][42][43][44][45][46]. The integrated charge capacity of the HCF films was calculated from 20 mV/s CV data.…”

Freestanding Gold/Graphene‐Oxide/Manganese Oxide Microsupercapacitor Displaying High Areal Energy Density

“…Notably, the outer surface areal capacitance of the Au/rGO/MnO 2 electrode was 2556 mF cm −2 , obtained from extrapolating the curve of q versus v −0.5 to v −0.5 =0 (Figure D), is significant, emphasizing the potential utilization of the electrode in supercapacitor applications. The calculated ratio between the outer surface and total area capacitance of the Au/rGO/MnO 2 electrode is 66 %, which is among the highest values published so far, similarly indicates suitability for energy‐storage devices.…”