NiFeZnP Nanosheets with Enriched Phosphorus Vacancies for Supercapattery Electrodes

Abstract

Designing and fabricating outstanding electrode materials via simple preparation routes are viable ways for improving the performance of electrochemical supercapacitors. We report on the synthesis of NiFeZn phosphide interconnected nanosheets with abundant phosphorus vacancies (P v -NiFeZnP) via a facile reduction route at room temperature. The fabricated P v -NiFeZnP was fully characterized using energy-dispersive spectroscopy, field emission scanning electron microscopy, electron paramagnetic resonance, and X-ray photoelectron spectroscopy techniques. Owing to the porous interconnected nanosheet structure and the superior stability enabled by the direct binder-free growth on Ni foam, the P v -NiFeZnP electrode, with optimized phosphorus vacancy formation, exhibits a superb electrochemical performance of 631.8 mC/cm 2 (equivalent to 1579.5 mF/cm 2 ), which is significantly higher than those reported in the literature. Also, the P v -NiFeZnP||activated carbon asymmetric device exhibits a very high Coulombic efficiency (∼100%) and excellent long-term stability (98.8% capacity retention after 7500 cycles). The fabricated device can deliver 122.1 μWh/cm 2 energy density at a power density of 750 μW/cm 2 . The fabricated NiFeZnP electrode is therefore a promising candidate for supercapacitor applications.

Compositionally variant bimetallic Cu–Mn oxysulfide electrodes with meritorious supercapacitive performance and high energy density

“…On the other side, the C 1 M 1 OS and C 1 M 3 OS electrodes displayed a (C f ) contribution of (B90, 80%) and C dl of (B10, 20%), respectively, indicating the predominance of the diffusioncontrolled process on the electrode surface. 77,78 This high contribution from diffusion-controlled reactions can be attributed to the direct deposition of the active material on the substrate, which enables good electrolyte accessibility and thus enhances the electrochemical activity of the material. This is also consistent with the calculated high number of electrochemically active sites for those electrodes.…”

Environmentally Benign Natural Hydrogel Electrolyte Enables a Wide Operating Potential Window for Energy Storage Devices

“… C s = I normalΔ t m normalΔ V where I is the discharging current (A), t is the discharging time (s), m is the mass of the active material, and Δ V is the potential window (V). The specific energy density ( E ) and the corresponding power density ( P ) are calculated using eqs and . , E = C s normalΔ V 2 2 × 3.6 P = E × 3600 normalΔ t where C s is the calculated capacitance, Δ V refers to the potential window after correction for the iR drop, and Δ t is the discharge time(s).…”

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“…The growing need for sustainable energy storage devices has prompted extensive research into novel technologies capable of meeting the increasing power needs of next-generation technology. 1,2 Novel energy storage devices with high power density, long life span, and sustainability are key to satisfying this pressing need. 3,4 A hybrid system (supercapattery), which includes supercapacitors (SCs) and batteries, can overcome the limitations of standard energy storage systems.…”

“…The growing need for sustainable energy storage devices has prompted extensive research into novel technologies capable of meeting the increasing power needs of next-generation technology. , Novel energy storage devices with high power density, long life span, and sustainability are key to satisfying this pressing need. , A hybrid system (supercapattery), which includes supercapacitors (SCs) and batteries, can overcome the limitations of standard energy storage systems. − Despite their rapid charge/discharge rates and long cycle life, SCs are frequently limited by their relatively low energy density . In contrast, batteries offer higher energy storage but shorter charge–discharge speeds and worse cycle stability.…”