NiF₂ Nanorod Arrays for Supercapattery Applications

Abstract

A electrode for energy storage cells is possible directly on Ni foam, using a simple reduction process to form NiF2 nanorod arrays (NA). We demonstrate NiF2@Ni NA for a symmetric electrochemical supercapattery electrode. With an areal specific capacitance of 51 F cm–2 at 0.25 mA cm–2 current density and 94% cycling stability, a NiF2@Ni electrode can exhibit supercapattery behavior, a combination of supercapacitor and battery-like redox. The symmetric electrochemical supercapattery delivers 31 W h m–2 energy density and 797 W m–2 power density with 83% retention in a 1 M KOH electrolyte, constituting a step toward manufacturing a laboratory-scale energy storage device based on metal halides. Producing self-grown hierarchically porous nanostructured electrodes on three-dimensional metal foams by displacement reactions may be useful for other metal halides as electrodes for supercapacitors, supercapatteries, and lithium-ion batteries.

Ribbon-like Nickel Cobaltite with Layer-by-Layer-Assembled Ordered Nanocrystallites for Next-Generation All-Solid-State Hybrid Supercapatteries

“…In this context, the slope of ∼0.549 for the log i versus log ν plot in Figure S3B proposes that semi-infinite diffusion is the predominant mechanism during redox-based charge storage process in NiCo 2 O 4 . Since both supercapacitor and battery-type behavior are experienced during the redox-based charge storage process, we collectively call it supercapattery charge storage in NiCo 2 O 4 . , Further, the good redox-based supercapattery behavior of ribbon-like NiCo 2 O 4 is ascribed to the vivacity of multiple reactive equivalents (Ni 2+ , Co 2+ , and Co 3+ ) and multi-redox possibilities (Ni 2+ /Ni 3+ , Co 2+ /Co 3+ , and Co 3+ /Co 4+ ), which allow more number of redox reactions during potential cycling . Moreover, the discrete porous architecture of the ribbon-like NiCo 2 O 4 also facilitates the lowly regulated diffusion of electrolyte ions/electrolytes to even the bulk-lying active redox centers during the charge storage process, which leads to good high-rate performance of the material …”

Defect-Engineered Nanostructured Ni/MOF-Derived Carbons for an Efficient Aqueous Battery-Type Energy Storage Device

“…Some authors still refer to battery-type Ni-based electrodes as pseudocapacitors and continue to carry out the calculation of energy storage in capacitance (Farad) rather than capacity (mAh). This misinterpretation has continued to generate some concern to researchers in the electrochemical energy storage community, ,− as it makes it very difficult for one to reasonably compare electrochemical data with literature. Another concern that one observes in the literature is the generalization that the charge storage in BTES is a purely diffusion-controlled (faradic) process, with no significant contribution to the energy storage mechanism by the capacitive process .…”

Ultra‐Fast In Situ Reconstructed Nickel (Oxy)Hydroxide Nanoparticle Crosslinked Structure for Super‐Efficient Alkaline Water Electrolysis by Sacrificing Template Strategy

“…[21] Apart from two pairs of peaks centered at 856.0/874.5 eV and 863.8/881.7 eV, attributed to Ni-O bonds, [22] two notable peaks generated from the 2p 3/2 and 2p 1/2 of Ni-F bonds are found at 858.9 and 877.1 eV, respectively. [23] In the F 1s spectrum, only the Ni-F bond can be detected at 685.4 eV (Figure 1d). [24] The Ni(OH) 2 •0.75H 2 O precursor has a flower-like structure, with nanosheets of approximately 50 nm thickness, as seen in the FESEM image (Figure 2a and S8, Supporting Information).…”