Electrochemical Energy Storage Properties of Ni-Mn-Oxide Electrodes for Advance Asymmetric Supercapacitor Application

Abstract

In this work, we report a facile one-spot synthesis process and the influence of compositional variation on the electrochemical performance of Ni-Mn-oxides (Ni:Mn = 1:1, 1:2, 1:3, and 1:4) for high-performance advanced energy storage applications. The crystalline structure and the morphology of these synthesized nanocomposites have been demonstrated using X-ray diffraction, field emission scanning electron microscopy, and transmission electron Microscopy. Among these materials, Ni-Mn-oxide with Ni:Mn = 1:3 possesses a large Brunauer−Emmett−Teller specific surface area (127 m 2 g −1 ) with pore size 8.2 nm and exhibits the highest specific capacitance of 1215.5 F g −1 at a scan rate 2 mV s −1 with an excellent long-term cycling stability (∼87.2% capacitance retention at 10 A g −1 over 5000 cycles). This work also gives a comparison and explains the influence of different compositional ratios on the electrochemical properties of Ni-Mn-oxides. To demonstrate the possibility of commercial application, an asymmetric supercapacitor device has been constructed by using Ni-Mn-oxide (Ni:Mn = 1:3) as a positive electrode and activated carbon (AC) as a negative electrode. This battery-like device achieves a maximum energy density of 132.3 W h kg −1 at a power density of 1651 W kg −1 and excellent coulombic efficiency of 97% over 3000 cycles at 10 A g −1 .

Efficient Flexible All-Solid Supercapacitors with Direct Sputter-Grown Needle-Like Mn/MnOx@Graphite-Foil Electrodes and PPC-Embedded Ionic Electrolytes

“…The BE of Mn in the pure oxide ( Figure 1 c) is 640.7 eV, which also matches the oxidation state close to Mn 2 O 3 or Mn (III). The separation value between these two states (Mn 2p 3/2 , Mn 2p 1/2 ) of Mn is 11.64 eV, which is also consistent with the literature [ 4 , 34 , 35 ]. The BEs of 528.12 and 529.46 eV from oxygen indicate that oxygen is bonded to the metal and only a few hydroxyl groups are present ( Figure 1 d).…”

“…A maximum areal capacitance of 8.69 mF/cm 2 is obtained at 5 mV/s for this SC. The variation in C A with scan rate ( Figure 2 c) shows that areal capacitance values decrease significantly with increasing the scan rate due to decrease of time involvement for the movement of electrolyte ions [ 4 , 39 , 40 ]. To further evaluate the areal capacitance (C A ) of this all-solid FSC device, the galvanostatic charge–discharge (GCD) tests at different current densities from 0.03 to 1.0 mA/cm 2 were carried out.…”

“…The relaxation time (τ 0 ) values for this SC cell consisting of Mn/MnO x @Graphite-foil electrodes and PGE are 0.78 and 0.54 s before and after 5000 CV cycles, respectively. These low values of the relaxation time signify the high-energy storage capability with a high rate and fast reversible adsorption/desorption of electrolyte ions at the electrode/electrolyte interface [ 4 , 46 , 48 ]. The overall electrochemical properties suggest very promising supercapacitive properties for the FSC cell with the direct sputter-grown needle-like Mn/MnO x @Graphite-foil electrodes and ionic-liquid-embedded polymer gel electrolyte (PGE) for supercapacitor applications where high performance and all-solid flexible devices especially in the next generation energy storage systems are required.…”

“…The growing demand for modern flexible portable electronics increases the need for lightweight, low-cost, high-performance compact power sources [ 1 , 2 , 3 ]. In terms of decentralized energy storage, peak power management, back-up energy storage, the electrochemical energy storage devices, including Li-ion batteries and supercapacitors (SCs) are recognized currently as the most promising devices [ 4 , 5 ]. However, these devices are generally too stiff and bulky to combine into flexible electronics.…”

Nitrogen and Phosphorus Co‐doped Nanoporous Carbons from Phosphoprotein/Silica Self‐Assemblies for Energy Storage in Supercapacitors

“…ECSs can be used reversibly in hundreds of thousands of cycles to load and unload charge/energy, without undergoing degradation or losing their charge storage capacity. [4][5][6] In addition to their high power density (or being able to discharge at high current density), ECSs are interesting for the following reasons, especially compared with batteries (e. g., lithium-ion batteries or LiBs): (i) they need less time to fully charge; (ii) they generally have long life cycles; (iii) they have high Coulombic efficiency (great reversibility); and (iv) the materials used in them are generally environmentally friendly. Some of the advantages of ECSs compared with batteries can be appreciated by comparing the mechanisms of energy storage and release in the two systems.…”