All‐carbon hybrids for high performance supercapacitors

A hybrid nanostructure with partially reduced graphene oxide (rGO) and carbon nanofibers (CNFs) was fabricated and used as supercapacitor electrodes. A straightforward, environmentally friendly, and low‐cost microwave‐assisted reduction process was developed for the synthesis of rGO/CNF hybrid structures. The fabricated supercapacitor devices showed a specific capacitance of 95.3 F g^?1 and a superior long‐term cycling stability. A capacitance retention of more than 97% after 11 000 galvanostatic charge discharge cycles was obtained. These and other results reported in this paper indicate that high‐rate, all‐carbon, rGO/CNF hybrid nanostructures are highly promising supercapacitor electrode materials.     

Fabrication of FeO@CuCo2S4 multifunctional electrode for ultrahigh-capacity supercapacitors and efficient oxygen evolution reaction

The outstanding multifunctional electrochemical properties of chalcogenide-based FeO@CuCo₂S₄, such as electrochemical energy storage (EES) and electrocatalytic oxygen evolution reaction are demonstrated. The FeO@CuCo₂S₄ film is fabricated using a two-step synthesis procedure. First, CuCo₂S₄ was grown on 3D porous nickel foam substrate using a mild hydrothermal growth technique, onto which FeO was then deposited via a magnetron sputtering. The FeO@CuCo₂S₄ film shows a cordillera-like morphology with a uniformly distributed island-like nanospheres on its surface. The optimized FeO@CuCo₂S₄ electrode delivers an ultrahigh specific capacitance of 3213 F g⁻¹ at 1 A g⁻¹. This FeO@CuCo₂S₄ electrode shows superior capacity retention and coulombic efficiency of ~116% and ~99%, respectively, after 10 000 charge/discharge stability cycles. Moreover, this superior electrode is also serves as an OER electrocatalyst in alkaline solution (1 M aqueous KOH), demonstrating better catalytic activity by attaining a low overpotential of ~240 mV at 10 mA cm⁻² and a small Tafel slope of 51 mV dec⁻¹. This FeO@CuCo₂S₄ catalyst has excellent current rate performance and endurance properties at a high current density rate of up to 100 mA cm⁻² even after 25 hours. The post-measurement HR-TEM, EDS-STEM mapping, and Raman analysis reveal the phase transformation of FeO@CuCo₂S₄ upon electro-oxidation.     

Battery-type and binder-free MgCo2O4-NWs@NF electrode materials for the assembly of advanced hybrid supercapacitors

In this study, the hetero-structure of MgCo₂O₄ nanowires (MCO-NWs) and microcubes (MCO-MCs) on the skeleton of nickel foam (NF) was realized through a simple hydrothermal method and subsequent annealing treatment, and then served as a binder-free cathode for assembly of high-performance hybrid supercapacitor (HSC). Such synthetic methodology avoided the traditional usage of conductive and binder reagents for the electrode fabrication. The electrochemical tests indicated its battery-type characteristics, and the MCO-NWs@NF exhibited a huge specific capacity (C_s) of 389.0 C g^?1 as well as 86.2% capacity retention when the current density boosted from 1 to 10 A g^?1. The assembled HSC with activated carbon (AC) as anode further demonstrated the advantages of this electrode material. After 5000 cycles at 6 A g^?1, the MCO-NWs@NF//AC HSC showed good long-term cycling stability without any decay in capacitance, and could deliver an energy density (E_d) of 37.9 W h kg^?1 at the power density (P_d) of 958.1 W kg^?1, higher than the 30.4 W h kg^?1 of MCs-based HSC. These impressive results regarding electrochemical performance suggest that MCO-NWs@NF may be a promising candidate to serve as a battery-type material in electrochemical energy storage applications such as HSCs, batteries, and so on.     

A hybrid composite of rGO/TiO2 as a double layer electrode with improved capacitance performance

Reduced graphene oxide (rGO) has unique properties that can revolutionize the performance of the functional devices. rGO hybrids can be designed with transition metal oxides for improved energy storage applications. Herein, a hybrid composite of conductive rGO with titanium dioxide, designed by a simple hydrothermal method, is reported to demonstrate a high double layer capacitance in aqueous electrolyte systems. The mesoporous structure of the composite provides short ion diffusion pathways and the resultant capacitance of the material is 334 F g⁻¹ with ~77% capacitance retention after 7000 charge-discharge cycles.     

Hierarchitecture Co2(OH)3Cl@FeCo2O4 composite as a novel and high-performance electrode material applied in supercapacitor

One-step hydrothermal reaction has successfully been used to prepared three-dimensional hierarchitecture Co₂(OH)₃Cl@FeCo₂O₄ composite without any annealing treatment. The samples are investigated to confirm the crystal structure, elemental composition, morphology structure and electrochemical performance. The results show the sample has a three-dimensional hierarchitecture that nanoblocks are assembled with nanoparticles. And the specific surface area is 87.5 m² g⁻¹ and the total pore volume is 0.17 cm³ g⁻¹. Meanwhile, the composite shows a high specific capacitance of 1110.0 F·g⁻¹ at 1 A·g⁻¹ and great cycling stability with 98.8% capacitance retention after 3000 cycles. To evaluate the electrochemical performances, the results are used to compare with the Co₂(OH)₃Cl and FeCo₂O₄ nanomaterials, indicating a higher capacitance and longer cycle stability shown by the as-synthesized sample. The as-synthesized Co₂(OH)₃Cl@FeCo₂O₄ composite has an outstanding electrochemical performance, predicting an enormous potential and promising future as a novel electrode material applied in supercapacitor.     

One‐pot synthesis of composite NiO/graphitic carbon flakes with contact glow discharge electrolysis for electrochemical supercapacitors

Thanks to their high power density and degree of reversibility, supercapacitors are electrochemical devices that narrow the gap between secondary batteries and traditional dielectric capacitors in the traditional Ragone plot. However, their use is still hindered by their capability to achieve higher energy density. In this work, we present a one‐pot synthesis procedure of composite graphitic carbon flake‐supported NiO for electrochemical energy storage application. We used cathodic contact glow discharge electrolysis by applying 120 Vdc terminal voltage between a thin Pt wire, slightly submerged in an aqueous solution of NiSO₄(H₂O)₆ + Na₂SO₄, and a large surface area carbon graphite anode. Strong active species generated within the micro‐plasma volume locally reduce the nickel precursors to form NiO materials, while at the anodically polarized graphite rod, the forces holding the graphene layers together are weakened by ion/solvent intercalation producing micrometer‐sized graphitic carbon flakes. The morphological characterization is carried out by electron microscopy, energy dispersive X‐ray spectroscopy, powder X‐ray diffraction, and micro‐Raman spectroscopy. Cyclic voltammetry, constant‐current charge/discharge, and electrochemical impedance spectroscopy in 5 mol l^?1 KOH solution are carried out to evaluate the electrochemical energy storage performance of the material. We show that carbon flake‐supported NiO exhibits the dual combination of electric double‐layer capacitance with faradic behavior, giving 495 F g^?1 specific capacitance at 2 A g^?1 current density. Copyright © 2015 John Wiley & Sons, Ltd.     

Improved low‐temperature performance of novel asymmetric supercapacitor with capacitor/battery‐capacitor construction

A concept for designing capacitor/battery‐capacitor asymmetric supercapacitor is proposed to improve low‐temperature capacitance, which consists of a capacitor‐type electrode (C) and a capacitor/battery‐type composite electrode (NiO/C). This construction overcomes the capacitor‐battery asymmetric supercapacitor's shortcoming of losing capacitance characteristics. By adjusting the NiO/C mass ratio to 1/2, the new NiO/C–C asymmetric supercapacitor maintains excellent capacitance feature (rectangular CV curves and symmetrical charge/discharge profiles) as well as enlarging the work potential to 1.5 V, showing improved low‐temperature capacitance in comparison with C‐C and NiO‐C constructions. It is believed to come from the decreased total inner resistance and charge‐transfer resistance due to the substitution of NiO electrode with NiO/C composite electrode in the asymmetric supercapacitor. Copyright © 2016 John Wiley & Sons, Ltd.     

A review of performance optimization of MOF‐derived metal oxide as electrode materials for supercapacitors

Metal‐organic frameworks (MOFs), as new class of porous materials, are constructed by inorganic metal centers and bridging organic links. Recently, MOFs have been proved to be effective templates for preparing metal oxides with large surface areas and controlled shape by directly annealing in air. There are lots of reports about metal‐organic framework‐derived metal oxides as electrode materials for supercapacitors. Metal‐organic framework‐derived metal oxides can offer higher capacitances compared with that prepared by other synthetic methods, likely attribute to high surface areas and optimal pore sizes. However, at present, the specific capacitances of MOF‐derived metal oxides received are far lower than theoretical values, and the cycle numbers could not meet practical demands. Accordingly, much effort has been made to improve the performance by further modifying MOFs. Thus, this paper focused on the advances in performance optimization of MOF‐derived metal oxide as electrode materials for supercapacitors as follows:

1. Dual metal MOF‐derived binary metal oxides. Metal oxides with 2 metal cations possess better electrical conductivity and richer redox active sites than single metal oxides.
2. Metal‐organic framework‐derived carbon/metal oxide composites (MO@C) or graphene/MOF‐derived graphene/metal oxide composites. Doping carbon not only facilitate transportation of electrodes but also contribution to extra double‐layer capacitance.
3. Hybrid MOF‐derived metal oxide composites (MO@MO). Metal oxide composites can produce some synergistic effects that the individuals cannot provide.
4. Metal‐organic framework‐derived metal oxides with a hollow structure. The Hollow structure could shorten ion diffusion distance and adapt to volume expansion generated during the ion intercalated/extracted process.

     

Simple synthesis of honeysuckle-like CuCo2O4/CuO composites as a battery type electrode material for high-performance hybrid supercapacitors

In this paper, porous CuCo₂O₄/CuO composites with novel honeysuckle-like shape (CuCo₂O₄/CuO HCs) have been prepared for the first time by a simple hydrothermal method and followed with an additional annealing process in air. The unique CuCo₂O₄/CuO HCs consisted of dense and slender petals with length of 1.3–1.5 μm and width of about 50 nm, and possessed a specific surface area of 36.09 m² g^?1 with main pore size distribution at 10.63 nm. When used as the electrode materials for supercapacitors, the CuCo₂O₄/CuO HCs exhibited excellent electrochemical performances with a high specific capacity of 350.69 C g^?1 at 1 A g^?1, a rate capability of 78.6% at 10 A g^?1, and 96.2% capacity retention after 5000 cycles at a current density of 5 A g^?1. In addition, a hybrid supercapacitor (CuCo₂O₄/CuO HCs//AC HSC) was assembled using the CuCo₂O₄/CuO HCs as positive electrode and activated carbon (AC) as negative electrode. The HSC device delivered a specific capacity of 187.85 C g^?1 at 1 A g^?1 and a superior cycling stability with 104.7% capacity retention after 5000 cycles at 5 A g^?1, and possessed a high energy density of 41.76 W h kg^?1 at a power density of 800.27 W kg^?1. These outstanding electrochemical performances manifested the great potential of CuCo₂O₄/CuO HCs as a promising battery-type electrode material for the next-generation advanced supercapacitors with high-performance.     

High‐performance porous lead/graphite composite electrode for bipolar lead‐acid batteries

In general, thicker active material bipolar electrode's specific capacity and cycle life are very poor owing to its low bonding strength between the active material and the substrate and the diffusion rate of the sulfuric acid electrolyte inside the active material. In this paper, we synthesize a novel attached and porous lead/graphite composite electrode for bipolar lead‐acid battery and can effectively solve these problems. The graphite/polytetrafluoroethylene emulsion is employed to improve the bonding strength and conductivity and the porous can provide electrolyte diffusion channels. The specific capacities of 2‐mm thick positive active material at 0.25, 0.5, 1 and 2 C can attain 75.99, 58.98, 47.97, and 33.36 mAh·g^?1. The discharge voltage platform is also relatively high and no rapid decline with increasing discharge rate. Furthermore, after 80 cycles, the specific capacity does not drop evidently. Copyright © 2017 John Wiley & Sons, Ltd.     

Fabrication of a ternary PANI@Fe3O4@CFs nanocomposite as a high performance electrode for solid-state supercapacitors

In this work, a solid-state high performance supercapacitor is fabricated based on a ternary polyaniline@Fe₃O₄@carbon fibers nanocomposite. To prepare the polyaniline@Fe₃O₄@carbon fibers electrodes, a two-step method including electrophoretic deposition of Fe₃O₄ nanoparticles on carbon fibres followed by an in situ polymerization process of polyaniline is utilized. The results show that the polyaniline@Fe₃O₄@carbon fibers nanocomposite with a layer by layer microstructure is successfully formed. The fabricated nanocomposite represents a specific surface area of 3.12 m² g⁻¹. The electrochemical measurements in a three-electrode configuration reveals a high specific capacitance of 245.5 F g⁻¹ at 0.5 A g⁻¹ and an excellent cycle stability (82.44% after 1000 cycle) of the polyaniline@Fe₃O₄@carbon fibers electrode. The as-fabricated solid-state supercapacitor based on the polyaniline@Fe₃O₄@carbon fiber nanocomposite cloth with a surface area of 25 cm² powers up a blue light-emitting diode for 4 min and delivers a high energy density of 78.6 Wh.kg⁻¹ at a power density of 1047.5 W kg⁻¹.     

Novel La0.7Sr0.3FeO3 − δ/(La0.5Sr0.5)2CoO4 + δ composite hollow fiber membrane for O2 separation with high CO2 resistance

Recently, the reported Perovskite/Ruddlesden‐Popper composite with significant improvement of oxygen surface kinetics has been adopted into gas separation process. Here, we report a novel La_0.7Sr_0.3FeO_{3 ? δ}/(La_0.5Sr_0.5)₂CoO_{4 + δ} (LSF‐LSC) composite hollow fiber membrane (HFM), which was characterized by X‐ray diffraction (XRD), scanning electron microscope (SEM), and thermal expansion test, etc. The O₂ permeation test results indicated that, under sweeping gas of pure He (100 mL min^?1), the composite HFM exhibited the superior O₂ permeability (0.72 mL min^?1 cm^?2) at the temperature of 950^°C with respect to the single La_0.7Sr_0.3FeO_{3 ? δ} (LSF) membrane, acid‐etched membrane, and (La_0.5Sr_0.5)₂CoO_{4 + δ} (LSC)‐coated membrane. Moreover, the composite membrane exhibited high CO₂ tolerance as well as phase stability. The generation of hetero‐interface between Ruddlesden‐Popper phase and perovskite phase could be responsible for the improvement of the oxygen transportation over the fabricated composite membrane.     

Preparation of La0.75Sr0.25Cr0.5Mn0.5O3−δ fine powders by carbonate coprecipitation for solid oxide fuel cells

A range of La_0.75Sr_0.25Cr_0.5Mn_0.5O_3−δ (LSCM) powders is prepared by the carbonate coprecipitation method for use as anodes in solid oxide fuel cells. The supersaturation ratio (R = [(NH₄)₂CO₃]/([La³⁺] + [Sr²⁺] + [Cr³⁺] + [Mn²⁺])) during the coprecipitation determines the relative compositions of La, Sr, Cr, and Mn. The composition of the precursor approaches the stoichiometric one at the supersaturation range of 4 ≤ R ≤ 12.5, whereas Sr and Mn components are deficient at R < 4 and excessive at R = 25. The fine and phase-pure LSCM powders are prepared by heat treatment at very low temperature (1000 °C) at R = 7.5 and 12.5. By contrast, the solid-state reaction requires a higher heat-treatment temperature (1400 °C). The catalytic activity of the LSCM electrodes is enhanced by using carbonate-derived powders to manipulate the electrode microstructures.     

Fabrication of ultrafine Gd2O3 nanoparticles/carbon aerogel composite as immobilization host for cathode for lithium‐sulfur batteries

Carbon aerogel (CA), possessing abundant pore structures and excellent electrical conductivity, have been utilized as conductive sulfur hosts for lithium‐sulfur (Li‐S) batteries. However, a serious shuttle effect resulted from polysulfide ions has not been effectively suppressed yet due to the weak absorption nature of CA, resulting in rapid decay of capacity as the cycle number increases. Herein, ultrafine (~3 nm) gadolinium oxide (Gd₂O₃) nanoparticles (with upper redox potential of ~ 1.58 V versus Li⁺/Li) are uniformly in‐situ integrated with CA through directly sol‐gel polymerization and high‐temperature carbonization. The Gd₂O₃ modified CA composites (named as Gdx‐CA, where x means molar ratio of Gd₂O₃ nanoparticles to carbon) are incorporated with S. Then, the products (S/Gdx‐CA) are acted as sulfur host materials for Li‐S batteries. The results demonstrate that adding ultrafine Gd₂O₃ nanoparticles can dramatically improve the electrochemical properties of the composite cathodes. The S/Gd2‐CA electrode (loading with 58.9 wt% of S) possesses the best electrochemical properties, including a high initial capacity of 1210 mAh g^?1 and a relatively high capacity of 555 mAh g^?1 after 50 cycles at 0.1 C. It is noteworthy that the performance of long‐term cycle (350 cycles) for the S/Gd2‐CA (317 mAh g^?1 after 100 cycles and 233 mAh g^?1 after 350 cycles at 1 C) is improved significantly than that of S/CA (150 mAh g^?1 after 150 cycles at 1 C). Overall, the enhancement of electrochemical performances can be due to the strong polar nature of the ultrafine Gd₂O₃ nanoparticles, which provide strong adsorption sites to immobilize S and polysulfide. Furthermore, the Gd₂O₃ nanoparticles present a catalytic effect. Our research suggests that adding Gd₂O₃ nanoparticles into S/CA composite cathode is an effective and novelty method for improving the electrochemical performances of Li‐S batteries.     

A novel organic/inorganic composite solid electrolyte with functionalized layers for improved room‐temperature rate performance of solid‐state lithium battery

High ionic conductivity at room temperature (RT) and good ion transport capability at electrode/electrolyte interface are fundamental requirements for high‐rate solid‐state lithium batteries (SSBs). In this work, we designed a poly (propylene carbonate) (PPC)‐based organic/inorganic composite solid electrolyte (CSE) membrane with high filling of tantalum‐doped lithium lanthanum zirconium oxide (LLZTO) and functionalized layers for enhancing the RT rate performance of SSB. The synergistic effect of LLZTO and interfacial functionalized layers endows the NCM622/CSE/Li battery with high‐rate and cycling performances at RT. The SSB with 20% LLZTO‐filled solid electrolyte shows the initial capacities of 162.0, 148.5 and 130.1 mAh g^?1 at 1C, 2C, and 3C respectively, with retention capacities of 115.6, 104, and 100.6 mAh g^?1 after 150 cycles. This strategy for an organic/inorganic CSE is of great practical significance for the development of high‐rate SSBs.     

Synthesis and electrochemical performance of Na3−xLixV2(PO4)3/C as cathode materials for Li‐ion batteries

Herein, a series of lithium‐sodium hybrid ion Na_3?xLi_xV₂(PO₄)₃/C (x = 2.5, 2.0, 1.5, 1.0, 0.5) as cathode materials are prepared by sol‐gel method. The lithium storage properties of Na_3?xLi_xV₂(PO₄)₃/C reveal that the lithium sodium ratio has a strong influence on material structure and the electrochemical properties. The multiple voltage platforms are observed at charge and discharge curve for the Na_0.5Li_2.5V₂(PO₄)₃ material, as it contains rhombohedral and monoclinic Li₃V₂(PO₄)₃ phases, whereas a single voltage platform can be observed when x is less than 2, which are mixtures of Na₃V₂(PO₄)3 with rhombohedral structure and Li₃V₂(PO₄)₃ with rhombohedral structure. Notably, NaLi₂V₂(PO₄)₃/C prepared by the calcination at 700°C for 8 hours contains a single rhombohedral phase. And when the charging and discharging voltage at the range 2.5 to 4.5 V and current density at 0.5C, NaLi₂V₂(PO₄)₃/C and Na_2.5Li_0.5V₂(PO₄)₃/C are prepared by the pre‐calcination at 400°C for 4 hours and subsequent calcination at 750°C for 8 hours exhibit high first‐cycle specific discharge capacities of 124.8 and 130.0 mAh·g^?1. The capacities are 118.4 and 115.1 mAh·g^?1 after 50 cycles, indicating excellent capacity retention.     

Enhanced coking resistance of Ni cermet anodes for solid oxide fuel cells based on methane on‐cell reforming by a redox‐stable double‐perovskite Sr2MoFeO6‐δ

Carbon deposition on a Ni‐based anode is troublesome for the direct power generation from methane‐based fuels using solid oxide fuel cell. In this paper, a redox‐stable double‐perovskite Sr₂MoFeO_6‐δ (SMFO) is applied as an independent on‐cell reforming catalyst over a Ni‐YSZ anode to improve coking resistance. The morphology, catalytic activity and electrochemical performance for wet methane/coal‐bed gas (CBG) are investigated. A Ni‐YSZ anode supported cell with SMFO generates a high power output of 1.77 W·cm^?2 and exhibits favorable stability operated on wet CH₄ at 800°C. Post‐mortem micro‐structural analyses of cells indicate the cell operated on CBG shows coking probably due to the heavy carbon compounds in CBG.     

The role of Al2Ca and Al2(Sm,Ca,La) particles in the microstructures and electrochemical discharge performance of as‐extruded Mg‐3wt.%Al‐1wt.%Zn‐based alloys for primary Mg‐air batteries

In this work, the role of Al₂Ca and Al₂(Sm,Ca,La) particles in the microstructures and electrochemical discharge performance of the as‐extruded Mg‐3wt.%Al‐1wt.%Zn‐based alloys has been reported and discussed for the anode design of Mg‐air batteries. The Al₂Ca and Al₂(Sm,Ca,La) particles strongly refine the grains of the as‐extruded AZ31 alloy from 9.1 ± 4.1 μm down to 5.1 ± 3.3 μm. The Al₂Ca and Al₂(Sm,Ca,La) particles increase the outputting cell voltage and discharge capacity of the modified AZ31 alloy. The AZ31‐Ca alloy exhibits the highest discharge capacity and anodic efficiency of 1153 mAh/g and 52.5%, respectively, at 10 mA/cm². The promoted discharge performance should be mainly attributed to the grain refinement (improving the corrosion resistance) and fine Al₂Ca phase throughout the matrix (beneficial for uniform dissolution of Mg phase). Additional Al₂(Sm,Ca,La) cubic particles further stimulate the anodic kinetics and aggravate the local dissolution of Mg phase near around, resulting in the deterioration of discharge performance.     

Promotion on electrochemical performance of Ba‐deficient Ba1 − xBi0.05Co0.8Nb0.15O3 − δ cathode for intermediate temperature solid oxide fuel cells

Reducing the operating temperature is the developing trend for solid oxide fuel cells. The key is to develop the cathode with high electrocatalytic activity for oxygen reduction reaction operated at reduced temperatures. Ba‐deficient Ba_1 ? xBi_0.05Co_0.8Nb_0.15O_3 ? δ (Ba_1 ? xBCN, 0 ≤ x ≤ 0.10) are synthesized by solid‐state reaction method and evaluated as novel cathodes for intermediate‐temperature solid oxide fuel cells. Ba_1 ? xBCN is preserved to primitive cubic perovskite phase and meets the compatibility requirement with gadolinium doped ceria oxide (GDC) electrolyte at 950°C. Though the Ba deficiency distorts the cell symmetry, it improves the charge transfer steps rapidly, ascribing to the improvement of oxygen vacancy concentration. The polarization resistance of Ba_0.95BCN is as low as 0.056 Ω cm² in air at 700°C. The peak power density of the single cell with this cathode is as high as 1.41 W cm^?2 at 750°C with wet H₂ as fuel and air as oxidant, indicating the great potential for enhanced performance of Co‐based cathodes with A‐site deficiency.     

Achieving high performance for aluminum stabilized Li7La3Zr2O12 solid electrolytes for all solid‐state Li‐ion batteries: A thermodynamic point of view

For the solid‐state reaction synthesis of Al containing Li₇La₃Zr₂O₁₂, various precursors have been used. Since there is a lack of general agreement for choosing precursors, a quantitative approach to build a consensus is required. In this study, a thermodynamic point of view for selecting the precursors in the field of Li₇La₃Zr₂O₁₂ synthesis was covered according to the Gibbs free energy and enthalpy change of precursors' decomposition reactions. In terms of Gibbs free energy change calculations, LiOH, La(OH)₃, and Al(OH)₃ were favorable whereas, LiOH, La₂O₃, and Al(OH)₃ were the preferred precursors for the enthalpy change calculations. Pellets prepared by using the favored precursors calculated from enthalpy change showed improved densification, higher ionic conductivity (2.11 × 10^?4 S/cm), and lower activation energy (0.23 eV) compared with Gibbs free energy change. As a thermodynamically favored aluminum precursor, Al(OH)₃ was discussed in the present study and hinders the ionic conductivity in comparison to Al₂O₃.