Delafossite CuCrO2 nanoparticles as possible electrode material for electrochemical supercapacitor

Delafossites are popularly known materials for thermoelectric and electrochemical device applications due to their layered structural features. In this paper, delafossite CuCrO₂ nanoparticles (NPs) have been synthesized using a simple chemical procedure and are investigated as a supercapacitor material. To determine the phases of delafossite CuCrO₂ NPs, the morphological and phase formation experiments were conducted using diffraction patterns and microscopic analysis. The cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) studies were performed to evaluate the supercapacitative behavior of delafossite CuCrO₂ NPs. As prepared delafossite CuCrO₂ NPs based electrode showed an outstanding electrochemical property as compared to annealed delafossite CuCrO₂ NPs at 300–500 °C. A good specific capacitance of ～464.7 Fg^-1 at 0.01 Vs^-1 was found for the fabricated supercapacitor using non-annealed delafossite CuCrO₂ NPs based electrode, which was further validated by GCD results. The electrochemical supercapacitor fabricated with both non-annealed and annealed delafossite CuCrO₂ NPs displayed considerably the outstanding cycling stability by maintaining up to ～88% after 5000 cycles. This work sets the pace for a new and efficient method of preparing delafossite CuCrO₂ for high-performance electrochemical supercapacitors.     

Manganese dioxide/cobalt tungstate/ nitrogen-doped carbon nano-onions nanocomposite as new supercapacitor electrode

Application of the electrochemical supercapacitors is one way to store energy, which has widely attracted scientists worldwide. In this regard, in the present work, a triple-segment nanocomposite of manganese dioxide, cobalt tungstate, and nitrogen-doped carbon nano onions (MnO₂/CoWO₄/NCNO) was prepared based on a facile chemical method. The synthesized nanomaterials were analyzed by X-ray diffraction, infrared, as well as scanning electron microscopy. The supercapacitive properties of the synthesized nanomaterials were checked using electrochemical impedance spectroscopy, galvanostatic charge-discharge and voltammetry methods. The value of specific capacitor for the prepared electrodes containing MnO₂, CoWO₄, NCNO, MnO₂/CoWO₄, and MnO₂/CoWO₄/NCNO in an alkaline electrolyte (KOH: 6 M) at a current density of 2 A/g have obtained as 209, 97, 170, 413, and 536 F/g, respectively (Three-electrode system). Also, the retained stability of the MnO₂/CoWO₄/NCNO electrode after 3000 consecutive charges and discharges was 96%. The supercapacitive behavior and excellent capacitance of the MnO₂/CoWO₄/NCNO electrode was due to the synergistic effects of MnO₂, CoWO₄, and NCNO. A two-electrode symmetric supercapacitor assembled device is fabricated and exhibits a high specific capacitance of 1036 F/g at 2 A/g. It shows that the MnO₂/CoWO₄/NCNO composite provides potential applications in energy storage.     

Ni@NiCo2O4 core/shells composite as electrode material for supercapacitor

A novel Ni@NiCo₂O₄ core/shells structure consisting of the Ni microspheres skeletons and nanosheet-like NiCo₂O₄ skins was designed and investigated as the electrochemical electrode for supercapacitor. Due to the unique architecture with Ni microspheres as the highly conductive cores improving the electrical conductivity of electrode and external nanosheet-like NiCo₂O₄ shells as the efficient electrochemical active materials facilitating the contact between the electrode and electrolyte, the as-prepared Ni@NiCo₂O₄ exhibited excellent electrochemical performance with high specific capacity of 597 F g⁻¹ (1 A g⁻¹) as well as remarkable capacitance retention of 96% (3000 cycles). These impressive results pave the way to design high-performance electrode materials for energy storage.     

Fabrication of polypyrrole (PPy)/carbon nanotube (CNT) composite electrode on ceramic fabric for supercapacitor applications

Polypyrrole (PPy)/carbon nanotube (CNT) composite electrodes are fabricated on ceramic fabrics for electrochemical capacitor applications. The CNTs are grown on the ceramic fabrics by the chemical vapor deposition (CVD) method and PPy is subsequently coated on them by chemical polymerization. The large surface area and high conductivity of the CNTs on the porous ceramic fabrics enhance their energy storage capacity. PPy provides not only additional capacitance as an active material, but also enhances the adhesion between the CNTs and ceramic fabrics. Furthermore, PPy acts as a conducting binder for connecting every individual CNT to increase the capacitance. The morphology of the PPy–CNTs on the ceramic fabrics is confirmed by SEM and TEM, and the electrochemical characteristics are investigated by cyclic voltammetry and galvanostatic charge–discharge tests.     

Fabrication of CuFe2O4@g-C3N4@GNPs nanocomposites as anode material for supercapacitor applications

The aim of this study was to synthesize CuFe₂O₄ together with g-C₃N₄ and GNPs in various combinations on the surface of Ni foam for use as anode materials in supercapacitors. The fabricated electrodes were investigated by XRD, FTIR, XPS, BET, SEM and TEM for content and by CV, GCD and EIS analysis for electrochemistry. The characterization results showed that CuFe₂O₄ was successfully synthesized together with g-C₃N₄ and GNPs in a nanosponge-like geometry. The highest value of specific capacitance was found to be 989 mF/cm² at 2 mA measurement in the triple combination. Moreover, the stability of this electrode was measured to be 70% after 1500 cycles at 16 mA, while the energy and power densities were calculated to be 27.8 mWh/cm² and 300 mW/cm², respectively. The EIS results show that the carbon-based component increased the Cs value by decreasing the charge transfer and diffusion resistances of the electrodes. Compared to its counterparts in the literature, its Cs value is quite high, but its stability is low, so it can be used in low-cycle applications.     

Hierarchical architecture of Ti3C2@PDA/NiCo2S4 composite electrode as high-performance supercapacitors

A novel Ti₃C₂@PDA/NiCo₂S₄ composites as high performance supercapacitor electrodes were synthesized by the hydrothermal treatment process. The chemical modification and uniformly coating of Ti₃C₂ surface by polydopamine (PDA) can prevent the structural collapse and over-oxidation of Ti₃C₂ during the hydrothermal synthesis of NiCo₂S₄. Furthermore, the confined-synthesis of smaller NiCo₂S₄ particles between the Ti₃C₂ layers, not only prevent the restacking of Ti₃C₂ that between the adjacent monolayers during cycling, but also afford high surface areas accessible to charge transfer and ion diffusion. Thereby, enhance the electrochemical cycling stability of the Ti₃C₂@PDA/NiCo₂S₄ composite. It is significant to explore how NiCo₂S₄ alters the microstructure, morphology as well as supercapacitors performance of Ti₃C₂ to tune the microstructure and performance of Ti₃C₂ by appropriate hydrothermal synthesis strategy. The experimental results exhibit a prominent improvement in the supercapacitor performance, the gravimetric capacitance of Ti₃C₂@PDA/NiCo₂S₄ composites achieve as high as 495 F g^-1 at 2 mV s^-1, which increase the 10 times as compared to the pristine Ti₃C₂. Furthermore, the cycling stability of the Ti₃C₂@PDA/NiCo₂S₄ composites electrode was enhanced significantly by the hierarchical architecture, and showed exceptional capacitance retention (81.16%) even after 3000 cycles. The dramatic improvement in the supercapacitors performance of Ti₃C₂@PDA/NiCo₂S₄ electrodes is attributed to impressive conductive matrix Ti₃C₂, the effective modification of small size Ni₂Co₂S₄, and the strong interfacial interaction between Ti₃C₂@PDA and NiCo₂S₄. This study demonstrating its attractive application prospect of Ti₃C₂ Mxenes modified with bimetallic sulfide as electrode materials for high-performance supercapacitors.     

Synthesis of reduced graphene oxide/tungsten trioxide nanocomposite electrode for high electrochemical performance

A facile and well-controllable reduced graphene oxide/tungsten trioxide (rGO/WO₃) nanocomposite electrode was successfully synthesized via an electrostatic assembly route at 350 rpm for 24 h. In this study, hexagonal-phase WO₃ (h-WO₃) nanofiber was well distributed on rGO sheets by applying optimal processing parameters. The as-synthesized rGO/WO₃ nanocomposite electrode was compared with pure h-WO₃ electrode. A maximum specific capacitance of 85.7 F g⁻¹ at a current density of 0.7 A g⁻¹ was obtained for the rGO/WO₃ nanocomposite electrode, which showed better electrochemical performance than the WO₃ electrode. The incorporation of WO₃ into rGO could prevent the restacking of rGO and provide favourable surface adsorption sites for intercalation/de-intercalation reactions. The impedance studies demonstrated that the rGO/WO₃ nanocomposite electrode exhibited lower resistance because of the superior conductivity of rGO that improved ion diffusion into the electrode. To evaluate the contribution of WO₃ to the rGO/WO₃ nanocomposite, the influence of mass loading of WO₃ on the capacitance was investigated.     

Highly stable mesoporous CeO2/CeS2 nanocomposite as electrode material with improved supercapacitor electrochemical performance

The performance of a pseudocapacitor electrode relies largely on the conductivity, cyclic stability, specific surface area and the mesoporosity of the nanomaterials. The CeO₂ is highly stable oxide but poor conductor, on the other hand, CeS₂ is highly conductive but its stability is questionable. Herein, we report the synthesis of CeO₂/CeS₂ nanocomposite, and exploit the properties of both the constituent materials and demonstrates that CeO₂/CeS₂ nanocomposite electrode exhibits an improved capacitance and energy density than CeO₂ nanomaterial. It encompasses large number of pores with a mean size of ～17?nm. The mesoporous nature of the CeO₂/CeS₂ nanocomposite electrode increases its activity, rapid diffusion and transportation of ions and facilitates surface-dependent reversible redox reactions. The nanocomposite electrode demonstrates high stability and its specific capacitance increases almost linearly up to 1000 cyclic voltammetry (CV) cycles. At a current density of 1?A/g it achieves a specific capacitance of 420?F/g. These findings evidently suggest the practical use of CeO₂/CeS₂ nanocomposite as electrode material for future supercapacitors.     

Intragranular nanocomposite powders as building blocks for ceramic nanocomposites

A powder-based bottom-up processing scheme is introduced for the production of ceramic nanocomposites. Internal displacement reactions between solid solution powders and metallic reactants proceeding via gaseous intermediates are utilized to generate nanostructured building blocks for the synthesis of ceramic nanocomposites. Subsequent rapid sintering results in ceramic nanocomposites, whose microstructures are inherited from the building blocks. This processing scheme is demonstrated for the production of titanium carbide nanocomposites featuring up to 28 wt.% intragranular tungsten inclusions derived from titanium-tungsten mixed carbide powders. Heat treatment of mixed carbide powders in evacuated ampoules containing titanium sponge and iodine at 1000°C for 24 h resulted in nanocomposite powders featuring tungsten precipitates within titanium carbide grains that were subsequently consolidated via spark plasma sintering at 1300°C for 10 min to produce titanium carbide/metallic tungsten nanocomposites. Transformation of mixed titanium–tungsten carbide powders to titanium carbide/metallic tungsten nanocomposite powders was analyzed via X-ray diffraction. Electron microscopy observations of microstructures pre- and post- sintering showed that the intragranular character of nanocomposite powders can be retained in sintered ceramic nanocomposites. The building block approach demonstrated in this work represents an improved method to make ceramic nanocomposites with majority intragranular character.     

A novel layered manganese oxide/poly(aniline-co-o-anisidine) nanocomposite and its application for electrochemical supercapacitor

A novel layered manganese oxide/poly(aniline-co-o-anisidine) nanocomposite [MnO₂/P(An-co-oAs)] was successfully synthesized by a delamination/reassembling process using P(An-co-oAs) ionomer and layered manganese oxide in aqueous solution. This nanocomposite obtained was then characterized by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), electron microscopy (SEM), and thermogravimetric (TG) analysis. X-ray diffraction and electron microscope analysis showed that the MnO₂/P(An-co-oAs) nanocomposite had a lamellar structure with increasing interlayer spacing. The MnO₂/P(An-co-oAs) nanocomposite exhibited substantially improved conductivity, which was near 100 times greater than that of its pristine MnO₂ (3.5 × 10⁻⁷ S cm⁻¹). The specific capacitance of the MnO₂/P(An-co-oAs) nanocomposite reached 262 F g⁻¹ in 1 M Na₂SO₄ at a current density of 1 A g⁻¹, which was significantly higher than that of either of its two pristine materials [MnO₂ (182 F g⁻¹) or P(An-co-oAs) (127 F g⁻¹)] owing to the synergic effect between the two pristine components. The fabrication mechanism of the nanocomposite was also proposed and discussed in this paper.     

Electrochemical performances of poly(3,4-ethylenedioxythiophene)-NiFe2O4 nanocomposite as electrode for supercapacitor

Poly 3,4-ethylenedioxythiophene (PEDOT)-based NiFe₂O₄ conducting nanocomposites were synthesized and their electrochemical properties were studied in order to find out their suitability as electrode materials for supercapacitor. Nanocrystalline nickel ferrites (5-20 nm) have been synthesized by sol-gel method. Reverse microemulsion polymerization in n-hexane medium for PEDOT nanotube and aqueous miceller dispersion polymerization for bulk PEDOT formation using different surfactants have been adopted. Structural morphology and characterization were studied using XRD, SEM, TEM and IR spectroscopy. Electrochemical performances of these electrode materials were carried out using cyclic voltammetry at different scan rates (2-20 mV/s) and galvanostatic charge-discharge at different constant current densities (0.5-10 mA/cm²) in acetonitrile solvent containing 1 M LiClO₄ electrolyte. Nanocomposite electrode material shows high specific capacitance (251 F/g) in comparison to its constituents viz NiFe₂O₄ (127 F/g) and PEDOT (156 F/g) where morphology of the pore structure plays a significant role over the total surface area. Contribution of pseudocapacitance (C_FS) arising from the redox reactions over the electrical double layer capacitance (C_DL) in the composite materials have also been investigated through the measurement of AC impedance in the frequency range 10 kHz-10 mHz with a potential amplitude of 5 mV. The small attenuation (∼16%) in capacitance of PEDOT-NiFe₂O₄ composite over 500 continuous charging/discharging cycles suggests its excellent electrochemical stability.     

Effect of electrolyte on the supercapacitive behaviour of copper oxide/reduced graphene oxide nanocomposite

Cupric oxide/reduced graphene oxide (CuO/rGO) nanocomposites were synthesized through a chemical reduction method using hydrazine hydrate as the reducing agent. The morphology, elemental composition, and bonding network of the CuO/rGOnanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy respectively. The XRD results reveal lattice spacing and lattice strain from 3.371 to 3.428 Å and 1.05 × 10⁻³to 5.44 × 10⁻³ respectively, with the increasing ratio of rGO: CuO from 1:1 to 1:5. The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS)and galvanostatic charge-discharge (GCD) studyofCuO/rGOas the electrode material showed excellent super-capacitive behavior in H₂SO₄ over Na₂SO₄ electrolytes. Moreover CuO/rGO nanocomposites exhibited better capacitance retention in H₂SO₄(75.69%) compared to Na₂SO₄(12.06%).     

RGO/KMn8O16 composite as supercapacitor electrode with high specific capacitance

Reduced graphene oxide/cryptomelane (RGO/KMn₈O₁₆) composites are successfully synthesized from α-MnO₂ nanorods and GO using a water-bathing precipitation method. The unique structure of KMn₈O₁₆ nanorods, with a length of 2–4 μm, dispersed on the surface of RGO leads to a much enhanced electrical conductivity and ionic transport, finally achieving composites with an improved electrochemical performance. Electrochemical measurement results show a specific capacitance of 222.3 F/g at a current density of 0.2 A/g, much higher than that of the original α-MnO₂. After 500 cycles at 2.0 A/g, the RGO/KMn₈O₁₆ composite electrode still retains 92.6% of its initial specific capacitance. The excellent electrochemical performance and durability observed for this composite electrode suggest its potential application for electrochemical capacitors.     

A novel EDOT–nonylbithiazole–EDOT based comonomer as an active electrode material for supercapacitor applications

A novel EDOT–nonylbithiazole–EDOT based bis(3,4-ethylene-dioxythiophene)-(4,4′-dinonyl-2,2′-bithiazole) comonomer was synthesized and was electrochemically deposited onto carbon fiber electrode as an active electrode material. An electrochemical impedance study on the prepared electrodes is reported in this paper. Capacitive behavior of the carbon fiber microelectrode/poly(3,4-ethylene-dioxythiophene)-(4,4′-dinonyl-2,2′-bithiazole) system was investigated with cyclic voltammetry (CV) experiments and electrochemical impedance spectroscopy. Variation of capacitance values by scan rate and specific capacitance values at different potentials are presented. Specific capacitance value for a galvanostatically prepared polymer film with a charge of 5 C cm⁻² was obtained about 340 mF cm⁻². Effect of the solvent and the deposition charge on the capacitive behavior of the film was investigated using electrochemical impedance spectroscopy. An equivalent circuit model was proposed and the electrochemical impedance data were fitted to find out numerical values of the proposed components. The galvanostatic charge/discharge characteristic of a film was investigated by chronopotentiometry and the morphology of the films electrodeposited at different deposition charges were monitored using FE-SEM.     

Binder-free carbon-coated TiO2@graphene electrode by using copper foam as current collector as a high-performance anode for lithium ion batteries

Anatase TiO₂ is widely used in lithium ion batteries (LIBs) due to its excellent safety and excellent structural stability. However, due to the poor ion and electron transport and low specific capacity (335 mAh g⁻¹) of TiO₂, its application in LIBs is severely limited. For the first time, we report a binder-free, carbon-coated TiO₂@graphene hybrid by using copper foam as current collector (TG-CM) to enhance the ionic and electronic conductivity and increase the discharge specific capacity of the electrode material without adding conductive carbon (such as super P, etc.) and a binder (such as polyvinylidene fluoride (PVDF), etc.). When serving as an anode material for LIBs, TG-CM displays excellent electrochemical performance in the voltage range of 0.01–3.0 V. Moreover, the TG-CM hybrid delivers a high reversible discharge capacity of 687.8 mAh g⁻¹ at 0.15 A g⁻¹. The excellent electrochemical performance of the TG-CM hybrid is attributed to the increased lithium ion diffusion rate due to the introduction of graphene and amorphous carbon layer, and the increased contact area between the active material and electrolyte, and small resistance with copper foam as the current collector without an additional binder (PVDF) and conductivity carbon (super P).     

Preparation and electrochemistry of NiO/SiNW nanocomposite electrodes for electrochemical capacitors

This paper studies nickel oxide/silicon nanowires (NiO/SiNWs) as composite thin films in electrodes for electrochemical capacitors. The SiNWs as backbones were first prepared by chemical etching, and then the Ni/SiNW composite structure was obtained by electroless plating of nickel onto the surface of the SiNWs. Next, the NiO/SiNW nanocomposites were fabricated by annealing Ni/SiNW composites at different temperatures in an oxygen atmosphere. Once the electrodes were constructed, the electrochemical behavior of these electrodes was investigated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). In 2 M KOH solution, the electrode material was found to have novel capacitive characteristics. Finally, when the NiO/SiNW composites were annealed at 400 °C, the maximum specific capacitance value was found to be as high as 681 F g⁻¹ (or 183 F cm⁻³), and the probing of the cycling life indicated that only about 3% of the capacity was lost after 1000 charge/discharge cycles. This study demonstrated that NiO/SiNW composites were the optimal electrode choice for electrochemical capacitors.     

Polyaniline grafted chitosan/GO-CNT/Fe3O4 nanocomposite as a superior electrode material for supercapacitor application

Developing appropriate stable electroactive electrode materials for supercapacitor application is the challenging issue, which attracts enormous attention in recent decades. In this regard, Fe₃O₄ nanoparticles are firstly synthesized on chitosan/graphene oxide-multiwall carbon nanotubes (CS/GM/Fe₃O₄). Then, polyaniline (PANI) is grafted on it via in situ chemical polymerization and named as CS/GM/Fe₃O₄/PANI. The as-prepared nanocomposites are characterized by Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy. The capacitive properties of the electrodes are investigated in a three electrode configuration in 0.5 M Na₂SO₄ electrolyte by various electrochemical techniques. The specific capacitance of CS/GM/Fe₃O₄/PANI electrode is 1513.4 Fg⁻¹ at 4 Ag⁻¹ which is 1.9 times higher than that of CS/GM/Fe₃O₄ (800 Fg⁻¹). Meanwhile, the electrodes exhibit appropriate cycle life along with 99.8% and 93.95% specific capacitance at 100 Ag⁻¹ for chitosan/GO-CNT/Fe₃O₄ and polyaniline grafted chitosan/GO-CNT/Fe₃O₄, respectively.     

Synthesis and characterization of polypyrrole/graphitic carbon nitride/niobium pentoxide nanocomposite for high-performance energy storage applications

Graphitic carbon nitride (GCN) has been employed as a supercapacitor electrode because of its high carbon-to-nitrogen ratio and flexible structure. However, its low surface area and poor conductivity continue to be obstacles for practical usage. GCN's electrochemical characteristics are enhanced by the hybrid structure it forms with polypyrrole and Nb₂O₅. The synthesized polypyrrole (Ppy)/GCN/niobium pentoxide (Nb₂O₅) (Ppy/GCN/Nb₂O₅) nanocomposite electrode was tested for supercapacitance by cyclic voltammetry (CV) and Alternating current impedance techniques in 6 M Potassium hydroxide(KOH) electrolyte. The Ppy/GCN/Nb₂O₅ is linked to a network of agglomerated GCN and Nb₂O₅ nanoparticles with additional spherical shapes. The specific capacitance of Ppy/GCN/Nb₂O₅ was determined to be 1177 Fg⁻¹ at a current density of 5 Ag⁻¹. The Ppy/GCN/Nb₂O₅ electrode in KOH has average specific energy and specific power densities of 33 Wh kg⁻¹ and 2991 W kg⁻¹, respectively. The electrode showed excellent capacitance-retention ability of 97% after 10,000 cycles. The results demonstrate the high stability and efficient performance of the Ppy/GCN/Nb₂O₅ electrode employed in supercapacitors. The performance of the Ppy/GCN/Nb₂O₅ electrode was found to be superior to those reported for other carbon-based materials.     

Rational design of binder-free ZnCo2O4 and Fe2O3 decorated porous 3D Ni as high-performance electrodes for asymmetric supercapacitor

The development of hierarchical, porous film based current collector has created huge interest in the area of energy storage, sensor, and electrocatalysis due to its higher surface area, good electrical conductivity and increased electrode-electrolyte interface. Here, we report a novel method to prepare a hierarchically ramified nanostructured porous thin film as a current collector by dynamic hydrogen bubble template electro-deposition method. At a first time, we report a porous 3D-Ni decorated with ZnCo₂O₄ and Fe₂O₃ by simple, low-cost electrochemical deposition method. The fabricated porous 3D-Ni based electrodes showed an excellent electrochemical property such as high specific capacitance, excellent rate capability, and good cycle stability. The asymmetric solid-state supercapacitor device was fabricated using porous, 3D Ni decorated with ZnCo₂O₄ and Fe₂O₃ as the positive and negative electrodes. The fabricated ZnCo₂O₄//Fe₂O₃ asymmetric device delivered an areal capacitance of 92?mF?cm^?2 at a current density of 0.5?mA?cm^?2 with a maximum areal power density of 3?W?cm^?2 and areal energy density of 28.8?mWh?cm^?2. The higher performances of porous, 3D current collector have a huge potential in the development of high performance supercapacitor.     

Porous Co3O4 nanoplatelets by self-supported formation as electrode material for lithium-ion batteries

In this paper, we have reported a simple and rapid approach for the large-scale synthesis of β-Co(OH)₂ nanoplatelets via the microwave hydrothermal process using potassium hydroxide as mineralizer at 140 °C for 3 h. Calcining the β-Co(OH)₂ nanoplatelets at 350 °C for 2 h, porous Co₃O₄ nanoplatelets with a 3D quasi-single-crystal framework were obtained. The process of converting the β-Co(OH)₂ nanoplatelets into the Co₃O₄ nanoplatelets is a self-supported topotactic transformation, which is easily controlled by varying the calcining temperature. The textural characteristics of Co₃O₄ products have strong positive effects on their electrochemical properties as electrode materials in lithium-ion batteries. The obtained porous Co₃O₄ nanoplatelets exhibit a low initial irreversible loss (18.1%), ultrahigh capacity, and excellent cyclability. For example, a reversible capacity of 900 mAh g⁻¹ can be maintained after 100 cycles.