Charge Storage Performance Research Articles

Polymerization of redox-active alizarin in biomass porous carbon with enhanced cycling stability for supercapacitor

Redox-active organic molecules have optimistic application prospects in energy storage due to their high theoretical capacitance, designable electrochemical activity and environmental friendliness. However, low conductivity and solubility in electrolyte severely hinder their redox activity. Here, alizarin molecules containing carbonyl and phenolic hydroxyl are encapsulated in biomass-derived porous carbon, and stable alizarin polymers are further grown on porous carbon substrate by electrochemical polymerization. Porous carbon as conductive network can improve electron transport properties, and provide suitable accommodation environment for confinement and polymerization of alizarin. The electrochemical polymerization strategy on carbon substrate allows alizarin to be connected by rigid C-O-C bond, which inhibits the dissolution of organic monomers while maintaining redox activity. The optimized polyalizarin/porous carbon composite (PAZ/PC-0.5) exhibits superior charge storage performance, with a specific capacitance of 355.8 F g−1 at 1 A g−1 and 220.8 F g−1 at high current density of 30 A g−1. Moreover, PAZ/PC electrode has more durable long-term charge-discharge stability (capacitance retention is 98 % after 10,000 charge and discharge cycles). The assembled symmetrical supercapacitor exhibits excellent energy-power characteristics (21.4 Wh kg−1 at 700 W kg−1) and durable cycle stability. This work sheds light on the design of stable organic electrode towards high-performance supercapacitor.

Modulation on interfacial states for the improved charge storage performance in HfO2 matrix embedded CoO nanoparticles-based memory capacitors

Modulation on interfacial states for the improved charge storage performance in HfO2 matrix embedded CoO nanoparticles-based memory capacitors

High-performance α-Fe2O3 nano cubes as anode for supercapacitors

Abundant availability, high theoretical specific capacitance and low cost of transition metal oxides such as iron oxides, make them attractive as electrode materials for energy storage. In order to achieve improved performance, high conductivity, shorter ion-diffusion path, and faster ion accessibility, rational design of morphology of electrode material is highly desirable. We have successfully synthesized mesoporous α-Fe2O3 nanocubes to achieve high specific capacitance and better retention. The as-prepared and annealed α-Fe2O3 nanocubes show high reversible redox activity along with good thermodynamic stability. These nanostructure give rise to high specific capacitance and ~90 % of the capacitance can be retained even after 1000 redox cycles, suggesting good cyclic stability. The electrochemical performance of mesoporous α-Fe2O3 nanocubes is attributed to the morphological features, which results in efficient K+ ion transport into the pores. A two electrode α-Fe2O3//NiO device is fabricated, which shows excellent power and energy density of ∼627 W/kg and ∼23.32 Wh/kg, respectively. Our work demonstrates that 3D nanoporous α-Fe2O3 electrodes forms promising material system as anode for improved charge storage performance.

In-situ synthesis AgO/AgNPs composite as binder-free cathode for high-performance aqueous AgO-Al batteries

Aqueous AgO-Al batteries are promising systems due to their ultrahigh specific capacity, energy density, and stable output voltage. However, they still suffer from the low utilization and sluggish kinetics of the cathode. In this study, the binder-free AgO/AgNPs composites were synthesized in-situ using a simple electrodeposition method. Due to the excellent conductivity and rich mesoporous structure of AgO/AgNPs materials, the electron and ion transfer kinetics were enhanced, thereby improving the charge storage performance of the electrode. As expected, the AgO-Al battery with the optimized AgO/AgNPs composite cathode demonstrated excellent rate performance, achieving a high discharge capacity of 325.1 mAh g−1, and a stable operating voltage platform of 1.55 V at the current density of 1000 mA cm−2. The maximum energy and power density were 687 Wh kg−1 and 6.2 kW kg−1, respectively. This work presents an effective strategy for designing high-performance AgO electrode materials for AgO-Al batteries.

A Flexible Asymmetric Supercapacitor with High-Performance and Long-Lifetime: Fabrication of Nanoworm-Like-Structured Electrodes Based on Polypyrrole-Thiosemicarbazone Complex.

A thiosemicarbazone-based iron(III) complex is prepared and used in the preparation of a supercapacitor electrode material. This electrode is produced by a solvothermal reaction of polypyrrole and the complex on carbon felt. The characterization of the complex and material is carried out using UV-vis, elemental analysis, FT-IR, XRD, BET, and TGA methods, and the surface morphology is examined using SEM technique. Because the interaction of electrode and electrolyte is of great importance in energy storage systems, as the surface area and pore volume increase, electrode ions at the electrode/electrolyte interface leak to the inner surfaces and interact with the larger surface area, which increases the charge storage performance. The electrode material, nano-worm structure, reached the highest specific capacitance value of 764.6 F g-1 at 5 mV s-1. Compared to the capacitance value of polypyrrole in its pure form, it is observed to exhibit an 187.2% increase. The highest specific capacitance value of the asymmetric supercapacitor (ASC) formed with a graphite electrode is 318.1 F g-1 at the current density of 1 Ag-1. Moreover, ASC reached a wide working potential of 1.8 V in an aqueous electrolyte and exhibited ultra-long cycle life (112%), maintaining its stability after 10000 cycles.

Simultaneously Enhanced Low Temperature Li+ Transport Kinetics and Crystal Stability of Nb1.94Mo0.06O5@C Anode Induced by Distorted NbO6 Octahedron

AbstractThe electrochemical performances of lithium‐ion batteries (LIBs) will be significantly degraded under low‐temperature conditions, which restricts their wide application in cold environments. Herein, the low‐temperature transport kinetics of a novel Nb1.94Mo0.06O5@C nanocomposite anode is accelerated greatly via engineering the microstructure and NbO6 octahedron. The detailed crystallographic features are characterized by using synchrotron radiation, spherical electron microscope, and density functional theory simulation methods. Both experimental and simulation analysis suggest that Mo6+ preferentially replaces Nb5+ in the regular octahedral location and distorts the NbO6 octahedron, resulting in a widened c‐axis spacing and a lowered ion diffusion barrier. Coupled with the enhanced electronic conductivity derived from surface carbon layer, Nb1.94Mo0.06O5@C anode exhibits an enhanced charge transfer process, improved Li+ diffusion kinetics, pronounced pseudo‐capacitance process, and excellent low temperature capacity. Furthermore, in situ X‐ray diffraction and ex situ electron microscope elucidate that the structural evolution of Nb1.94Mo0.06O5@C is highly reversible, unveiling its excellent cycling stability. The full cell assembled with LiNi0.6Co0.2Mn0.2O2 cathode demonstrates excellent practicality. This study reveals the critical role of distorting NbO6 octahedron and expanding crystal spacing in facilitating rapid Li+ diffusion and enhancing charge storage performance of Nb2O5 at low temperatures.

V2O5-MnO2 nanocomposites as an efficient electrode material for high-performance aqueous supercapacitors

Redox-active supercapacitors are very interesting due to their high energy density (>25 Wh kg−1 at device level) and redox charge storage mechanism. In this work, V2O5-MnO2 nanocomposites are synthesized by a scalable hydrothermal approach. MnO2 in V2O5 provides better structural stability with reasonable electrochemical performance, in which V2O5 enhances the cyclic stability and rate capabilities. The V2O5-MnO2 -based electrodes deliver a specific capacitance of 266 F g−1 at 0.5 A g−1 and are stable up to 6500 cycles with 97 % capacitance retention at 5 A g−1. The kinetic study depicts that composite electrodes have a 64 % diffusive and 36 % capacitive charge storage contribution to the overall charge storage at 1 mV s−1. In symmetric full cells, the composite materials show a wide active potential window of 2.5 V and retain 83 % capacitance after 10000 continuous GCD cycles at an applied current density of 2 A g−1. The promising charge storage performance is due to a suitable conducting matrix and the effective coating of MnO2 nanoparticles over the unique V2O5 niddle shape (two-dimensional) micro-rods.

Improving Electrochemical Performance in Planar On-Chip Zn-ion Micro-Batteries via Interlayer Strategies.

The imperative development of planar on-chip micro-batteries featuring high-capacity electrodes and environmentally safer, cost-effective, and stable systems is crucial for powering forthcoming miniaturized systems-on-chip smart devices. However, research in the area of high-stability micro-batteries is limited due to the complex fabrication process, the stability of micro-electrodes during cycling, and the challenge of maintaining higher capacity within a limited device footprint. In response to this need, this study focuses on providing highly stable and high-capacity micro-electrodes. This involves adding a PEDOT layer between the electrode material and the current collector, applied within a planar polyaniline cathode and zinc anode device structure to enhance charge storage performance. This straightforward strategy not only improves device stability over long-term cycling and reduces charge transfer resistance but also increases charge storage capacities from 17.64 to 19.75 µAhcm- 2 at 0.1 mAcm- 2. Consequently, the Zn-ion micro-batteries achievenotable peak areal energy and power of 18.82 µWhcm- 2 and 4.37 mWcm- 2, respectively. This work proposes an effective strategy to enhance the electrochemical performance of planar micro-batteries, a critical advancement for the development of advanced portable electronics.

Breaking barriers of CeO2 in energy storage: Hydrothermal energized preparation of mesoporous carbon added CeO2 nanohybrids as supercapacitor electrodes

Inspired by the excellent physio-chemical properties of nano-sized materials, this study details the hydrothermal preparation and electrochemical characterization of mesoporous carbon added CeO2 nanostructures towards the energy storage applications. Cubic CeO2 is observed for the crystal structure and phase of the prepared materials. The formation of nano-sized (∼ 7 nm) quasi spherical-like structure is found from the TEM analysis and it is mainly ascribed to the combined effect of mesoporous carbon and hydrothermal treatment. The charge storage performance of the prepared composites is examined using three-electrode mode. The capacitive behaviour of mesoporous carbon is additionally supported for electrochemical performance in addition to the battery-like behavior of the CeO2 electrodes resulting in an increase of specific capacity by 102.6 %. Hybrid supercapacitor cell is devised and it could yield a specific energy of 31 W h kg–1 (562 W kg–1) and retain 81 % capacity after 3000 continuous charge discharge cycles. With this efficient composite, the future of energy storage may pave the way for more sustainable and powerful energy solutions.

One-step pulsed laser deposition of carbon/metal oxynitride composites for supercapacitor application

Abstract Advanced material composite of nanocarbons and metal-based materials provides a synergistic effect to obtain excellent electrochemical charge-storage performance and other properties. Herein, 3D porous carbon-metal oxynitride nanocomposites with tunable carbon/metal and oxygen/nitrogen ratio are synthesized uniquely by simultaneous ablation from two different targets by single-step pulsed laser deposition at room temperature. Co-ablation of titanium and vanadium nitride targets together with graphite allowed us to synthesize carbon-metal oxynitride porous nanocomposite and exploit them as a binder-free thin film supercapacitor electrode in aqueous electrolyte. We show that the elemental composition ratio and hence the structural properties can be tuned by selecting target configuration and by manipulating the ablation position. We investigate how this tuning capability impacts their charge-storage performances. We anticipate the utilization of as-synthesized various composites in a single PLD production run as next-generation active materials for flexible energy storage and optoelectronic applications.

Mn-deficient ZnMn2O4/Zn0.5Mn0.5Fe2O4 cathode for enhancing structural reversibility and stability of zinc-ion batteries

Aqueous zinc-ion batteries have surfaced as a viable energy storage technology due to their safety, eco-friendliness, and cost-effectiveness. Binary zinc manganite oxide (ZnMn2O4 or ZMO) stands out as the potential cathode material owing to its considerable theoretical capacity and high operating voltage. However, high electrostatic repulsion of Zn2+ ions within ZMO leads to sluggish diffusion and poor reversibility of Zn2+ ions insertion/extraction that can reduce charge storage and overall cycling performance. This study addresses this challenge by introducing FeCl3 during the synthesis to form ZMO/Zn0.5Mn0.5Fe2O4 (ZMFO) cathode material. This cathode features Mn-deficient structures, which can reduce the electrostatic repulsion via low Mn occupancies and lattice parameters enlargement, thus facilitating Zn2+ ions diffusion. Ex-situ X-ray diffraction analyses further show that the cathode is able to maintain good structural reversibility during the charge-discharge cycles. Additionally, the ZMO/ZMFO cathode exhibits smaller particle sizes than pristine ZMO, providing a wider surface area. The presence of ZMFO with a large unit cell volume can also enhance Zn storage capacity and accelerate Zn2+ ions kinetics. Highlighting those advantages, aqueous zinc-ion batteries with ZMO/ZMFO cathode show a capacity of ~230 mAh g−1 at 0.05 A g−1 and retain 99 % of its initial capacity at 0.2 A g−1 after 200 cycles of charge-discharge.

Advanced Porous Gold-PANI Micro-Electrodes for High-Performance On-Chip Micro-Supercapacitors.

The downsizing of microscale energy storage devices is crucial for powering modern on-chip technologies by miniaturizing electronic components. Developing high-performance microscale energy devices, such as micro-supercapacitors, is essential through processing smart electrodes for on-chip structures. In this context, we introduce porous gold (Au) interdigitated electrodes (IDEs) as current collectors for micro-supercapacitors, using polyaniline as the active material. These porous Au IDE-based symmetric micro-supercapacitors (P-SMSCs) show a remarkable enhancement in charge storage performance, with a 187% increase in areal capacitance at 2.5 mA compared to conventional flat Au IDE-based devices, despite identical active material loading times. Our P-SMSCs achieve an areal capacitance of 60 mF/cm2, a peak areal energy density of 5.44 μWh/cm2, and an areal power of 2778 μW/cm2, surpassing most reported SMSCs. This study advances high-performance SMSCs by developing highly porous microscale planar current collectors, optimizing microelectrode use, and maximizing capacity within a compact footprint.

Facile and scalable fabrication of flexible microsupercapacitor based on boron modified 2D/2D 1 T MoS2/MXene hybrids

Micro-supercapacitors (MSCs) with outstanding flexibility and electrochemical performance are critical for portable and miniaturized electronics. This study utilizes the potential utilization of Boron-modified MoS2/MXene heterostructure for fabricating highly efficient and durable microsupercapacitors. The Boron incorporation and hybrid formation significantly enhance the electrochemical performance of 1 T MoS2 and MXene (Ti3C2Tx) by activating their basal plane. The boron modified MoS2/Ti3C2Tx(B-1 T MoS2/Ti3C2Tx_) demonstrates excellent energy storage performance with a capacitance of around 420 Fg−1 in two-electrode system. Laser scribed graphene (LSG), chosen for its superior wettability, serves as the current collector facilitating the development of these MSC based on B-1 T MoS2/Ti3C2Tx. The resulting MSC demonstrates a high areal capacitance of nearly 72.31 mF/cm2 and excellent stability over 10,000 cycles. Density functional theory (DFT) simulations support these findings, indicating that hybridization with Ti3C2Tx and B substitution enhances the conductivity of the 1 T-MoS2 system. The quantum capacitance of B-substituted hybrid system surpasses that of the pristine material, validating the experimental observations of enhanced charge storage performance.

Planar Zn-Ion Microcapacitors with High-Capacity Activated Carbon Anode and VO2 (B) Cathode.

The downsizing of microscale energy storage devices plays a crucial role in powering modern emerging devices. Therefore, the scientific focus on developing high-performance microdevices, balancing energy density and power density, becomes essential. In this context, we explore an advanced Microplotter technique to fabricate hybrid planar Zn-ion microcapacitors (ZIMCs) that exhibit dual charge storage characteristics, with an electrical double layer capacitor type activated carbon anode and a battery type VO2 (B) cathode, aiming to achieve energy density surpassing supercapacitors and power density exceeding batteries. Effective loading of VO2 (B) cathode electrode materials combined with activated carbon anode onto confined planar microelectrodes not only provides reversible Zn2+ storage performance but also mitigates dendrite formation. This not only results in superior charge storage performance, including areal energies of 2.34 μWh/cm2 (at 74.76 μW/cm2) and 0.94 μWh/cm2 (at 753.12 μW/cm2), exceeding performance of zinc nanoparticle anode and activated carbon cathode based ZIMCs, but also ensures stable capacity retention of 87% even after 1000 cycles and free from any unwanted dendrites. Consequently, this approach is directed toward the development of high-performance ZIMCs by exploring high-capacity materials for efficient utilization on microelectrodes and achieving maximum possible capacities within the constraints of the limited device footprint.

Spinel nickel ferrite (NiFe2O4) materials synthesized via spray-pyrolysis for electrochemical supercapacitor application

To explore potential applications of NiFe2O4-based supercapacitors in various energy storage systems, including portable electronic devices, electric vehicles, and grid energy storage, highlighting the advantages and challenges of using NiFe2O4 in these applications. To identify and propose future research directions for further improving the performance of NiFe2O4 supercapacitors. In the study focuses on optimizing concentration of synthesis to achieve desirable structural and electrochemical properties, characterizing the synthesized materials, and assessing their specific capacitance, energy density, power density, cycle stability, and rate capability. The different molar precursor solutions were utilized for the formation of NiFe2O4 thin films by using the cost-effective spray pyrolysis technique. The impact of different molarities on the structural, morphological, elemental, optical, and charge storage performance of NiFe2O4 thin films has been studied. In the XRD studies identified the cubic crystalline structure with Fd-3 m space group symmetry of NiFe2O4. The FE-SEM shows the grain-like surface morphology of NiFe2O4 thin films. The EDAX study reveals that NiFe2O4 thin films were stoichiometric. Bandgap energy values of the thin films were observed in the range of 1.97 to 2.2 eV with allowed direct band gap transitions. The maximum specific capacitance for NiFe2O4 thin film was found to be 707 Fg−1 at 2 mVs−1 with the wider potential window of − 0.8 to + 1 .6 V in 1 M KOH aqueous electrolyte. GCD study confirms the pseudocapacitive behavior of NiFe2O4 thin films. The maximum specific energy and specific power were found to be 83.88 WhKg−1 and 5.294 KWkg−1 at a current density of 0.002 Ag−1. Such as spinel ferrite NiFe2O4 thin film electrodes as an excellent candidate material for electrochemical supercapacitor applications.

Tailoring Multi-Metallic Phosphide Heterostructures for High Energy Density Hybrid Supercapacitors

Transition metal phosphides have emerged as a cost effective and resourceful materials that gained extreme attention in the energy sector due to deliverance of high capacitance as well as good redox ability comparable with other oxide materials, which makes them budding material for next-generation electrochemical energy storage (EES) systems. Thanks to the metal-phosphorous chelate in the structure which probes the storage mechanism in EES systems. The electrochemical performance can be enhanced by combining multi-metals in the phosphide to collectively utilize the individual features which will increase the charge efficiency. Herein, tri-metallic Ni-Co-Mo-P electrode on Ni-foam substrate was prepared using simplified hydrothermal-calcination-phosphorylation process. The introduction of Mo enhances the electronic conductivity in the trimetallic phosphide electrode which is reflected in the increased electrochemical performance in comparison to NiCoP electrode. Although, Ni-Co-Mo-P electrode delivers superior activity compared to oxide and precursor electrode, however, the capacity retention till 10 A/g was observed to be 60%, which is higher than other prepared electrodes. The enhanced charge storage performance can be attributed to increased number of electrochemical surface area facilitating more redox reactions. The asymmetric supercapacitor device is constructed with Ni-Co-Mo-P // rGO that delivered high energy and power density with satisfactory cyclic capability.

LiF modified hard carbon from date seeds as an anode material for enhanced low-temperature lithium-ion batteries

The performance of traditional Li-ion batteries deteriorates when operating at sub-zero temperatures mainly due to the slow diffusion of Li-ions in commercial negative electrode materials. Various alternative anodes have been explored, but complex fabrication methods hinder practical implementation. This work proposes a cost-effective anode material, a porous structured nitrogen-doped hard carbon synthesized from date seeds with further LiF modification to achieve an artificial LiF-rich solid electrolyte interphase (SEI) layer. The resulting anode material showcases promising characteristics, achieving a specific capacity of 525 mAh g−1 after 50 cycles at room temperature. Furthermore, it maintains a substantial capacity of 280 mAh g−1 after 100 cycles at −20 °C. Notably, even when subjected to a high current of 2C at −20 °C, the electrode still provides a remarkable capacity of 72 mAh g−1 after 500 cycles. The outstanding charge storage performance at low temperatures is attributed to the predominance of capacitance-controlled charge storage mechanisms in the prepared anode. Post-mortem analysis confirms structural stability and formation of a uniform LiF-rich SEI layer. This novel approach presents a practical solution to the difficulties encountered by LIBs in cold environments, paving the way for improved battery performance and longevity.

On the atomic structure of monolayer V4C3Tz and the study of charge storage processes in an acidic electrolyte using SPEIS and in-situ X-ray absorption spectroscopy

Monolayer V4C3Tz is synthesized and its atomic structure is studied using high-end transmission electron microscopy. X-Ray diffraction reveals key 3D to 2D crystal transformations as a V4AlC3 crystal is transformed into V4C3Tz in synthesis processes. The charge storage properties of V4C3Tz film electrodes are investigated for supercapacitor applications in 3 M H2SO4. V4C3Tz film electrodes shows an excellent capacitance of up to 469.6 F g−1 and 845.7 F cm−3, rate performance up to 30 A g−1 and cycling stability up to 10,000 cycles. A combination of electrochemical kinetics/mass transport models, staircase potentio-electrochemical impedance spectroscopy and in situ X-Ray absorption spectroscopy reveals, for the first time for this MXene, the underlying charge storage mechanisms, consisting of double layer capacitance, pseudocapacitance and a minor contribution from mass transport-controlled processes. The latter two implying a outstanding redox activity superior to Ti-based MXenes. The stability in standard environments, mechanical flexibility and the demonstrated excellent charge storage performance of V4C3Tz makes it one of the best candidates for supercapacitor applications, especially in miniaturized devices.

Facile synthesis, enhanced annealing-structural investigation and supercapacitive potentials of NiFe2O4 spinel nanopowder

Herein, we examined and optimized the influence of annealing temperature on microstructural and electrochemical charge storage properties of spinel NiFe2O4 nanopowder synthesized from a simple one-pot sol-gel route. Microstructural techniques encompassing Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, x-ray diffractometry, and Fourier transform infra-red spectroscopy indicate the resulting powder are composed of spinel NiFe2O4 nanoparticle with metal oxygen vibration, crystal properties and lattice strain, all dependent on annealing temperature. Electrochemical charge storage performance of the electrode fabricated from the synthesized material were investigated with the aid of cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy measurements. The obtained results showed that the charge storage performance and rate capability of NiFe2O4 electrode is dependent on the annealing temperature. The study also showed that the electrode from the material annealed at 400 °C demonstrated optimum electrochemical charge storage performance having exhibited optimum specific capacitance and capacity values of 1128 Fg−1 and 58 mAh g−1 at 5 mVs−1 scan rate and 0.5 Ag−1 current density, respectively. The electrode EIS fitted equivalent circuit values were also found dependent on annealing temperature indicating the charge transfer process and rate capability of spinel NiFe2O4 nano-powder can be tailored by simply varying the annealing temperature. The study demonstrates cheap route by which spinel NiFe2O4 powder can be prepared. It also unveils the effect annealing temperature on the microstructural build-up and electrochemical charge storage performance of the material.

FeNP@MIL-101(Fe)-Based Carbon Nanotube Composite for Energy Storage Applications.

Metal-organic frameworks (MOFs) are of great interest for energy applications due to their high porosity, high charge storage capacity, and large number of active redox sites. It is important to enhance the performance of metal-organic frameworks through modification in order to increase their potential applications. Unique Fe nanoparticle (NP) in the Materials of Institute Lavoisier (MIL) series embedded in the carbon nanotube (CNT), FeNP@MIL-101(Fe)/CNT-based, nanocomposites have been synthesized using suitable hierarchical micromesoporous structures. These were fabricated by simple and straightforward solvothermal methods, and their electrochemical charge storage performance was investigated. The energy storage application using the FeNP@MIL -101(Fe)/CNT composite as a supercapacitor electrode was implemented for the first time. Various techniques were used to characterize this composite. It has excellent electrochemical properties when used as electrode material in 1 M KOH solution, including a high capacitance of up to 1305 F g-1 at 1 A g-1 and a long cycling stability of 95.7% capacitance retention after 10,000 cycles. Moreover, symmetric two-electrode electrochemical experiments showed that the composite achieved an energy density of 98.65 Wh kg-1 and a power density of 9000 W kg-1, The combination of microporous and mesoporous structures, increased surface area, and higher electrical conductivity are the main reasons for the high performance. The integration of FeNP@MIL-101(Fe) with the CNT creates new ion diffusion pathways, improves the hierarchical pore properties, and exposes the FeNP@MIL-101(Fe) cluster to more redox active sites, which improves the charge storage performance.