Charge-discharge Characteristics Research Articles

Инновационные магнитные наноматериалы для улучшения хранения энергии

Background: Finding effective energy storage technologies is crucial for transitioning to sustainable energy systems. Magnetic nanoparticles have emerged as options due to their distinctive magnetic characteristics, which can considerably improve the performance of energy storage systems. Objective: This research aims to investigate innovative magnetic nanoparticles and assess to increase the efficiency and capacity of energy storage systems. The emphasis is on developing materials with optimal magnetic characteristics and incorporating them into current energy storage methods. Methods: Co-precipitation and thermal breakdown were used to create a range of new magnetic nanomaterials. Vibrational sample magnetometry, X-ray diffraction, and cyclic voltammetry were used to determine these materials' magnetic characteristics, structural integrity, and electrochemical performance. Subsequent integration into supercapacitors and lithium-ion batteries was carried out to evaluate energy storage capacity. Results: The synthesized magnetic nanoparticles showed improved magnetic saturation and charge-discharge characteristics compared to standard materials. When used in supercapacitors, they increased capacitance by 20% and improved cycle stability by 25%. Similarly, these nanomaterials improved the energy density of lithium-ion batteries by 15% and increased their longevity by 30%. Conclusion: The unique magnetic nanoparticles created in this work significantly improve the performance of energy storage devices. The increased capacitance, energy density, and operational stability indicate that these materials for future energy storage applications. Further study is required to optimize these materials for commercial application and investigate their scalability and environmental effects.

Unveiling magnetite metal-organic frameworks for asymmetric pseudo-supercapacitor with high energy density and magnetocapacitance

Utilizing innovative techniques for electrode fabrication and incorporating novel energy storage concepts through external stimuli forces is crucial for enhancing the specific capacity and commercial feasibility of energy storage devices. The performance of supercapacitors hinges on both capacitive behavior, which enhances charge-discharge characteristics and power density, and ion-diffusion behavior, which boosts energy density. This study delves into the impact of external magnetic fields on supercapacitor performance by enhancing pseudo-capacitive behavior through a facile redox pathway and promoting the diffusion coefficient of the electrolyte. We presented magneto-electrophoretic deposition (M-EPD) to apply a high-surface-area zeolitic imidazolate framework (ZIF), which serves as a robust binder-free strategy. Specifically, the Fe3O4-ZIF-67 nanocomposite is uniformly supported on ferromagnetic nickel foam (NF) and demonstrates an impressive specific capacitance of 656.7 F g−1 (328.4 C g−1) at 1 A g−1. In addition, coin cell supercapacitors assembled with Fe3O4-ZIF-67/NF as positive and Fe3O4-ZIF-67-MWCNT/CF as negative electrodes achieve outstanding energy density (103.3 W h kg−1) at a power density of 750 W kg−1, coupled with excellent cycling stability (83.61 % capacity retention) after 10,000 cycles at 20 A g−1. Notably, the cell exhibits superior magnetocapacitance and the highest diffusion coefficient under an external magnetic field of 100 mT. The energy density reaches 163.2 W h kg−1 at a power density of 750 W kg−1, with a coulombic efficiency of 77.7 %. This represents a 1.58-fold enhancement compared to the absence of the magnetic field. The results demonstrated that ferromagnetic coupling between metal−oxygen−metal centers is enhanced via oxygen 2p orbitals, thereby creating a facile pseudocapacitance mechanism. The ZIF-67 shell further regulates the charge-discharge behavior of the electrode through the interplay between diffusive and capacitive mechanisms. This work introduces a promising new approach for preparing high-surface-area MOF-based electrodes and stimuli-responsive, high-performance electrochemical energy storage devices.

Nanocomposites for Lithium‐Ion Battery Anodes Made of Silicon and Polyaniline Doped with Phytic Acid

The properties of lithium‐ion battery (LIB) anodes fabricated from nanoscale silicon Si and polyaniline (PANI) as a binder are reported. PANI is prepared by in situ polymerization of aniline in the presence of phytic acid, which serves both as dopant and as a gel‐forming agent. PANI pellets obtained by dry compression are used to investigate the morphology and to measure the resistivity of PANI and Si/PANI composites. The anodes are fabricated using the slurry technique. Their properties as a function of precursor ratio are studied in the half‐cell cells by charge–discharge characteristics, cyclic voltammetry, electrochemical impedance spectroscopy and cyclic lifetime. It is shown that stable cycling (>350 cycles at a current of 300 mA g−1) is inherent only to thin Si/PANI layers with composite loading <0.7 mg cm−2. The discharge capacity in this case is as high as 500–800 mAh g−1.

Comprehensive Review of Li-Rich Mn-Based Layered Oxide Cathode Materials for Lithium-Ion Batteries: Theories, Challenges, Strategies and Perspectives.

Lithium-rich manganese-based layered oxide cathode materials (LLOs) have always been considered as the most promising cathode materials for achieving high energy density lithium-ion batteries (LIBs). However, in practical applications, LLOs often face some key problems, such as low initial coulombic efficiency, capacity/voltage decay, poor rate performance and poor cycle stability. It seriously shortens the lifespan of lithium-ion batteries and hinder the large-scale commercial application of LLOs. Herein, firstly, the basic theories of LLOs were systematically reviewed, including the structural characteristics, the working mechanism of LLOs, the preparation methods of LLOs (liquid phase co-precipitate method, sol-gel method, hydrothermal synthesis method, solid phase method, low heat solid-phase method, high temperature solid-state method etc.), and electrochemical characteristics of LLOs (first charge discharge characteristics and reversible efficiency, cycling performance, high and low temperature performance and thermal stability etc.). Then, key challenges faced by LLOs were systematically discussed. Finally, the LLOs modification strategies used to address these challenges (element doping, surface modification, defect engineering, structural and morphological control etc.) were elaborated in detail. This important review provides potential insights and directions for further improving the electrochemical performance of LLOs, and provides a necessary theoretical basis for accelerating the large-scale commercial application of LLOs. It possesses important scientific research value and far-reaching social significance.

Fabrication of Na and K based MnO2 nanocomposites for supercapacitive applications

α-Na0.5Mn0.93O2@Na0.91MnO2 (NaMnO) and K0.48Mn1.94O5@Na0.91MnO2 (KNaMnO) nanocomposites have been synthesized using solid-state reaction method. FESEM results convey the formation of column-shaped morphology. FTIR exhibited a shift in the vibration frequency upon potassium loading. Cyclic voltammetric curves are scanned (0 V–0.8 V) at different scan rates (5 mV/s to 100 mV/s) in 1M KOH electrolyte. Galvanostatic charge-discharge characteristics, for different current densities, have shown non-linear or pseudocapacitive characteristics of the prepared electrodes. High specific capacitance of ∼361 F/g and ∼143 F/g, at a current density of 1A/g, has been achieved for KNaMnO and NaMnO samples, respectively. KNaMnO sample exhibited higher capacitive retention (116 %), up to 2000 cycles, and obeys lower series resistance, charge transfer resistance, and Warburg impedance parameters, thus, convey higher efficiency of this compound for supercapacitor applications.

Li1.4Al0.4Ge0.1Ti1.5(PO4)3: A stable solid electrolyte for Li-CO2 batteries

In this study, a solid electrolyte, Li1.4Al0.4Ge0.1Ti1.5(PO4)3 (LAGTP), with a sodium superionic conductor-type crystal structure, was prepared using a facile solution-based method. LAGTP exhibited exceptional ionic conductivity (1.05 × 10−3 S cm−1) and a low activation energy (0.237 eV). The LAGTP pellet was employed as a solid-state electrolyte in a Li-CO2 battery, showcasing charge-discharge characteristics via a reversible electrochemical reaction (4Li+ + 3CO2 ↔ 2Li2CO3 + C). As-synthesized multi-walled carbon nanotubes, drop-cast on carbon cloth, were used as the cathode. The battery underwent 60 cycles with a cut-off capacity of 1000 mAh g−1 at various current densities, and a full-depth charge and discharge test was conducted at 100 mA g−1. During the charge/discharge process, the particle size of the dead lithium increased on the cathode surface, leading to the blockage of active sites for conversion. Post-cycling analyses were performed to elucidate the cathode degradation mechanism. The incorporation of LAGTP significantly enhanced battery cycle life and safety, making it a suitable candidate for use in next-generation, high-performance Li-CO2 batteries.

Peak-shaving cost of power system in the key scenarios of renewable energy development in China: Ningxia case study

Renewable energy has developed rapidly in Ningxia, and it has become the first provincial power system in China whose renewable energy power generation output exceeds the power load of the whole region. The access of a high proportion of renewable energy puts forward higher requirements for the peak-shaving capacity of the Ningxia power system. In order to solve the problem of calculating the peak-shaving cost in the key scenarios of renewable energy development in Ningxia, a quantitative model of the peak-shaving cost of the power system considering time-of-use price is proposed. We take Ningxia power system as an example to study. First, the key scenarios of the Ningxia power system peak-shaving are obtained, and the technical cost characteristic boundaries of various peak-shaving resources are determined. Second, according to the characteristics of typical daily renewable energy and load in Ningxia, the quantification model of the power system peak-shaving cost is established. The model takes the minimum total cost of the power system as the objective function and considers the constraints such as technical output of thermal power units, charge-discharge characteristics of energy storage and time-of-use price mechanism. Finally, the model is solved and the peak-shaving cost and unit output under the optimal scheme are obtained. This example shows that the model can effectively evaluate the peak-shaving cost and unit output of the Ningxia power system under the key scenarios of peak-shaving.

Synthesis of Nano-electrolytic Manganese Dioxide for Alkaline Batteries Mediated by Organic Additives

This article discusses the impact of adding organic additives like glycine (GLY), sucrose (SUC), and saccharine (SACCH) on the electrical characteristics and microstructure of electrolytic manganese dioxide (EMD), which is made from an acidic aqueous sulphate solution. The structure and chemistry of EMD were ascertained by means of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). To assess the material's potential for use in alkaline batteries, its charge-discharge properties were ascertained. It was found that the majority of MnO2 in all the EMD samples was in the γ-phase, which is electrochemically active and useful for energy storage applications. When glycine, sucrose, and saccharine were added to the solution as organic additives, the electrochemical deposition of manganese dioxide (MnO2) resulted in an increase in current efficiency and a decrease in energy consumption. The SEM images demonstrated that when EMD was deposited with an additive, small grain sizes and discrete particles free of agglomeration were formed, but large grain sizes were obtained in the absence of additives. Charge-discharge characteristics suggested that the additions improve the ability of MnO2 structure to store energy. This suggested that the additions may have an impact on the morphology and size of the particles, and consequently, the electrochemical activities of the material that was electrodeposited. In the case of the additives examined in this paper, the outcome was the creation of a material with possible use in battery technology.

Enhancing energy storage property of polypropylene‐based sandwich composites with surface‐modified nonzero dimensional nanomaterials

AbstractPolypropylene (PP) is a classical organic material for dielectric capacitor, exhibiting typical linear charge–discharge characteristics. However, its low energy density fails to meet the operating requirements of high‐power and energy storage systems. In this study, techniques such as spray‐coating, lamination hot‐pressing, melt blending, and in situ melt‐drawing are employed to fabricate PP‐based sandwich‐structured composite dielectrics. The outer layers consist of BN nanosheets (BNNSs)/PP composite, while the middle layer comprises Ba0.7Sr0.3TiO3@Polydopamine (BST@PDA)/PP. The introduction of BNNSs with a wide bandgap improves the breakdown strength of composites. BST@PDA increases the overall polarization of the composites and alleviates the local electric field concentration caused by hetero‐interfacial field distortion. When the filling concentration of BNNSs is 0.10 wt% and that of BST@PDA nanowires is 3 wt%, the composite demonstrates a high dielectric constant and low dielectric loss. Additionally, the sandwich‐structured composite, exhibiting a high charge–discharge efficiency of 97.80%, presents enhanced breakdown strength (Eb ~ 453 MV/m) and increased energy storage density (Ue ~ 5.67 J/cm3), which are 39.38% and 189.29% higher than neat PP (325 MV/m, 1.96 J/cm3), respectively. This study offers a viable and efficient approach to augment the energy storage density of PP‐based dielectrics.

Impact of annealing on the resistance of Li3PO4 electrolyte–LiNi0.5Mn1.5O4 electrode interfaces

The operation of solid-state Li batteries, which are promising power supplies for portable electronic devices and electric vehicles, is accompanied by heating. Therefore, investigating the thermal stability of battery systems is essential. In this study, we report the impact of annealing on the interface of a Li3PO4 electrolyte and LiNi0.5Mn1.5O4 electrode in thin-film batteries. The batteries with the interface annealed at 200 °C show low Li3PO4–LiNi0.5Mn1.5O4 interface resistance of 7.2 Ω cm2. Furthermore, the batteries exhibit stable charge–discharge characteristics with high current density up to 1170 μA cm−2, similar to those of batteries with the non-annealing interface. The batteries with the interface annealed at 450 °C show high Li3PO4–LiNi0.5Mn1.5O4 interface resistance of 490 Ω cm2, resulting in low battery performance. X-ray photoemission spectroscopy indicates that the P in Li3PO4 is reduced by high-temperature annealing, possibly causing the performance degradation of batteries. This study provides an in-depth understanding of the interfaces of solid-state batteries and is expected to facilitate the development of thermally stable batteries.

Holistic Energy Awareness and Robustness for Intelligent Drones

Drones represent a significant technological shift at the convergence of on-demand cyber-physical systems and edge intelligence. However, realizing their full potential necessitates managing the limited energy resources carefully. Prior work looks at factors such as battery characteristics, intelligent edge sensing considerations, planning, and robustness in isolation. But a global view of energy awareness that considers these factors and looks at various tradeoffs is essential. To this end, we present results from our detailed empirical study of battery charge-discharge characteristics and the impact of altitude and lighting on edge inference accuracy. Our energy models, derived from these observations, predict energy usage while performing various manoeuvres with an error of 5.6%, a 2.5X improvement over the state-of-the-art. Furthermore, we propose a holistic energy-aware multi-drone scheduling system that decreases the energy consumed by 21.14% and the mission times by 46.91% over state-of-the-art baselines. To achieve system robustness in the event of link or drone failure, we observe trends in Packet Delivery Ratio to propose a methodology to establish reliable communication between nodes. We release an open-source implementation of our system. Finally, we tie all of these pieces together using a people-counting case study.

Charge–Discharge Performances and Mechanisms of Zn-Ion Batteries with β-MnO2, γ-MnO2, and Mn2O3 Positive Electrodes

In the present study, the charge–discharge characteristics of zinc-ion batteries fabricated with β-MnO2, γ-MnO2, or Mn2O3 as the positive-electrode material were evaluated. MnOOH is widely believed to be formed in the discharge reaction of γ-MnO2. However, when β-MnO2 was used as the positive-electrode material, we observed the formation of Mn2O3 and Mn3O4 instead of MnOOH in the first discharge reaction, and no reformation of β-MnO2 upon charging occurred. Furthermore, during the charge–discharge process, zinc was dissolved from the negative electrode, and basic zinc compounds were observed as byproducts at both the positive and negative electrodes. For the second cycle onwards, the amounts of Mn2O3 and Mn3O4 increased during discharging and decreased during charging. The process showed a stable discharge capacity of 200 Ahkg−1 until ∼30 cycles, thereafter decreasing to 105 Ahkg–1 by the 100th cycle.

Non-conjugated electrochromic supercapacitors with atom-economic arylamine-based AB2-polyamides

A highly atom-economic AB2-type hyperbranched polyamide, HPA-TPA, was judiciously designed and prepared. HPA-TPA showed remarkable electrochromic behaviours and charge–discharge characteristics with the aid of the hyperbranched architecture.

THERMAL PERFORMANCE ANALYSIS OF LITHIUM-ION BATTERY PACK BY INTEGRATING PHASE CHANGE MATERIAL WITH CONVECTIVE SURFACE COOLING TECHNIQUE

The thermal behavior of the lithium-ion battery (LIB) pack has a substantial impact on its cycle life, charge-discharge characteristics, and safety. This research presents a comparative experimental analysis of the thermal performance of a lithium-ion battery pack designed for an electric bike, both with and without using phase change material (PCM). In both cases, a novel approach of passing air over the battery pack casing is employed to induce forced convection conditions, ensuring compliance with IP67 standards. The study examines the temporal variation of battery pack temperature at various constant discharge rates. The study demonstrated that the forced convection cooling method was more effective in maintaining the battery pack maximum temperature (<i>T</i><sub>max</sub>) below the optimal and safe temperature limits as compared to the natural convection cooling method in the absence of phase change materials. With the incorporation of PCM, the <i>T</i><sub>max</sub> value is found to be 12.4°C lower than that of the baseline case. Furthermore, the temperature homogeneity within the battery pack was significantly enhanced, as the maximum temperature difference [(Δ<i>T</i>)<sub>max</sub>] was reduced by 3.3°C compared to the baseline case. The combination of natural convection cooling and PCM is the most effective in controlling the battery temperature at 0.75 C discharge rate. The experimental data presented in this work could provide a good practical insight into the battery thermal management for electric bikes application.

Mns-MWCNT Composite, as a Superior Electrode Material for Asymmetric Flexible Quasi Solid-State Supercapacitors

Nowadays, renewable and sustainable energy sources are being explored and promoted to curb global pollution and to solve the issue of depleting fossil fuel resources. However, these renewable energy sources are intermittent in supply, therefore, it becomes necessary to store them for future usage. The traditional storage devices for electrical energy storage are different kinds of batteries but the sluggish performance of batteries, use of toxic heavy metals, issues pertaining to safety and low cycling efficiency are some of its major drawbacks. Recent proliferation of portable, wearable and flexible electronics and adoption of electric vehicles have forced the scientists to look for fast charging, light weight, leak proof, safe, toxic material free, durable energy storage devices like supercapacitors. Supercapacitors possess fast charge-discharge characteristics, high cycling stability and eco-friendliness in comparison to batteries. But they suffer from extremely low energy density (<10 Wh kg-1), high cost, bulk size, high self-discharge and significant drop in power density while increasing its energy density. The rational synthesis of electrode-materials has a significant impact on the development of high-performance electrodes for energy storage devices. Traditionally semiconducting materials like transition metal oxides are used as pseudocapacitive materials but transition metal oxides have very low electronic and ionic conductivity. Recently, transition metal sulfides, another class of semiconductors, are being investigated as they exhibit better conductivity and reaction kinetics compared to oxides. In this work, α-MnS is selected as an alternative to transition metal oxides. α-MnS is the most stable polymorph among other possible crystal structures of MnS, and has a hexagonal sheet like structure along with high operational potential window than many other metal sulfides. Although it is more conducting than transition metal oxides, it still needs conductivity enhancers like activated carbon, graphene, multiwall carbon nanotubes (MWCNT) etc. External mixing of conductivity enhancers is not effective enough to enhance the conductivity. Hence, MWCNT is mixed during the synthesis step to have a better bonding with α-MnS and create high conductivity channels. α-MnS + MWCNT composite shows a specific capacitance of 115 F g-1 at 1 A g-1 in 3 M KOH electrolyte under 3 electrode configuration. α-MnS + MWCNT composite is deposited on flexible conducting carbon cloth as cathode material and Vulcan carbon is deposited on carbon cloth as anode material. A mixture of poly vinyl alcohol PVA+ 3 M KOH is used as the gel type electrolyte. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), galvanostatic charge discharge (GCD), electrochemical impedance spectroscopy (EIS), cycling stability are performed to characterize the active material and the device performance. The assembled device shows a potential window of 1.4 V, alongside a specific capacitance of 27.7 F g-1 at 1 A g-1 and with 80% of capacity retention after 10,000 cycles. These results prove that transition metal sulfides can be viable alternative materials for supercapacitor application. This quasi-solid state or gel type electrolyte significantly reduces the conductivity and specific capacitance. Enhancing the ionic conductivity of the gel and finding out the optimum thickness of gel electrolyte layer between the electrodes are expected to open new pathways in enhancing the performance of the device. Figure 1

Passivated Bi2Se3 electrode in Na2CO3 solution to improve anode efficiency in aqueous Li-ion batteries

Efficient anode materials are crucial for the success of aqueous rechargeable lithium-ion batteries (ALIBs) since many materials degrade significantly during electrochemical reactions. In this study, the modification of Bi2Se3 with Na2CO3 was explored to enhance the charge–discharge characteristics of the anode. The passivated Bi2Se3 electrode exhibited improved electrochemical performance, maintaining high charge and discharge capacities of 816 mAh·g−1 after the 5th cycle and 570 mAh·g−1 after the 100th cycle with stable Coulombic efficiency of 98.0 ± 1.2 %. Charge-discharge profiles and cyclic voltammetry revealed the lithium intercalation and deintercalation, while impedance spectroscopy indicated changes in the electrode structure during cycling. These findings highlight the potential of using Bi2Se3 electrodes with a pre-formed surface film to enhance the stability and performance of ALIBs.

A mathematical model and microcontroller-based method for measuring dielectric permittivity and discharge characteristics with Arduino ATmega 328: a case study in a physics laboratory

A microcontroller-based measuring instrument and a new mathematical model are used to investigate capacitor permittivity and dielectric materials' charge-discharge characteristics. In this study, a prototype capacitive permittivity measurement apparatus for dielectric materials was carefully developed using an Arduino microcontroller, a resistor, and a capacitor. The experimental setup comprises a capacitor-resistor circuit, wherein a 5-volt power supply sourced from the microcontroller interfaces with a computer. During the charging process, a comprehensive evaluation of model-data alignment was performed, yielding values of 0.54252156, 0.9951, and 111.2508701 for the sum of squares error (SSE), the coefficient of determination (R-squared), and the sum of squares total (SST), respectively. Similarly, the analysis extended to the discharging process, unveiling values of 5.10174756, 0.962805684, and 137.1647082 for SSE, R-squared, and SST, respectively. These findings confirm the accuracy of the microcontroller that was programmed by incorporating a model in precisely measuring the relative permittivity of dielectric materials and capacitance values, with an R-squared value above 0.95 following capacitor literature benchmarks. The novelty of this study is that this configuration enabled the precise assessment of both permittivity and the charge-discharge characteristics of the dielectric materials within the capacitor. This methodology made it possible to accurately measure the permittivity and charge-discharge characteristics of dielectric materials within a capacitor. The scientific significance of this research lies in its ability to provide a carefully developed instrument capable of investigating the permittivity of dielectric materials and capacitor capacitance measurements. Scholars, international engineering communities, and academics can use this technological breakthrough to advance research into dielectric material properties and capacitor characteristics.

Design and application: Simplified electrochemical modeling for Lithium-ion batteries in whole lifespan

In order to expedite battery development cycles and optimize design, electrochemical model is widely employed to investigate battery performance. However, while these models have been proven efficient in reducing experimental costs, most of them do not sufficiently account for capacity degradation throughout the entire life cycle of the battery. To address this issue, a pseudo-two-dimensional model is developed to better characterize charge-discharge characteristics, taking into account capacity fading effects. Firstly, the impact of relevant design parameters on internal resistance is addressed, which is significant for optimizing battery design and reducing internal resistance. Secondly, to shorten battery charging time, a two-step constant current charging strategy with the negative electrode potential as the threshold is proposed and its efficacy is verified. Compared to constant current-constant voltage charging strategies, the designed novel approach reduces the charging time by 20 % and significantly reduces capacity fading caused by thickening solid electrolyte interphase films. Finally, the retired battery specific load profiles are input into the model to analyze changes in battery performance and estimate battery life for a second use.

DIRECTING THE UNIFORMITY OF THE LEVEL OF PULSE CHARGING OF LI-ION BATTERIES USED IN AUTOMOTIVE INDUSTRY

The lithium-ion (Li-ion) battery is widely used in modern electronics, serves as a power source in electric vehicles and for energy storage in renewable energy systems. The strengths of Li-ion batteries are their high energy density. Modern Li-ion batteries can include arrays of cells, the lifetime of which is determined by factors that depend on charge-discharge characteristics. Li-ion batteries connected in series have different aging rates due to different capacities. The capacity deviation increases as the battery has been used, generating an increase in compensation current, which continues to increase until ignition. To solve this problem, a pulse device and a charging method in a charge equalization battery were proposed in this paper. A numerical simulation of how to charge real Porsche Taycan car batteries was performed. The results obtained confirmed the effectiveness, the energy losses did not exceed 2% of the battery capacity. A bench diagram was developed for studying and programming the operating modes of battery control units for hybrid and electric cars.

Porous Carbons Activated by Different Methods as Positive Electrode Materials for Zn-Carbon Capacitors

Porous carbon materials prepared with different activation methods were evaluated as positive electrodes for zinc-ion capacitors. Higher capacities were obtained with chemically activated carbons than with steam-activated carbons, with KOH-activated carbon showing the highest capacity. Furthermore, the dependence of charge–discharge characteristics on electrolyte was explored using seven different electrolyte types. Gas evolution was observed during the charging reaction in alkaline electrolytes such as potassium hydroxide and tetraethylammonium hydroxide, but no gas generation was observed in acidic electrolytes. In addition, the discharge capacity tended to be higher for chlorine- ion-containing electrolytes such as zinc chloride and ammonium chloride.