High Electrochemical Performance Research Articles

Enhanced electrochemical performance of the MoS2/Bi2S3 nanocomposite-based electrode material prepared by a hydrothermal method for supercapacitor applications.

Supercapacitors are widely used energy storage systems in the modern world due to their excellent electrochemical performance, fast charging capability, easy handling, and high power density. In the present work, pure MoS2 and MoS2/Bi2S3 nanocomposites with different compositions of bismuth were synthesized by the hydrothermal method. The structural properties of the electrode materials were studied using the XRD technique, which confirmed the formation of MoS2 and the secondary phase of Bi2S3 while increasing Bi substitution. The morphological studies of the synthesized electrode materials were performed using SEM, TEM, and HRTEM techniques, which indicated the 3D layered hierarchical structure of MoS2 nanospheres and the nanosheet-like structure of Bi2S3. The electrochemical properties of pristine MoS2 and MoS2/Bi2S3 nanocomposites were analysed by CV, CP, and EIS techniques using a 2 M KOH electrolyte in a three-electrode system. The CV curves show evidence of significant improvement in the electrochemical performance of MoS2/Bi2S3 composites compared to that of pure MoS2. The calculated specific capacitances of MoS2/Bi2S3 nanocomposites were relatively higher than those of pristine MoS2. The 20 mol% Bi added sample showed a maximum specific capacitance of 371 F g-1, compared to pristine MoS2 and other samples at a current density of 1 A g-1. The kinetics of the electrochemical process was studied. The Nyquist plots indicated that the Bi-added nanocomposites had lower Resr and RCT values, which resulted in high electrochemical performance. The experimental results revealed that Bi-substitution can further enhance the electrochemical energy storage performance of MoS2 for supercapacitor applications.

A disposable and low-cost laser-scribed graphene electrochemical sensor for simultaneous detection of hydroquinone, paracetamol and methylparaben

• A new disposable LSG sensor was fabricated using Polyetherimide substrate. • Sensor presented high reproducibility, sensitivity, and selectivity. • A LSG sensor was applied to simultaneous detection of emerging pollutants. • A porous graphene-like material with high electrochemical performance was developed. A novel and inexpensive laser-scribed graphene (LSG) sensor using polyetherimide (PEI) substrate was fabricated using CO 2 laser. The material was characterized by scanning electron microscopy (SEM), Raman spectroscopy, and electrochemical techniques, demonstrating a high porous carbonaceous material, which resulted in an electroactive area with 3.4-fold enhancement compared to geometric area and a high heterogeneous electron transfer rate constant (k°) of 3.20x10 -2 cm/s for ferricyanide redox probe. As a proof of applicability, the LSG-PEI sensor was applied for simultaneous detection of hydroquinone (HQ), paracetamol (PA), and methylparaben (MP) emerging pollutants (EP) in tap water and natural (lake) water samples, providing recoveries between 93.1% and 118% with limits of detection of 9.42x10 -8 , 3.23x10 -7 , and 2.95x10 -7 mol/L for HQ, PA, and MP, respectively.

Durable Dual-Methylpiperidinium Crosslinked Poly(Binaphthyl-Co-Terphenyl Piperidinium) Anion Exchange Membranes with High Ion Transport and Electrochemical Performance

Durable Dual-Methylpiperidinium Crosslinked Poly(Binaphthyl-Co-Terphenyl Piperidinium) Anion Exchange Membranes with High Ion Transport and Electrochemical Performance

Co-containing metal-organic framework for high-performance asymmetric supercapacitors with functionalized reduced graphene oxide.

Nowadays, supercapacitors are the most coveted eco-friendly and sustainable next-generation energy storage devices. In this regard, developing supercapacitors with high energy density and power density has always been a challenge for researchers. Herein, we have exploited an electroactive Co-containing metal-organic framework (Co-MOF) using cheap and commercially available starting materials under refluxing conditions and explored its energy storage properties in three- and two-electrode methods. The Co-MOF exhibited a specific capacitance of 425 F g-1 at 2 A g-1, maintaining a capacitance of ∼78% over 2200 successive charge-discharge cycles in a three-electrode system. The two-electrode asymmetric supercapacitor (ASC) using Co-MOF as the working electrode and as-synthesized p-phenylenediamine (PPD)-functionalized reduced graphene oxide (PPD-rGO) as the counter electrode divulged a specific capacitance of 72.5 F g-1 at 2 A g-1 current density with ∼70% capacitive retention after 2200 successive charge-discharge cycles over a broad potential window of 0-1.6 V. Moreover, the ASC demonstrated a maximum power density of 11.9 kW kg-1 at 10 A g-1 and a maximum energy density of 25.8 W h kg-1 at 2 A g-1 current density. Owing to the stable electrochemical redox (Co2+/Co3+)-mediated pseudocapacitive behavior of the Co-MOF and the high surface area and electrical conductivity of in situ generated PPD-intercalated rGO, the fabricated ASC unveiled high-performance supercapacitive behaviors. To investigate the practical applicability of this material, solid-state (ASC) devices were fabricated by employing the Co-MOF as the positive electrode and PPD-rGO as the negative electrode in a KOH-based gel electrolyte, which could power a commercially available light-emitting diode bulb (∼1.8 V) for several seconds. Therefore, the elucidated high electrochemical energy storage performance of the prepared Co-MOF makes it a very promising electrode material for supercapacitors.

Hydrothermally prepared MnSe electrode as a promising pseudocapacitive material for high-performance supercapacitor

Energy storage devices (ESDs) need designing and development of high electrochemical performance and promising electrode materials.

Covalently Interlayer‐Confined Organic–Inorganic Heterostructures for Aqueous Potassium Ion Supercapacitors (Small 4/2023)

Aqueous Potassium Ion Supercapacitors A covalently interlayer-confined polyaniline–MoS2 hybrid with a dual charge storage mechanism is developed for supercapacitors. In the hybrid, confined polyaniline induces a favorable phase transition, facilitates cross-layer electron transfer, and decreases K+ diffusion barrier, thus enabling high electrochemical performance. More details can be found in article number 2204275 by Shude Liu, Seong Chan Jun, and co-workers.

Facile synthesis of cobalt-doped sodium lithium manganese oxide with superior rate capability and excellent cycling performance for sodium-ion battery

In this work, cobalt-doped sodium lithium manganese oxide (NLMC) was synthesized by a solid-state reaction method. Crystal structure and morphology of the NLMC material were examined using X-ray diffraction, selected area electron diffraction, scanning eletron microscopy, transmission electron microscopy, energy dispersive spectroscopy, and inductively coupled plasma - optical emission spectrometry analysis. The NLMC material was utilized to fabricate CR2032-type coin cells, and later evaluated for its electrochemical characteristics. The partial substitution of manganese ions in the structure by cobalt and lithium ions is the main reason for the outstanding electrochemical properties. The NLMC material was delivers a specific capacity of 112 mAh/g at a current density of 0.1C; up to higher current density of 1C, it has retained a specific capacity of 63 mAh/g. In addition, the NLMC material exhibited an excellent cycling performance, it is able to remains up to 97.7% specific capacity over 100 cycles at the current density of 0.1C. The presented results provide new pathway of obtaining high electrochemical performance of the sodium manganese-based materials by employing other transitional elements to partially substitute manganese in the crystal structure.

A high-performance hybrid direct carbon fuel cell with tandem catalysis in the dendritic channeled anode

Hybrid direct carbon fuel cells (HDCFCs) are promising to achieve high power density, good fuel-electrode contact, and high carbon-fuel conversion efficiency due to increased reaction sites and hybrid routines of carbon utilization. However, the performance of HDCFC is greatly restricted by mass transfer and detrimental carbon deposition. The so-called CO–CO2 shuttle process, i. e., the coupling of the electrochemical reaction of CO to CO2 and subsequent discharge of CO2 towards the C fuel surface for gasification, is the key mass transfer process needed to be optimized. This study demonstrates a novel high-performance HDCFCs anode by integrating C-gasification tandem catalysis in dendritic channel anode support (t-HDCFCs), which greatly enhances the CO–CO2 shuttle and mitigates carbon deposition. As a result, the t-HDCFC delivers a comparable or even higher electrochemical performance than the other HDCFCs under the same operation conditions, such as a peak power density of 556 mW cm−2 at 750 °C.

Creation of nanopores and nitrogen doping in the surface layers of reduced graphene oxide electrode via ions implantation resulting in enhanced electrochemical performance for supercapacitor

Nitrogen doping is an effective way to enhance the electrochemical performance of carbon materials. In this study, the surface layers of graphene oxide (GO) film was firstly implanted by nitrogen ions, and then annealed at nitrogen atmosphere to obtain the nitrogen-doped reduced GO (NrGO) electrode for supercapacitor. Uniformly distributed nanopores are created in the surface layers of NrGO electrode, and also as high as 9.9 % nitrogen content is doped into its surface layers. The synergistic effects of these surface modifications significantly improve its electrochemical performance. The specific capacitance is increased from 148 F g−1 (original reduced GO (rGO)) to 270 F g−1 (NrGO), tested at current density of 0.5 A g−1 in symmetrical cells with 6 M KOH electrolyte. The volumetric capacitance of NrGO reaches 416 F cm−3, and its volumetric energy density is 14.3 Wh L−1 with power density of 191.7 W L−1. This study provides an exploration via nitrogen ions implantation to fabricate graphene-based electrodes with high electrochemical performance.

Biomass Hierarchical Porous Carbonized Typha angustifolia Prepared by Green Pore-Making Technology for Energy Storage.

The cost-effective biomass-derived carbon with high electrochemical performance is highly desirable for the sustainable development of advanced energy storage devices. In this manuscript, Typha angustifolia with a large output and loose porous characteristics was selected as the raw material of biomass. In the synthesis process, KHCO3, which is more environmentally friendly, is used as a pore-forming agent, and the low-cost, easy-to-clean fluxing agent NaCl is used to assist the pore-forming process. Based on the analysis of thermogravimetric-infrared test results, the calcination procedure of porous carbon was designed reasonably, so that the functions of the pore-forming agent and fluxing agent could be fully exerted. Its high electrochemical performance is attributed to combined contributions from high surface area and hierarchical porous structures. The as-prepared carbon also showed an outstanding capacitance of 317.2 F/g at a current density of 1 A g-1 and a high capacitance retention of over 97.83% after 5000 cycles at a current density of 4 A g-1. This work provides an outstanding renewable candidate and a feasible route design strategy for the fabrication of high-performance electrodes.

Enhanced cycling performance of surface-amorphized Co3S4 as robust cathode for supercapacitors

The interfacial engineering via surface amorphization is an effective strategy to regulate the structure and character of material. Herein, a facile hydrothermal method followed by NaBH4 treatment is proposed to fabricate surface-amorphized Co3S4 (SA-Co3S4). XRD and SEM characterization implies the micro flower structure of Co3S4. TEM test further demonstrates the heterointerface between crystal Co3S4 core and defect-rich amorphous Co3S4 surface, which can reduce electron/ion transport path and accelerate internal charge transfer rate, thus enhancing the integral electrical conductivity. Electrochemical measurements imply that the SA-Co3S4 displays satisfying specific capacitance of 1043.9 F g−1 at 0.5 A g−1 and good rate performance. By employing SA-Co3S4 as a cathode, and active carbon as an anode, the asymmetric supercapacitor exhibits a high energy density of 41.9 Wh kg−1 at a power density of 162 W kg−1 and good cycling durability (above 90 % retention rate after 10,000 cycles). This work offers a novel structure design strategy for fabricating cobalt sulfide materials with high conductivity and electrochemical performances.

Improving Flexibility and Capacitive Charge Storability in Free-Standing Carbon Nanofiber Electrodes

Energy storage devices with higher volumetric energies and power densities are crucial in delivering high electrochemical performances without being bulky. Herein, a flexible free-standing carbon nanofiber (CNF) electrode with and without graphene is derived from electrospun polyacrylonitrile nanofiber mesh. The embedded graphene enhanced the conductivity of the polymeric solution, generating significant “whipping” motion to create better fiber cross-linking that enhances the flexibilities of CNFs. Besides, the presence of graphene reduced the population of surface oxygenated functional groups when compared to the pristine CNF. Raman spectroscopy demonstrated lower defect states in graphene-embedded CNFs, favorable for better electrical conductivity. Both the reduced surface functional group and reduced impedance (1.0 Ω compared to 1.1 Ω of pristine CNF) show that a graphene-embedded CNF recorded improved rate capability compared to a pristine CNF. When fabricated into a symmetry supercapacitor, a volumetric energy density of ∼4 mWh cm–3 at a power density of ∼63 mW cm–3 was achieved, which is one of the highest reported values based on our knowledge.

High Electrochemical Performance of a Nanostructured Electrode Material Based on a Cobalt-Manganese Layered Double Hydroxide

In this work, alpha-cobalt hydroxide (Co(OH)2) and cobalt/manganese layered double hydroxide (CoMn-75-LDH) were synthesized using the Tower method. The alpha phase was confirmed for Co(OH)2 through XRD analysis. Furthermore, the TEM images showed that the materials are formed by nanoparticles with an average size of ~5 nm. Cyclic voltammetry and galvanostatic charge/discharge measurements were carried out and the CoMn-75-LDH presented a superior electrochemical behavior to Co(OH)2. The presence of Mn2+/3+ ions in the crystal structure of CoMn-75-LDH, verified by XPS analysis, enhanced the electrical conductivity of the material, providing more electroactive sites, as a result, the electrochemical performance of the material was improved. Electrochemical studies showed that CoMn-75-LDH has a specific capacitance of 677 F g-1 at current density of 0.5 A g-1 compared to Co(OH)2, whose specific capacitance value was 268.7 F g-1 at the same current density. In addition, the electrochemical signature of Co(OH)2 revealed that the electrode material exhibits an extrinsic pseudocapacitive behavior instead of the typical behavior of battery-type materials due to its nanostructured morphology. Also, electrochemical studies showed that the charge storage mechanism for CoMn-75-LDH is controlled by both the capacitive and diffusion process.

Synthesis of V2O5·nH2O nanobelts@polyaniline core–shell structures with highly efficient Zn2+ storage

Aqueous zinc-ion batteries (AZIBs) are regarded as attractive candidates for next-generation energy storage devices. Among various cathode materials, V2O5·nH2O (VOH) possesses a high theoretical capacity but poor cycle stability due to the susceptibility of its open structure to damage by the quick shuttling of Zn2+. Herein, the structural stability of VOH is directly improved by wrapping polyaniline (PANI) on the VOH nanobelts (VOH@PANI). As a cathode material for AZIBs, the VOH nanobelts@PANI core–shell structures exhibit an outstanding cycle stability of 98% after 2000 cycles at 2 A g−1. The improved conductivity and additional energy storage contribution of the PANI endow VOH@PANI with a specific capacity as high as 440 mAh g−1 at 0.1 A g−1, substantially higher than pure VOH (291 mAh g−1). At the same time, high energy and power densities of 349 Wh kg−1 and 3347 W kg−1 are achieved. This work not only demonstrates that p-type doped PANI coatings on VOH can boost the Zn2+ storage of VOH, but also provides a novel method to enhance cathode materials for high electrochemical performance.

Study on the limiting factors of the cycle life of alkaline poly(vinyl alcohol)-based zinc–air batteries

Flexible zinc–air batteries (FZABs) arouse extensive research interests due to their high energy density and extremely low cost. However, FZABs based on poly(vinyl alcohol) (PVA) alkaline gel polymer electrolyte (GPE) suffer from poor cycling life, which seriously hinders their commercial application. Although most previous efforts focus on optimizing and developing the electrodes and the electrolyte materials with high electrochemical performance to improve the battery cycle life, the limiting factors of the cycle life of the FZAB remain obscure. Herein, a PVA–KOH-based FZAB was assembled to explore the limiting factors of the battery cycle lifespan by setting an array of comparative experiments. The results demonstrate that the decline of the OH− ion content in the PVA–KOH GPE is the key factor in shortening the battery cycle life. The ZnO and carbonate formation in the GPE as well as the poor water retention capability of the GPE contribute to the decrease of OH− ion content in the PVA–KOH GPE. Due to the widely used PVA–KOH GPE in FZABs, this work can provide valuable theoretical guidance and reference for most of the research works centered on prolonging the cycle lifetime of the FZABs.

Recent advance in two-dimensional MXenes: New horizons in flexible batteries and supercapacitors technologies

MXenes (two dimensional (2D) transition metal (TM) carbides (TMCs), TM nitrides (TMNs), and TM carbonitrides (TMCNs) are emerged as future biggest 2D materials (2DMs) family with novel applications in different nanotechnological research in academic as well as industrial level. MXenes NMs have the potential to be classified as a “wonder material” in the category of 2D nanomaterials (NMs). MXenes were studied and synthesized for over a decade since their first discovery in 2011, and till now more than 50 members are experimentally studied and more than 100 are theoretically investigated. Synthesis techniques are not restricted to the first introduced top-down HF based etching method but new innovative synthesis methods, such as, water (H 2 O)-free etching, molten salts etching and bottom-up method, like Chemical vapor deposition (CVD) method etc were also studied, providing multifunctional surface chemistry based MXenes NMs with novel configuration, and desirable characteristics. MXenes are used as important components in a number of flexible energy storage devices (FESDs), for instance secondary batteries, supercapacitors (SCs), Micro-SCs (MSCs) and Micro-batteries (MBs), etc due to their distinctive layered structures, high electrochemical performance and fascinating functional capabilities. In this review, we first will discuss in detail the MXenes NMs synthesis methods, secondly selected properties, and third their applications in various FESDs. After that, we will summarize and discuss the most present problems associated with MXenes NMs synthesis and their applications in FESDs, and possible solutions to those problems. Finally we will discuss the presents interesting vision for the future progress of the MXenes-based NMs in wearable and FESDs, their limitations, and suggestions.

An aqueous aluminum-ion electrochromic energy storage device with visual energy level

Electrochromic energy storage devices (EESDs) integrate energy storage and electrochromism into one smart device that can realize the visualization of the energy level by the naked eyes, which has attracted extensive attention in recent years. It is critical to explore suitable electrode materials for achieving both high electrochromic and electrochemical performance. Herein, we propose an aqueous aluminum-ion electrochromic energy storage device (AIEESD) by assembling the polyaniline (PANI) electrochromic cathode, Al metal frame anode and AlCl 3 electrolyte, which yields an open-circuit voltage of ∼1.22 V and a fast self-bleaching behavior without any energy input. Additionally, the developed device exhibits outstanding electrochromic energy storage performances with discharging capacity of 68.1 mAh m −2 , excellent rate capability, large optical modulation (ΔT = 55% at 630 nm) and high coloration efficiency (93.62 cm 2 C −1 at 630 nm). Moreover, the prototype device can reversibly switch between the multicolor (transparent, light yellow, green and dark blue) when the voltage changes from 0.4 to 2.5 V, which means the energy status can be monitored by the obvious color transition. These results show that the AIEESD in this work has great application prospects for smart windows and energy storage displays. An aqueous aluminum-ion electrochromic energy storage device based on PANI cathode has been developed, and it demonstrates fast spontaneous bleaching process without any external energy input. The as-assembled device exhibits both high electrochromic and energy storage performances due to the multivalent-ions interaction with PANI materials. Importantly, the device demonstrates its energy level by displaying multi-colors from dark blue, green, light yellow to transparent and shows potential applications in graphic display. • An aqueous aluminum-ion electrochromic energy storage device is developed. • The prototype device can achieve the visualization of the energy status. • The device demonstrates energy retrieve function and multicolor graphical display.

Self-adaptable gel polymer electrolytes enable high-performance and all-round safety lithium ion batteries

High safety and electrochemical performance of lithium batteries are a pair of irreconcilable contradictions. Adding flame retardants to electrolytes or introducing the flame retarded structures to various polymeric matrices can attain the purpose of an improved fire-safety, but there is almost no positive contribution and even are many negative effects on the electrochemical performance of batteries due to chemical or/and physical incompatibility with electrolyte, electrode, etc.. Inspired by nature, we delicately design an intelligent self-adaptable gel polymer electrolyte (GPE) based on a novel copolymer with functional pendent groups, which can assist lithium ion migration, afford redox stability, promote cyclization reaction and suppress combustion by a synergy of the pendent groups. Using this copolymer-based GPE, not only deliver the various batteries superior long-term cycling performance at room temperature, but also a thermal shutdown function at high temperature and a flame retardancy exposed to fire can be achieved. Significantly, LiFePO4/GPE/graphite pouch battery with an initial capacity of 24.06 mAh possesses a capacity retention of 75.9% and a coulombic efficiency of 99.6% after 200 cycles at 0.5 C, and meanwhile presents excellent resistance to mechanical damage, high temperature and flame, demonstrating a proof of concept for extensively high safety of the practical LIBs.

A simple synthesis of Li3Fe(MoO4)3@C composite anode materials with high initial Coulombic efficiency and high capacity stability for lithium ion batteries

At present, it is still challenging to fabricate anode materials for lithium-ion batteries with excellent electrochemical performances by simple process on a large scale. In this paper, by using a conventional solid state reaction technique along with a mechanical ball milling method, an unique Li3Fe(MoO4)3@C composite was synthesized. The amorphous carbon introduction is helpful in mitigating the volume expansion and enhancing the structural stability and electrochemical performance of the composite materials. After 100 cycles at 200 mA g−1, the Li3Fe(MoO4)3@C composite electrode maintained a high reversible capacity of 739 mAh/g with an initial Coulombic efficiency of 82 %. In addition, the rate performances of the composite electrode is also remarkable, and the reversible capacity is up to 740 mAh/g at 1600 mA g−1. This work can provide inspiration for the preparation of molybdenum based transition metal oxide composites with high electrochemical performances for other alkali metal secondary batteries.

A Low Cost, High Electrochemical Performance Carbon Coated Zinc Borate Anode Material for Sodium-ion Batteries

A Low Cost, High Electrochemical Performance Carbon Coated Zinc Borate Anode Material for Sodium-ion Batteries