High-performance Supercapacitors Research Articles

The Preparation of N, P-Doped NiSe Nanorod Electrode Materials on Nickel Foam Using the Microwave Method for High-Performance Supercapacitors.

Transition metal selenides have the leading position in the field of energy storage and conversion due to their high theoretical capacity, good electrical conductivity, and cycling stability. Nickel is widely used for the construction of positive electrodes in devices due to its good conductivity, variable valence state, and ideal redox activity. NiSe materials have high internal resistance and are prone to volume change during charging and discharging, thus affecting the practical application of this electrode material, and the reported NiSe materials have not achieved a more desirable capacity value. Therefore, in this study, N, P-NiSe nanoelectrode materials were prepared using nickel foam as the nickel source and hexachlorocyclotriphonitrile as the nitrogen and phosphorus dopant using an efficient, energy-saving, and simple microwave method. It was also characterised by XRD and XPS to confirm the successful preparation of N, P-NiSe materials. In addition, the material yielded a high capacitance value (3184 F g-1) and good cycling stability (72% of the initial capacitance value was retained after 4000 cycles) in electrochemical tests. To demonstrate its excellent suitability for practical applications, an asymmetric supercapacitor was assembled using N, P-NiSe as the anode and activated carbon as the cathode. At an operating voltage of 1.6 V, the device achieved an energy density of 289.06 Wh kg-1 and a power density of 799.26 W kg-1 and retained 80% of its initial capacity after 20,000 cycles.

Wet spun cellulose nanocrystal/MXene hybrid fiber regulated by bridging effect for high electrochemical performance supercapacitor

Wet spun cellulose nanocrystal/MXene hybrid fiber regulated by bridging effect for high electrochemical performance supercapacitor

Dense graphene composite hydrogels as advanced electrode materials for high-performance supercapacitors

In this work, alanine functionalized nanocellulose/graphene composite hydrogels (NCGHalas) were prepared via an easy hydrothermal reaction using alanine, GO, and nanocellulose as reactant. Thanks to this synthesis strategy, NCGHalas exhibited large bulk density, abundant heteroatom functional groups, reasonable porous structure and moderate specific surface area. Based on the above characteristics, the aqueous symmetric supercapacitors (ASSC) assembled by NCGHala25 presented high gravimetric and volumetric specific capacitance of 276.5 F g−1 and 320.8 F cm−3 at 0.3 A g−1, excellent rate performance (77.9 % at 10 A g−1), and long working life of 95.4 % retention after 10,000 cycles at 10 A g−1. Furthermore, the NCGHala25 based ASSC also exhibited large gravimetric and volumetric specific energy densities of 9.6 Wh kg−1 and 11.1 Wh L−1. More importantly, the flexible solid-state supercapacitors (FSSC) fabricated by NCGHala25 and PVA-KOH electrolyte delivered high specific capacitance (178.2 F g−1, 0.3 A g−1), and this value can be maintained for 74.2 % even at 10 A g−1.

Physical activation assisted porous activated carbon from Strychnos Potatorum shells for high-performance symmetric supercapacitors

Herein, low-cost activated carbon (AC) prepared from Strychnos Potatorum shells using CO2 as an activating agent via physical activation technique. Waste biomass-derived AC have the merits of excellent conductivity and highly porous with high-surface area. Electrochemical assessments indicated that the prepared Strychnos Potatorum derived activated carbon (SPAC) electrode exhibited superior electrochemical performance. The experimental data showed that the specific capacitance of 352.5 F g−1 at 0.5 A g−1 and retained 140 F g−1 at 20 A g−1. Symmetric supercapacitors SPAC//SPAC device displayed an impressive specific capacitance of 147 F g−1 at 0.1 A g−1 and an energy density of 20.41 W h kg−1 at 100 W kg−1 and retained 2.7 Wh kg−1 at 10000 W kg−1. Furthermore, these supercapacitors demonstrated exceptional cyclability, maintaining capacity retention of 92.3 % over 10,000 charge–discharge cycles at 1 A g−1. This research work underscores the promising potential of AC materials derived from Strychnos Potatorum shells in development of high-performance supercapacitors.

Chemical Route Synthesis of Nanohybrid Mo–V Oxide and rGO for High-Performance Hybrid Supercapacitors

Chemical Route Synthesis of Nanohybrid Mo–V Oxide and rGO for High-Performance Hybrid Supercapacitors

The effect of thermoelectric augmentation dramatically increased the specific capacity for electrochemical energy storage

Conventional methods to enhance the performance of electrode materials include morphological modification and defect engineering, but the limited number of active sites for the electrode remains a huge obstacle to achieving high-performance supercapacitors. In this work, we proposed a strategy to improve the electrode performance under the condition of limited active sites through the thermoelectric effect, and designed thermoelectric electrodes of the p-type Fe0.3Co0.7Sb3 cathode and the n-type Cu0.3Ag1.7Se anode for supercapacitors, respectively. In particular, the charge carriers generated by the thermoelectric effect accelerate the electrochemical reaction process at the interface between the thermoelectric electrode and the electrolyte under the temperature difference (ΔT) condition, thus increasing the specific capacity of the electrode. The p-Type Fe0.3Co0.7Sb3 cathode and the n-Type Cu0.3Ag1.7Se anode exhibit a 150% and 208% increase in the specific capacity, respectively. Furthermore, electrodes with different conduction types and various thermoelectric properties, such as n/p-type bismuth telluride and n/p-type half-Heusler thermoelectric materials are also studied, confirming the universality of the above phenomenon in thermoelectric electrodes. This work provides a universal route for the thermoelectric effect to promote the energy density of supercapacitors used in high temperature difference environments.

Controlled preparation of carbon cloth decorated with nanostructured Mn(OH)2/Mn3O4 electrodes for high-performance asymmetric supercapacitors

Environmentally friendly aqueous asymmetric supercapacitors are expected to exhibit excellent energy storage properties, stable performance, and facile production protocols. This study focused on the fabrication and characterisation of an asymmetric supercapacitor (ASC) with a commercial activated carbon (AC) negative electrode and Mn(OH)2/Mn3O4 composite on carbon cloth (hCC) positive electrode. The Mn-based electrode was synthesised using a one-step electrodeposition process. The morphology and crystalline structure of the composite electrode were modified by varying the deposition time of the Mn(OH)2/Mn3O4 nanostructures on carbon cloth substrate which greatly influence the electrochemical performance of the asymmetric systems. The best ASC used the AC electrode and a Mn(OH)2/Mn3O4@hCC electrode prepared using electrodeposition over an optimised time of 3 h. It exhibited a remarkable specific energy density of 40.7 Wh kg−1 at a power density of 100 W kg−1. In addition, this ASC demonstrated stable long-term performance, retaining 88 % of its capacitance after 5000 charge–discharge cycles, showing its great application potential in the field of supercapacitors.

Synthesis of ZnO and NiO nano ceramics composite high-performance supercapacitor and its catalytic capabilities

NiO and ZnO mixed nanocomposites were manufactured using the solution combustion process. As-prepared samples were analyzed using XRD. The XRD shows an average crystallite size of 35–40 nm. The elemental composition determined by EDS indicates a nearly equal proportion of Ni and Zn, with an atomic ratio of Ni/Zn = 0.96. The specific capacitances of NiO is 295.5 Fg-1, ZnO is 117.3 Fg-1 and ZnO/NiO nanocomposites is 561.75 Fg-1 which are more than NiO and ZnO alone. This study shows that constructing binary oxide nanocomposites is an approach for developing high-performance supercapacitor electrode materials. Experimental observations on catalytic activity revealed that NiO/ZnO increased catalytic activity. Furthermore, adding NiO to ZnO in the composite increased the overall amount of oxygen vacancies in the samples. Our research lays the door for a simple, inexpensive, nontoxic, and quick technique to synthesize binary transition metal oxide-based electrode materials for high-performance supercapacitors.

Design and fabrication of reduced graphene oxide (RGO) incorporated NiCo2S4 hybrid composites as electrode materials for high performance supercapacitors

One of the most promising bimetallic sulphides for use in energy-storage systems is NiCo2S4, but further research is required to give it a high reversibility and electrochemical reaction capacity. In this study, we show the rational materials design of an ideal NiCo2S4 nanoparticle as a NiCo2S4/RGO nanocomposite, embedded in a reduced graphene oxide (RGO) matrix. NiCo2S4 nanoparticles, which ranged in size from 20 to 25 nm and were firmly fixed on the surface of RGO sheets, made up the produced composite. As predicted, the produced nanocomposite displayed a high specific surface area, a mesoporous structure, and high conductivity, resulting in a large electroactive area and rapid electron and ion motion. Additionally, we present the advancements in material science, showcasing the NiCo2S4/RGO nanocomposite electrode, which has a long cycle life of 5000 cycles, a high capacitance retention of 85.6 %, and an exceptional specific capacitance of 1505 Fg-1 at 1 Ag-1. A high active-material loading asymmetric supercapacitor serves as an example of the real-world use. The NiCo2S4/RGO nanocomposite exhibits an exceptional 48 Whkg-1 energy density at a power density of 985 Whkg-1, while maintaining a high power density of 7227 Wkg-1 density of 25 Whkg-1. The exceptional stability and electrochemical efficiency of the NiCo2S4/RGO nanocomposite validate that our methodical materials science and technology optimisation in the areas of active substance synthesis, electrode expansion, and device design/fabrication will help advance the development of high-performance supercapacitors in future years.

Chitosan-based high-performance flexible supercapacitor via “in-situ co-doping/self-regulation-activation” strategy

The construction of N, P co-doped hierarchically porous carbons (NPHPC) by a facile and green approach is crucial for high-performance energy storage but still an enormous challenge. Herein, an environment-friendly “in-situ co-doping, self-regulation-activation” strategy is presented to one-pot synthesize NPHPC using a phytic acid-induced polyethyleneimine/chitosan gel (PEI-PA-CS) as single precursor. NPHPC displayed a specific surface area of up to 1494 m2 g−1, high specific capacitance of 449 F g−1 at 1 A g−1, outstanding rate capability and cycling durability in a wide temperature range (−20 to 60 °C). NPHPC and PEI-PA-CS electrolyte assembled symmetric quasi-solid-state flexible supercapacitor presents superb energy outputs of 27.06 Wh kg−1 at power density of 225 W kg−1. For capacitive deionization (CDI), NPHPC also exhibit an excellent salt adsorption capacity of 16.54 mg g−1 in 500 mg L−1 NaCl solution at a voltage of 1.4 V, and regeneration performance. This study provides a valuable reference for the rational design and synthesis of novel biomass-derived energy-storage materials by integrating phytic acid induced heteroatom doping and pore engineering.

Design of High-Performance Symmetric Supercapacitor Based on WSe2 Nanoflakes for Energy Storage Applications

Design of High-Performance Symmetric Supercapacitor Based on WSe₂ Nanoflakes for Energy Storage Applications

NiAl LDH nanosheets based on Ag nanoparticles-decoration and alkali etching strategies for high performance supercapacitors

Layered double hydroxides (LDHs) represent a category of two-dimensional layered intercalation materials, showing significant potential as electrode materials for the production of high-energy-density supercapacitors due to their tunable composition, ease of synthetic modification, and low cost. Here, we constructed alkali-etched NiAl LDH-OH nanosheets/Ag nanoparticles (NPs) composite material (Ag@NiAl LDH-OH) for high-performance supercapacitors through a simple solvent-thermal reaction. The alkali treatment is employed to selectively etch some Al3+ ions, generating cation vacancies as active sites for energy storage. Additionally, under the simultaneous influence of strong alkalis and vacancies, the interlayer spacing of LDHs expands, aiding in the promotion of interlayer ion mobility. Meanwhile, the decoration of silver nanoparticles ensures excellent electron conductivity in the NiAl-LDH-OH nanosheets, thereby facilitating improved utilization of the active substance and achieving outstanding rate performance. The Ag@NiAl LDH-OH electrode, when prepared, demonstrates a significant increase in specific capacitance, reaching 1790 F g−1 at a current density of 1 A g−1. This represents approximately 7 times the specific capacitance of the pristine NiAl LDH electrode, with a capacity retention of 79 % even under a high current density of 20 A g−1. Moreover, the assembled asymmetric supercapacitor (ASC) attains a maximum energy density of 138.25 Wh kg−1 at a power density of 700 W kg−1, maintaining 81 % of its initial specific capacitance after 20000 cycles. This research introduces novel pathways for advancing high-energy-density SCs.

Enhanced electrochemical characteristics of Mn$$-$$Al-co-doped SnO2 nanostructures for high-performance supercapacitor application

Enhanced electrochemical characteristics of Mn$$-$$Al-co-doped SnO2 nanostructures for high-performance supercapacitor application

Mo modulating the structure of monoclinic vanadium dioxide boosting the aqueous ammonium-ion storage for high-performance supercapacitor

Supercapacitors (SCs) using ammonium-ion (NH4+) as the charge carrier (NH4+-SCs) have attracted continuous attention and vanadium-based materials are proved to have high-efficient NH4+-storage properties. Monoclinic vanadium dioxide, VO2(B), as an anode material applied to SCs has been rarely reported and modulating its electronic structure for boosted NH4+-storage is full of challenge. In this work, molybdenum-doped VO2(B) (Mo-doped VO2(B)) is designed and synthesize to enhance its NH4+-storage. The introduction of Mo atom into the crystal structure of VO2(B) can modulate its crystal structure and bring in some defects. Experimental results manifest that Mo-doped VO2(B) with 2 % Mo-doping shows the best electrochemical properties. Mo-doped VO2(B) achieves the specific capacitance of 1403 F g−1 (390 mAh g−1) at 0.1 A g−1 and the capacitance retention of about 98 % after 5000 cycle, superior to that of VO2(B) (893 F g−1, 248 mAh g−1 at 0.1 A g−1 and 60 % capacitance retention. The hybrid supercapacitor (HSC) assembled by Mo-doped VO2(B) and active carbon delivers good electrochemical performance with the energy density of 38.6 Wh kg−1 at power density of 208.3 W kg−1. This work proves that the Mo-doping is an efficient strategy for boosted NH4+-storage of VO2(B) and this strategy is like a Chinese idiom “like adding wings to a tiger” to guide the design of electrode materials for high-efficient NH4+-storage.

Solvothermal synthesis of Ni/Co-based metal-organic framework with nanosheets-like structure for high-performance supercapacitor

In the present investigation, we have successfully synthesized Ni/Co-based metal-organic framework thin films on stainless steel substrates via facile and low-cost solvothermal methods using 1,4-benzenedicarboxylic acid as an organic linker. X-ray diffraction technique (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), and electrochemical studies have been used to characterize the Ni/Co-MOF electrode materials. The purity and crystallinity of Ni/Co-MOF thin films were studied with the help of XRD. FESEM images showed the Ni/Co-MOF thin films have a nanosheets-like morphology which is suitable for supercapacitor applications. Functional groups present in the sample were confirmed by Fourier Transform Infrared Spectroscopy. The electrochemical performance of Ni/Co-MOF coated stainless steel was studied in 1M KOH electrolyte at various scan rates and current densities. The NiCo2-MOF material provides a specific capacitance of 1070 Fg-1 at the current density of 0.5 mAcm-2. Additionally, the NiCo2-MOF electrode exhibits an excellent energy density of 30.96Whkg-1 at a power density of 3.2kWkg-1 and outstanding cyclic stability with 85% retention after 5000 charge/discharge cycles. The results suggest that NiCo2-MOF offers excellent electrochemical performance and may be a potential candidate for supercapacitor application.

Hydrothermal synthesis of Ni, Co hydroxide nanosheet array on vertically suspended carbon cloth for flexible high-performance supercapacitors

The investigation of Ni(OH)2 electrode materials has been a prominent issue in the field of electrochemical energy. The slow ion diffusion kinetics and inherent low electronic conductivity of Ni(OH)2 restrict its electrochemical performance and application in practice. In this work, mixed-phase nickel-cobalt layered double hydroxide (NiCoLDH) array structures are successfully grown directly on vertically suspended carbon cloth (CC). In contrast to the traditional hydrothermal method, the vertically suspended carbon cloth affordes adequate reaction sites to ensure optimum array structure growth. This unique structure realizes a large mass loading of the active material. Meanwhile, the introduction of flexible electrode substrate carbon cloth effectively enhances the mechanical properties of the electrode. Due to the powerful electrochemistry kinetics, NiCoLDH/CC-1.5 exhibites a great capacitive and excellent rate performance of 1516.5 F g−1 at 1 A g−1 and 1073.75 F g−1 even at 20 A g−1. The assembled asymmetric supercapacitor demonstrates a favorable cycling stability (capacitance retention of 90.11 % after 10,000 cycles at 5 A g−1).

Structural and Electrochemical Evolution of Water Hyacinth-Derived Activated Carbon with Gamma Pretreatment for Supercapacitor Applications.

This study introduces a gamma pretreatment of water hyacinth powder for activated carbon (AC) production with improved electrochemical properties for supercapacitor applications. The structural and morphological changes of post-irradiation were meticulously analyzed using scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). The pretreatment significantly modifies the pore structure and reduces the particle size of the resulting activated carbon (WHAC). Nitrogen adsorption-desorption isotherms indicated a substantial increase in micropore volume with escalating doses of gamma irradiation. Electrochemically, the activated carbon produced from pretreated WH at 100 kGy exhibited a marked increase in specific capacitance, reaching 257.82 F g-1, a notable improvement over the 95.35 F g-1 of its untreated counterpart, while maintaining 99.40% capacitance after 7000 cycles. These findings suggest that gamma-pretreated biomasses are promising precursors for fabricating high-performance supercapacitor electrodes, offering a viable and environmentally friendly alternative for energy storage technology development.

Rational design of copper phosphate based polyanionic framework for high performance supercapacitor

The key to high-performing supercapacitors is their abundance, low cost, and ability to deliver high capacitance in a wide electrochemical window. A new class of phosphate-based polyanion material has been developed to deliver high capacitance via the effective utilization of their oxidation states. Cu3(PO4)2 was synthesized by the facile hydrothermal technique and delivers an ultra high specific capacitance of about 814 F/g with multiple discharge plateaus at a current density of 1 A/g within a voltage window ranging from 0.4 v to -1.2 V. This intriguing behavior is mainly due to the multi functional Cu while interacts with the electrolytic ions and also the inductive effect of a phosphate group (PO4)2− contributes to a high discharge voltage of -1.2 V during charging and discharging process. It shows exceptional cyclic stability of 100 % over 10,000 cycles without sacrificing its coulombic efficiency and it is pertinent the structural stability of the system. The symmetric device was fabricated and delivered power density and energy density of 4.5 kW/kg and 31.5 Wh/kg, and also maintained excellent cyclic stability at 92 % with high reversibility of charged ions. This offers new insights into the high potential of using polyanion-type compounds as high-capacity materials for advanced energy storage systems.

Electrochemical evaluation of low crystalline CoFe2O4@Reduced graphene oxide nanocomposite for hybrid supercapacitor application

The development of high-performance and cost-effective energy storage materials remains of significant scientific interest. Here, low-crystalline (LC) binary transition metal oxide (BTMO) CoFe2O4 is studied for its application in a hybrid supercapacitor. This disordered LC CoFe2O4 material was prepared by the co-precipitation method, and to improve the electron transport property of the LC CoFe2O4, a composite was prepared with reduced graphene oxide (RGO). LC CoFe2O4@rGO interconnected network enhances the electrolyte ion diffusion within the material. This CoFe2O4@RGO shows an electrochemical performance of 2247.82 mF cm−2 at a current density of 1 mA cm−2. The cyclic stability study is performed to CF@RGO 20 % electrode for 2000 cycles at 30 mA cm−2 current density. Further, to understand the charge storage mechanism, Dunn analysis is done, the capacitive and diffusion contributions to charge storage are studied. Besides, the charge transfer and diffusion characteristics of the material were studied using electrochemical impedance spectroscopy. So, these LC CoFe2O4@RGO based materials with improved ion diffusivity and flexibility in synthesis make them attractive candidates for the development of high-performance and cost-effective supercapacitor.

Synthetic nanoarchitectonics with ultrafast Joule heating of graphene-based electrodes for high energy density supercapacitor application

This study presents a novel approach for the development of high-performance supercapacitor (SC) electrodes using the Flash Joule Heating (FJH) method. Here, we report a direct and rapid synthesis of graphene-based electrodes via FJH. The technique involves microwave-assisted decomposition of citric acid and urea to form CNDs as precursors, followed by Flash Joule Heating (FJH) leading to the formation of graphene in seconds. The scalability of this method paves the way for the rapid production of graphene-based SC electrodes. Based on the characterisation using XRD, Raman, SEM and TEM, the FJH-treated CNDs yielded graphene on carbon fibre cloth with well-defined morphologies leading to superior electrochemical performance in supercapacitors. The FJH processed electrodes exhibited exceptional electrochemical performance with a specific capacitance of 279 F g⁻¹ at 1 A g⁻¹, significantly outperforming unflashed and low current flash processed electrodes. This exceptional performance can be attributed to the formation of high-quality, few-layered graphene with enhanced electrical conductivity and efficient ion transport properties. Moreover, a Symmetric supercapacitor is also assembled which demonstrated a specific capacitance of 106.5 F g⁻¹ at 1 A g⁻¹. It also exhibited an impressive energy density of 44.4 W h kg−1 at a power density of 1000 W kg⁻¹. This work demonstrates the feasibility of FJH as a rapid, scalable and cost-effective technique for the production of high-performance graphene-based electrodes for supercapacitor applications.