Flexible Solid-state Supercapacitors Research Articles

The construction of a flexible solid-state asymmetric supercapacitor device using nickel-copper oxide nanoplates and carbon nanosphere serving as positive and negative electrode, respectively with excellent electrochemical capabilities

Here, nickel-copper oxide nanoplates (NCN) and carbon nanosphere (CNS) as positive and negative electrodes are synthesised via a hydrothermal protocol without adding any surfactant and binders. The NCN and CNS electrodes in KOH electrolyte exhibit superior specific capacitance of ∼ 2362.5 F g−1 and ∼ 246.11 F g−1 at 1 A g−1 respectively. The NCN and CNS retained 98.54 % and 97.88 % of the initial capacitance after 3000 galvanostatic charge–discharge (GCD) cycles, respectively. Additionally, an asymmetric supercapacitor (ASC) device NCN//CNS is constructed using NCN and CNS as positive and negative electrodes, utilizing poly(vinyl alcohol) PVA − KOH gel electrolyte separator. The ASC device demonstrates a maximum energy density of 50.4 Wh kg−1 (181.44 KJ kg−1) with a power density ∼ 750 W kg−1 at 1 A g−1, maintaining 90.4 % cyclic stability after 10,000 GCD cycles. The electrochemical outputs of the device present significant potential for the advancement of high-performance ASC devices in electronic applications.

Flexible solid-state asymmetric supercapacitor based on reduced graphene oxide (rGO)/ruthenium oxide (RuO2) composite electrode

Energy storage in flexible supercapacitor devices extensively depends on electrode design with good electrochemical as well as mechanical properties. Here, a cost-effective and scalable method is proposed for the synthesis of a reduced graphene oxide/ruthenium oxide (rGO/RuO2) composite thin film for flexible supercapacitor. The successive ionic layer adsorption and reaction (SILAR) method used to synthesize rGO/RuO2 composite electrode allowed the synthesis of amorphous RuO2 with optimized rGO composition. The morphological structure of rGO/RuO2 composite examined using a scanning electron microscope showed compact spherical microparticles coated on rGO sheets. The electrochemical measurements of rGO/RuO2 composite electrode revealed that the composite material achieved a specific capacitance of 1371 F g−1 at a scan rate of 5 mV s−1. Due to the combined impact of rGO and RuO2, a flexible solid-state asymmetric supercapacitor (FSS-ASC) of configuration rGO/RuO2/PVA-H2SO4/WO3 exhibited Cs of 114 F g−1 at 5 mV s−1 with 88% of capacitance retention after 5000 galvanostatic charge-discharge (GCD) cycles. The FSS-ASC provided a remarkable specific energy of 23 Wh kg−1 and a specific power of 613 W kg−1. The electrochemical features of rGO/RuO2 composite show a promising way to fabricate flexible supercapacitors.

Bio-based conductive polyurethane composites derived from renewable castor oil with enhanced self-healing ability for flexible supercapacitors

To alleviate the pressure on the petrochemical industry and address environmental concerns, the utilization of polyurethane (PU) derived from castor oil (CO) (as an ester polyol replacement of petrochemical-based materials) has garnered significant attention in recent decades. Extending the service life of materials requires imparting self-healing properties to vegetable oil-based polymers, an aspect that has received limited attention in current studies. However, low self-healing efficiency still poses a significant challenge, and non-conductivity also remains an obstacle in current research, crucial for their application in electronic devices. In this work, we present the first series of electrically self-healing biopolymer composites constructed by incorporating carbon nanotube (CNT) networks into crosslinked castor oil-based polyurethane (BPU) through a simple curing process. These materials address the challenges mentioned above and exhibit improved mechanical, electrical, and self-healing capabilities compared to other bio-based self-healing materials. The resulting BPU/CNT composite demonstrated exceptional repeated self-healing capacity, restoring both mechanical properties and electrical performance even after experiencing severe mechanical damage. Notably, this composite served as a conductive substrate in flexible solid-state supercapacitor (FSSC) devices. Consequently, the FSSC derived from the composite conductive substrate achieved an impressive 92.4 % self-healing efficiency even after undergoing 7 cutting/healing cycles. The device remained virtually unchanged even after being bent at a 180° angle with a bending radius of 1.6 mm, indicating excellent repeatability and durability. The exceptional self-healing ability, with ∼98 % electrical recovery at 100 °C for 70 s and 93 % at 80 °C after 6 min, of these composites was attributed to the synergistic interactions of the dynamic exchange reactions of disulfide bonds and dense hydrogen bonds within the BPU matrix, which provide a reversible dynamic polymer network. The healing efficiency of these dynamic bonds was evaluated by adjusting the composition ratio of the long linear chain of pTHF in hybrid polyols of the crosslinked polymer network. Overall, this work highlights a series of green, simple, and highly efficient self-healing polymer composites derived from renewable castor oil, and it establishes an essential framework for future sustainable polymer composite design.

Human-friendly flexible solid-state biodegradable supercapacitor based on Ti3C2Tx MXene film without adhesive structure

With the rapid development of biomedical technology, biodegradable and implantable energy storage devices for biosensor and bioelectronics applications have attracted the great attention of scientists. However, the limited energy density, poor biocompatibility, and excessive space occupation of existing biodegradable energy storage devices pose major challenges to their application in the biomedical field. To address these challenges, in this work, flexible Ti3C2Tx film with an adhesive-free structure construction is proposed as electrode material for the flexible solid-state biodegradable supercapacitor (FSBSC). The morphology and structure of MXene films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A 0.9% NaCl saline, similar human body fluids was used as the electrolyte solution to construct symmetrical FSBSC (Ti3C2Tx//NaCl-PVA//Ti3C2Tx-FSBSC) Poly(vinyl alcohol) (PVA). The Ti3C2Tx//NaCl-PVA//Ti3C2Tx-FSBSC exhibits a high capacitance of 112 F/g at 1 A/g, excellent rate capability (73.2% at 20 A/g), long lifetime (81.6% after 10,000 cycles), and high specific energy/power (62.3 Wh/kg at 1000.8 W/kg). The charge storage mechanism was analyzed using ex situ XRD, TEM, and density function theory (DFT). DFT results show that the Ti3C2Tx (Tx = O)) electrode possesses metallic properties. The calculated adsorption energies (Eads) and smaller diffusion barriers of Na+ ions further proved the outstanding performance of the Ti3C2Tx electrode. Moreover, the apparatus is entirely biodegradable, thereby paving a promising path for the progression of bioelectronics and biomedical energy storage technologies.

PH-Regulated host-guest architecture in molybdenum Dioxide/Carbon sphere composites for flexible solid-state supercapacitors

Compositing molybdenum dioxide (MoO2) with carbon sphere (CS) can greatly enhance the conductivity and structural instability to achieve its high theoretical capacitances. The controllable regulation of local architecture and host–guest interaction in the two-phase composites is highly desirable, but commonly hindered by the significant difference in formation mechanism between MoO2 and CS. Herein, a pH-regulated pre-intervention strategy was developed to provide control over the MoO2/CS architecture by adjusting the interplay between the precipitation kinetics of MoO2 and the polymerization effect of hydrochar precursor. By varying the pre-synthesis pH from 10.0 to 0.1, the corresponding dominant formation process of precursor changes from inside-out Ostwald ripening to protonation-induced electrostatic interactions, resulting in the structural evolution of MoO2/CS from hollow CS-encapsulating MoO2 nanosheets and solid CS-supporting MoO2 nanoparticles. The electrochemical test proved the former architecture possesses faster electrode kinetics, lower charge/ion-transfer resistance, and better electrochemical stability. An extended oxidation-etching method was further introduced to prepare mesoporous CS with excellent supercapacitive properties. A flexible solid-state asymmetric supercapacitor composed of optimal MoO2/CS structure as the positive electrode and mesoporous CS as the negative electrode delivers a high energy density of 52.3 W h kg−1 and power density of 14500 W kg−1, and good cycling stability with 89.7 % retention of the initial capacitance after 8000 cycles.

In situ growth of binder-free CoNi0.5-MOF/CC electrode for high-performance flexible solid-state supercapacitor application.

Metal organic frameworks (MOFs) with binder-free electrodes have shown promise for portable electrochemical energy storage applications. However, their low specific capacitance and challenges associated with the attachment of active materials to the substrate constrain their practical utility. In this research, we prepared a CoNi0.5-MOF/CC electrode by in situ growth of CoNi0.5-MOF on an H2O2-pretreated carbon cloth (CC) without using any binder. It exhibits a higher specific capacitance of 1337.5 F g-1 than that of CoNi0.5-MOF (∼578 F g-1) at a current density of 1 A g-1 and an excellent rate ability of 88% specific capacitance retention at a current density of 10 A g-1 after 6000 cycles. The as-assembled flexible asymmetric solid-state supercapacitor based on the CoNi0.5-MOF/CC positive electrode and a nitrogen-doped graphene (N-Gr) negative electrode exhibits an energy density of 61.46 W h kg-1 at a power density of 1244.56 W kg-1 and holds a stable capacitance of ∼125 F g-1 at 1 A g-1 when the flexible supercapacitor is bent, showing great potential for flexible electronics application. The H2O2 is indicated to play an important role, enhancing the adhesion of CoNi0.5-MOF on CC and reducing its charge transfer resistance by functionalizing the carbon fiber during the pretreatment of the CC matrix. The results provide a great way to prepare a flexible asymmetric solid-state supercapacitor with both high power density and high energy density for practical application.

High-performance flexible solid-state asymmetric supercapacitor with NiCo2S4 as a cathode and a MXene-reduced graphene oxide sponge as an anode

Ti3C2 MXenes have revealed immense potential in energy storage systems.

Ni-MOF Based Flexible Solid-State Supercapacitors in Aqueous and Non-Aqueous Electrolytes

Supercapacitors are high power density devices which acts a bridge between the batteries and conventional capacitors. Several emerging materials like Metal Organic Frameworks (MOFs) have been developed as electrode material for energy storage. MOFs are highly porous materials containing metal centers and organic moieties called ligands [1].They are widely employed for energy storage applications owing to their structural and morphological tunability [2]. In our recent research work, Ni MOF is synthesized using microwave assisted solvothermal technique at different temperature and metal to ligand ratios. Ni MOF is synthesized by varying metal to ligand ratio (M:L) as 1:1, 2:1, 3:1 and 4:1. The solution is heated by microwave irradiation technique [3] from room temperature to 150, 165, 180 and 200 °C to obtain light green colored samples. It is interesting to observe that different synthesis parameters lead to different morphologies thereby resulting in improved performance of Ni MOF. The structural and electrochemical characterizations reveal “why does a particular morphology exhibits better charge storage capacity?” The three electrode configuration experiments were conducted in aqueous electrolyte to evaluate the charge storage capacity. The results show that globules (∼1360 F g-1) perform better than nanoflower (∼850 F g-1), flakes (∼650 F g-1) and plates (∼450 F g-1) [4] respectively in 2M KOH at 0.5 A g-1. The reason is attributed to the low solution resistance (R sol) for globules, reduced charge transfer resistance (R ct) and the global and local n values of CPE.The synthesized material (Ni MOF) will be used as positive electrode material for flexible asymmetric supercapacitor. Recently, flexible state supercapacitors (FSSCs) have gained popularity due to their formability, flexibility and high energy density. Here, the objective is to increase energy density and power density by extending the operating potential window of the device. Hence, the aqueous electrolyte is substituted with PVDF based ionogels (ionic liquid gel polymer) to impart flexibility, bendability and high power density to FSSC. It is observed that the potential window improved remarkably from ~0.6 V (aqueous electrolytes) to ~5 V (ionic liquid). The reason is attributed to the absence of water, results in thermodynamic stability of the electrolyte. Also, the ionic liquid based FSSCs are non-flammable, non-toxic, thermally stable. In order to improve the conductivity and charge storage capacity some additives are incorporated in the gel polymer matrix. Herein, certain polar solvents are added to enhance the conductivity due to their high dielectric constant giving rise to faster ionic dissociation. MOF based flexible supercapacitors are fabricated and tested for their energy and power densities in conjunction with electrochemical and structural characteristics .

Doped Micron Silicon and Mxene Based Composite Anodes for High-Performance Li-Ion Batteries

With the world's energy needs constantly increasing, renewable energy sources must be technologically advanced and integrated with energy storage devices to ensure their uninterrupted operation. In recent decades, researchers have devoted substantial efforts to improve the energy density of lithium-ion batteries (LIBs) [1]. While graphite remains the commercial anode in LIBs, it’s very low theoretical capacity (372 mAh g-1) restricts its use in high-energy applications. Silicon (Si), owing to its high theoretical capacity of 4200 mAh g-1, natural abundance, and appropriate Li uptake potential (0.4 V vs Li/Li+), is a promising anode material [2]. However, its massive volume expansion restricts its practical use.In this study, micron-sized Si particles are combined with graphite. Micron Si is less expensive, and the synthesis process is simpler. The well-ground mixture (Si-G) is mixed with a polymer solution to generate pyrolytic carbon (upon carbonising). This aids in the buffering of mechanical stresses caused by Si volume expansion. Furthermore, direct exposure of Si to the electrolyte is avoided, stabilising the solid electrolyte interphase (SEI). The addition of a dopant improves the intrinsic conductivity of the material, resulting in increased capacity by providing electron and Li-ion transport channels. To further enhance the composite's performance, synthesized Mxene is added to promote the charge transport between micron Si. Using various techniques such as SEM-EDAX, XRD, Raman, and XPS spectroscopy, the composite's morphology and structure is studied which reveals uniformly distributed Si, C, and Mxene sheets that retain the sheet architecture.As an anode, the composite exhibits outstanding electrochemical performance which was evident by its impressive lithium storage specific capacity of 2003 mAh g-1 (based on weight of Si) even after long term cycling (at 1C rate). Additionally, the composite demonstrates superior rate performance with a specific capacity of 2439 mAh g-1 at 10 C rate, highlighting its potential for high-power applications. Moreover, the electrode displayed a low charge transfer impedance and fast electron transport, which improved the electrochemical performance. The reason for this improved performance is the unique structure consisting of Mxene and doping, which significantly increased the Li ion diffusion and the active sites. Also, low-cost micron Si is used which has a high tap density. Thus, this work provides an approach to develop high-capacity LIBs based on silicon. Keywords: Lithium-ion battery, micron silicon anode, Mxene, doping. References Liu, L. Kang, J. Hu, E. Jung, J. Zhang, S.C. Jun, Y. Yamauchi, Unlocking the Potential of Oxygen-Deficient Copper-Doped Co 3 O 4 Nanocrystals Confined in Carbon as an Advanced Electrode for Flexible Solid-State Supercapacitors, ACS Energy Lett. 6 (2021) 3011–3019. https://doi.org/10.1021/acsenergylett.1c01373.Zhou, Y. Liu, C. Du, Y. Ren, T. Mu, P. Zuo, G. Yin, Y. Ma, X. Cheng, Y. Gao, Polyaniline-encapsulated silicon on three-dimensional carbon nanotubes foam with enhanced electrochemical performance for lithium-ion batteries, Journal of Power Sources. 381 (2018) 156–163. https://doi.org/10.1016/j.jpowsour.2018.02.009.

Facile synthesis of layered reduced graphene oxide/polyaniline (rGO/PANI) composite electrode for flexible asymmetric solid-state supercapacitor

For supercapacitors, composite electrodes with a combination of reduced graphene oxide and polyaniline (rGO/PANI) have gained a lot of attention due to their synergistic effects. In this study, rGO-PANI composite thin films were deposited on a stainless steel substrate with various mass loadings by successive ionic layer adsorption and reaction (SILAR) method. The specific surface area rises from 13 m2 g−1 to 30 m2 g−1 with the introduction of rGO. Due to the composition modification and specific surface area enhancement, the specific capacitance (capacity) of 1348 F g−1 (1255C g−1) was obtained at 0.89 mg cm−2 mass deposition. Additionally, rGO/PANI/PVA-H2SO4/AC flexible asymmetric solid-state supercapacitor (ASSS) showed specific energy of 20 Wh kg−1 at specific power of 1198 W kg−1. The device maintained almost 96 % of Cs at bending angle of 160° and 75 % over 5000 cycles. This work illustrates a simple way to improve the capacity and stability of PANI via rGO composition for supercapacitor applications.

Highly Ionic Conductive, Stretchable, and Tough Ionogel for Flexible Solid-State Supercapacitor.

The increasing demand for wearable electronics calls for advanced energy storage solutions that integrate high electrochemical performances and mechanical robustness. Ionogel is a promisingcandidate due to its stretchability combined with high ionic conductivity. However, simultaneously optimizing both the electrochemical and mechanical performance of ionogels remains a challenge. This paper reports a tough and highly ion-conductiveionogel through ion impregnation and solvent exchange. The fabricated ionogel consists of double interpenetrating networks of long polymer chains that provide high stretchability. The polymer chains are crosslinked by hydrogen bonds that induce large energy dissipation for enhanced toughness. The resultant ionogel possesses mechanical stretchability of 26, tensile strength of 1.34MPa, and fracture toughness of 4175Jm-2 . Meanwhile, due to the high ion concentrations and ion mobility in the gel, a highionic conductivity of 3.18Sm-1 at room temperature is achieved. A supercapacitor of this ionogel sandwiched with porous fiber electrodes provides remarkable areal capacitance (615mFcm-2 at 1mAcm-2 ), energy density (341.7µWhcm-2 at 1mAcm-2 ), and power density (20mWcm-2 at 10mAcm-2 ), offering significant advantages in applications where high efficiency, compact size, and rapid energy delivery are crucial, such as flexible and wearable electronics.

SiC and N, S-doped carbon nanosheets and lignin-enhanced organohydrogel for low-temperature tolerant solid-state supercapacitors

The rational design of porous carbon materials and hydrogel electrolytes with excellent mechanical properties and low-temperature tolerance are significance for the development of flexible solid-state supercapacitors. In this study, we introduce a novel methodology for synthesizing SiC/N, S-doped porous carbon nanosheets from bamboo pulp red liquor (RL). We leverage the SiO2 and the sodium salt in RL as templates and sodium lignosulfonate as sulfur dopants for the pyrolysis process and use NH4Cl as a nitrogen dopant. This innovative approach results in a material with a remarkable specific surface area of 1659.19 m2 g−1, a specific capacitance of 308 F g−1 at a current density of 1 A g−1 and excellent stability. Additionally, we harness alkali lignin extracted from RL to enhance a poly (vinyl alcohol) (PVA) matrix, creating a gel electrolyte with low-temperature tolerance and outstanding mechanical properties. A flexible solid-state supercapacitor, which incorporates our electrodes and gel electrolyte, demonstrates high energy density (5.2 W h kg−1 at 251 W kg−1 power density). Impressively, it maintains 82 % of its capacitance over 10,000 cycles of charge and discharge. This provides a new solution for the development of flexible solid-state supercapacitors.

Self-supported heterojunction nanofibrous membranes for high-performance flexible asymmetric capacitors

Rational design of an electrode material with high flexibility and electrochemical performance is the key to wearable energy storage devices. Herein, a facile and productive needleless electrospinning method was introduced to prepare self-supported and flexible nanofibrous electrode materials for asymmetric capacitor. The MnO2 nanoclusters and ZIF67-derived Co3O4 nano-sheets were sequentially deposited on the surface of N, B-doped carbon nanofibers (hetero-junction MnO2/Co3O4/NB-PCNF). Attributing to the constructed multi-pathway for redox reactions on electrode, the specific capacitance of NB-PCNF and MnO2/Co3O4/NB-PCNF can reach up to 204.2F/g and 141.43F/g at a small current density of 0.1 A/g, respectively. In long-term cycling tests, the electrode materials exhibited excellent cycling stability and good rate capability. The electrodes were assembled with Potassium-ion hydrogel electrolyte to form a flexible asymmetric solid-state supercapacitor (FASS-SC). FASS-SC can reach a voltage window of 1.6 V. It provided 28.2 W h/kg at an energy density of 600 W/kg and a specific capacitance retention of 94.18 % after 10,000 cycles. The FASS-SC offers new research ideas for future flexible devices and wearable technologies.

Performance of solid-state symmetric supercapacitors based on Dy2S3 electrodes

Rare earth metal sulfides show good capacitance retention and better charge discharge performance. Dysprosium based materials could be a promising candidate for the utilization in supercapacitors due to it's multiple transition states. The dysprosium sulfide (Dy2S3) thin films were deposited on stainless steel (SS) substrate using facile successive ionic layer adsorption and reaction (SILAR) method. The films exhibits orthorhombic crystal structure and spherical nanoparticles morphology. The electrochemical supercapacitive performance of Dy2S3 film showed maximum specific capacitance (Cs) of 273 F g−1 at a scan rate of 5 mV s−1 with excellent (83 %) cycling performance over 2000 cycles in 1 M Na2SO4 electrolyte. The industrial application of SILAR deposited Dy2S3 thin film was examined by fabricating flexible solid-state symmetric supercapacitor (FSS-SSC) device with configuration Dy2S3/PVA-Na2SO4/Dy2S3. It exhibited Cs of 26 F g−1 with specific energy of 17 Wh kg−1 and specific power of 520 W kg−1. A good cyclic stability was observed with capacitive retention of 79 % at the scan rate of 100 mV s−1 after 5000 cyclic voltammetry (CV) cycles. This study highlights the potential application of Dy2S3 for supercapacitor application.

Flower-like FeCoNi ternary composite formed by interweaving nano needles for positive electrode material of supercapacitor

Ternary layered double hydroxide (LDH) are potential electrode material choices for supercapacitors (SCs) due to their various oxidation states and high theoretical specific capacitance. In this paper, FeCoNi-LDH composite with cross-braided flowers of nanoneedles has been prepared by a single-step hydrothermal method. By highlighting the structural and morphological advantages, the obtained ternary LDH shows lower resistivity in comparison with the binary LDH. As electrode material, the ternary LDH exhibits excellent electrochemical properties, such as superb specific capacitance of 2163.3 F·g−1 at 0.5 A·g−1 and good cycle retention rate of 93.8% after 5000 cycles at 20 A·g−1. Meanwhile, the assembled asymmetric flexible solid-state supercapacitor device can provide 44.8 Wh·kg−1 energy density at 807.5 W·kg−1. Moreover, two devices in series can also light up miniature light bulbs of different hues and maintain them for a long period when they are connected in series.

Hydro/solvothermally grown ZnS/MnO2-metal organic framework based hydrogel for all solid-state flexible supercapacitor

Flexible hydrogel-based supercapacitor (SC) has amassed significant attention because of its outstanding mechanical endurance, which allows it to maintain stable electrochemical performance even after numerous bending cycles. This feature demonstrates its enormous potential for seamless integration into bendable and wearable electronic devices while maintaining energy storage efficiency. Hence, we report hydro/solvothermally grown bimetallic ZnS/MnO2 Metal-organic Framework (MOF) based hydrogel fabricated via freeze drying method for an all solid-state based SC. The successful formation of cubic structured ZnS/MnO2-MOF is confirmed from X-ray diffraction analysis. A detailed morphological analysis of ZnS/MnO2-MOF based hydrogel reveals uniform dispersion of ZnS/MnO2-MOF in the hydrogel with a randomly oriented nanosheets like structure consisting of pores on the surface. The electrochemical measurements of ZnS/MnO2-MOF hydrogel based all-solid state symmetric SC with PVA-KOH electrolyte illustrates 112 F/g of specific capacitance at 1.5 A/g. Additionally, it also results in 30.3 Wh/kg of energy density with corresponding power density of 1050 W/kg. Furthermore, the device shows an exceptional stability, as indicated by its ability to retain 63 % of its capacitance over 20,000 cycles. This outstanding performance of the device is ascribed to the high conductivity of bimetallic MOF, PVA-KOH solid electrolyte. The electrodes presented here provides a promising alternative to traditional SCs performances.

Preparation of vanadium-based electrode materials and their research progress in solid-state flexible supercapacitors

Preparation of vanadium-based electrode materials and their research progress in solid-state flexible supercapacitors

Unravelling the trifunctional electrochemical properties of WSe2 nanosheets for self-powered hydrogen production

Two dimensional materials have received increasing recognition for their utility in electrochemical energy storage and conversion devices, as well as for self-powered systems. In this work, we are reporting the trifunctional electrochemical properties (such as energy-storage, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER)) of WSe2 nanosheets (prepared by a solvothermal method) towards the development of a self-powered system for uninterrupted hydrogen (H2) production. First, we have examined the energy storage properties of the WSe2 nanosheets in the form of flexible solid-state supercapacitor (FSSC) that shows the presence of ion-intercalation pseudocapacitance in the WSe2 nanosheets. The fabricated WSe2 FSSC possess a high device capacitance, energy density, and power density with 119% capacitance retention over 5,000 cycles. Second, we explored the electrocatalytic properties of WSe2 nanosheets that indicated they possess effective HER and OER properties with low overpotential (115 mV for HER and 312 mV for OER), respectively. Finally, a proof-of-concept self-powered system comprising a solar cell, WSe2 FSSC, and lab-scale WSe2 electrolyzer (with a low overpotential of 1.604 V at 10 mA cm−2) was demonstrated to overcome the power fluctuation issues for effective and uninterrupted H2 production.

Lignin/soy protein isolate-based hydrogel polymer electrolytes for flexible solid-state supercapacitors with low temperature resistance

Lignin/soy protein isolate-based hydrogel polymer electrolytes for flexible solid-state supercapacitors with low temperature resistance

NH3-Induced In Situ Etching Strategy Derived 3D-Interconnected Porous MXene/Carbon Dots Films for High Performance Flexible Supercapacitors

HighlightsPorous MXene (p-MC) films with 3D-interconnected ion transmission paths are constructed by NH3-induced in situ etching strategy.The flexible p-MC film electrodes exhibit a superior capacitance of 688.9 F g−1 with a good rate capability.The as-assembled p-MC solid-state flexible supercapacitors reveal superior electrochemical performance (99.7 F g−1 at 1 A g−1) and excellent flexibility.