Sodium-ion Hybrid Supercapacitors Research Articles

Polyacrylic acid tethered onto the surface of vinyl functionalized silica nanoparticles for flexible hydrogel electrolytes of sodium ion hybrid supercapacitors

Hydrogel electrolytes, where water solvents and salts are confined in the porous networks of polymeric or inorganic solids, are attractive because they can resolve technical challenges of liquid electrolytes such as leakage, water decomposition, and mechanical instability. Herein, we demonstrate polyacrylic acid tethered onto the surface of vinyl functionalized silica nanoparticles (PAA-VSNP) hydrogel electrolytes through a sol-gel and radical polymerization process. The synthesis chemistry, the associated chemical structure, and the morphology of PAA-VSNP hydrogel electrolytes were comprehensively characterized analyzing FTIR, XPS and 13C and 29Si solid-state MAS NMR spectroscopies. The resulting PAA-VSNP hydrogel electrolytes were mechanically stable as verified by the stretchability up to 1122.75% of original length as well as ionically conductive as demonstrated by higher ionic conductivity of 20.23 mS cm−1 and lower activation energy of 0.106 eV than those of PVA counterparts. Integrating this PAA-VSNP hydrogel electrolytes with activated carbon and Na3V2(PO4)3/carbon composite and, flexible sodium ion hybrid supercapacitors (AC//PAA-VSNP //NVP@C SHSC SHSC) full cells could be fabricated. The as-fabricated AC//PAA-VSNP//NVP@C SHSC achieved a long-term cyclability over 4000 cycles and flexibility, delivering the larger energy and power densities 86.95 W h kg−1 and 19.94 kW kg−1 than those of AC//PVA//NVP@C and other works using hydrogel electrolytes.

Carbon nanofibers confined polyoxometalate derivatives as flexible self-supporting electrodes for robust sodium storage

Flexible self-supporting film electrodes, which eliminate the need for additional adhesive, conductive agents, or current collectors, offer significant advantages in terms of mechanical properties, specific capacity, and energy density for energy storage applications. In this study, we successfully developed a flexible film electrode by incorporating derivatives of Mo and Fe-based polyoxometalates (POMs-D) into carbon nanofibers (CNFs). The integration of CNFs significantly enhanced the structural stability of POMs-D, while the internally formed electrical field facilitated efficient electron transfer, resulting in good performance in sodium storage. The film electrode demonstrated a high capacitive contribution of 90.0 % for sodium uptake/release at a scan rate of 1.0 mV s−1. It maintained a capacity of approximately 170 mA h g−1 even after 8000 cycles at a current density of 3.0 A g−1. Moreover, the film electrode exhibited a decent capacity with a 40.0-fold increase in current density, along with high power capability and energy density in sodium-ion hybrid supercapacitors, showcasing the versatility. These findings unveil the structure-functionality relationship and offer an advanced approach for developing high-performance film electrode materials, opening new possibilities in the fields of material science and energy storage.

Composite cathode with low-defect NiFe Prussian blue analogue on reduced graphene oxide for aqueous sodium-ion hybrid supercapacitors

Although sodium-ion hybrid supercapacitor (Na-ion HSC) has attracted great interest, exploitation of suitable cathode materials for reversible Na+ insertion reaction remains a challenge. Herein, a novel binder-free composite cathode with highly crystallized NiFe Prussian blue analogue (NiFePBA) nanocubes in-situ grown on reduced graphene oxide (rGO) was fabricated via sodium pyrophosphate (Na4P2O7)-assisted co-precipitation and the subsequent ultrasonic spraying and chemical reduction. Profiting from the low-defect PBA framework and close interface contact of PBA and conductive rGO, the NiFePBA/rGO/carbon cloth composite electrode exhibits a high specific capacitance of 451F g−1, remarkable rate performance and satisfactory cycling stability in aqueous Na2SO4 electrolyte. Impressively, the aqueous Na-ion HSC assembled with the composite cathode and activated carbon (AC) anode manifests a high energy density of 51.11 Wh kg−1, superb power density of 10 kW kg−1 and the intriguing cycling stability. This work may open a door for scalable fabrication of binder-free PBA cathode material for aqueous Na-ion storage.

Preparation of two-dimensional sodium-boron phosphide nanosheets used for Na-ion hybrid supercapacitor devices

The development of high-performance sodium-ion hybrid supercapacitors (NISCs) are assembled using facile bulk preparations of sodium boron phosphide (Na-BP) nanosheets as the negative electrode (battery type) and mesocarbon microbeads (MCMB) as the positive electrode (capacitor type). The Na-BP is optimized through different annealing temperatures ranging from 700 to 900 °C under an inert atmosphere. The structural and morphological characterization of the as-prepared materials were investigated by XRD, micro-laser RAMAN, FE-SEM and FE-TEM. The hybrid NISCs were assembled with an Na-BP-700//MCMB, Na-BP-800//MCMB and Na-BP-900//MCMB device configuration with a wide potential of 1–4 V vs. (Na/Na+) and their revealed a gravimetric specific capacitance (Csp) of 48.66 F/g, 83.33 F/g and 125 F/g @ 0.1 A/g, respectively. Finally, Na-BP-900//MCMB device is exhibiting excellent capacity retention of 73.52% even after 10,000 cycles at 0.3 A/g. Moreover, sodium boron phosphide (Na-BP) facile preparations by annealing method and efficient scaleable process for preparing without pre-sodiations for future hybrid supercapacitor devices.

Recent Advancements in Energy Storage Based on Sodium Ion and Zinc Ion Hybrid Supercapacitors

The hybrid supercapacitor is appealing for commercial applications which have the aptitude to supply high energy density without compromising other supercapacitor properties. The Review is the complete insight of a reported Na+- and Zn+-based hybrid supercapacitor with the principle of the working mechanism. The combination of different semiconductor-based electrodes as the anode or cathode has been presented so researchers can update the progress of the sodium-ion-based hybrid supercapacitor (Na-HSC). In pursuit of replacing the activated carbon (AC)-based electrode due to its limited capacitance which results from an imbalance between the cathode and anode, we provide this Review with tables, figures, and their comparative studies. Society is moving toward smart electronic and hybrid devices that require flexibility, resilience, and high safety as people closely interact with these devices. The zinc ion hybrid supercapacitor (Zn-HSCs) is a comprehensive solution to toxic and explosive sodium-ion and lithium-ion devices. This Review represents recent reported metal oxides, chalcogenides, ceramics, MXenes, and carbon-based materials used for Zn-HSCs. Additionally, the hybrid capacitors with flexibility and the lightweight micro-supercapacitors have been studied and presented along with their challenges for pragmatic usage.

Application of 2D Materials to Potassium-Ion Hybrid Capacitors.

Metal-ion hybrid supercapacitors (MICs) are a new type of electrochemical energy storage (EES) device, consisting of a battery-type electrode and a supercapacitor (SC)-type electrode. Exhibiting the advantages of both batteries and SCs (e. g., good energy density, excellent power density and long cycle life), these advanced energy storage devices have considerable commercial application prospects. Among MICs, potassium-ion hybrid supercapacitors (PICs) have several further advantages, including abundancy of resources, low standard electrode potential, and low cost. PICs are regarded as potential substitutes for lithium- or sodium-ion hybrid supercapacitors. However, the practical applications of PICs remain limited, owing to the imbalance of kinetics and capacity between the electrodes, the slow ion/electron diffusion rate, and the poor electrode structural stability. Recently, 2D materials with distinct structures and fascinating features have elicited widespread attention for application in PICs, thus achieving significant enhancements, ranging from charge storage capacity to reaction kinetics. This Review discusses research progress in 2D materials for PICs. Firstly, the energy storage principle and development requirements of MICs are introduced. The pivotal advantages and significant roles of 2D materials in the fabrication of PICs are then discussed in detail. Lastly, the challenges and prospects of the application of 2D materials to high-performance PICs are presented.

Controlled design of metal oxide-based (Mn2+/Nb5+) anodes for superior sodium-ion hybrid supercapacitors: Synergistic mechanisms of hybrid ion storage

Due to the different energy storage mechanisms, anode electrodes have been challenging to match cathode ones in sodium-ion hybrid supercapacitors (Na–HSCs), resulting in low energy and power densities of the device. As a result, engineering anode materials with excellent electrochemical performance has aroused a great deal of interest. In this work, metal oxides (Mn2+/Nb5+) embedded into interconnected hollow carbon nanoboxes (MnO@HCNb and NaNbO3@HCNb) are fabricated by a simple template-assisted CVD method. Such a unique structure provides shortened solid-state transportation pathway and sufficient adsorption sites for Na+, with differing energy storage mechanisms from traditional Faradic reaction. Benefiting from it, the MnO@HCNb electrode exhibits an outstanding rate performance and an ultra-long lifespan of more than 10,000 cycles with 88.6% of capacity retention, which is rarely reported for oxide-based anodes. Moreover, energy storage mechanism of the composite and the important role of Mn/Na2O interface generated inside the core (MnO) - shell (C) structure during conversion reaction have been revealed. Hybrid ion storage mechanisms (adsorption, Faradic reaction and intercalation) are proposed with desirable compatibility, exhibiting uniform capacitive electrochemical behavior. Coupling with activated carbon cathode, a full cell of Na-HSC demonstrates a high energy density of 116 Wh kg−1 at 99 W kg−1 and 56.4 Wh kg−1 at 1.8 kW kg−1. Indeed, this work is inspiring to other researchers to further improve the electrochemical performance of anode materials by adjusting their energy storage mechanisms through structural reconstruction.

Capacitive conjugated ladder polymers for fast-charge and -discharge sodium-ion batteries and hybrid supercapacitors

A novel conjugated ladder polymer is developed, showing high capacity and rate capability in organic sodium-ion batteries and hybrid supercapacitors.

Hollow Structures Based on Prussian Blue and Its Analogs for Electrochemical Energy Storage and Conversion.

Due to their special structural characteristics, hollow structures grant fascinating physicochemical properties and widespread applications, especially in electrochemical energy storage and conversion. Recently, the research of Prussian blue (PB) and its analog (PBA) related nanomaterials has emerged and has drawn considerable attention because of their low cost, facile preparation, intrinsic open framework, and tunable composition. Here, the recent progress in the study of PB- and PBA-based hollow structures for electrochemical energy storage and conversion are summarized and discussed. First, some remarkable examples in the synthesis of hollow structures from PB- and PBA-based materials are illustrated in terms of the structural architectures, i.e., closed single-shelled hollow structures, open hollow structures, and complex hollow structures. Thereafter, their applications as potential electrode materials for lithium-/sodium-ion batteries, hybrid supercapacitors, and electrocatalysis are demonstrated. Finally, the current achievements in this field together with the limits and urgent challenges are summarized. Some perspectives on the potential solutions and possible future trends are also provided.

High performance sodium ion hybrid supercapacitors based on Na2Ti3O7 nanosheet arrays

Sodium ion hybrid supercapacitors (SICs) have attracted considerable attentions as a result of the highly cost-effective advantages. However, the large radius of Na+ ions imparts the serious capacity fading and poor rate performance. In order to obtain the ideal SICs with appealing electrochemical performance, we utilized porous Na2Ti3O7 nanosheet arrays as anode and hierarchical carbon nanosheets on Al foils as cathode. The assembled SICs can afford a high energy density of 49.0 Wh kg−1 at the power density of 825 W kg−1 in the voltage window of 1.0–4.0 V. Even at the ultrahigh power density of 4000 W kg−1, the SICs still manifested an energy density of 35.6 Wh kg−1. Meanwhile, the SICs demonstrated superior electrochemical performance at a current density of 3.3 A g−1, with a capacity retention of 73.89% going through 2000 cycles. In this regard, it is considered that engineering array architecture is an efficient way for high performance SICs.

Caging Nb2 O5 Nanowires in PECVD-Derived Graphene Capsules toward Bendable Sodium-Ion Hybrid Supercapacitors.

Sodium-ion hybrid supercapacitors (Na-HSCs) by virtue of synergizing the merits of batteries and supercapacitors have attracted considerable attention for high-energy and high-power energy-storage applications. Orthorhombic Nb2 O5 (T-Nb2 O5 ) has recently been recognized as a promising anode material for Na-HSCs due to its typical pseudocapacitive feature, but it suffers from intrinsically low electrical conductivity. Reasonably high electrochemical performance of T-Nb2 O5 -based electrodes could merely be gained to date when sufficient carbon content was introduced. In addition, flexible Na-HSC devices have scarcely been demonstrated by far. Herein, an in situ encapsulation strategy is devised to directly grow ultrathin graphene shells over T-Nb2 O5 nanowires (denoted as Gr-Nb2 O5 composites) by plasma-enhanced chemical vapor deposition, targeting a highly conductive anode material for Na-HSCs. The few-layered graphene capsules with ample topological defects would enable facile electron and Na+ ion transport, guaranteeing rapid pseudocapacitive processes at the Nb2 O5 /electrolyte interface. The Na-HSC full-cell comprising a Gr-Nb2 O5 anode and an activated carbon cathode delivers high energy/power densities (112.9 Wh kg-1 /80.1 W kg-1 and 62.2 Wh kg-1 /5330 W kg-1 ), outperforming those of recently reported Na-HSC counterparts. Proof-of-concept Na-HSC devices with favorable mechanical robustness manifest stable electrochemical performances under different bending conditions and after various bending-release cycles.

High-Performance Sodium Ion Capacitor Based on MoO2@rGO Nanocomposite and Goat Hair Derived Carbon Electrodes

Sodium ion based energy storage system is a rising alternative for imminent energy need. Especially sodium ion hybrid supercapacitors have attracted much attention because they store energy through battery-type anode and offer power by capacitor-type cathode. Accomplishing high energy and power densities in a single device is of significant interest, which can probably be done merely by making hybrid devices. Herein we have synthesized biomass (goat hair) derived activated carbon cathode with a high surface area of 2042 m2g–1 and MoO2@rGO composite anode materials. Goat hair, keratin rich biomass, has a great impact economically, and over 40 million tons per year is produced. Besides, reduced graphene oxide (rGO) has been used to facilitate the chemical stability, mechanical strength, and feasible pathway for electrochemical reactions of MoO2. Each electrode individually (half-cell) and combinedly (full-cell) showed good electrochemical performance which is almost equal to previously reported sodium ion b...

Bismuth oxide nanoflake@carbon film: A free-standing battery-type electrode for aqueous sodium ion hybrid supercapacitors

Aqueous hybrid supercapacitors are promising due to their low cost and high safety. Herein, a free-standing battery-type electrode of Bi2O3 nanoflake@C on carbon cloth is designed for aqueous sodium ion hybrid supercapacitors. Due to the integration of nanoarray architecture and the conductive carbon, the Bi2O3@C electrode exhibits a high specific capacity of 207mAh/g at 2A/g (6C), good rate capability and cycling stability (133mAh/g after 1000 cycles). With the activated carbon as the capacitive electrode and neutral sodium salts as the electrolyte, a 1.9V hybrid supercapacitor is assembled, delivering a high energy density of 18.94Wh/kg. The device can still maintain 72.3% of initial capacity after 650 cycles. The present work holds great promise for developing next-generation hybrid supercapacitors.

Rapid redox kinetics in uniform sandwich-structured mesoporous Nb2O5/graphene/mesoporous Nb2O5 nanosheets for high-performance sodium-ion supercapacitors

Sodium-ion hybrid supercapacitors have received great attracts for next-generation energy storage applications due to their high energy and power densities, as well as the abundant sodium resource. However, electrodes based on transition-metal oxides often suffer from low reversible capacity and sluggish redox kinetics, which seriously constrains the rate and cycling performance of the devices. Herein, a facile two-step hydrolysis synthesis is used to prepare uniform sandwich-like mesoporous Nb2O5/graphene/mesoporous Nb2O5 (G@mNb2O5) nanosheets as sodium storage materials. The mesoporous Nb2O5 layers on graphene are constructed by several nanometer-sized Nb2O5 particles. In virtue of the structural features, the G@mNb2O5 nanosheets electrode demonstrates high-rate capacity (293 and 125mAhg−1at 50 and 2000mAg−1, respectively) and stable cycling performance due to the rapid redox kinetics, including significantly increased surface pseudocapacitive contribution, improved sodium-ion diffusion coefficient, and short characteristic relaxation process. By employing activated carbon as cathode, a full sodium-ion hybrid device successfully demonstrates a high energy density of 56.1Whkg−1 at 120Wkg−1, and 9.7Whkg−1 at 7200Wkg−1, as well as a stable capacitance retention of ∼ 89% at 1Ag−1. The availability of capacitive Na-ion storage system presented here is attractive for cost-effective energy storage applications.

General Synthetic Method for N-Doped Macroporous Graphene-Encapsulated Mesoporous Metal Oxides and Its Application As New Anode Materials for Sodium-Ion Hybrid Supercapacitors

Employing graphene as an electrode material is advantageous for energy storage devices because it is flexible, highly electrically conductive, chemically stable, and has large theoretical surface area. However, graphene generally suffers from serious agglomeration and re-stacking due to its strong pi-pi stacking and van der Waals interactions between graphene nanosheets during charge-discharge process. To fully use the potential merits of graphene and improve the kinetics of electrode materials in energy storage devices, composites of graphene and metal oxides have been tested as electrode. Metal oxides in the composites, prevent the re-stacking of graphene. Graphene layers in the composites also suppress the volume change and agglomeration of metal oxide and provide a highly conductive matrix for metal oxide. We report a general method to synthesize mesoporous metal oxide@N-doped macroporous graphene composite by heat-treatment of electrostatically co-assembled amine-functionalized mesoporous silica/metal oxide composite and graphene oxide, and subsequent silica removal to produce mesoporous metal oxide and N-doped macroporous graphene simultaneously. Four mesoporous metal oxides (WO3-x, Co3O4, Mn2O3 and Fe3O4) were encapsulated in N-doped macroporous graphene. Used as an anode material for sodium-ion hybrid supercapacitors (Na-HSCs), mesoporous reduced tungsten oxide@N-doped macroporous graphene (m-WO3-x@NM-rGO) gives outstanding rate capability and stable cycle life. Ex situ analyses suggest that the electrochemical reaction mechanism of m-WO3-x@NM-rGO is based on Na+ intercalation/de-intercalation. To the best of our knowledge, this is the first report on Na+ intercalation/de-intercalation properties of WO3-x and its application to Na-HSCs.

Three-Dimensional Fibrous Network of Na0.21 MnO2 for Aqueous Sodium-Ion Hybrid Supercapacitors.

Sodium-ion hybrid supercapacitors are potential energy-storage devices and have recently received enormous interest. However, the development of cathode materials and the use of nonaqueous electrolyte remain a great challenge. Hence, aqueous Na-ion hybrid supercapacitors based on a three-dimensional network of NaMnO2 were developed. The cathode material was synthesized by the electro-oxidation of potassium manganese hexacyanoferrate nanocubes. The oxidized compound was confirmed to be Na0.21 MnO2 by various physical characterization methods. Manganese dioxide is a well-characterized material for aqueous asymmetric pseudocapacitors, but its usage at high operating voltages is limited due to the electrochemical stability of water. Nevertheless, high-potential and high-performance aqueous supercapacitors exhibiting a cell potential of 2.7 V were developed. Further, the practical applicability of an asymmetric supercapacitor based on NaMnO2 (cathode) and reduced graphene oxide (anode) was demonstrated by powering a 2.1 V red LED.

General Synthesis of N-Doped Macroporous Graphene-Encapsulated Mesoporous Metal Oxides and Their Application as New Anode Materials for Sodium-Ion Hybrid Supercapacitors

A general method to synthesize mesoporous metal oxide@N-doped macroporous graphene composite by heat-treatment of electrostatically co-assembled amine-functionalized mesoporous silica/metal oxide composite and graphene oxide, and subsequent silica removal to produce mesoporous metal oxide and N-doped macroporous graphene simultaneously is reported. Four mesoporous metal oxides (WO3− x , Co3O4, Mn2O3, and Fe3O4) are encapsulated in N-doped macroporous graphene. Used as an anode material for sodium-ion hybrid supercapacitors (Na-HSCs), mesoporous reduced tungsten oxide@N-doped macroporous graphene (m-WO3− x @NM-rGO) gives outstanding rate capability and stable cycle life. Ex situ analyses suggest that the electrochemical reaction mechanism of m-WO3− x @NM-rGO is based on Na+ intercalation/de-intercalation. To the best of knowledge, this is the first report on Na+ intercalation/de-intercalation properties of WO3− x and its application to Na-HSCs.

Hybrid Supercapacitors: High‐Performance Sodium‐Ion Hybrid Supercapacitor Based on Nb2O5@Carbon Core–Shell Nanoparticles and Reduced Graphene Oxide Nanocomposites (Adv. Funct. Mater. 21/2016)

High-power anode materials are essential for development of high-performance sodium-ion battery–supercapacitor hybrid systems (sodium-ion hybrid supercapacitors, Na-HSCs). On page 3711, J. Lee and co-workers report the synthesis of Nb2O5@carbon core–shell nanoparticles and reduced graphene oxide nanocomposites (Nb2O5@C/rGO), and their application to Na-HSCs as anode materials. The Na-HSCs using Nb2O5@C/rGO anode materials deliver high energy and power densities with stable cycle life.