Ion Hybrid Capacitors Research Articles

A Novel Hierarchical Structure of SnCu2Se4/d-Ti3C2Tx/NPC for a Lithium/Sodium Ion Battery and Hybrid Capacitor with Long-Term Cycling Stabilities

To alleviate kinetics imbalance and capacity insufficiency simultaneously, a novel hierarchical structure (SnCu2Se4/d-Ti3C2Tx/NPC) composed of delaminated Ti3C2Tx, SnCu2Se4 nanoparticles, and N-doped porous carbon layers is designed as a battery-type anode for lithium/sodium ion hybrid capacitor (LIC/SIC). The combination of SnCu2Se4 nanoparticles with high specific capacity, d-Ti3C2Tx with accelerated ion diffusion path, and NPC with enhanced electronic conductivity makes the SnCu2Se4/d-Ti3C2Tx/NPC composite possess excellent cycling stabilities in half-cell lithium-ion and sodium-ion batteries (LIB and SIB), with capacities of 114 mAh g-1 after 6000 cycles at 10 A g-1 for LIB and 296 mAh g-1 after 900 cycles at 1.0 A g-1 for SIB. The rate performance is also outstanding, with recovered capacity of 738 mAh g-1 at 0.1 A g-1 after cycles at current densities up to 50 A g-1 for LIB. Subsequently, LIC and SIC based on the SnCu2Se4/d-Ti3C2Tx/NPC anode and activated carbon cathode exhibit high energy densities of 147.9 and 158.6 Wh kg-1 at a power density of 100 W kg-1, respectively. They also possess distinctive long lifespans with capacity retentions of 78 and 81% after 10,000 cycles at 1.0 A g-1, respectively, demonstrating the feasibility of SnCu2Se4/d-Ti3C2Tx/NPC toward energy devices requiring high energy density, power density, and long-term stability.

Construction of porous carbon nanosheets by dual-template strategy for zinc ion hybrid capacitor

Carbonaceous zinc ion hybrid capacitors (CZHCs) have attracted numerous interests thank to the advantages of large energy density of zinc-ion battery and excellent security and high power density of supercapacitors. Nevertheless, the preparation of carbon cathode is relatively complex, and it is urgent to develop a simple and efficient preparation method. Herein, the porous carbon nanosheets (C-Xs) were prepared by dual-template strategy combined K2CO3 activation from anthracene molecules, which present unique layered sheet-like structures and high surface area, displaying excellent zinc storage properties as cathode for Zn‖C-X ZHCs. Zn‖C-800 ZHC achieves high discharge capacity of 121.7 mAh g−1, maximum energy density and power density of 109.3 Wh kg−1 and 15.6 kW kg−1 in 3 M ZnSO4 electrolyte, respectively. Moreover, the capacity retention of 96.2% and coulombic efficiency of ∼100% is obtained after 30,000 cycles. This work opens up a simple and efficient rout for the synthesis of carbon nanosheet cathode by dual-template strategy for ZHC.

Halloysite nanotube@N-doped graphene heterostructure enabled advanced potassium ion hybrid capacitor anode

Graphene is considered one of the most promising candidates for potassium ion hybrid capacitor (PIHC) anode due to its excellent electrical conductivity and short ion diffusion pathway. However, the relatively weak adsorption ability for potassium ion (K+) and poor K-storage ability of graphene hinder further large-scale application. Herein, a three-dimension electronic modulation strategy is proposed to introduce the electron deficient in graphene by fabricating a stable heterostructure with wrapping nitrogen-doped graphene (NG) on halloysite nanotube (HNTs) noted as HNTs@NG. The electronic structure of graphene is modulated in two-dimension (2D) plane direction through doping N atoms and perpendicular to 2D plane through forming covalent bonds between carbon atoms and oxygen atoms. The graphene with fine-regulated electronic structure delivers a high rate capability (387.1 mA h g−1 at 0.05 A g−1) and good capacity retention (105.8 mA h g−1 at 1.0 A g−1 over 2000 cycles) of HNTs@NG, and further insures energy density and cycle stability of as-developed PIHC. This finding offers an effective way to modulate electron structure of graphene to achieve the development advanced PIHC.

Ultra-small ZnS enhanced by Fe-N-C for advanced potassium-ion hybrid capacitors: Electronic transfer dynamics and ion adsorption capability

Metal sulfides are considered as potential anode candidates for potassium ion batteries (PIBs) and hybrid capacitors (PIHCs) due to their abundant energy reserves and decent theoretical capacity. Unfortunately, sulfide has severe volume expansion and slow kinetic reactions, resulting in unsatisfactory electrochemical properties. Herein, we have prepared both internal ultra-small ZnS nanoparticle cores and Fe-N-C shells (ZnS@FeNC), which exhibit excellent K+ storage properties, by a " kill two birds with one stone " approach. The synergistic effect between the ultra-small ZnS nanoparticles and the Fe-N-C network was verified as the origin of the enhanced K+ storage. The presence of the Fe-N-C bond can effectively enhance the potassium energy storage property of ZnS. More specifically, the Fe-N-C backbone alleviates the volume change of ZnS nanoparticles and facilitates the diffusion of KFSI electrolytes and the insertion/extraction of K+. When applied as PIBs, the ZnS@FeNC presents excellent specific capacity (471 mAh g−1 under 0.1 A g−1), stable cycling capability (0.011% capacity decay per cycle under 1 A g−1). More importantly, the PIHC devices exhibit the coexistence of excellent energy density (142.88 Wh kg−1 at 200.5 W kg−1) and excellent-power density (10025 W kg−1 with 36.1 Wh kg−1 retained) with ultra-long lifespan (88% capacity retention at 1 A g−1 after 3000 cycles). This unique structural design of this KFSI electrode provides indispensable guidance for energy storage materials.

In situ construction of hollow Ni3S2-Co9S8 heterostructures with enhanced reaction kinetics for potassium ion storage

Owing to high theoretical capacity, nickel sulfide and cobalt sulfide were highly competitive anode materials for potassium ion batteries (PIBs). However, the slow reaction kinetics and poor structural stability during the cycle hinder its application in the anode materials of PIBs. An exquisite heterogeneous structure of bimetal sulfide Ni3S2-Co9S8 nanotube wrapped with a nitrogen-doped carbon layer is prepared by in situ growth and solvothermal strategies. Such a well-designed structural provides a channel for the rapid diffusion of potassium ions, promotes charge transfer at the heterojunction interface and effectively improves the reaction kinetics. When used as the anode for PIBs, the Ni3S2-Co9S8@NSC exhibits an excellent capacity of 419 mA h g−1 after 200 cycles at 0.1 A g−1 and an excellent rate performance of 220 mA h g−1 at 5 A g−1. And after 200 cycles at 1 A g−1 and 2 A g−1, there are 285 mA h g−1 and 238 mA h g−1 high reversible capacities, respectively. Moreover, potassium ion hybrid capacitor can provide good energy density (148 Wh kg−1), power density (6639.3 W kg−1) and excellent cycle reversibility. Based on experiments and DFT calculations, the heterojunction structure in the composite can not only optimize the electronic structure and distribution to improve the conductivity, but also improve the potassium ion adsorption energy to accelerate the reaction kinetics. The excellent electrochemical properties reveal the advantages of reasonably designing carbon coated hollow heterostructures for energy storage.

In-situ evolution of CoS/C hollow nanocubes from metal-organic frameworks for sodium-ion hybrid capacitors

Alkaline ion hybrid capacitors bridge the performance gaps between batteries and supercapacitors by combining their merits in terms of energy and power densities. However, the poorly matched electrochemical kinetics between anodes and cathodes leads to reduced energy density and inadequate material utilization. Herein, a hybrid composite has been synthesized by the treatment of a cobalt-based metal–organic-framework (ZIF-67 nanocube), involving the chemical etching-coordination reaction and subsequent carbonization together with sulfidation treatment. The as-prepared material with a hollow structure is composed of nanosized CoS nanoparticles uniformly encapsulated in the mesoporous shells of carbon hollow nanocubes (CoS/C HC). The unique architecture endows CoS/C HC with abundant electrochemical active interfacial sites, good mechanical robustness, and effectively alleviated volume variation. CoS/C HC as electrode material exhibits distinguished sodium storage capabilities relating to specific capacity and prolonged cycling durability at high current densities. Moreover, a sodium-ion hybrid capacitor assembled by using CoS/C HC as anode and activated carbon as cathode delivers an energy density of 199 Wh kg−1 and a power density of 7113 W kg−1. The novel electrode material makes the hybrid capacitors more commercially possible by increasing the utilization of active material and improving structural stability.

N doped porous carbon nanosheets with enhanced zinc ion storage capability

Aqueous zinc ion hybrid capacitors are promising energy storage devices due to their high security, excellent environmentally friendly, big power density and zero carbon emissions. Herein, an aqueous zinc ion hybrid capacitor is designed using an N doped porous carbon nanosheet cathode, which prepares by in-situ self-activated and self-doped strategy from ethylenediamine tetraacetic acid tripotassium salt. The superior ions storage performance is owing to the electric dual layer capacitor deriving from ion adsorption/desorption, Zn2+ deposition/stripping and extra pseudo-capacitance of vibration in valence of nitrogen functionalities. Additionally, the results of theoretical calculation show that the adsorption energy between N-5, N-6 and zinc ions is −4.816 and −3.453 eV, respectively, and higher than those of other N groups. Consequently, the N doped porous carbon nanosheet cathode displays big discharge capacity of 204.7 mAh g−1 and high energy density of 143 Wh kg−1. Moreover, the Zn‖N doped porous carbon nanosheet zinc ion hybrid capacitor presents superior cycle stability with 95.5% of initial capacity after 20,000 cycles. This study opens up a universal method by incorporating reversible redox reactions through N functionalities to enhance the zinc ions storage properties of zinc ion hybrid capacitor.

A flexible zinc ion hybrid capacitor integrated system with layers-dependent V2CTx MXene

Ti3C2Tx MXene with unique physical and chemical properties are recently sparked tremendous interest in the energy storage field. Compared to Ti3C2Tx, V2CTx MXene is a more promising candidate for energy storage due to a low number of atomic layers in the V2CTx structure and varied valence states of vanadium. Herein, we report a flexible V2CTx electrode with different layers (named accordion-like V2CTx, multi-layer V2CTx, and few-layer V2CTx, respectively) fabricated by using electrophoretic deposition, then assembled a flexible zinc ion hybrid capacitor (ZIHC) by virtue of zinc anode and gel electrolyte. The areal capacitance of few-layer V2CTx based ZIHC is 54.12 mF cm−2 at 0.1 mA cm−2, which is greater than those of accordion-like V2CTx and multi-layer V2CTx based ZIHC. The outstanding electrochemical performance of few-layer V2CTx based ZIHC is attributed to its richer active sites and shorter ion transport routes. Additionally, the few-layer V2CTx based ZIHC also owns well cycling stability, with 81.48 % capacity retention after 8000 cycles, and a low self-discharge rate of 6.4 mV h−1, making it suitable for wearable devices. So, the V2CTx based ZIHC is integrated with a Ti3C2Tx based pressure sensor to monitor diverse human activities, demonstrating its steady and long-term power supply capacity as the energy storage device.

Hollow ppy@Ti2Nb10O29-x@NC bowls: A stress–release structure with vacancy defects and coating interface for Li capacitor

Interfacial coatings and lattice defects are effective strategies to optimize the electrochemical performance of bimetallic oxides. For safe potential window and large theoretical capacity, Ti2Nb10O29 presents considerable energy storage potential in lithium ion system. In this work, the composite (ppy@TNO-x@NC), used in lithium ion batteries and lithium ion hybrid capacitors, was prepared by the high volume density carbon bowl derived from biomass as the matrix, the Ti2Nb10O29 (TNO) containing oxygen vacancy as storage energy body, and the ultra-thin toughness polymer as coating. TNO modified by vacancy defects offers desirable electrochemical activity to acquire good ion embedding capacity. The ultrathin interfacial coating inhibits lattice misalignment caused by defects in bimetallic oxides, thus maintaining high stability of material. In addition, the hollow carbon bowl with large space utilization improves electron conduction and structural reliablity of material. In fact, as for lithium half battery, ppy@TNO-x@NC can deliver high capacitance of 325.1 mAh/g and retain 86.5 % capacitance after up to 2000 cycles. While for lithium-ion hybrid capacitor, the maximum energy density and power density of ppy@TNO-x@NC//AC reach 144.9 Wh kg−1 and 10 kW kg−1, respectively.

Surface engineering towards high-energy carbon cathode for advanced aqueous zinc-ion hybrid capacitors

Opportunities coexist with challenges for the development of carbon-based cathodes with a high energy density applied for zinc ion hybrid capacitors (ZIHCs). In the present study, a facile and effective surface engineering approach is demonstrated to greatly improve the energy storage ability of commercial carbon paper (CP) in ZIHC. Benefiting from the introduced oxygen functional groups, larger surface area and improved surface wettability upon air calcination, the assembled aqueous ZIHC with the functionalized carbon paper (FCP) exhibits a much higher areal capacity of 0.22 mAh/cm2 at 1 mA/cm2, outperforming the counterpart with blank CP by over 5000 times. More importantly, a superior energy density and power density of 130.8 µWh/cm2 and 7460.5 µW/cm2, are respectively delivered. Furthermore, more than 90% of the initial capacity is retained over 10000 cycles. This surface engineering strategy to improve the energy storage capability is potentially applicable to developing a wide range of high-energy carbon electrode materials.

Flexible zinc ion hybrid capacitors with high energy density and long cycling life based on nanoneedle-like MnO2@CC electrode

Zinc ion hybrid capacitor (ZIHC), as a new type of energy storage device, show great potential due to their high energy density and power density. However, their undesired structure deformation and poor cycling stability urgently need to be addressed. Herein, we developed a flexible ZIHC device with nanoneedle-like MnO2@CC as the cathode electrode and activated carbon derived from biomass material loofah as the anode electrode. During the charging generation, the by-products of Zn4(OH)6SO4⋅xH2O is proved to formed on the surface of the electrode, which is one of the key factors for the high capacity. Therefore, the flexible ZIHC device with ZnCl2/MnSO4/PVA electrolyte presents a good specific capacity of 1217.4 mF cm−2 at 2 mA cm−2, and high energy-power densities characteristic (676.3 μWh cm−2 at 2000 μW cm−2). More importantly, the device can maintain good performance after bended repeatedly, and the capacity of the device did not decay after 5000 cycles in aqueous electrolyte. The results of our study contribute greatly to the development of safe, reliable, and high electrochemical performance flexible ZIHC.

Architectural van der Waals Bi2S3/Bi2Se3 topological heterostructure as a superior potassium-ion storage material

• A hexagram-like 1D/2D van der Waals heterostructure (vdWH) composed of regularly crosslinked Bi 2 S 3 nanowires on Bi 2 Se 3 nanoplates was fabricated. • The Bi 2 S 3 /Bi 2 Se 3 vdWH potassium ion anode delivers a specific capacity over 600 mA h g -1 at 50 mA g −1 and a high-rate capability up to 2500 mA g −1 . • The behavior of heterogeneous interfacial reaction in terms of the trapping ability and diffusion kinetics was realized. • The potassium ion battery exhibits an energy density of 208 Wh Kg −1 over 850 cycles. • The potassium ion hybrid capacitor exhibits an energy density of 106 Wh Kg −1 over 3000 cycles. We design a hexagram-like 1D/2D van der Waals heterostructure composed of regularly crosslinked aligned 1D Bi 2 S 3 nanowires on 2D Bi 2 Se 3 nanoplates, termed Bi 2 S 3 /Bi 2 Se 3 vdWHs, for use as anode materials for potassium ion batteries (PIBs) and hybrid capacitors (PIHCs). Thanks to the mixed dimensional topological heterostructures, the abundant network-contacted heterojunctions facilitate ordered ion/electron transport around the surface network and interior topological materials, and simultaneously promoting the K + diffusion, electron transfer, and electrolyte infiltration. The Bi 2 S 3 /Bi 2 Se 3 vdWHs deliver an attractive specific capacity over 600 mA h g -1 at 50 mA g −1 , a high-rate capability up to 2500 mA g −1 , and excellent cycling stability. Theoretical models, in tandem with operando X-ray diffraction and HRTEM analysis reveal the behavior of heterogeneous interfacial reaction in terms of the trapping ability and diffusion kinetics, confirming the reversible conversion reaction of Bi 2 S 3 /Bi 2 Se 3 vdWHs. Finally, the full cells of PIBs and PIHCs coupled with Bi 2 S 3 /Bi 2 Se 3 vdWHs anodes exhibit excellent performances of 208 and 106 Wh kg −1 over 850 and 3000 cycles, respectively, demonstrating their feasibility towards practical applications. Our study provides a new insight into architectural strategies for heterogeneous interfaces to realize intelligent kinetic control strategies of chalcogenide topological materials for advanced energy storage.

Cover Image

AbstractRechargeable aqueous zinc ion hybrid capacitors were developed in this work via engineering a Zn‐anode/electrolyte interface and 3D Graphene‐like Carbon Cathode. The designed hybrid device realizes the battery‐like specific energy (203 Wh kg–1) and supercapacitor‐type power capability (4.9 kW kg–1) and cycling stability (96.75% retention over 30000 cycles) at a much lower price than the commercial supercapacitors and Li‐ion batteries. This work (DOI: 10.1002/inf2.12344) provides a scalable yet cost‐effective approach for developing a next‐generation Zn‐ion‐based energy storage system. image

Supermolecule-mediated defect engineering of porous carbons for zinc-ion hybrid capacitors

Zinc ion hybrid capacitors hold great potential for future energy storage that requires both high energy density and high power capability. However, the charge storage mechanism of porous carbon cathode is ambiguous in Zn2+ ion-containing aqueous solutions, albeit porous carbon usually stores charge by electric double-layer capacitance. Herein, we developed a supermolecule-mediated direct pyrolysis carbonization strategy to convert sustainable sodium lignosulfonate resources into three-dimensional highly heteroatom-doped porous carbons with large mesopores. Through this strategy, we obtained lignin-derived porous carbons with high heteroatom dopings (14.9 at% nitrogen and 4.7 at% oxygen) and relatively high specific surface areas. Furthermore, the nitrogen doping configurations were mainly edge-nitrogen dopants even under high pyrolysis temperatures (> 900 °C). Lignin-derived nitrogen-doped porous carbon showed a high gravimetric specific capacitance of 266 F g−1 with high rate capability, which is endowed by the increased surface pseudocapacitance. First-principles calculations and molecular dynamics simulations indicate that the edge nitrogen and oxygen dopants contribute to the reversible adsorption/desorption of zinc ions and protons. Pores size less than 6.8 Å can cause a significant diffusion energy barrier for the hydrated zinc ions, thus degrading the capacitance and rate capability.

Molten Salt Self-Template Synthesis Strategy of Oxygen-Rich Porous Carbon Cathodes for Zinc Ion Hybrid Capacitors.

Porous carbon materials are widely used in capacitive energy storage devices because of their chemical stability, low cost, and controllable textures. Molten salt self-template methods are powerful and sustainable synthesis strategies for preparing porous carbons with tunable pore textures and surface chemistries. Herein, we propose a self-template synthesis strategy for preparing oxygen-rich porous carbons (ORC) by directly carbonizing potassium chloroacetate (ClCH2COOK) as the single carbon source. The potassium chloride salts generated in the carbonization play the roles of the template and etchant agent in the pore formation process. The as-prepared ORC samples feature abundant mesopores (average pore sizes of 1.95-2.19 nm and mesopore ratio of 36.4%), high specific surface areas (1410-1886 m2 g-1), and high oxygen doping levels (4.3-8.2 atom %). The zinc ion hybrid capacitors with an ORC cathode exhibited an ultrahigh capacitance of 308 F g-1 at 0.5 A g-1 and a high energy density of 136.5 Wh kg-1 at a power density of 570 W kg-1. Density functional theory demonstrates that oxygen-containing functional groups are conducive to the adsorption of Zn ions. Our work proposes a general synthesis methodology for the synthesis of oxygen-rich porous carbons for a variety of electrochemical energy storage devices.

Porous carbon nanofibers derived from low-softening-point coal pitch towards all-carbon potassium ion hybrid capacitors

Porous carbon nanofibers derived from low-softening-point coal pitch towards all-carbon potassium ion hybrid capacitors

Flexible reduced graphene oxide/V2O5 composite battery-type cathode and MXene capacitor-type anode for aqueous zinc ion hybrid supercapacitors with high energy density

To meet the rapid development of flexible supercapacitors with both high energy density and power density, hybrid ion capacitors like lithium and sodium ion capacitors have attracted more and more attention. However, the hidden danger associated with the using of organic electrolytes limit their practical application. In this regard, a new configuration flexible zinc-ion hybrid supercapacitor (ZHSC) based on free-standing films of RGO-V 2 O 5 (RGV) battery-type cathode and RGO-MXene (RGM) capacitor-type anode in aqueous electrolyte has been designed. The RGM/RGV system consists of specific layered structure, short ion diffusion pathway, high electrical conductivity and exceptional structural stability. As a result, the ZHSC based on RGM/RGV exhibits excellent electrochemical performance, including a large specific capacity of 175 F g −1 at 0.5 mV s −1 , a maximum energy density up to 107.2 Wh kg −1 (321.6 W kg −1 ) and a high capacitance retention of 81% of its initial capacitance (10,000 cycles). Additionally, the ZHSC displays a high specific capacity of 125 F g −1 at 0.5 mV s −1 even in an aqueous gel electrolyte. More importantly, supercapacitors based on the composite films exhibit stable flexibility electrochemical performance. The investigation provides an essential strategy to synthesize composite films for application in high performance flexible hybrid supercapacitors. • A novel flexible aqueous zinc-ion hybrid supercapacitor (ZHSC) was fabricated. • The electrodes consist of specific layered structure, short ion diffusion pathway and high electrical conductivity. • The ZHSC delivers ultrahigh specific capacitance, excellent energy density and power density in aqueous electrolyte. • The ZHSC shows stable electrochemical performance under different bending states.

B, F Co-doping flexible carbon nanofibers as a fast and stable anode for potassium-ion hybrid capacitor

Potassium ion hybrid capacitors (PIHCs) have attracted widespread attention as combining the advantages of potassium ion batteries (PIBs) with supercapacitors. However, the sluggish kinetics caused by the large radius of K+ hinder the practical application of PIHCs. Herein, we synthesized a boron and fluorine co-doping interlaced network porous carbon nanofibers (BF-PCNFs), which was used as the freestanding anode of PIHCs the freestanding anode of PIHCs to alleviate large volume expansion and increase conductivity. Benefiting from the B, F co-doping and porous interlace nanostructure of BF-PCNFs, the anode shows 185 mA h g−1 under a load of 12.6 mg cm−2, a reversible capacity of 176 mA h g−1 at 1000 mA g−1 after 6000 cycles, and the capacity retention from 100 mA g−1 to 5000 mA g−1 is 62%. Furthermore, the PIHCs based on BF-PCNFs as anode and activated carbon as cathode exhibit an energy density of 87 Wh kg−1 and a power density of 393 W kg−1. The capacity retention is as high as 78% over 4000 cycles. Considering the exceptional rate performance, long cyclability and high-mass-loading, our work may supply a new strategy for designing novel energy storage devices with outstanding performance.

Pseudocapacitive Vanadium Nitride Quantum Dots Modified One-Dimensional Carbon Cages Enable Highly Kinetics-Compatible Sodium Ion Capacitors.

The kinetics incompatibility between battery-type anode and capacitive-type cathode for sodium ion hybrid capacitors (SIHCs) seriously hinders their overall performance output. Herein, we construct a SIHCs device by coupling with quantum grade vanadium nitride (VN) nanodots anchored in one-dimensional N/F co-doped carbon nanofiber cages hybrids (VNQDs@PCNFs-N/F) as the freestanding anode and the corresponding activated N/F co-doped carbon nanofiber cages (APCNFs-N/F) as cathode. The strong coupling of VN quantum dots with N/F co-doped 1D conductive carbon cages effectively facilitates the ion/electron transport and intercalation-conversion-deintercalation reactions, ensuring fast sodium storage to surmount aforesaid kinetics incompatibility. Additionally, density functional theory calculations cogently manifest that the abundant active sites in the VNQDs@PCNFs-N/F configuration boost the Na+ adsorption/reaction activity well which will promote both "intrinsic" and "extrinsic" pseudocapacitance and further improve anode kinetics. Consequently, the assembled SIHCs device can achieve high energy densities of 157.1 and 95.0 Wh kg-1 at power densities of 198.8 and 9100.5 W kg-1, respectively, with an ultralong cycling life over 8000 cycles. This work further verified the feasibility of kinetics-compatible electrode design strategy toward metal ion hybrid capacitors.

Dimensional engineering of anode materials for high performance potassium ion hybrid capacitor—A review

Dimensional engineering of anode materials for high performance potassium ion hybrid capacitor—A review