Li-ion Hybrid Capacitors Research Articles

Nanoporous Nb2O5 with an Amorphous Structure for the Application as a Binder-Free Anode of a Hybrid Li-Ion Capacitor

Nanoporous Nb₂O₅ with an Amorphous Structure for the Application as a Binder-Free Anode of a Hybrid Li-Ion Capacitor

Hierarchical porous carbon originated from the directing associated with activation as high-performance electrodes for supercapacitor and Li ion capacitor

A template-directing methodology combined with post-activation methodology is developed to synthesize hierarchical porous carbon (HPC) with a unique nanocage-like morphology and exceptional structural integrity, utilizing light MgO nanocapsules as templates and coal pitch as precursor. The specific surface area and pore volume of HPC can be precisely adjusted by varying the mass ratio between the chemical activator and PC. This optimized pore structure significantly enhances the kinetics of electrolyte ion diffusion, which is a crucial point for the high-performance supercapacitors. The superior capacitive energy-storage behavior with respect to capacitance and rate capability (168 and 160 F g−1 at 1 and 100 A g−1) can be delivered by HPC electrode as compared to commercial activated carbon and pristine PC. The great compatibility to high gravimetric and areal capacitances (173 F g−1 and 1391 mF cm−2) can still be achieved even at 8 mg cm−2 for HPC electrode. Moreover, a full hybrid Li ion capacitor fabricated using HPC, delivers outstanding rate capability, excellent Ragone performance, and exceptional cyclability, establishing the potential of this material for advanced energy storage systems. The successful integration of template-directed synthesis with activation techniques presents a scalable approach to convert coal pitch into high-performance electrode materials.

Green synthesis of MOF/CNT gels via in-situ physical mixing strategy toward quasi-solid-state Li-ion hybrid capacitor

Compositing metal-organic frameworks (MOFs) with carbon nanotubes (CNTs) can effectively improve their conductivity and structural instability to achieve excellent supercapacitor performance. However, the two main traditional composite strategies of ex-situ physical mixing and in-situ chemical growth still have some limitations, such as the heterogeneous dispersity and the destruction of CNTs, etc. In this work, we propose a green in-situ physical mixing method to construct advanced MIL-100-Fe/CNT architecture. An adding content of 10 % for CNTs results in the optimal composite structure within homogeneous dispersion and favorable interactions between MOF host and CNT guest, achieving a high specific capacitance of 431.6 F g−1 at the current density of 1 A g−1, which is much higher than of the pristine MOF (143.1 F g−1). An in-depth electrochemical study illustrates that the moderate addition of CNTs promotes the fast charge transfer dynamics of Li-ion in the composite electrode while the excessive CNTs will lead to localized aggregation and property degradation. A quasi-solid-state Li-ion hybrid capacitor device was assembled, displaying a high energy density of 20.2 W h kg−1 and a long cycle life of 89.4 % capacitance retention after 8000 cycles. The contribution has provided a new direction for constructing advanced MOF-based composite architectures for energy storage applications.

Edge-rich reduced microcrystalline graphite oxide for Li-ion hybrid capacitors with ultrahigh volumetric energy density

Compact and high-performance carbon cathode materials are vital to improve the gravimetric and volumetric energy/power density of advanced energy storage devices such as lithium-ion hybrid capacitors (LIHCs). Graphite has a high mass density and the areal specific capacitance at the edge plane is far larger than that in the basal plane. Hence, increasing the proportion of edges can effectively improve the specific capacitance of the carbon material. However, it is challenging to expose more edges of graphite due to its high thermal and chemical stability. In this work, a compact cathode is prepared through a facile high-temperature ammonia treatment of microcrystalline graphite oxide (MGO). The obtained edge-rich reduced microcrystalline graphite oxide (ER-RMGO) demonstrates abundant edge sites, a high mass density of 1.48 g cm−3 and an extremely high areal specific capacitance of up to 319.3 μF cm−2. As a result, the fabricated Li-ion hybrid capacitor delivers an ultrahigh volumetric energy density of 392 Wh L−1 and power density of 9.49 W LkW L−1. This work sheds light on the great potential of microcrystalline graphite derived edge-rich carbon materials for compact capacitive energy storage.

Effect of Na-ion doping on the improved electrochemical performances of olivine structured LiNi1/3Mn1/3Co1/3PO4 for Li-ion hybrid capacitors

Effect of Na-ion doping on the improved electrochemical performances of olivine structured LiNi1/3Mn1/3Co1/3PO4 for Li-ion hybrid capacitors

Hierarchical Electrode Constructed by carbon-coated Metal-Organic Framework Derivatives Supported on two-dimensional Ti3C2 nanosheets for Hybrid Li-ion Capacitors

BackgroudMetal-organic frameworks (MOFs) (e.g., Co-MOF) had been a popular platform for synthesis electrode materials for lithium-ion capacitors (LICs) because of their high theoretical specific capacity and unique structural advantages. Recent researches have focused on the development of MOFs derivative-based composites with high specific surface area, high structural stability, and high electrical conductivity. Methods: Here a distinct Ti3C2/Co3O4@C heterostructure composite was prepared by a straightforward method via hydrogen bonding with carbon-coated Co-MOF derivative anchored on Mxene-Ti3C2 nanosheets. The carbon-coated hollow Co3O4 polyhedra could shorten Li+ diffusion paths, increase the specific surface area and mitigate structural changes during the Li+ storage process. Moreover, Ti3C2 sheets were acted as a conductive network, which could increase the Li+ transport rate and stability of the structure. SignificantServing as anode material, Ti3C2/Co3O4@C electrode showed a specific capacity of 1341 mAh/g at current density of 0.1 A/g, with 93% capacity maintenance at 2 A/g after 1000 cycles in the lithium-ion half cell. Furthermore, Ti3C2/Co3O4@C//AC LIC delivered a high energy of 106 Wh/kg at 7632 W/kg. The distinct heterostructure, straightforward, and excellent performance of the Ti3C2/Co3O4@C composite as anode could provide application prospects in LICs with high energy/power density.

Nanostructured Octahedral MnF2 as Anode Material for constructing Ultra-High Power Li-ion Hybrid Capacitors

Nanosizing materials is an effective approach to increase the contact area between the material and electrolyte, resulting in high specific capacity due to the availability of more active sites. In this study, well-formed nano-MnF2 was synthesized using a safe fluorine source through a one-step solvent thermal method. The specific capacity of nano-MnF2 as an anode material was 624.8 mAh g−1 after 200 cycles at 0.1A g−1, and it could reach up to 67.6 mAh g−1 after 6000 cycles at 2A g−1. Meanwhile, the use of ex-situ measurements confirmed that the capacity growth of MnF2 in cycling is mainly due to its valence change. Additionally, lithium-ion hybrid capacitors (LIHCs) assembled using high-performance Mn-150 as the anode material and coconut shell biomass-derived carbon (CSBC) as the cathode material exhibited high specific capacitance (66.9F g−1 at 0.05A g−1), greater energy density (163.8Wh kg−1 at 105W kg−1), and higher power density (63000W kg−1 at 20.9Wh kg−1). The successful assembly of Mn-150//CSBC LIHCs and their ultra-high-power density demonstrate the great potential of MnF2 anode materials in LIHCs, providing new insights for future development of anode materials for LIHCs.

Manipulating chaotropic anion enables lacked H-bond aqueous electrolyte for lithium-ion hybrid capacitor

Aqueous electrochemical energy storages have multiple advantages especially safety performance in the energy storage process. The high concentration aqueous electrolytes with a wide electrochemical stable voltage window (ESW) solves the key problems of aqueous electrochemical energy storages. It effectively breaks the limitation of H2O molecule decomposition to realize aqueous electrochemical energy storage with high operating voltage. However, the slow ion transport and high cost limit their application in power-type storages. Here, the lacked H-bond aqueous electrolyte (LHE) is proposed by investigating the structures and properties of aqueous electrolytes with various chaotropic anions. The LHE achieves high conductivity, low viscosity, and low cost while ensuring a wide ESW. These excellent properties originate from the OTf− effect on the solvation structure of cations and the number of H-bonds. An aqueous Li-ion hybrid capacitor (LHC) with the LHE exhibits high operating voltage of 2.5 V and high ESW utilization of 92.6 %. The aqueous cathode electrolyte interphase formed by anions on the cathode surface also achieved a long cycle life for the LHC. It has guided the development of novel electrolytes for electrochemical energy storage.

High-performance dual carbon Li-ion hybrid capacitor constructed from N, S - co-doped candle soot derived carbon nanoparticles anode and porous carbon cathode

Lithium-ion capacitors (LICs) are one of the emerging and fast-growing energy storage devices due to their combination of high power/energy characteristics with long cyclic life. However, the kinetic imbalance between anode and cathode is a major hurdle in achieving high-performance LICs. In this work, we propose a dual carbon LIC device using a candle soot pollutant as the single source for the first time to derive a novel N, S-co-doped fractal-like carbon nanoparticles (NS-CSC) as anode and an activated co-doped porous carbon (NS-ACSC) as a cathode. The NS-CSC anode and NS-ACSC cathode half-cell demonstrate an outstanding reversible ion storage capacity of 2258 mAh g−1 and 125 mAh g−1 at 50 mA g−1, respectively. Benefitting from the doped carbon electrodes, the mass ratio optimized dual carbon NS-CSC//NS-ACSC (1:2) LIC device achieves high specific energy of 101.7 Wh kg−1 at 113 W kg−1, retaining a capacity of 81 % after 7000 cycles at 2 A g−1. Moreover, the fabricated LIC device powers a red light-emitting diode for a continuous 15 min, indicating its potential use in practical applications. This work emphasizes that the candle soot pollutant-derived carbon nanoparticles have the potential for use as an electrode in advanced energy storage devices.

MoS2-Graphene Composite Electrode for High Energy Hybrid Li-Ion Capacitors

A hybrid Li-ion capacitor represents an emerging class of devices, which results from the coupling of high energy density battery-type electrode materials at one side and high-power EDLC electrode at other side. Here, we develop a simple and scalable method including ball-milling, followed by heating process to synthesize MoS2/graphene composite material. The structural and morphological analyses were carried out by powder X-ray diffraction (PXRD) analysis and scanning electron microscopy (SEM) technique. The composite electrode delivers high specific capacity (725 mAh g−1 at 0.1 A g−1 and 265 mAh g−1 at 5 A g−1). The hybrid device composed of MoS2/graphene composite electrode as negative electrode and commercial activated carbon as the positive electrode exhibits a high energy density of 117 Wh kg−1 at 200 W kg−1 and a maximum power density of 3.9 kW kg−1 at 79 Wh kg−1. The hybrid device showed a long cycle stable Li storage capacity (62% after 5000 cycles at 1 A g−1).

Perovskite fluoride NaNiF3 with hollow micron sphere structure as anode for Li-ion hybrid capacitors

Perovskite fluoride NaNiF3 with hollow micron sphere structure as anode for Li-ion hybrid capacitors

A High-Energy Density Li-Ion Hybrid Capacitor Fabricated from Bio-Waste Derived Carbon Nanosheets Cathode and Graphite Anode.

The Li‐ion hybrid capacitor (LIHC) system explores the possibility of achieving both high energy and power density in a single energy storage system with an intercalation anode and capacitive cathode. However, to achieve a high power and energy‐based system, the properties of the cathode electrode material are vital. Here, bio‐waste plant stem‐derived activated porous carbon is explored as a cathode for LIHC application. A specific surface area of 1826 m2 g−1, enhanced degree of crystallinity, and graphitization results for porous carbon from activation by potassium hydroxide. When employed as supercapacitor material, the device exhibits good rate capability, energy, and power attributes with a specific capacitance of 116 F g−1 (1 A g−1). Simultaneously when tested for LIHC application the formulated device shows good capacity retention for 2500 cycles with a high energy density of 125 Wh kg−1 at a power density of 69 W kg−1. The work demonstrates unique, cost‐effective strategy to develop a crystalline high surface area carbon from any such bio‐waste sources to be employed as potential electrodes for energy storage applications.

Ultra-high capacity and ultra-long cyclability anode materials of non-layered vanadium carbide(V8C7)@carbon microspheres for biapplications in Li-ion battery and Li-ion capacitor

The main factor affecting the electrochemical performance of Li-ion hybrid capacitor (LIHCs) is the imbalance of kinetics between anode and cathode. Although 2D Layered Mxenes widely applied to energy storage owing to their remarkable electrical conductivity and adjustable interlamellar spacing, the synthesis process is time-consuming and hazardous. Therefore, Non-layered transition metal carbides (TMC) have gradually become a research hotspot. Herein, a facile two-step method is reported to synthesize the V8C7 nanoparticles grown in situ in carbon microspheres (V8C7 @CMs). The V8C7 @CMs provide high specific capacity (774 mAh g−1 after 330 cycles at 0.1 A g−1) in half cell. The long cycle stability with extraordinary rate capability (150 mAh g−1 after 5000 cycles at 1 A g−1, 100 mAh g−1 - 13000 cycles - 2 A g−1, and 70 mAh g−1 - 20000 cycles-5 A g−1) can be demonstrated. In order to realize the construction of high-performance LIHCs, it is also very important to design the cathode materials reasonably. So, the cathode material, nitrogen doped grapefruit peel biochar (NGPB), with outstanding rate performance and superior cycle stability, was designed and synthesized by the method of calcination. The performance tests indicates that the specific capacity is kept at 125 mAh g−1 after 2000 cycles at 1 A g−1, 120 mAh g−1-2000 cycles-2 A g−1 and 115 mAh g−1-2000 cycles-5 A g−1. Then, the constructed V8C7 @CMs//NGPB-2 LIHCs demonstrates high power density (PD) (9358 W kg−1), energy density (ED) (95.55 Wh kg−1) and excellent long cycle stability (a capacity retention rate of 74.7% after 10,000 cycles at 0.1 A g−1, 77%−5000 cycles-1 A g−1). Based on the above research, it is found that the key to realize high-performance LIHCs is to develop long-cycle stable and super rate capability anode materials.

Hierarchical architecture of two-dimensional Ti3C2 nanosheets@Metal-Organic framework derivatives as anode for hybrid li-ion capacitors

Two-dimensional (2D) layered metal carbides materials called MXenes (e.g., Ti3C2) are significantly attentioned as electrode material for lithium-ion capacitors (LICs) because of its large surface-to-volume ratio and ultra-high electronic conductivity. Whereas, as anode electrode material, the performance and application prospects of Ti3C2 are severely restricted to its lower theoretical capacity. In this work, a straightforward and effective strategy to surmount the restrictions was developed to combine layered Ti3C2 nanosheets with dual Co/Zn metal–organic framework (MOF) polyhedrons derivatives through electrostatic assembly. Co3O4/ZnO polyhedrons could prevent the stacking of Ti3C2 nanosheets and provide prominent lithium storage capacity. Furthermore, the advanced structure of Ti3C2@Co3O4/ZnO as anode material could provide short Li+ paths, large electrolyte channels and excellent structural stability to enhance the electrochemical performance for LICs. As a result, the prepared Ti3C2@Co3O4/ZnO composite exhibited a specific capacity of 585.7 mAh/g at 0.1 A/g, and the electrode still delivered a capacity of 229 mAh/g at 2 A/g after 1000 cycles with 93% capacity retention in lithium-ion half cell. In addition, by assembling with activated carbon (AC) as cathode and Ti3C2@Co3O4/ZnO as anode, the LIC revealed an ultra-high energy density of 196.8 Wh/kg at a power density of 174.9 W/kg, and delivered a high energy output of 87.5 Wh/kg even at a power density of 3500 W/kg. And its capacitance retention reaches 75% after 6000 cycles at 2 A/g. The advanced structure, handy preparation, and outstanding performance of layered carbon-based material Ti3C2@hollow polyhedrons composite might provide promising applications in LICs.

A free-standing VN/MXene composite anode for high-performance Li-ion hybrid capacitors.

The Li-ion hybrid capacitor (LIHC) is considered as a promising candidate for electrochemical energy storage owing to the high energy and power density. However, the sluggish anodic reaction kinetics and high reaction voltage greatly hinder the overall performance of LIHCs. Herein, a free-standing VN/MXene composite anode with high specific capacity and low reaction voltage was prepared by a simple vacuum filtration method. The obtained VN/MXene composite anode shows a high discharge specific capacity of 501.7 mA h g−1 at 0.1 A g−1 and excellent rate capability (191.8 mA h g−1 at 5 A g−1), as well as much extended cycling stability (1500 cycles at 2 A g−1). When combined with an egg white-derived activated carbon (E-AC) cathode, the assembled LIHC delivers a high specific capacity of 59.1 F g−1 and a high energy density of 129.3 W h kg−1 with a power density of 449.7 W kg−1. Even at a high current density of 5 A g−1, the LIHC still maintains an exciting energy density of 42.81 W h kg−1 at 11 249 W kg−1. Meanwhile, the cycling life can be extended to 5000 cycles with a high capacity retention of 98% at 1 A g−1. We believe that this work opens up new possibilities for developing advanced free-standing MXene-based electrodes for Li-ion storage.

Hierarchical Electrode Constructed by Carbon-Coated Metal-Organic Framework Derivatives Supported on Two-Dimensional Ti3c2 Nanosheets for Hybrid Li-Ion Capacitors

Hierarchical Electrode Constructed by Carbon-Coated Metal-Organic Framework Derivatives Supported on Two-Dimensional Ti3c2 Nanosheets for Hybrid Li-Ion Capacitors

Fe3O4 Nanoparticles on 3D Porous Carbon Skeleton Derived from Rape Pollen for High-Performance Li-Ion Capacitors.

Herein, a three-dimensional (3D) Fe3O4@C composite with hollow porous structure is prepared by simple solution method and calcination treatment with biomass waste rape pollen (RP) as a carbon source, which is served as an anode of Li-ion capacitor (LIC). The 3D interconnected porous structure and conductive networks facilitate the transfer of ion/electron and accommodate the volume changes of Fe3O4 during the electrochemical reaction process, which leads to the excellent performance of the Fe3O4@C composite electrode. The electrochemical analysis demonstrates that the hybrid LIC fabricated with Fe3O4@C as the anode and activated carbon (AC) as the cathode can operate at a voltage of 4.0 V and exhibit a high energy density of 140.6 Wh kg−1 at 200 W kg−1 (52.8 Wh kg−1 at 10 kW kg−1), along with excellent cycling stability, with a capacity retention of 83.3% over 6000 cycles. Hence, these encouraging results indicate that Fe3O4@C has great potential in developing advanced LICs electrode materials for the next generation of energy storage systems.

Nickel Fluoride Nanorods as Anode Materials for Li-Ion Hybrid Capacitors

Nickel Fluoride Nanorods as Anode Materials for Li-Ion Hybrid Capacitors

Hybrid Li-Ion Capacitor Operated within an All-Climate Temperature Range from -60 to +55 °C.

Lithium-ion capacitors (LICs) have been considered as an advanced energy storage system owing to their high energy and power densities. However, their application in a wide temperature range is still a great challenge due to the reduced ionic conductivity of the electrolyte and the poor electric conductivity of the battery-type transition metal oxide electrodes. Herein, an all-climate LIC is well-fabricated with TiNb2O7@expanded graphite as the anode and activated carbon as the cathode in an optimized electrolyte, which can be operated within a wide temperature range from -60 to +55 °C. Benefitting from the synergetic effect of the improved electrode and electrolyte, the LIC exhibits an outstanding energy density of 119 W h kg-1 and a power density of 5110 W kg-1 based on the total mass of both negative and positive electrodes. Moreover, it can deliver a capacity retention of as high as 42% at -60 °C and function at a superior rate capability at a high temperature of +55 °C, which exhibits an all-climate feature and the potential for wide applications under some extreme conditions.

Secondary Bonding Channel Design Induces Intercalation Pseudocapacitance toward Ultrahigh-Capacity and High-Rate Organic Electrodes.

Organic electrode materials have shown extraordinary promise for green and sustainable electrochemical energy storage devices, but usually suffer from low specific capacity and poor rate capability, which is largely caused by inactive components and diffusion-controlled Li+ intercalation. Herein, high-rate Li+ intercalation pseudocapacitance in organic molecular crystals is achieved through introducing weak secondary bonding channels, far exceeding their theoretical capacity based on redox chemistry at functional groups. The authors' combined experimentally electrochemical characterization with first-principles calculations show that the heterocyclic organic molecule 2,2'-bipyridine-4,4'-dicarboxylic acid (BPDCA) crystal permits a four-electron redox reaction at conventional CO and CN groups and a six-electron intercalation pseudocapacitance along conjugated alkene hydrogen bonding channels (H2 NC5 H⋯OC(OH)) and heterocyclic aromatic stacking channels (C5 H3 N⋯NH3 C5 ). The BPDCA electrode delivers an ultrahigh reversible capacity of 1206mAhg-1 at 0.5Ag-1 and an exceptional rate capability. A 4.8V high-energy/power-density BPDCA anode-based hybrid Li-ion capacitor is thus realized. This work opens a new avenue for developing organic intercalation pseudocapacitive materials via secondary bonding structure design.