Anode Material For Lithium-ion Capacitors Research Articles

Molten salts synthesis of NbB nanoparticles for lithium-ion capacitor applications

Lithium-ion capacitors (LICs), despite having great energy density and power density, possess many practical challenges, including matching optimization of kinetic imbalance. To address the issues, here, niobium monoboride (NbB) nanoparticles are presented as an anode material for LICs. The abundant pore size distribution and intercalation-type Li+ storage mechanism of NbB nanoparticles allow for fast redox kinetics in charge and discharge process. Therefore, the half-cells with NbB achieve excellent electrochemical performance, including a great capacity (197 mAh g-1 at 0.1 A g−1 for 1000 cycles) and superior cycle life (118 mAh g-1 at 1 A g−1 for 5000 cycles). Also, NbB//AC LIC-1 device fabricated with the NbB as anode and commercial activated carbon (AC) as cathode reveals a great specific capacitance of 28.1 F g−1 at 0.05 A/g, and remains over 70 % initial capacitance after 12,000 cycles. In this work, nanoscale NbB presents excellent lithium storage performance and matches well with carbon cathodes, indicating that transition metal borides (TMBs) have huge potential in the energy storage field.

Hierarchical architecture of ZIF-8@ZIF-67-Derived N-doped carbon nanotube hollow polyhedron supported on 2D Ti3C2Tx nanosheets targeting enhanced lithium-ion capacitors

The matching of long cycle life, high power density, and high energy density has been an inevitable requirement for the development of efficient anode materials for lithium-ion capacitors (LICs). Here, we introduce an N-doped carbon nanotube hollow polyhedron structure (Co3O4-CNT-800) with high specific surface area and active sites, which is anchored with two-dimensional (2D) Ti3C2Tx nanosheets with metallic conductivity and abundant surface functional groups by electrostatic adsorption to form a hierarchical multilevel hollow semi-covered framework structure. Benefiting from the synergistic effect between Co3O4-CNT-800 and Ti3C2Tx, the composites exhibit superior energy storage efficiency and long cycling stability. The Co3O4-CNT-800/Ti3C2Tx electrodes exhibit a high specific capacity of 817C/g at a current density of 0.5 A/g under the three-electrode system, and the capacity retention rate is 91 % after 5000 cycles at a current density of 2 A/g. Additionally, we assembled Co3O4-CNT-800/Ti3C2Tx as the anode and Activated carbon (AC) cathode to form LIC devices, which showed an electrochemical test result of 90.01 % capacitance retention after 8000 cycles at 2 A/g, and the maximum power density of the LIC was 3000 W/kg and the maximum energy density was 121 Wh/kg. This work pioneered the combination of N-doped carbon nanotube hollow polyhedron structure with two-dimensional Ti3C2Tx, which provides an effective strategy for preparing LIC negative electrode materials with high specific capacitance and long cycling stability.

CO2-derived nitrogen doped porous carbon as advanced anodes for lithium-ion capacitors

Porous carbon is considered one of the most promising anode materials for lithium-ion capacitors due to its high ionic and electronic conductivity, high lithium storage capacitance and high chemical stability. However, the green and low-carbon preparation is a great challenge for the current porous carbon, especially for heteroatoms doped porous carbon. Herein, we report a low-carbon and environmentally friendly method to prepare N-doped porous carbon by the novel reaction of greenhouse gas CO2 with 5LiH-LiNH2. N-doped porous carbon delivers a reversible lithium storage capacity of 904 mAh g−1 at 0.1 A g−1, When paired with commercial activated carbon, the as-assembled lithium-ion capacitors provide a high energy density of 112 Wh kg−1 at a power density of 198.6 W kg−1 with a capacitance retention of 72% at 1.0 A g−1 after 6000 cycles. This work provides a green and low-carbon strategy for converting greenhouse gas CO2 into N-doped porous carbon for high-performance lithium-ion capacitors.

One-dimensional Fe7S8 nanorods encapsulated in N, S co-doped carbon shells accelerate lithium storage kinetics for lithium-ion capacitors

Abstract The slow kinetics of battery-type anode materials for lithium-ion capacitors (LICs) hinder their matching with capacitive-type cathodes. Designing anode materials with greater capacity and improved rate performance is a key to solving this challenge. Here, we fabricated one-dimensional N, S co-doped carbon encapsulated Fe7S8 nanorods to realize fast lithium storage kinetics and stable cycling performance. The matched Fe7S8@C//AC LICs achieved an extraordinary energy density of 101 Wh kg−1 and a power density of 3927 W kg−1.

Construction of anode materials for NiSe-based high energy density lithium-ion capacitors

Nickel selenide has been extensively used in energy storage applications because of its easily adjustable morphology, high theoretical specific capacity, abundant reserves, and low price. It is an idealized anode material for lithium-ion capacitors (LICs). However, the volume effect and ion transport efficiency during the transmission process are low, resulting in improved cycle and rate performance. In view of the above problems, NiSe/carbon nanotube@polyaniline (NiSe/CNT@PANI) nanocomposites are prepared by the hydrothermal method and in-situ polymerization. After 100 cycles at 0.1 A·g−1, the charge specific capacity is 529.3 mAh·g−1. After 300 cycles at 1 A·g−1 and 2 A·g−1, the charge specific capacity is still 271.8 mAh·g−1 and 173.5 mAh·g−1, respectively. Furthermore, the constructed NiSe/CNT@PANI//AC LICs have an initial reversible capacity of 50.9 mAh·g−1 at 0.1 A·g−1, a cycle retention rate of 56.5% after 3000 cycles at 1 A·g−1. When the power density is 199.5 W·kg−1, the energy density is 91.7 Wh·kg−1, and the energy density reaches 53.1 Wh·kg−1 at a high power density of 1995.4 W·kg−1. These results indicate that NiSe/CNT@PANI composites have broad application prospects in LICs.

Metal-organic frameworks (MOFs)-derived Mn2SnO4@C anode based on dual lithium storage mechanism for high-performance lithium-ion capacitors

Lithium-ion capacitors (LICs) are an emerging energy storage device that combines high energy density with high power density. Tin dioxide (SnO2) is considered a promising anode material due to its high theoretical capacity and low redox potential. However, severe volume expansion limits its practical application. In this study, a rhombic-shaped Mn2SnO4@C composite material with a uniform carbon coating was synthesized through pyrolysis of metal–organic frameworks (MOFs) and employed as an anode material for LIC. The material exhibited a dual lithium storage mechanism through alloying and conversion reactions. The Mn2SnO4@C anode exhibited excellent cycling stability due to the synergistic effect between Mn and Sn, and the uniform carbon coating. The anode maintained a capacity retention over 100 % at various current densities and a specific capacity reached 944 mAh g−1 after rate testing. Furthermore, a novel LIC was assembled using Mn2SnO4@C anode and coconut shell biomass carbon (CSBC) cathode, delivering an ultrahigh energy density of 217.9 Wh kg−1 at 210 W kg−1 and maintaining 25.1 Wh kg−1 even at a high power of 21 kW kg−1. This work applied alloy-conversion dual lithium storage mechanism anode materials to LICs, providing a new avenue for next-generation high-performance LICs.

Interphase stabilized electrospun SnO2 fibers as alloy anode via restricted cycling for Li-ion capacitors with high energy and wide temperature operation

The second-generation supercapacitor comprises the hybridized energy storage mechanism of Lithium-ion batteries and electrical double-layer capacitors, i.e, Lithium-ion capacitors (LICs). The electrospun SnO2 nanofibers are synthesized by a simple electrospinning technique and are directly used as anode material for LICs with activated carbon (AC) as a cathode. However, before the assembly, the battery-type electrode SnO2 is electrochemically pre-lithiated (LixSn + Li2O), and AC loading is balanced with respect to its half-cell performance. First, the SnO2 is tested in the half-cell assembly with a limited potential window of 0.005 to 1 V vs. Li to avoid the conversion reaction of Sn0 to SnOx. Also, the limited potential window allows only the reversible alloy/de-alloying process. Finally, the assembled LIC, AC/(LixSn + Li2O), displayed a maximum energy density of 185.88 Wh kg−1 with ultra-long cyclic durability of over 20,000 cycles. Further, the LIC is also exposed to various temperature conditions (–10, 0, 25, & 50 °C) to study the feasibility of using them in different environmental conditions.

A Comprehensive Review of Graphene-Based Anode Materials for Lithium-ion Capacitors

Lithium-ion capacitors (LICs) are considered to be one of the most promising energy storage devices which have the potential of integrating high energy of lithium-ion batteries and high power and long cycling life of supercapacitors into one system. However, the current LICs could only provide high power density at the cost of low energy density due to the sluggish Li+ diffusion and/or low electrical conductivity of the anode materials. Moreover, the serious capacity and kinetics imbalances between anode and cathode result in not only inferior rate performance but also unsatisfactory cycling stability. Therefore, designing high-power and structure stable anode materials is of great significance for practical LICs. Under this circumstance, graphene-based materials have been intensively explored as anodes in LICs due to their unique structure and outstanding electrochemical properties and attractive achievements have been made. In this review, the recent progresses of graphene-based anode materials for LICs are systematically summarized. Their synthesis procedure, structure and electrochemical performance are discussed with a special focus on the role of graphene. Finally, the outlook and remaining challenges are presented with some constructive guidelines for future research.

Robust and Fast Lithium Storage Enabled by Polypyrrole-Coated Nitrogen and Phosphorus Co-Doped Hollow Carbon Nanospheres for Lithium-Ion Capacitors.

Lithium-ion capacitors (LICs) have been proposed as an emerging technological innovation that integrates the advantages of lithium-ion batteries and supercapacitors. However, the high-power output of LICs still suffers from intractable challenges due to the sluggish reaction kinetics of battery-type anodes. Herein, polypyrrole-coated nitrogen and phosphorus co-doped hollow carbon nanospheres (NPHCS@PPy) were synthesized by a facile method and employed as anode materials for LICs. The unique hybrid architecture composed of porous hollow carbon nanospheres and PPy coating layer can expedite the mass/charge transport and enhance the structural stability during repetitive lithiation/delithiation process. The N and P dual doping plays a significant role on expanding the carbon layer spacing, enhancing electrode wettability, and increasing active sites for pseudocapacitive reactions. Benefiting from these merits, the NPHCS@PPy composite exhibits excellent lithium-storage performances including high rate capability and good cycling stability. Furthermore, a novel LIC device based on the NPHCS@PPy anode and the nitrogen-doped porous carbon cathode delivers a high energy density of 149 Wh kg−1 and a high power density of 22,500 W kg−1 as well as decent cycling stability with a capacity retention rate of 92% after 7,500 cycles. This work offers an applicable and alternative way for the development of high-performance LICs.

Anchoring perovskite-Type FeMnO3 microspheres on CNT conductive networks via electrostatic self-assembly for high-performance lithium-ion capacitors

Lithium-ion capacitors (LICs) are emerging energy storage devices that integrate the high energy density of lithium-ion batteries with the high-power density of supercapacitors. However, their practical performance is severely limited by the sluggish reaction kinetic for battery-type anodes. To address this issue, we propose an electrostatic self-assembly strategy for fabricating perovskite-type FeMnO3 microspheres anchored within the carbon nanotube conductive network (FeMnO3-CNTCN) as the anode materials for LICs. In the well-interconnected 3D construction, FeMnO3 microspheres with multi-step redox reaction can provide abundant active sites for the lithium storage, while highly conductive and flexible CNT substrate ensures fast lithium-ion transport and electron transfer. Benefiting from the synergistic interplay between two components, the FeMnO3-CNTCN anode exhibits the splendid cyclability and rate performance. Furthermore, the entire LIC with FeMnO3-CNTCN anode delivers a superior energy density of 163 Wh kg−1 at a power density of 245 W kg−1, along with a capacity retention of 83% after 10,000 cycles. These results demonstrate the promising prospect of FeMnO3-CNTCN in high-performance LICs, and the proposed electrostatic self-assembly strategy opens up a chance for the facile synthesis of the composite materials in advanced energy storage.

Cationic intermediates assisted self-assembly two-dimensional Ti3C2Tx/rGO hybrid nanoflakes for advanced lithium-ion capacitors

Two-dimensional (2D) material MXenes have been intensively concerned in energy-storage field due to these unique properties of metallic-like conductivity, good hydrophilicity and high volumetric capacity. However, the self-restocking of ultra-thin 2D materials seriously hinders these performances, which significantly inhibits the full exploitation of MXenes in the field of energy storage. To solve this issue, a strategy to prepare delaminated Ti3C2Tx (MXene) nanoflakes/reduced graphene oxide (rGO) composites is proposed using the electrostatic self-assembly between positively charged Ti3C2Tx with tetrabutylammonium ion (TBA+) modification and negatively charged graphene. The nanoflakes of Ti3C2Tx/rGO are well dispersed and arranged in a face-to-face structure to effectively alleviate the self-restacking and provide more electroactive sites for accessible of electrolyte ions. The prepared delaminated Ti3C2Tx/rGO anode shows a high reversible capacity up to 1394 mAh g−1 at a current density of 50 mA g−1. Moreover, a lithium-ion capacitor (LIC) was assembled with delaminated Ti3C2Tx/rGO anode and activated carbon (AC) cathode which can exhibit a specific capacity of 70.7 F g−1 at a current density of 0.1 A g−1 and deliver an ultrahigh energy density of 114 Wh kg−1 at a relatively high power density of 3125 W kg−1. These good electrochemical performances demonstrate the potential of delaminated Ti3C2Tx/rGO as an anode material for lithium-ion capacitors.

Effect of Size of TiO2(B) Nanosheets on Electrochemical Properties for Fast Li Ion Intercalation

Bronze-phase TiO2, TiO2(B), has a theoretical Li+ storage capacity comparable to graphite and thus has been studied as an anode material for lithium-ion capacitors and lithium-ion batteries. Since Li+ diffusion proceeds along the b axis in the open tunnel structure of TiO2(B), its power density is expected to improve by shortening the b-axis dimension. Although miniaturized TiO2(B), such as TiO2(B) nanotubes1 or nanoparticles2, have been proposed as high-rate Li+ storage materials, difficulty in size-controlled synthesis of such materials impedes sufficient investigation to verify the effect of shortened b-axis dimension of TiO2(B) on the performance. TiO2(B) nanosheets can be downsized in b-axis dimension by controlling the sonication condition for TiO2 nanosheets used as a precursor material. In this study, by preparing size-regulated TiO2(B) nanosheets, the charge storage mechanism of TiO2(B) related to fast Li+ intercalation was analyzed.TiO2 nanosheets, prepared by exfoliating H2Ti4O9 nanosheets, were downsized by ultrasonic treatment, resulting in the fabrication of size-regulated TiO2 nanosheets. TiO2 nanosheets were vacuum impregnated into a porous current collector, i.e. vertically-aligned rGO nanosheet film,3 and thermally treated at 350°C for 2 hours under N2 flow conditions to convert to TiO2(B). The TiO2(B) nanosheet electrodes were used as the working electrode and lithium foil was used for the counter and the reference electrodes. A three-electrode flat cell was used for electrochemical characterization. The electrolyte was 1 M LiPF6 in a 1:1 mixture of ethylene carbonate (EC) and diethyl carbonate (DEC).Based on atomic force microscopy images, small, medium, and large size TiO2 nanosheets with average diameter of 70, 150, and 300 nm were successfully obtained by changing the sonication time. Cyclic voltammograms revealed that the capacities of TiO2(B) nanosheet electrodes at a scan rate of 0.5 mV s−1 and 20 mV s−1 were 186 mAh (g-TiO2)−1(=Li0.56TiO2) and 76 mAh (g-TiO2)−1 (=Li0.23TiO2) for the large-sized nanosheets, 334 mAh (g-TiO2)−1 (=Li1.0TiO2) and 156 mAh (g-TiO2)−1 (=Li0.4TiO2) for the medium-sized nanosheets, and 332 mAh (g-TiO2)−1 (=Li1.0TiO2) and 211 mAh (g-TiO2)−1 (=Li0.63TiO2) for the small-sized nanosheets, respectively. The medium- and small-sized TiO2(B) nanosheets exhibited Li+ storage capability comparable to the theoretical capacity of TiO2(B) (335 mAh g− 1), while the large-sized TiO2(B) nanosheets with longer Li+ transport path could only be charged to ~50% SOC under the same conditions. The charge storage mechanism of TiO2(B) nanosheets based on b-value analysis4 suggested that shortening the b-axis length of TiO2(B) was effective for increasing the capacitive contribution related to near-surface Faradic reaction.AcknowledgmentsThis work was partly supported by Advanced Low Carbon Technology Research and Development Program (ALCA) (JPMJAL1008) from Japan Science and Technology Agency (JST).References S. Brutti, V. Gentili, H. Menard B. Scrosati and P. G. Bruce, Adv. Energy Mater., 2, 322 (2012).Y. Ren, Z. Liu, F. Pourpoint, A. R. Armstrong, C. P. Grey and P. G. Bruce, Angew. Chem. Int. Ed., 51, 2164 (2012).D. Mochizuki, R. Tanaka, S. Makino, Y. Ayato and W. Sugimoto, ACS Appl., Energy Mater., 2, 1033 (2019).J. Wang, J. Polleux, J. Lim and B. Dunn, J. Phys. Chem. C, 111, 14925 (2007).

In-situ thermally fabricated porous and heterogeneous yolk-shell selenides wrapped in carbon as anode for high-performance hybrid lithium-ion capacitors

Lithium-ion capacitors (LICs) are a relatively new hybrid system that combines the merits of Faradaic and capacitive behaviors, demonstrating great potentials in modern applications. However, the mismatch in reaction kinetics between these two types of electrode materials, the slow Faradaic reaction in the battery anode and the rapid adsorption/desorption process in the capacitor cathode, severely restricts the application of LICs. In this study, the porous yolk-shell selenide frameworks (ZnSe@CoSe2) are constructed using the core-shell ZIF-8@ZIF-67 as precursor by a sequential thermal program. Detailed morphological investigation discloses that the yolk-shell structure is in-situ formed during the early incubation at lower temperature. The yolk-shell ZnSe@CoSe2 frameworks in an N-doping carbon layer (Z@C@P) as the anode material for lithium-ion batteries, which exhibits high rate capability and good cycle stability at a high current density of 2 A/g, which greatly bridges the kinetic gap with the capacitor-type electrode. Thereby, the assembled LICs with active carbon show high energy density, power density and capacity retention rate. To the best of our knowledge, the selenides are firstly used as anode material for LICs with such extraordinary performance, and the unique structural and compositional design strategies can also benefit the development of high-performance electrodes for energy-storage devices.

Sulfur covalently bonded to porous graphitic carbon as an anode material for lithium-ion capacitors with high energy storage performance

Sulfur covalently bonded to porous graphitic carbon is utilized as an anode for lithium-ion capacitors with high energy storage performance.

Carbon-coated Li3VO4 with optimized structure as high capacity anode material for lithium-ion capacitors

Due to the high capacity, moderate voltage platform, and stable structure, Li3VO4 (LVO) has attracted close attention as feasible anode material for lithium-ion capacitor. However, the intrinsic low electronic conductivity and sluggish kinetics of the Li+ insertion process severely impede its practical application in lithium-ion capacitors (LICs). Herein, a carbon-coated Li3VO4 (LVO/C) hierarchical structure was prepared by a facial one-step solid-state method. The synthesized LVO/C composite delivers an impressive capacity of 435mAh/g at 0.07A/g, remarkable rate capability, and nearly 100% capacity retention after 500 cycles at 0.5 A/g. The superior electrochemical properties of LVO/C composite materials are attributed to the improved conductivity of electron and stable carbon/LVO composite structures. Besides, the LIC device based on activated carbon (AC) cathode and optimal LVO/C as anode reveals a maximum energy density of 110Wh/kg and long-term cycle life. These results provide a potential way for assembling the advanced hybrid lithium-ion capacitors.

Vanadium-Based Polyoxometalate As Anode Materials for Lithium–Ion Capacitors

Because of the increasing demand for portable devices, renewable energy systems, and electric vehicles, energy storage system has been developed intensively over the past decade. Researchers have intensively studied low-cost, high energy density, high power density, and high-safety energy storage devices. Lithium-ion batteries (LIBs) have advantages of high energy density and no memory effect. However, the power density is relatively low. In contrast to LIBs, supercapacitors (SCs) exhibit high power density and long cycling life, but low energy density. Therefore, lithium ion capacitors (LICs) which combine the superiorities of LIBs and SCs has been announced recently in order to achieve both high energy density and power density. Polyoxometalates (POMs) are a class of anionic polynuclear transition metal oxides, and they possess multiple redox reactions which can store many charges per molecule. Hence, POMs have been employed as electrode materials for energy storage devices, such as LIBs, sodium-ion batteries (NIBs), and SCs, and most of them exhibit high capacity. In this work, a vanadium-based POM (V-POM) was utilized as anode material for LICs. V-POM exhibited high specific capacities as well as good cycling stability. A full cell comprised with V-POM anode and porous carbon cathode were assembled, and it showed high energy density and high power density. These results demonstrated that V-POM anode material is suitable for LIC applications. Furthermore, we also utilized several in operando techniques to investigate the charge storage mechanisms of this V-POM anode including X-ray Absorption Spectroscopy and X-ray diffraction.

A novel calendula-like MnNb2O6 anchored on graphene sheet as high-performance intercalation pseudocapacitive anode for lithium-ion capacitors

In this paper, for the first time, we investigated MnNb2O6 as a new rate capability type anode material for lithium-ion capacitors (LICs), which exhibit excellent charge storage capacity and reasonably superior cycling stability.

Holey graphene-wrapped porous TiNb24O62 microparticles as high-performance intercalation pseudocapacitive anode materials for lithium-ion capacitors

It is desirable to develop an energy storage system with both high energy density and high power density along with excellent cycling stability to meet practical application requirements. Lithium-ion capacitors (LICs) are very promising due to the combined merits of the high power density of electrochemical capacitors and the high energy density of batteries. However, the lack of high rate performance anode materials has been the major challenge of lithium-ion capacitors. Herein, we designed and synthesized holey graphene-wrapped porous TiNb24O62 as an anode material for lithium-ion capacitors. Pseudocapacitive storage behaviors with fast kinetics, high reversibility, and excellent cycling stability were demonstrated. The hybrid material can deliver a high capacity of 323 mAh g−1 at 0.1 A g−1, retaining 183 mAh g−1 at 10 A g−1. Coupled with a carbon nanosheet-based cathode, an LIC with an ultrahigh energy density of 103.9 Wh kg−1 was obtained, and it retained 28.9 Wh kg−1 even under a high power density of 17.9 kW kg−1 with a high capacity retention of 81.8% after 10,000 cycles.

A novel high energy hybrid Li-ion capacitor with a three-dimensional hierarchical ternary nanostructure of hydrogen-treated TiO2 nanoparticles/conductive polymer/carbon nanotubes anode and an activated carbon cathode

Lithium ion capacitors (LICs) are considered to be high-performance energy storage devices that have stimulated intense attention to bridge the gap between lithium ion battery and supercapacitor. Currently, the major challenge for LICs has been to improve the energy density without sacrificing the high rate of power output performance. Herein, we designed a three-dimensional (3D) hierarchical porous nanostructure of hydrogen-treated TiO2 nanoparticles wrapped conducting polymer polypyrrole (PPy) framework with single-walled carbon nanotubes (SWCNTs) hybrid (denoted as, H-TiO2/PPy/SWCNTs) anode material for LICs through a conventional and green approach. Such a unique network can offer continuous electron transport and reduce the diffusion length of lithium ions. A greatly lithium storage specific capacity is achieved with reversible discharge capacity ∼213 mA h g−1 (based on the mass of TiO2) over 50 cycles (@ 0.1 A g−1), which is almostly three times compared with raw TiO2 (a commercial TiO2 nanoparticles powder). In addition, coupled with commercial activated carbon (AC) cathode, the fully assembled H-TiO2/PPy/SWCNTs//AC LICs delivers a maximum energy and power densities of 31.3 Wh kg−1 and 4 kW kg−1, a reasonably good cycling stability (∼77.8% retention after 3000 cycles) within the voltage range of 1.0–3.0 V.

Controllable Formation of Niobium Nitride/Nitrogen-Doped Graphene Nanocomposites as Anode Materials for Lithium-Ion Capacitors

Niobium nitride/nitrogen-doped graphene nanosheet hybrid materials are prepared by a simple hydrothermal method combined with ammonia annealing and their electrochemical performance is reported. It is found by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) that the as-obtained niobium nitride nanoparticles are about 10-15 nm in size and homogeneously anchored on graphene. A non-aqueous lithium-ion capacitor is fabricated with an optimized mass loading of activated carbon cathode and the niobium nitride/nitrogen-doped graphene nanosheet anode, which delivers high energy densities of 122.7-98.4 W h kg(-1) at power densities of 100-2000 W kg(-1), respectively. The capacity retention is 81.7% after 1000 cycles at a current density of 500 mA g(-1). The high energy and power of this hybrid capacitor bridges the gap between conventional high specific energy lithium-ion batteries and high specific power electrochemical capacitors, which holds great potential applications in energy storage for hybrid electric vehicles.