High-energy Lithium-ion Capacitors Research Articles

A practical high-energy lithium-ion capacitor enabled by multiple conducting bridges triggered electrode current reallocation

Lithium-ion capacitors (LICs), consisting of a battery-type anode and capacitive cathode, hold great promise for achieving high-energy and high-power densities. However, the sluggish migration of electrons and ions in the anode hinders the attainment of the "dual-high" target. To circumvent this obstacle, we propose a novel strategy employing multiple conducting bridges to augment charge dynamics for the hard carbon (HC) anode and activated carbon (AC) cathode. In this approach, graphene nanosheets are deposited in-situ via a self-propagating high-temperature synthesis methodology to establish connections between isolated HC (or AC) powders. Subsequently, carbon nanotubes are introduced to fill the inter-particle gaps, forming a network of multiple conducting bridges. Through the experimental investigation and finite elemental simulation, we demonstrate that this approach triggers prompt inter-particle electrons and ions migration, resulting in a homogeneous redistribution of the current at the electrode scale. This engenders a substantial enhancement in electronic conductivity (∼3 fold), and a significant improvement in the ion diffusion. Consequently, we fabricate a 1000 F LIC pouch cell displaying a state-of-the-art device performance of 30.3 W h kg−1 and 8.1 kW kg−1, coupled with a remarkable cycle life of 87.9% retention after 10,000 cycles. This study thus represents a distinctive avenue for regulating charge dynamics at the electrode scale and optimizing the performance of practical LICs.

Metal-organic framework-derived nitrogen-doped three-dimensional porous carbon loaded CoTe2 nanoparticles as anodes for high energy lithium-ion capacitors

In this work, we propose a strategy to use MOF-derived carbonaceous materials to modify Co-based nanoparticle anodes, so as to achieve heteroatom doping, structure and electronic properties of composite electrode materials in one step. In more detail, this paper uses the cobalt-based metal-organic framework (ZIF-67) as the precursor matrix to synthesize Co, Co3O4 and CoTe2 nano-particles embedded in carbon nanocubes composite electrode materials through carbonization, oxidation and tellurization reactions in sequence. As a result, electrochemical experiments and test results show that the reversibility of Li+ storage of the half-cell CoTe2@NC composite is significantly enhanced, and it has a higher rate capacity, ultra-fast charging capability and long cycle stable life. On this basis, we built the lithium-ion capacitor (CoTe2@NC//HPC) for the first time, which achieves a high energy density of 144.5 Wh kg−1 while maintaining a high-power density of 10 kW kg−1. Finally, the device exhibits excellent electrochemical structural stability, and can still maintain an original capacity of 90.95% after 1000 charging-discharging cycles. Thus, the rational design and development of partially coated nanoparticle structures derived from MOF is of great significance for improving the energy density and power density of advanced energy storage devices.

High-Accuracy Parameters Identification of Non-Linear Electrical Model for High-Energy Lithium-Ion Capacitor

With the development of extreme fast charging technology, charging stations need to use energy storage stations to reduce the rising peak to average power ratio (PAPR). Lithium-ion capacitor (LIC) is a chemical power source that uses both Faraday process and non-Faraday process to store energy. Because of its attractive performance in terms of rate characteristics and chemical stability, it is suitable for some energy storage stations that consider both power density and energy density. It is important to describe the current-voltage characteristics of LIC to predict the charge and discharge efficiency in the early design of energy storage power stations. During the test, however, a full discharge or charge results in a high temperature rise, and the electrical model parameters near a specific temperature point cannot be accurately obtained. The short current pulses cannot stabilize the polarization. In this paper, a high-accuracy parameters identification method based on an improved Butler-Volmer-Equation-Based electrical model is used to summarize the phenomena caused by the rate of change of high-energy LIC. The accuracy of the method is tested under the dynamic stress condition test. The maximum voltage error is less than 2%. Energy efficiency calculation based on the used model is simulated by the design condition from the energy storage station of the Haizhu line in Guangzhou. The maximum error is less than 0.2%.

Multi-dimensional hybrid heterostructure MoS2@C nanocomposite as a highly reversible anode for high-energy lithium-ion capacitors

Lithium-ion capacitors (LICs) are a new generation of hybrid energy storage devices, and there is room for improvement in power characteristic, energy density and cycling life. This paper proposes a facile and high-efficiency strategy for the preparation of high-performance MoS2 based anodes, here we have successfully synthesized a multi-dimensional hybrid heterogeneous composite material (MoS2@C) in which nanoparticles, nanoflakes and hollow nanospheres coexist. The strong adhesion of the Mo-O-C bond formed between MoS2 and carbon ensures favorable structural integrity, while the architecture made of nanoflakes reduces the diffusion distance of Li+. In addition, the voids of the hollow structure can alleviate the volume change during repeated Li+ intercalation/de-intercalation processes and ensure good contact between the material and the electrolyte solution. Moreover, due to the confinement effect of the hollow structure and carbon and the introduction of oxygen vacancies, excellent rate performance is achieved. Given this, in a wide potential window of 0–4.5 V, the MoS2@C//AC device has the highest energy density (189.68 Wh kg−1), the maximum power density (11.25 kW kg−1), subordinate self-discharge rate and long lifespan. Therefore, this research work provides some important ideas and insights for the rational design of MoS2-based high-performance LICs anode materials.

Defect-rich and N-doped hard carbon as a sustainable anode for high-energy lithium-ion capacitors

Lithium-ion capacitors (LICs) are regarded as the most potential devices in the energy storage systems. Unfortunately, the mismatched in the intrinsic kinetics and specific capacities between anode and cathode lead to a depressed electrochemical performance. Thus, designing an advanced electrode material that combines high performance with low-cost is one of the main challenges for LICs, especially in a sustainable anode material until now. Here, a high-energy LIC has been successfully developed using the defect-rich and N-doped hard carbon (DNC) as anode, which is prepared through the carbonization process of the low-cost biowaste sepia without additional template or catalyst. The DNC shows nanospherical structure with a diameter of about 100 nm. Owing to the two-pronged strategy of N-doping and defect engineering, it delivers a high specific capacity (580.3 mAh g−1 at 0.05 A g−1), excellent rate capability, and long cycle stability (1000 cycles). The electrochemical kinetic analysis and density functional theory (DFT) calculations have confirmed its prominent pseudocapacitive behaviors and excellent Li+ storage capability. As expected, the as-fabricated LIC delivers a remarkable energy density (101.7 Wh kg−1), an outstanding rate capability (56.3 Wh kg−1 at 12.5 kW kg−1), and a superior cycle lifespan (3000 cycles), demonstrating the tremendous potential for the next-generation energy storage systems.

Regulation of the cathode for amphi-charge storage in a redox electrolyte for high-energy lithium-ion capacitors.

Operating the cathodes of lithium-ion capacitors in an extended potential window for amphi-charge storage was proposed to be combined with a redox electrolyte-enabled capacity for balancing the typical gap between the capacity of the anode and that of the cathode. As a result, the as-obtained lithium-ion capacitors showed a three-fold increase in energy density.

Fast lithium storage in defect-rich carbon encapsulated Fe3C nanoparticles as anode material toward high-energy lithium-ion capacitors

Lithium-ion capacitors (LICs) can combine the high energy density of battery-type electrode and high power density of capacitor-type electrode, which is considered as one of the most promising electrochemical storage devices. The challenge of developing superior performance LICs is designing suitable electrode materials to overcome the kinetic imbalance between the battery-type anode and the capacitor-type cathode. Herein, defect-rich carbon encapsulated Fe3C nanoparticle (Fe3C@DRC) was obtained via a modified sol-gel method with a calcination process. The defect-rich and microporous structure effectively boosts kinetics and provides additional reaction sites for lithium-ion intercalation/deintercalation process, which leads to an excellent capacity (215 mAh g−1 at 1 A g−1 after 800 cycles) and rate capability (128.8 mAh g−1 even at 10 A g−1). Then a novel Fe3C@DRC//AC LIC was consisted using Fe3C@DRC as anode and activated carbon as cathode. The Fe3C@DRC//AC LIC demonstrates a wide potential window (0–4 V), delivers a high energy density of 187.8 Wh kg−1 at a power density of 200 W kg−1, reached a high power density of 4000 W kg−1 at an energy density of 80 Wh kg−1, and coupled with a reasonable life span (84.8% after 6000 cycles at a current density of 1 A g−1). The study indicates that the introduction of defect-rich strategy may push the practical application of high-rate and high-energy LIC anode materials in energy fields.

All carbon based high energy lithium-ion capacitors from biomass: The role of crystallinity

We report all carbon-based high energy Li-ion capacitor from environmentally threatening bio-source, prosopis juliflora. The pyrolyzed carbon exhibits a few layers of graphene-like structure and tubular morphology with multiple inherent heteroatoms like N, S, and Ca. Presence of such heteroatoms are certainly beneficial to the betterment of electrical conductivity, and pore generation which eventually results in an enhancement in capacity/capacitance of carbonaceous materials. The electrochemical pre-lithiation strategy is used to mitigate the irreversibility observed, and eventually employed as a negative electrode in a hybrid configuration. This LIC delivered a high energy density of ∼216 and 185 Wh kg−1 at ambient (25 °C) and elevated temperature (55 °C) conditions, respectively. Further, ∼94% initial capacity is retained after 5000 cycles with minimum fading of 0.0013% per cycle at ambient temperature. This results clearly demonstrate that the surface functionality and heteroatom doping with tubular structure synergistically facilitates the Li+ and electron transport properties to realize higher energy density for this fascinating all carbon-based Li-ion capacitor.

Metal organic framework derived Nb2O5@C nanoparticles grown on reduced graphene oxide for high-energy lithium ion capacitors.

Nb2O5@carbon/reduced graphene oxide (M-Nb2O5@C/rGO) composites are fabricated by annealing the precursor of graphene oxide supported Nb-based metal organic frameworks for the first time. The lithium ion capacitor using M-Nb2O5@C/rGO as the anode and activated carbon as the cathode delivers a high energy density of 71.5 W h kg-1 and excellent cycling stability.

Hard@Soft Integrated Morning Glory Like Porous Carbon as a Cathode for a High-Energy Lithium Ion Capacitor.

A lithium ion capacitor (LIC) is a hybrid energy storage device that combines the energy storage mechanism of lithium ion batteries and supercapacitors and presents their complementary features. However, imbalances of the capacity and kinetics between cathode and anode still remain challenges. Herein, to address the issue of low capacity in the cathode, we constructed a morning glory like porous material crimped from an opening sandwich structure consisting of a hard carbon inner layer and soft carbon outer layer, by coating graphene oxide containing flaky phenolic resin with coal tar pitch followed by carbonization and activation. Both the hard@soft carbon integrated design and the reduced graphene oxide network cocontributed to a favorable electrical conductivity and a developed microporosity. To deal with the sluggish kinetics limitation of the anode, a structure-optimized MnO@C electrode prepared by pore creation of CO2 from an MnCO3@polydopamine precursor was chosen due to its excellent rate performance. The LIC with this configuration can deliver a maximum energy density of 117.6 Wh kg-1 and an favorable capacity retention of 76% after 3000 cycles at 2050 W kg-1. Furthermore, the energy density of 27.8 Wh kg-1 can still be delivered even at a high power density of 10250 W kg-1. In general, this well-designed hybrid capacitor has a potential to make up the gap between lithium ion batteries and supercapacitors.

Carbon Nanowires: Peapod-like Li3 VO4 /N-Doped Carbon Nanowires with Pseudocapacitive Properties as Advanced Materials for High-Energy Lithium-Ion Capacitors (Adv. Mater. 27/2017)

Carbon Nanowires: Peapod-like Li₃ VO₄ /N-Doped Carbon Nanowires with Pseudocapacitive Properties as Advanced Materials for High-Energy Lithium-Ion Capacitors (Adv. Mater. 27/2017)

High-Energy Electrochemical Capacitors Utilizing Chemically Reduced Graphite Oxide As Negative Electrode Material

Taking into account power needs for portable devices, the energy storage through electrochemical reactions seems to be a crucial technology, especially due to the growing technological advances requirements. Electrochemical capacitors have attracted great attention as promising energy storage devices because of their high power density and cycle life noticeably longer than batteries [i],[ii]. Recently, extensive works have been focused on enhancing both the energy and power density accompanied by reasonable cost of device production as well as its environment-friendly character. One of the approaches is idea initiated in 2001 [iii], of improving capacitors performance by merging advantages of capacitors and lithium-ion batteries. This procedure was aimed to increase the energy of the capacitor while maintaining the level of supplied power. Starting from 2001 till now in the literature we can find examples of different methods involving various electrode materials [iv],[v],[vi],[vii],[viii],[ix],[x]. Asymmetric supercapacitors composed of battery-type electrode and a high surface area carbon electrode [xi] combine the advantages and reduces the drawback of redox and capacitive based systems. Therefore, the asymmetric design offers the advantages of supercapacitors (power rate, cycle life) and batteries (energy density) [xii]. This work is focused on high-energy electrochemical capacitors utilizing chemically reduced graphite oxide (CRGO) as a negative electrode material and activated carbon (AC) with the well-developed surface area as a positive electrode material. For comparison, electrochemical characteristic of capacitors utilizing graphite negative electrode was also performed. The pre-lithiation process, made by electrochemical intercalation of lithium ions into graphite, has been chosen as the main method of negative electrode material preparing. Performed electrochemical measurements, i.e., cyclic voltammetry and galvanostatic charging/discharging presented improved energy efficiency compared with results for symmetric cells (i.e. AC/AC capacitor). All measurements were performed in the organic electrolyte to provide a wide range of operating voltage. In the case of the hybrid system energy density has been improved and exceed 90 Wh kg-1 accompanied by good power profile. Additionally, good cycle performance was also achieved. Chemically reduced graphite oxide (CRGO) displays excellent performance at current densities up to 8 A g-1and, therefore, it can be considered as a very promising material for high energy Lithium-ion capacitors (LICs). Moreover, for more detailed analysis, measurements in three-electrode cells were also conducted. Fig. 1 shows an example of cyclic voltammetry curves for two systems composed of activated carbon cathode and graphite or CRGO anode. For graphite anode, Faradaic reactions can be observed in very narrow working range (134 mV) comparing to the positive electrode (1266 mV). CRGO characteristics merge two mechanisms of lithium storage, namely, Faradaic and capacitive one. In result, the quite good proportion of working potentials between positive and negative electrodes (772 mV vs. 628 mV, respectively) can be seen. The intercalation of lithium ions into graphite material occurs relatively slowly, hence the difference in power between the electrochemical capacitors and lithium-ion batteries. The electrode with the slowest sweep of potential will determine the power of the device. In this case chemically reduced graphite oxide seems to be promising material as an anode in lithium ion capacitors due to the merged lithium insertion movement, that’s why the energy storage can take place comparatively fast, as in the positive electrode. Financial support from the project DEC-2013/09/D/ST5/03886 is gratefully acknowledged. Fig. 1. Comparison of working potentials positive and negative electrodes in hybrid systems AC/G(Li) and AC/CRGO(Li), obtained from cyclic voltammetry measurements. [i] A. Burke, J. Power Sources 91 (2000) 37 [ii] P. Simon, Y. Gogotsi, Nat. Mater. 7 (2008) 845 [iii] G.C. Amatucci, F. Badway, A.D. Pasquier, T. Zheng, J. Electrochem. Soc. 148 (2001) A930 [iv] D. Cericola, R. Kötz, Electrochimica Acta 72 (2012) 1 [v] W.J. Cao, J. Shih, J.P. Zheng, T. Doung, J. Power Sources 257 (2014) 388 [vi] S.R. Sivakkumar, A.G. Pandolfo, J. Appl. Electrochem. 44 (2014) 105 [vii] X. Sun, X. Zhang, H. Zhang, N. Xu, K. Wang, Y. Ma, J. Power Sources 270 (2014) 318 [viii] S. Dsoke, B. Fuchs, E. Gucciardi, M. Wohlfahrt-Mehrens, J. Power Sources 282 (2015) 385 [ix] J. Zhang, Z. Shi, J. Wang, J. Shi, J. Electroana. Chem. 747 (2015) 20 [x] K. Naoi, P.Simon, Electrochem. Soc. Interface 17 (1) (2008) 34 [xi] J.W. Long, D. Belanger, T. Brousse, W. Sugimoto, M.B. Sassin, O. Crosnier, MRS Bull. 36 (2011) 513 [xii] Z.J. Fan, J. Yan, T. Wei, L.J. Zhi, G.Q. Ning, T.Y. Li, F. Wei, Adv. Funct. Mater. 21 (2011) 2366 Figure 1

A study about the use of carbon coated iron oxide-based electrodes in lithium-ion capacitors

Carbon coated iron oxide nanoparticles (α-Fe2O3, cIO) obtained from ferrocene display very promising performance in terms of both, capacity retention at high current density and cycling stability. Because of these characteristics, cIO can be considered as interesting material for the realization of high energy lithium-ion capacitors (LICs). In this work we investigated for the first time the use of this conversion electrode in LICs. We showed that the use of cIO enables the realization of LICs with an operative voltage of 3.4V, able to display promising values of energy and power. However, due to a degradation process occurring on the cIO electrode, the cycling stability of the investigated LIC was limited to some thousand of cycles. Taking into account these results, it is evident that in order to develop cIO-based LICs the improvement of the cycle life of these LICs is presently the main challenge that needs to be overcome.

Li2RuO3 as an Additive for High-Energy Lithium-Ion Capacitors

A high-energy lithium ion capacitor that has Li2MoO3 as an alternative lithium source instead of metallic lithium has been proposed. For further improvement, we suggest Li2RuO3 as a new additive to improve the energy density in the positive electrode. The choice of Li2RuO3 is made based on its highly reversible characteristics for Li+ insertion and extraction and its structural stability in the operating voltage window of advanced lithium ion capacitors. The electrochemical and structural properties of Li2RuO3 have been thoroughly investigated to demonstrate its potential use in lithium ion capacitors. The high reversibility of Li2RuO3 and the metallic feature of Li2–xRuO3 may be responsible for improvements in the volumetric energy density and safety. This versatile approach may yield higher energy density without significant power loss in lithium ion capacitors.

Graphene decorated with molybdenum dioxide nanoparticles for use in high energy lithium ion capacitors with an organic electrolyte

An electrode material consisting of graphene decorated with molybdenum dioxide nanoparticles (G–MoO2) is developed. The material exhibits not only a high specific capacitance but also an excellent cycling performance as well as good rate capability in lithium ion capacitors (LICs). The specific capacitance of the G–MoO2 containing 10 wt% G reaches 624.0 F g−1 at a current density of 50 mA g−1, much higher than 269.2 F g−1 for the MoO2 particles alone. Even at a current density of 1000 mA g−1, a high specific capacitance of 173.2 F g−1 is obtained. The capacitance retention remains 91.2% after 500 cycles. Moreover, G–MoO2 provides a high specific energy density of 33.2 W h kg−1 at a power density of 3000 W kg−1. The influences of the synergistic effect of nanostructured MoO2 and conducting G on the electrochemical performance of the LICs are discussed.