Ultralong Cycle Life Research Articles

High performance lithium ion battery cathode based reduced holey graphene oxides from spent lithium ion batteries

The search of alternatives to the commercial electrodes is a key to the development of advanced lithium ion batteries (LIBs). Compared to extensive efforts and progress made on their anode applications for LIBs, the graphene and its derivatives as cathodes have attracted less concerns. Herein, a series of reduced holey graphene oxides (rhG-x) with different “worm-like” and holey structures were synthesized based on the modified Hummer's treatment and thermal reduction of graphite anode from spent LIBs. Benefiting form the rhG-x annealed at x = 400 °C with optimized oxygen-containing groups and electronic conductivity, as well as the “worm-like” and holey structures, the rhG-400 as cathode for LIBs delivers a high reversible capacity (e.g., 109.6 mAh g−1 at 0.05 A g−1) and excellent rate capability (e.g., 75.0, 68.2, 50.3 and 37.0 mAh g−1 at 2, 5, 10 and 20 A g−1, respectively) and maintains an ultra-long cycling life over 2000 cycles with high reversible capacity of 137.4 mAh g−1.

Ti3−yNbyC2Tx MXenes as high-rate and ultra-stable electrode materials for supercapacitors

Despite being a promising supercapacitor electrode material, the development of Ti3C2Tx has still been limited by many obstacles, such as restacking Ti3C2Tx nanosheets and non-electrochemically active fluorine terminations on the surface. Herein, new double transition metal Ti3−yNbyC2Tx MXenes are prepared by etching Ti3−yNbyAlC2 solid solution MAX precursors obtained by self-propagating high-temperature synthesis method for the first time. The synthesized Ti3−yNbyC2Tx MXenes exhibit larger interlayer spacing and more surface -O terminations than Ti3C2Tx, resulting in superior rate performance and high cycling stability as supercapacitors electrode materials. In particular, Ti2.9Nb0.1C2Tx demonstrates a high volumetric specific capacity of 1014 F cm−3 at a scan rate of 2 mV s−1, superior rate performance with a volumetric specific capacity of 422 F cm−3 at a scan rate of 2000 mV s−1, and ultra-long cycling life up to 84000 cycles at a current density of 10 A g−1. This work expands the practical applicability of the MXenes family in energy storage applications and provides a promising strategy to tailor the MXenes interlayer structure and surface chemistry.

A novel Li2NaVO4 @C anode for high performance lithium-ion batteries

Porous Li2NaVO4 @C is prepared by a sol-gel method with large intercalation distance and abundant active sites. The carbon network can help improve the electronic transmission and avoid collapse of material structure during Li+ intercalation/deintercalation. The carbon modified Li2NaVO4 anode shows high first discharge capacity (655.3 mA h g−1 @0.1 C), superior rate capability (128.6 mA h g−1 @20 C and 55.4 mA h g−1 @50 C) and ultra-long cycle life at 10 C high current density (183.7 mA h g−1 @5000 cycles), revealing great application prospects in lithium-ion batteries (LIBs) electrodes.

Variable-Tint Electrochromic Supercapacitor with a Benzyl Hexenyl Viologen-Prussian Blue Architecture and Ultralong Cycling Life

A highly efficient, separator-free, low-cost, dual-function electrochromic supercapacitor (ESC) with a benzyl hexenyl viologen (BHV) based gel film and a Prussian blue (PB) film as the anode and cathode, respectively, has been fabricated. The BHV//PB ESC operates over a wide potential window of 2 V and offers a specific capacitance of 67 F g–1 with energy and power density maxima of 37.2 Wh kg–1 and 6.7 kW kg–1, respectively. Simultaneously, during the charging process, the ESC undergoes a reversible and uniform color transition from pale blue to a deep rich purple hue, corresponding to a transmission modulation of ∼68% at 550 nm and an integrated visible light modulation of ∼50%, superior to those of most ESCs in the literature. The ESC offers a visually perceptible level of charging through the variable tints it acquires during charging or discharging. The ESC also sustains high external temperatures with ease, as even at 60 °C, the contrast is ∼80% at 550 nm, making it suitable for hot weather conditions. The ESC delivers an ultralong cycling life, for it does not undergo any major optical modulation loss even after 5000+ color–bleach cycles and retains 85% of its initial capacitance after 5000 charge–discharge cycles. The evolution of the charge–discharge mechanism from being predominantly ionic diffusion controlled to largely surface reaction controlled with scan rate is also demonstrated. The remarkable chemical and electrochemical cycling stability, the very high optical contrast, the reasonably fast switching kinetics, and the color purity of the bleached and colored states achieved over a geometric area of 4 × 3 cm2 are clear indicators of the potential the BHV//PB ESC has for practical deployment as a window that not only provides visual/thermal comfort but also has stored-up energy to power any external electronic device.

Microfluidic-oriented assembly of Mn3O4@C/GFF cathode with multiscale synergistic structure for high-performance aqueous zinc-ion batteries

The electrochemical activity and long-term stability of cathodic materials, as well as active ion transport, are key factors for efficient energy storage in aqueous zinc-ion batteries (ZIBs). Here, a freestanding Mn3O4@C nanowire-implanted graphene-based fiber fabric (Mn3O4@C/GFF) cathode with a multiscale synergistic structure was fabricated using a facile microfluidic assembly method. In this architecture, Mn3O4 nanowires are hosted by a conductive carbon layer and then anchored in the interlayer of a self-assembled graphene-based fiber framework. The hierarchical structure enhances electrical conductivity and relieves ion leaching, thereby boosting the electrochemical activity and long-term stability of cathodic materials. Furthermore, the layer-by-layer assembled structure of the Mn3O4@C/GFF cathode provides ample available channels for active ion transport, accelerating the electrochemical kinetics. Consequently, the Mn3O4@C/GFF cathode exhibits enhanced electrochemical performance with a high capacity of 374.8 mAh g−1 at 0.2 A g−1 and ultralong cycle life (158.7 mAh g−1 retained over 5000 cycles at 2 A g−1). Therefore, this study provides a multiscale synergistic strategy for fabricating advanced cathodes for high-performance ZIBs.

Local structural features of medium-entropy garnet with ultra-long cycle life

Local structural features of medium-entropy garnet with ultra-long cycle life

Understanding the Highly Reversible Potassium Storage of Hollow Ternary (Bi-Sb)2S3@N-C Nanocube

Metal sulfide anodes have aroused much attention in potassium ion batteries (PIBs) owing to their high theoretical capacities, but the sluggish kinetics and inferior cycling performance caused by severe volumetric change and particle pulverization greatly hinder their further development. Herein, robust hollow structure design together with phase structure engineering endow (Bi-Sb)2S3@N-C anode with superior (de)potassiation kinetics and excellent electrochemical performances in PIBs. Specifically, in situ X-ray diffraction combined with density functional theory calculations and ex situ X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy (TEM) analyses indicated a fresh reaction mechanism of (Bi-Sb)2S3 anode with a distinctive multistep (de)potassiation route along (003) plane of (Bi,Sb) alloy thanks to the Bi-Sb phase regulation in (Bi-Sb)2S3 anode, ensuring it with superior reaction kinetics. Moreover, in situ TEM characterization revealed the advantages of the hollow nanostructure with carbon shell, facilitating fast ion transport kinetics and high tolerance of volume change as well as enabling the structural integrity of electrode material during (de)potassiation. As a result, the (Bi-Sb)2S3 hollow nanocube with N-doped carbon shell ((Bi-Sb)2S3@N-C) delivers a high initial Coulombic efficiency of 66.3%, a great rate performance of 289 mAh g-1 at 2.0 A g-1, and an ultralong cycling life (89% retention after 220 cycles at 0.1 A g-1 and 85% retention after 1600 cycles at 2.0 A g-1) in PIBs. Furthermore, the full cell of (Bi-Sb)2S3@N-C//PTCDA affords a high reversible capacity of 281 mA h g-1 at 1.0 A g-1 after 300 cycles. This work combines structural design and in situ techniques, proving a successful nanostructure engineering strategy to rationalize alloy-type electrode materials for PIBs.

Optimizing the Fermi Level of a 3D Current Collector with Ni3 S2 /Ni3 P Heterostructure for Dendrite-Free Sodium-Metal Batteries.

Rechargeable sodium-metal batteries (RSMBs) with high energy density and low cost are attracting extensive attention as promising energy-storage technologies. However, the poor cyclability and safety issues caused by unstable solid electrolyte interphase (SEI) structure and dendrite issues limit their practical application. Herein, it is theoretically predicted that constructing the Ni3 S2 /Ni3 P heterostructure with high work function can lower the Fermi energy level, and therefore effectively suppressing continuous electrolyte decomposition derived from the electron-tunneling effect after long-term sodiation process. Furthermore, the Ni3 S2 /Ni3 P heterostructure on 3D porous nickel foam (Ni3 S2 /Ni3 P@NF) is experimentally fabricated as an advanced Na-anode current collector. The seamless Ni3 S2 /Ni3 P heterostructure not only offers abundant active sites to induce uniform Na+ deposition and enhance ion-transport kinetics, but also facilitates the formation of stable SEI for dendrite-free sodium anode, which are confirmed by cryogenic components transmission electron microscopy tests and in situ spectroscopy characterization. As a result, the Na-composite anode (Ni3 S2 /Ni3 P@NF@Na) delivers stable plating/stripping process of 5000 h and high average Coulombic efficiency of 99.7% over 2500 cycles. More impressively, the assembled sodium-ion full cell displays ultralong cycle life of 10000 cycles at 20 C. The strategy of stabilizing the sodium-metal anode gives fundamental insight into the potential construction of advanced RSMBs.

Mixed cellulose ester membrane as an ion redistributor to stabilize zinc anode in aqueous zinc ion batteries

Aqueous zinc-ion batteries (AZBs) with high energy density, low cost and environmental characteristics, have become the promising device for energy storage. However, uncontrolled zinc dendrite growth remains an impediment to the popularization of AZBs. The unrestricted two-dimensional (2D) ions diffusion is the main cause of the above defect. In this work, mixed cellulose ester (MCE) membrane is proposed as the separator. A dense homogeneous pore structure can achieve a physical shunting effect on ion diffusion, which can control and homogenize the ion motion. Further, the mechanism of this physical pore effect is confirmed by comparing the behavior of Zn deposition in MCE systems with different pore sizes but the same composition. As conjectured, a membrane with a smaller pore size is more favorable. In addition, the MCE contains many polar oxygen-containing functional groups that can facilitate and modulate ion diffusion through coordination. This chemical ion guiding effect, together with the above physical pore effect, gives the separator the ability to suppress dendrite formation. Zn/Zn symmetric cells with this membrane exhibit ultralong cycle life exceeding 1250 h at 0.5 mA cm−2 and 1000 h at 5 mA cm−2. And the Zn//MnO2 battery presents excellent cycle stability for more than 500 cycles with a capacity retention of 90.67%. This work proposes MCE separators and reveals their coordinated regulation of physical and chemical effects on metal-based anodes. This will shed light on the development of high-performance separators and AZBs.

An InSitu Fabricated Graphene/Bipolar Polymer Hybrid Material Delivers Ultralong Cycle Life over 15000 Cycles as a High-Performance Electrode Material.

Organic electrode materials are promising for the future energy storage systems owing to their tunable structures, abundant resources, and environmental friendliness. Many advanced lithium-ion batteries with organic electrodes have been developed and show excellent performance. However, developing organic materials with overall superior performance still faces great challenges, such as low capacity, poor stability, inferior conductivity, and low utilization of active sites. To address these issues, a bipolar polymer (Fc-DAB) is designed and further polymerized insitu with three-dimensional graphene (3DG), offering a hybrid material (Fc-DAB@3DG) with a variety of merits. Fc-DAB possesses stable polymer backbone and multiple redox-active sites that can improve stability and capacity simultaneously. The embedded highly conductive 3DG network endows Fc-DAB@3DG with stable conductive framework, large surface area, and porous morphology all together, so the fast diffusion of ions/electrons can be achieved, leading to high utilization of active sites and enhanced electrochemical performance. As a result, Fc-DAB@3DG cathode delivers capacity of ≈260mAhg-1 at 25mAg-1 , ultra-long cycle life over 15000 cycles at 2000mAg-1 with retention of 99.999% per cycle, and remarkable rate performance. The quasi-solid Li-metal battery and full cell fabricated using this material also exhibit superior electrochemical performance.

Bismuth−Antimony Alloy Embedded in Carbon Matrix for Ultra-Stable Sodium Storage

Alloy-type anodes are the most promising candidates for sodium-ion batteries (SIBs) due to their impressive Na storage capacity and suitable voltage platform. However, the implementation of alloy-type anodes is significantly hindered by their huge volume expansion during the alloying/dealloying processes, which leads to their pulverization and detachment from current collectors for active materials and the unsatisfactory cycling performance. In this work, bimetallic Bi-Sb solid solutions in a porous carbon matrix are synthesized by a pyrolysis method as anode material for SIBs. Adjustable alloy composition, the introduction of porous carbon matrix, and nanosized bimetallic particles effectively suppress the volume change during cycling and accelerate the electrons/ions transport kinetics. The optimized Bi1Sb1@C electrode exhibits an excellent electrochemical performance with an ultralong cycle life (167.2 mAh g-1 at 1 A g-1 over 8000 cycles). In situ X-ray diffraction investigation is conducted to reveal the reversible and synchronous sodium storage pathway of the Bi1Sb1@C electrode: (Bi,Sb) Na(Bi,Sb) Na3(Bi,Sb). Furthermore, online electrochemical mass spectrometry unveils the evolution of gas products of the Bi1Sb1@C electrode during the cell operation.

Lithiophilic Magnetic Host Facilitates Target‐Deposited Lithium for Practical Lithium‐Metal Batteries

Lithium-metal shows promising prospects in constructing various high-energy-density lithium-metal batteries (LMBs) while long-lasting tricky issues including the uncontrolled dendritic lithium growth and infinite lithium volume expansion seriously impede the application of LMBs. In this work, it is originally found that a unique lithiophilic magnetic host matrix (Co3 O4 -CCNFs) can simultaneously eliminate the uncontrolled dendritic lithium growth and huge lithium volume expansion that commonly occur in typical LMBs. The magnetic Co3 O4 nanocrystals which inherently embed on the host matrix act as nucleation sites and can also induce micromagnetic field and facilitate a targeted and ordered lithium deposition behavior thus, eliminating the formation of dendritic Li. Meanwhile, the conductive host can effectively homogenize the current distribution and Li-ion flux, thus, further relieving the volume expansion during cycling. Benefiting from this, the featured electrodes demonstrate ultra-high coulombic efficiency of 99.1% under 1mA cm-2 and 1 mAh cm-2 . Symmetric cell under limited Li (10 mAh cm-2 ) inspiringly delivers ultralong cycle life of 1600 h (under 2mA cm-2 , 1 mAh cm-2 ). Moreover, LiFePO4 ||Co3 O4 -CCNFs@Li full-cell under practical condition of limited negative/positive capacity ratio (2.3:1) can deliver remarkably improved cycling stability (with 86.6% capacity retention over 440 cycles).

Modulating vacancies concentration ratio of cationic and anionic in WO3 for driving high performance magnesium ions storage

Vacancy engineering is an efficient strategy for optimizing the electrochemical performance of electrodes for energy storage devices. However, it is still a challenge for modulating the concentration ratio of cationic vacancies and anionic vacancies in the electrode via a simple method for enhancing the electrochemical performance. Herein, cationic (W) vacancies and anionic (O) vacancies are constructed in WO3 simultaneously, and the concentration ratio of W and O vacancies is modulated by adding various content of glucose to regulate the W vacancies concentration via at a fixed O vacancies concentration. The characterization and DFT results confirm that moderate concentration ratio of W and O vacancies would not only expose more active sites, enhance the electronic conductivity and electrostatic potential, but also inhibit the vacancies gathering to maintain structural stability. In addition, the O−□−O bonding induced via moderate content of W vacancies owns rich-anionic environment to adsorb more Mg2+ as well as reduces electrostatic repulsive-force between Mg2+ and cationic lattice to facilitate Mg2+ diffusion. Therefore, the moderate concentration ratio of W and O vacancies make VW-O/WO3-1.0 cathode achieve high specific capacity of about 100 mAh g−1 at 50 mA g−1, excellent rate capacity of 37.7 mAh g−1 at 500 mA g−1 and ultralong cycling life about 1500 cycles. These findings raise the possibility for designing advanced electrodes through vacancy species and controllable concentration engineering.

The Negative-Charge-Triggered "Dead Zone" between Electrode and Current Collector Realizes Ultralong Cycle Life of Aluminum-Ion Batteries.

Typically, volume expansion of the electrodes after intercalation of active ions is highly undesirable yet inetvitable, and it can significantly reduce the adhesion force between the electrodes and current collectors. Especially in aluminum-ion batteries (AIBs), the intercalation of large-sized AlCl4 - can greatly weaken this adhesion force and result in the detachment of the electrodes from the current collectors, which seems an inherent and irreconcilable problem. Here, an interesting concept, the "dead zone", is presented to overcome the above challenge. By incorporating a large number of OH- and COOH- groups onto the surface of MXene film, a rich negative-charge region is formed on its surface. When used as the current collector for AIBs, it shields a tiny area of the positive electrode (adjacent to the current collector side) from AlCl4 - intercalation due to the repulsion force, and a tiny inert layer (dead zone) at the interface of the positive electrode is formed, preventing the electrode from falling off the current collector. This helps to effectively increase the battery's cycle life to as high as 50000 times. It is believed that the proposed concept can be an important reference for future development of current collectors in rocking chair batteries.

Tailoring the d‐Band Center over Isomorphism Pyrite Catalyst for Optimized Intrinsic Affinity to Intermediates in Lithium–Oxygen Batteries

AbstractRechargeable lithium–oxygen batteries (LOBs) are regarded as one of the most promising candidates for the next generation of energy storage devices. Nevertheless, the lack of understanding of the relationships between structure, property, and performance of catalysts limits the rational development of efficient cathode catalysts, and therefore, hinders the commercial application of LOBs. Herein, a d‐band center regulation strategy is proposed to construct an isomorphism composite of NiS2‐CoS2@nitrogen‐doped carbon (NiS2‐CoS2@NC) as an advanced cathode catalyst for boosting the electrocatalytic activities of LOBs. Density functional theory calculations reveal that the introduction of Ni atoms not only redistributes the internal charges on the isomorphism structure but also modulates the adsorption capacities of the intermediates by tuning the d‐band center, thus promoting oxygen reduction reaction/oxygen evolution reaction kinetics and reducing the reaction overpotentials. As expected, NiS2‐CoS2@NC catalyzed LOBs present superior electrochemical performance including large initial discharge/charge specific capacity of 14 551/13 563 mAh g−1, an ultralong cycle life over 490 cycles at a current density of 500 mA g−1, and excellent rate performance. The insight into the regulation of the adsorption capacity of the catalyst by tailoring its d‐band center facilitates the rational construction of efficient electrocatalysts for LOBs and other electrocatalytic systems.

Bimetal heterostructure NiCo2Se4 anode confined by carbon nano boxes for ultrafast and stable potassium storage

Transition metal selenides (TMSes) are regarded as promising anodes for potassium ion batteries (PIBs) benefit from their high theoretical capacity. However, the slow kinetics of potassium ion transport, poor charge transfer ability and short cycle life limit the development of transition metal selenide anode. In this article, the dice-shaped NiCo2Se4@N-doped carbon (NCS@NC) nanocomposite is designed for efficient and stable potassium storage. The in-situ formed carbon shell can not only act as a highly conductive framework to accelerate charge transfer, but also limit the volume fluctuation caused by the potassium ion repeated insertion/ extraction process. The in-situ and ex-situ characterization as well as theoretical calculation show that the heterogeneous interface formed by the heterogeneous metal species in NCS@NC spontaneously establish internal electric fields, which significantly accelerates the ion transport. As results, advanced NCS@NC anode with greatly enhanced electrochemical performance is obtained due to the synergy between the three-dimensional structure design and the heterogeneous interface strategy. NCS@NC anode displays extraordinary rate capacity (471.9 mAh g-1 at 2 A g-1) and ultralong cycle life at high current density (454.5 mAh g-1 at 2 A g-1 after 1000 cycles), which indicates that our modification strategy provides an alternative solution for designing advanced PIBs anodes.

Polynitrosoarene Radical as an Efficient Cathode Material for Lithium-Ion Batteries.

Organic radical batteries (ORBs) with radical-branched polymers as cathode materials represent a valuable alternative to meet the continuously increasing demand on energy storage. However, the low theoretical capacities of current radical-contained compounds strongly hamper their practical applications. To address this issue, a chemically robust polynitrosoarene (tris(4-nitrosophenyl)amine) with a pronounced radical property is rationally designed as an efficient cathode for ORBs. Its unique multi-nitroso structure displays remarkably reversible charge/discharge capability and a superior capacity up to 300 mA h g-1 (93% theoretical capacity) after 100 cycles at 100 mA g-1 within a broad potential window of 1.3-4.3 V (vs Li+/Li). Moreover, the ultra-long cycle life is also achieved at 1000 mA g-1 with 85% preservation of the capacity after 1000 cycles, making it the best-reported organic radical cathode material for lithium-ion batteries.

Wide-voltage-window amphiphilic supramolecule excluded-volume electrolytes for ultra-durable full-cell aqueous potassium-Ion batteries

Aqueous potassium-ion batteries (AKIBs) are promising candidates for large-scale energy storage. However, the performance of AKIBs is restricted the dissolution of electrode materials and the narrow voltage window of aqueous electrolytes. Herein, we report the amphiphilic supramolecule modified aqueous K-ion electrolytes with synergistic functions of excluded-volume effect and hydrogen bond networks, which greatly reduce the activity of water molecules, inhibit the dissolution of active materials, and expand the operation voltage window (>3.4 V). Moreover, the as-assembled full-cell AKIBs exhibit an open-circuit voltage of 2.0 V, good rate capability, wide operating temperature range (−20 to 90 °C), and ultralong cycling life (with a capacity retention of 97.8 % after 10,000 cycles at 10 C). The study makes it possible for aqueous electrolytes to possess wide voltage window and temperature endurance, greatly expanding the choices of practicable electrolyte and paving the way of high-voltage aqueous batteries towards sustainable, safety and low-cost energy storage.

Mesoporous Gold Film with Surface Sulfur Modification to Enable Dendrite-Free Lithium Plating/Stripping for Long-Life Lithium Metal Anodes.

The formation of a lithiophilic phase is an effective method to inhibit the growth of lithium dendrites and obtain high-performance Li metal anodes (LMAs). Nonetheless, previous studies have overlooked the underlying mechanistic studies that modulate the structure of the lithiophilic phase as well as lithiophilicity. A self-supporting sulfur-modified mesoporous gold film on nickel foam (SMGF@NF) for LMAs is created with mesoporous structure, which can provide sufficient active sites for uniform lithium deposition. The synergistic promotion of lithiophilic gold and sulfurleads to uniform lithium nucleation and induces consistent lithium removal during lithium stripping. The doping of S promotes the decomposition of bistrifluoromethanesulfonimide lithium saltto generate lithium fluorde, thus forming a more stable solid electrolyte interface. Combining the multifaceted advantages of SMGF@NF, its lithium-plated electrode can achieve ultralong cycle life in symmetrical batteries (over 1000h at 0.5mA cm-2 and 1 mAh cm-2 ) and ultralow overpotential (≈10mV). Meanwhile, the Li-SMGF@NF||LiFePO4 full cell achieves a high cycling performance and rate capability (92.4% capacity retention after 1000 cycles at 5 C). The study probes into the composite electrode surface composition and structure, revealing the mechanism of high-performance LMAs.

Hybridization of Layered Titanium Oxides and Covalent Organic Nanosheets into Hollow Spheres for High-Performance Sodium-Ion Batteries with Boosted Electrical/Ionic Conductivity and Ultralong Cycle Life.

While development of a sodium-ion battery (SIB) cathode has been approached by various routes, research on compatible anodes for advanced SIB systems has not been sufficiently addressed. The anode materials based on titanium oxide typically show low electrical performances in SIB systems primarily due to their low electrical/ionic conductivity. Thus, in this work, layered titanium oxides were hybridized with covalent organic nanosheets (CONs), which exhibited excellent electrical conductivity, to be used as anodes in SIBs. Moreover, to enlarge the accessible areas for sodium ions, the morphology of the hybrid was formulated in the form of a hollow sphere (HS), leading to the highly enhanced ionic conductivity. This synthesis method was based on the expectation of synergetic effects since titanium oxide provides direct electrostatic sodiation sites that shield organic components and CON supports high electrical and ionic conductivity with polarizable sodiation sites. Therefore, the hybrid shows enhanced and stable electrochemical performances as an anode for up to 2600 charge/discharge cycles compared to the HS without CONs. Furthermore, the best reversible capacities obtained from the hybrid were 426.2 and 108.5 mAh/g at current densities of 100 and 6000 mA/g, which are noteworthy results for the TiO2-based material.