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[Display omitted] • Carbon dots derived from low-cost lignite show high yields and water solubility. • The surface-induced assembly of CDs on PAN fibers brings in high flexibility. • The as-prepared CNF@CDs with 3D structures possess boosted reaction kinetics. • The as-prepared CNF@CDs were directly employed as binder-free anodes for SIBs. • The CNF@CDs anode for SIBs shows a reversible capacity of 223 mAh g−1 at 20 mA g−1. Flexible electrodes with superior stability, high performance, and low cost have drawn numerous considerations in energy storage devices. Here, we developed a facile and robust strategy to prepare coal-based carbon dots (i.e., CDs) with high yields derived from lignite by microwave-assisted mild oxidation and further fabricate a carbon nanofiber film decorated with CDs (i.e., CNF@CDs) by electrospinning water-soluble CDs with polyacrylonitrile (i.e., PAN) through thermal treatment and carbonization and applied as flexible electrodes for sodium-ion batteries. The as-prepared CNF@CDs as binder-free anode presents a reversible capacity of 223 mAh g−1 at 20 mA g−1 and obtains a high capacity retention of 96% over 400 cycles. The outstanding electrochemical properties were attributed to the unique structure of CNF@CDs with the optimal ratio of carbon nanofiber and coal-based carbon dots, in which carbon fiber with the 3D framework facilitates the speed of ion diffusion and electron transport as well as the surface-induced assembly of CDs on the surface of the PAN fibers brings in strong structure stability and electrode integrity. The current study supplies a novel and effective approach to constructing flexible electrodes with superior stability and high performances from low-cost materials, which has potential application prospects in flexible energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • The vacancy-defective graphene sheets are constructed successfully through polyacrylonitrile thermally mediated. • Vacancy defects on graphene sheets can enhance electrons/ions transport kinetics • The assembled aqueous zinc-ion hybrid supercapacitors exhibit a high energy density and outstanding cycling stability. The electrochemical behavior of graphene sheets in energy storage system is closely related to its electronic structures. Specifically, structural vacancy defects can expose more active sites and enhance the electrochemical performance. However, it is still a challenging problem to realize valid defect regulation on improving the reaction kinetics of electrode materials. Herein, vacancy-defective graphene sheets were constructed through the thermal mediated method via intercalation of polyacrylonitrile nanofibers. The vacancy defects were generated from the NH 3 gas resulting from polymer decomposition at gradient carbonization temperature. The obtained composites of the graphene sheets and carbon nanofibers demonstrate that the vacancy defects benefit to charge transport, allowing more electrons to pass through the interlayered structure, and enhance the adsorption capacitance during the reversible electrochemical process. In addition, the as-assembled Zn ion hybrid supercapacitors exhibit a high energy density of 129.9 Wh kg−1 and outstanding cyclic stability (99.8 % after 10,000 cycling). The confined polymer-mediated thermal modification strategy can afford abundant vacancy defective sites and exhibit promising outlook for constructing high-performance graphene-based electrode materials for Zn ion hybrid supercapacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Dual oxide co-decorated necklace-like CNF (TiO 2 @SiO 2 /CNF) flexible electrocatalytic membrane interlayer was prepared. • The necklace-like structure enhances structural stability and provides more active sites. • The TiO 2 @SiO 2 /CNF synergistically combined the advantages of high conductivity and high electrocatalytic activity. • The Li-S batteries with TiO 2 @SiO 2 /CNF interlayer achieve outstanding rate performance and cycling stability. Lithium-sulfur (Li-S) batteries are regarded as new energy storage systems due to their low cost and high specific energy density; however, their commercial prospects are hindered by the shuttle effect of lithium polysulfides (LiPSs). Herein, the fabricating necklace-like carbon nanofibers membrane co-decorated by TiO 2 and SiO 2 (TiO 2 @SiO 2 /CNF) is prepared by the electrospinning technique as an interlayer to catalyze the conversion of LiPSs in Li-S batteries. The necklace-like nanofibers provide a three-dimensional conductive network, enabling SiO 2 synergy with TiO 2 to accelerate the redox kinetics of LiPSs through an enhanced interfacial effect. The Li-S batteries based on TiO 2 @SiO 2 /CNF interlayers exhibit an impressive specific capacity of 658 mAh g−1 at 3.0C, and their performances are decayed only 0.05 % per cycle at 1.0C within 500cycles. Our study reveals that the shuttle effect addition of LiPSs can be significantly improved by rational structural design, thus enhancing the electrochemical performance of Li-S batteries. The synthesis of necklace-like TiO 2 @SiO 2 /CNF presents a promising strategy for designing functional interlayers for advanced Li-S batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • The NB-PCNF and MnO 2 /Co 3 O 4 /NB-PCNF were successfully fabricated via needleless electrospinning. • The co-doping of multiple non-metallic atoms enhances the electrochemical capability of carbon nanofibers. • The heterogeneous structure in MnO 2 /Co 3 O 4 /NB-PCNF can effectively improve the electrical conductivity. • A flexible asymmetric solid-state supercapacitor (FASS-SC) exhibits excellent electrochemical performance. Rational design of an electrode material with high flexibility and electrochemical performance is the key to wearable energy storage devices. Herein, a facile and productive needleless electrospinning method was introduced to prepare self-supported and flexible nanofibrous electrode materials for asymmetric capacitor. The MnO 2 nanoclusters and ZIF67-derived Co 3 O 4 nano-sheets were sequentially deposited on the surface of N, B-doped carbon nanofibers (hetero-junction MnO 2 /Co 3 O 4 /NB-PCNF). Attributing to the constructed multi-pathway for redox reactions on electrode, the specific capacitance of NB-PCNF and MnO 2 /Co 3 O 4 /NB-PCNF can reach up to 204.2F/g and 141.43F/g at a small current density of 0.1 A/g, respectively. In long-term cycling tests, the electrode materials exhibited excellent cycling stability and good rate capability. The electrodes were assembled with Potassium-ion hydrogel electrolyte to form a flexible asymmetric solid-state supercapacitor (FASS-SC). FASS-SC can reach a voltage window of 1.6 V. It provided 28.2 W h/kg at an energy density of 600 W/kg and a specific capacitance retention of 94.18 % after 10,000 cycles. The FASS-SC offers new research ideas for future flexible devices and wearable technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • ● A dual network organohydrogel based asymmetric supercapacitor exhibits temperature tolerance from −20 to 80 °C. • ● High operation voltage of 1.7 V and a high energy density of 51.1Wh kg−1 is obtained with the supercapacitor. • ● Over the repeated cycles of heating and cooling between –20 and 80 °C, 94% of the initial capacitance is retained. • ● The supercapacitor exhibits mechanical stability over bending regardless of the temperature. It is highly desirable for supercapacitors to achieve mechanical flexibility and temperature tolerance, as well as high energy density, to fully utilize their superior characteristics of high-power density and long cycle stability to realize their potential as practical wearable energy storage devices. We devise a novel strategy to fabricate a flexible asymmetric supercapacitor based on dual network organohydrogel, exhibiting high energy density and electrochemical stability over a wide temperature range spanning 100 ℃. A three-dimensional core–shell NiCo 2 O 4 @MnO 2 nanostructure is selected as the positive electrode to supply multiple ion diffusion channels through its mesoporous structure, and nano structured N-doped carbon nanofibers as the negative electrode to increase the contact area with electrolyte, and 6 M KOH based organohydrogel as electrolyte. The resulting supercapacitor exhibits high electrochemical performance including a high operation voltage of 1.7 V and high energy density of 51.1 Wh kg−1 at a power density of 850 W kg−1 and is stable over temperature changes between –20 and 80 ℃. This work demonstrates a high-performance supercapacitor designed with 3D asymmetric electrodes and a dual network organohydrogel, suitable as a practical energy storage device, requiring mechanical stability and stability against temperature change. [ABSTRACT FROM AUTHOR]

Recently, Li-ion capacitor as a kind of novel energy storage device with high energy density and power density have caused wide concern. In this study, the porous carbon nanofiber/molybdenum disulfide nanoflake-flowerballs composite material is successfully prepared via hydrothermal method using the three-dimensional porous carbon nanofibers as a carrier. The molybdenum disulfide nanoflake-flowerballs are uniformly distributed and fill in three-dimensional porous carbon nanofibers skeleton, and the clear composite material with nanofiber morphology is formed. This material presents moderate specific surface area (81.67 m2 g−1) and good electrical conductivity (22.32 S cm−1) and is used as the anode in the Li-ion capacitor, and the big energy density at high power density (the energy density could reach 75.5 Wh kg−1 and 22.5 Wh kg−1 at power densities of 0.075 kW kg−1 at 30 kW kg−1, respectively) are achieved, which has broad application prospect in the energy storage field. • The three-dimensional PCNF loading MoS 2 nanoflake-flowerballs was constructed. • The MoS 2 nanoflake-flowerballs inner nanofibers provide the large reaction area. • The three-dimensional PCNF skeleton offers conductive path. • The 3D-PCNF/MoS 2 -NFFBs used as the anodes of LICs exhibit excellent properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • This is a direct synthesis of BCN nanofibers were directly obtained using CVD technique. As per other literature review, BCN in its nanotubular form showed multifunctional properties and applications. • When applied as an electrode, the monolithic BCN/MoS2 electrode is fabricated by a simple and scalable CVD process followed by direct magnetron sputtering at room temperature. Boron carbon nitrogen (BCN) nanofibers was synthesized using chemical vapor deposition (CVD) followed by depositing molybdenum disulfide (MoS 2) forming a core–shell structure. This core–shell nanocomposite was directly grown on carbon paper to form working electrode, where it displayed excellent energy storage ability as well as hydrogen evolution reaction (HER) catalytic activity. We believe that during the shell deposition, it effectively etched the inert basal plane of MoS 2 , leading to the formation of entrenched valleys and to the further increasing of the active edge sites. Coupled with high surface area and high density BCN nanofibers core, the MoS 2 /BCN nanofiber catalyst demonstrated a very low overpotential of 85 mV in acidic media at a current density of 10 mA cm−2 for HER. In addition, the optimally tuned MoS 2 /BCN nanofiber also showed superior electrochemical performance as a supercapacitor with higher specific capacitance of 446.3 A g−1 at current density of 0.25 A g−1. Overall, this excellent catalytic activity is found to be due to their abundant active sites and fast ion transfer capability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Protein-assisted bendable Cu-free anode for flexible Li-ion battery applications. • Hydroxy-functionalized mesoporous carbon nanofiber matrix with high bendability. • Enhanced Li-ion diffusivity and electron conductivity of Cu-free electrode. • Fundamental approach to achieve highly bendable mesoporous carbon matrix. Several approaches have been proposed for development of a current collector-free bendable energy storage electrode for flexible lithium-ion battery applications, such as construction of a hybrid composite structure and introduction of a simple synthesis procedure. However, a more fundamental strategy is required to achieve a highly bendable electrode using carbonaceous materials. We report a novel strategy for development of a protein-assisted bendable Cu-free anode using a hydroxy-functionalized mesoporous carbon nanofiber (CNF) matrix. Zinc oxide nanoparticles and glutamic acid were used as modification agents during the preparation of CNFs and mesoporous CNF structure with N dopants and rich hydroxy groups (Glu-PCNF). The resultant Glu-PCNF electrode exhibited competitive Li-ion storage capabilities, such as a high specific capacity of 469.87 mAh/g at a current density of 100 mA/g and fast energy storage (113.6 mAh/g at 2,000 mA/g). Moreover, the Glu-PCNF electrode maintained its energy storage performance after 1,000 cycles of bending, which demonstrates its high bendability. Therefore, the Cu-free Glu-PCNF electrode, with a high bendability and competitive energy storage performance, can accelerate the implementation of next-generation electronic devices with wearable and flexible functions. [ABSTRACT FROM AUTHOR]

The three-dimensional structure of SnSe microsheets cross-linked by nitrogen-doped carbon nanofibers (SnSe/NCF) is precisely designed and synthesized by electrospinning method and one-step selenization method, which has good electrochemical performance as a flexible anode for Na-ion batteries. [Display omitted] • A binder-free electrode (SnSe/NCF) has been developed by electrospinning and heat treatment process. • The as-prepared SnSe/NCF electrodes exhibit good electrical conductivity and flexibility. • The as-prepared SnSe/NCF electrodes improve the kinetics and reduce the volume expansion of SnSe. Transition metal selenides are regarded as the promising anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacitie. However, they still suffer from some fatal flaws including short lifetime and sluggish cycling kinetics. Herein, a free-standing, binder-free electrode was developed by electrospinning and subsequent thermal treatment process, in which three-dimensional (3D) N-doped carbon nanofibers and tin selenide are cross-linked with each other (SnSe/NCF). The synergistic effect of SnSe microsheets and carbon fibers shortens the ion transport channel and increases more active sites. N-doped carbon network not only improves electrical conductivity but also prevents pulverization of the material. The as-prepared SnSe/NCF electrodes exhibit good electrical conductivity and flexibility owing to the highly carbonized carbon nanofiber network. The SnSe/NCF electrode exhibits superior specific capacity with (576.7 mAh g−1 at 0.2 A g−1), ultra-long lifetime (286.4 mAh g−1 after 2100 cycles at 2.0 A g−1) and excellent rate performance (576.7 mAh g−1 at 5 A g−1) as a stand-alone anode for SIBs. This work provides a promising approach for developing flexible energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrodes show enhanced conductivity, high flexibility, and good porosity. • Freestanding electrodes provided rapid diffusion kinetics and a significant Na+ ion storage capacity. • Excellent specific capacity of mixed metal oxides 489 mAh/g at 20 mA/g with good rate performance as compared to metal oxide 365 mAh/g at 20 mA/g. • Mixed metal oxides show Improved ICE (71%) showing the formation of a smooth and stable solid electrolyte interface as compared to metal oxide (41%) • Good cycling stability over 500 charge/discharge cycles by retaining 94% of the capacity. The development of next-generation highly flexible materials as electrodes in sodium-ion batteries has significant potential. To overcome electrode deterioration and limited ionic and electronic mobility, surface-engineered materials are required. In this work, metal and mixed metal decorated freestanding CNFs electrodes exhibited quick diffusion kinetics as well as a substantial Na+ storage capacity. Mixed metal oxides exhibited ICE of 71% and a specific capacity of 489 mAh/g over 500 cycles, which is far better than metal oxides that demonstrated ICE of 43% and a specific capacity of 365mAh/g. This extraordinary synergy may encourage the development of advanced methods that combine self-supportive, highly flexible, and porous properties for further energy storage devices. [ABSTRACT FROM AUTHOR]

Textual abstract: Dual-function electrochromic-energy storage devices were constructed by using lamella self-assembled Cu-doped NiO nanosheets, which simultaneously possess excellent electrochromic and capacitive properties. [Display omitted] • Self-assembled Cu-doped NiO was prepared as electrochromic-energy storage material. • 1% Cu doped NiO showed excellent electrochromic, capacitive properties and stability. • Intelligent EESDs with visual observation of storage level were constructed. • The color of EESD changed with the energy storage level, proving its bifunctionality. • After charging, a EESD provided 1.48 V, and two in series could light up a LED light. In this study, a novel bifunctional lamella self-assembled nanosheet arrays of Cu-doped NiO electrode was hydrothermally synthesized to improve and balance its electrochromic-energy storage performance. When Cu doping amount was 1%, the as-prepared nanostructured electrode exhibited both excellent electrochromic properties including large optical modulation (77.1% at 550 nm) and long stability (98.3% retention of maximum optical modulation after 4000 cycles), and good capacitive properties, especially high area specific capacitance (94.7 mF/cm2 at 0.2 mA/cm2) as well as excellent capacitance stability (100% at 50 mV/s for 2000 cycles; 80.6% retention at 0.8 mA/cm2 for 5000 cycles). These excellent properties may benefit from the large active specific surface area and low charge transport resistance. Meanwhile, the self-assembled structure and cross-linked nanosheets optimize the structural stability of the film. Notably, an electrochromic-energy storage device (EESD) was constructed and demonstrated excellent electrochromic-energy storage performance. In charging process, two integrated EESDs in series turned into dark brown and an LED was lit up. While, in discharging process, the EESD gradually became colorless and the LED went out. This study may point out the direction for developing new visualized energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • All-carbon aerogels of helical carbon nanocoils (CNCs)/reduced graphene oxide (rGO)/carbon nanofibers (CNFs) are successfully synthesized. • CNCs prevent the stacking of rGO and enlarge the spaces between rGO. Moreover, the growth of CNFs improves the specific surface area and conductivity. • Our work provides new inspiration for the design of multidimensional rGO-based aerogels for energy storage electrodes. Reduced graphene oxide (rGO)-based aerogels with multidimensional structures have shown enormous potential for electrodes in supercapacitors. Currently, the interlayer stacking of rGO largely limits their capacitance performance and leads to poor structural stability. Herein, the multidimensional all-carbon aerogel of helical carbon nanocoils (CNCs)/rGO/carbon nanofibers (CNFs) has been synthesized by hydrothermal self-assembly and in-situ chemical vapor deposition (CVD). In this ternary electrode, three-dimensional (3D) CNCs serve as the inner skeleton, which facilitates the construction of 3D porous architectures and reinforces the structural stability. The intercalated CNCs prevents the stacking of rGO and effectively enlarges the spaces between rGO. Moreover, the uniform growth of one-dimensional CNFs improves the specific surface area and electrical conductivity. Due to the synergistic effect and hierarchical assembly of these components, the CNCs/rGO/CNFs electrode not only exhibits a high areal capacitance of 1581.7 mF cm−2 at 0.5 mA cm−2 in a 6 M KOH electrolyte but also shows excellent cycling durability with 108.1% capacitance retention over 30,000 cycles. This work provides inspiration and guidance for the design of multidimensional electrode materials, which has huge application potential in future energy storage devices. [ABSTRACT FROM AUTHOR]

Synopsis. CoFe2O4@SnO2 heterostructure decorated CNFs as functional cathode additives can potentially chemisorb and catalyze the conversion of polysulfides to enhance the performance of lithium sulfur batteries. [Display omitted] • CoFe2O4@SnO2 decorated carbon nanofiber viz. CoFe@SnCNF is fabricated. • CoFe@SnCNF is used as a functional additive in cathode of LSBs. • CoFe@SnCNF supresses the shuttling and expedites the conversion of polysulfides. • Cathode using CoFe@SnCNF achieved excellent cycle and rate performance. Lithium-sulfur batteries (LSBs) are the promising next-generation energy storage devices; however, the uncontrolled shuttle effect and sluggish redox kinetics severely hinder their commercial success. To solve these barriers, herein, a heterostructure constructed from CoFe 2 O 4 and SnO 2 decorated over the carbon nanofiber framework (CoFe@SnCNF) is reported as a sulfur redox catalyst in the cathode of LSB. A synergism between the multiple adsorptive and catalytic sites of the heterostructure enables an efficient lithium polysulfide (LiPS) entrapment and expedites their conversion, meanwhile the carbon nanofiber framework provides a long-range electrical conduction. Based on these merits, the CoFe@SnCNF integrated sulfur cathode with an areal sulfur loading of ~ 2.2 mg cm−2 retained 71.1 % of initial capacity after 100 cycles at 0.2 C, and showed excellent cyclability with a capacity fading rate of only 0.11 % over 200 cycles at 0.5 C. Even under a raised sulfur loading of 5.3 mg cm−2, the cathode still showed an impressive performance with an initial capacity of 442.3 mAh g−1 that retained 78.1 % after 80 cycles. The findings of this work shed light on the feasibility for further development of novel heterostructure by synergistically coupling various polysulfide adsorbing and catalyzing materials. [ABSTRACT FROM AUTHOR]

• One-step K 2 FeO 4 activation is used to modify carbon nanofiber electrode of VRFB. • The one-step activation is less time-demanding, mild, and more efficient. • Highly porous, graphitic, and oxygen-functionalized carbon nanofiber was obtained. • Modified electrode exhibits superior kinetics for both vanadium redox reactions. • Carbon nanofiber as bifunctional electrode can enhance VRFB performance greatly. Herein, a one-step method is applied to prepare porous, graphitic, and oxygen-functionalized carbon nanofiber as bifunctional electrode for vanadium redox flow battery (VRFB). Potassium ferrate is used to increase microporous structure, graphitization degree, and oxygen-containing group of carbon nanofiber synchronously at high temperature. This method is less time-demanding, highly efficient, and mild compared with typical two-step strategy (potassium hydroxide and ferric chloride treatment). Carbon nanofiber is modified at different mass ratio of carbon nanofiber and potassium ferrate (1:1, 1:3, and 1:5). The carbon nanofiber treated by one-step method with mass ratio of 1:3 (CNF-PF-3) demonstrates the best electrocatalysis towards V3+/V2+ redox reaction. Moreover, CNF-PF-3 also exhibits outstanding electrocatalysis towards VO2+/VO 2 + redox reaction. The electrochemical performance of carbon nanofiber is improved by accelerating ion diffusion, electrochemical reaction, and electron transfer, systematically. It is due to an obvious increase in surface area, conductivity, active sites, and hydrophilcity for carbon nanofiber. The cell using CNF-PF-3 as bifunctional electrode presents the best energy storage performance compared with the cell using CNF-PF-3 at one side and pristine cell. Energy efficiency of the cell using CNF-PF-3 as bifunctional electrode reaches 75.5% at 100 mA cm−2, which is 9.9% higher than that of pristine cell. [ABSTRACT FROM AUTHOR]

• Free-standing S, N co-doped porous carbon nanofibers (SN-PCNF) are prepared. • SN-PCNF capture lithium polysulfide by the strong chemisorption of the N, S doping. • SN-PCNF@S with 80% S loading exhibits 554 mA h·g−1 after 150 cycles at 0.1 C. • DFT calculations reveal the binding energy of polysulfide with N, S doped carbon. Lithium–sulfur batteries are promising next-generation energy storage device, but polysulfide shuttling which results in the capacity decay, still remains a great challenge. In this work, we proposed a sulfur and nitrogen co-doped strategy to increase interaction between the lithium sulfides and host. Herein, free-standing S and N dually doped porous carbon nanofibers (donated as SN-PCNF) are prepared and serve as efficient sulfur host materials. Benefitting from the S and N co-doped strategy, the chemical adsorption of lithium polysulfides increases, thus the free-standing SN-PCNF@S cathode delivers an initial discharge capacity of 1133 mA h·g−1 with 80% sulfur loading. Furthermore, the DFT calculations reveals the stronger polysulfide binding with nitrogen and sulfur co-doped carbons than that with nodoped or nitrogen single-doped carbons. [ABSTRACT FROM AUTHOR]

• SnSe quantum-dots embedded in carbon nanofibers (E-SnSe) were first fabricated via feasible electrospinning. • The E-SnSe electrode shows the best cycling stability reported so far for SnSe-based anodes. • The E-SnSe electrode reveals the mixed electrochemical redox behaviors during the cycling. • The Na 3 V 2 (PO 4) 3 @C//E-SnSe full cell shows the potential application prospects with cycling performance of 1500 cycles. Engineering suitable tin selenide (SnSe) anode for sodium ion batteries (SIBs) with both excellent cycling durability and remarkable rate capability has received enormous attention. The effective regulation of morphology and size has been shown to promote electrochemical performance. The irregular shape and micron size of obtained SnSe by conventional construction methods (high energy ball milling) is detrimental to the anode performance. Herein, SnSe quantum-dots (E-SnSe) and SnSe nanoparticles (B-SnSe) are synthesized by means of a feasible electrospinning technique together with subsequent high-temperature selenylation and high energy ball milling, respectively, and both are examined as anode materials for SIBs. As compared to B-SnSe electrode, the E-SnSe electrode delivers a larger discharge capacity of 268 mAh g−1 after 750 cycles at 2 A g−1 and more remarkable cycling durability over 1500 cycles even at much higher rate of 5 A g−1, which is the best cycling stability reported so far for SnSe-based anodes. The significantly enhanced performance is attributed to unique three-dimensional (3D) conductive carbon network structure of E-SnSe, which could boost rapid electron/sodium ion transport with the remarkable contribution of pseudocapacitance and dramatically improve the structure evolution of SnSe resulted from the conversion and alloying process. Furthermore, the assembled Na 3 V 2 (PO 4) 3 @C//E-SnSe full cell shows an output voltage of above 2.0 V, ultralong cycle life of 1500 cycles with a high reversible discharge capacity of about 100 mAh g−1 at 1 A g−1 and superior rate capability with 86.4% capacity retention after 35 cycles, showing the potential application prospects in a large scale energy storage field. [ABSTRACT FROM AUTHOR]