High-capacity Lithium-ion Batteries Research Articles

Simulated Crystal Growth of Intermediate Phases Formed during Li and O Extraction of Nano-Li2MnO3 Cathode Material

Li2MnO3 is considered as a potential candidate for high capacity (theoretical capacity of 458 mAh/g) lithium ion batteries applicable in electric vehicles owing to its larger number of exploitable Li ions. However, it is vulnerable to degradation originating from complex phenomena such as the oxygen release, phase transformation and Li+ /H+ exchange reaction, but the detailed mechanisms governing these degradation behaviors have not been fully understood yet. In the current work, spontaneous crystal growth of the nano-Li2MnO3 structures via the amorphisation and crystallisation technique is carried out with systematic removal of oxygen and lithium contents in a quest to explore the formation of different intermediate structures/phases. The simulated nano-architectures crystallised into multi-grained (except for Li1.75MnO2.75) and highly defective structures. To study the formation possible phases, the XRD patterns were measured for all intermediate structures and reveal emergence of new Mn3O4 peak at 2Ө~ 29⁰ and strong cubic spinel LiMn2O4 at 2Ө~ 37⁰. Microstructural analysis revealed the formation of layered and spinel-type structures for low lithium and oxygen content nanostructures. These findings shed light towards mechanisms that take place during the cycling of nanostructured high capacity oxide electrodes during lithium and oxygen extraction that will help guide the optimisation of new Li-rich materials for rechargeable lithium batteries.

Photo-oxidation of an organosulfur for photo-charging of lithium-ion batteries

Polymers of organosulfur with S-S bonds are potential cathode materials for high-capacity lithium-ion batteries, and the photo-oxidation of organosulfurs can be applied in the future to the photo-charging of batteries. Herein, we present the photo-oxidation of dithiobiuret (DTB), a simple organosulfur molecule with two neighbouring tautomeric thiol/thione groups (-SH/>C=S) that can form a disulfide (S-S) bond by reversible intramolecular oxidative cyclization. Aqueous solutions of DTB with different pH values were irradiated by visible light from a halogen lamp. Photo-oxidation was confirmed by ultraviolet (UV) absorption spectroscopy, on comparison of the UV absorption spectra of DTB and chemically oxidized DTB. The rate of photo-oxidation depended on the pH of the DTB solution, and the highest photo-oxidation rate of ∼ 2.8 × 10−3 min.−1 was observed at a pH of ∼ 3.1.

The Role of Electrolyte Additives on the Interfacial Chemistry and Thermal Reactivity of Si-Anode-Based Li-Ion Battery

Silicon (Si) has gained huge attention as an anode material for next-generation high-capacity lithium-ion batteries (LIBs). However, despite its overwhelming beneficial features, its large-scale co...

A Flexible Si@C Electrode with Excellent Stability Employing an MXene as a Multifunctional Binder for Lithium-Ion Batteries.

Silicon is a promising anode material with high capacity for lithium-ion batteries (LIBs) but suffers from poor conductivity and large volume change during charge/discharge. Herein, by using two-dimensional conductive MXene as a multifunctional binder instead of conventional insulating polymer binders such as poly(vinylidene fluoride) or carboxymethylcellulose sodium (PVDF and CMC, respectively), a free-standing, flexible Si@C film was fabricated by simple vacuum filtration and directly used as anode for LIBs. In the MXene-bonded Si@C film, MXene constructed a three-dimensional conductive framework in which Si@C nanocomposites were embedded. Its loose and porous structure provided much space to buffer the large volume expansion of Si@C nanoparticles and thus led to significantly superior cycle stability compared with conventional CMC- and PVDF-bonded Si@C electrodes. Moreover, the porous structure and the metallically conductive MXene offered fast ion transport and outstanding conductivity of the MXene-bonded Si@C film, which were favorable for its rate performance. These results promise good potential of the MXene-bonded Si@C film electrode for LIBs.

Co-axial fibrous silicon asymmetric membranes for high-capacity lithium-ion battery anode

Silicon as a promising candidate for the next-generation high-capacity lithium-ion battery anode is characterized by outstanding capacity, high abundance, low operational voltage, and environmental benignity. However, large volume changes during Si lithiation and de-lithiation can seriously impair its long-term cyclability. Although extensive research efforts have been made to improve the electrochemical performance of Si-based anodes, there is a lack of efficient fabrication methods that are low cost, scalable, and self-assembled. In this report, co-axial fibrous silicon asymmetric membrane has been synthesized using a scalable and straightforward phase inversion method combined with dip coating as inspired by the hollow fiber membrane technology that has been successfully commercialized over the last decades to provide billions of gallons of purified drinking water worldwide. We demonstrate that ~ 90% initial capacity of co-axial fibrous Si asymmetric membrane electrode can be maintained after 300 cycles applying a current density of 400 mA g−1. The diameter of fibers, size of silicon particles, type of polymers, and exterior coating have been identified as critical factors that can influence the electrode stability, initial capacity, and rate performance. Much enhanced electrochemical performance can be harvested from a sample that has thinner fiber diameter, smaller silicon particle, lower silicon content, and porous carbon coating. This efficient and scalable approach to prepare high-capacity silicon-based anode with outstanding cyclability is fully compatible with industrial roll-to-roll processing technology, thus bearing a great potential for its future commercialization.

New Amorphous Iron-Based Oxyfluorides as Cathode Materials for High-Capacity Lithium-Ion Batteries

A novel two-step strategy to prepare amorphous oxyfluorides, containing both divalent and trivalent 3d-metals, as cathode materials for lithium batteries is presented. The first step involves the preparation of hydrated fluorides M2+M3+2F8(H2O)2 (M2+ = Mn, Fe, Co, Ni, Cu; M3+ = V, Fe) by microwave-assisted solvothermal synthesis. Besides the MnFe2F8(H2O)2 and CuFe2F8(H2O)2 phases, three new compounds, Fe1.3V1.7F8(H2O)2, CoFe2F8(H2O)2, and NiFe2F8(H2O)2, which are isostructural with Fe3F8(H2O)2, have been unraveled. The second step consists in the decomposition of M2+M3+2F8(H2O)2 into amorphous oxyfluorides M2+M3+2F8–2xOx via suitable thermal treatments.. The amorphous materials show a greater electrochemical activity toward Li than their parent phases, among them being CuFe2F6O, which displays the best performance as a cathode material with a first discharge capacity of 310 mAh·g–1. We show that such a large capacity results from cumulative insertion and displacement reactions.

Preparation of porous carbon anode materials for lithium-ion battery from rice husk

Porous carbon anode materials is synthesized by using rice hull natural SiO2 as templates, and the materials with a specific surface area of 332 m2g−1 has possessed micropores, mesopores and macropores microstructure. The materials display a high capacity of 756.9 mAhg−1 after 150 charge-discharge cycles at 0.2C and 620 mAh/g after 600 cycles at 2C, the coulomb efficiency is close to 100%. The excellent performance makes it a promising candidate for high-capacity lithium-ion batteries.

(Invited) Evolution of the Electrode−Electrolyte Interface of Ni-Rich Layered Oxides

Commercial high capacity lithium ion batteries employ Ni-rich layered oxides (derived from LiCoO2) as cathodes with practical capacities of ~190 mA h g-1. However, the practical capacity is still far below the theoretical capacity of layered structures which can exceed 250 mA h g-1. Reactions at the cathode-electrolyte interfaces (CEI) are known to contribute to capacity fade and impedance growth particularly when cycling to high voltages (≥4.5 V) and at high temperatures. The capacity fade and impedance growth arise from a combination of electrolyte decomposition, surface oxygen loss, and transition metal dissolution resulting from reactions at the CEI. I will summarize a range of spectroscopy, microscopy, transport studies of model systems under thermal and electrochemical stress that provide insight into what drives the evolution of the CEI layer and how it impacts the battery performance.[1-5] These studies reveal how the negative aspects of the CEI can be suppressed in order to reduce the gap between practical and theoretical capacities. This work was supported as part of NECCES, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DESC0012583 [1] Journal of The Electrochemical Society (Editor’s Choice), 164, A3727-A3741 (2017) [2] Chemistry of Materials 29, 7345–7352 (2017) [3] Langmuir 33, 9333–9353 (2017) [4] Applied Physics Letters 108, 263902 (2016) [5] Chemistry of Materials, 30 958–969 (2018)

Si-Doped Carbon Xerogel for High Capacity Lithium and Sodium Ion Battery Anodes

The use of dopants such as silicon, tin, and, more recently, antimony in carbonaceous anodes is a promising area of research to increase the performance of lithium and sodium ion batteries [1-3]. The biggest obstacle to the progress of this technology is the stability of these inclusions in the carbon material during charging and discharging, most notably the volume change of the active material [4-8]. An electrode design was synthesized that consists of a carbon xerogel via a sol-gel process (CX), which acts as a support structure for a dopant, silicon nanoparticles (SiNPs), and provides electronic conductivity. Syntheses have been made using poly(sodium 4-styrenesulfonate) (PSS) as a coating or binder. These syntheses showed positive results on the cyclability of the CX/SiNPs composite. A 5-fold increase was observed in the number of charge/discharge cycles before the reversible capacity was less than 80% the initial capacity when compared with a composite with no coating and conventional binder. The gradual loss in capacity in the coated composite is still unknown, but may be due to the interplay between SEI formation and the volume expansion of the SiNPs. These problems are now being addressed by various techniques to improve the chemical and mechanical stability, and tailoring the microporosity and mesoporosity to reduce the irreversibly capacity loss and increase the accessibility to the dopant material.

Nanostructured Cobalt Oxide Directly Grown on Carbon Cloth for High-Capacity Lithium-Ion Battery Electrodes

Nowadays, with the breakthrough development of various smart devices and electric vehicles that require a large power supply, rechargeable lithium-ion batteries are the most attractive energy storage system because of their high energy density and long lifetime by low self-discharge rate and no memory effect [1,2]. However, due to ever-increasing demands for rechargeable batteries with higher energy density, it is necessary to develop suitable electrode materials to satisfy the sufficient capacity and energy density required for large-scale energy storage systems [3]. As a commercial lithium-ion battery anode, graphite is widely used due to its low operating potential and high stability. However, it cannot fulfill the considerable demands of large-scale energy storage owing to its low practical capacity. As alternatives, transition metal (TM; Mn, Fe, Co and Ni) oxides have attracted great attention due to their high capacity. In this work, we develop the cobalt oxide (Co3O4) with attractively nanostructured architectures (nanowire, nanosheet) directly grown on carbon cloth substrate by a facile hydrothermal reaction followed by heat treatment process. For this, first, Co(NO3)2 and urea are dissolved in deionized water, and then carbon cloth is immersed in the solution. During the hydrothermal reaction, Co2(OH)2CO3·xH2O nanowires or Co2(OH)2CO3 nanosheets are grown on carbon cloth at 90 or 120 °C, respectively. After thermal treatment at 350 °C for 1 h in furnace, Co3O4 nanowires or nanosheets can be obtained. When tested as anodes for LIBs, as-fabricated electrodes without any conductive agents and polymeric binders exhibit high specific capacity because of their large specific surface area and enough space to buffer the volume change during conversion reaction. Therefore, it is considered that these high-performance electrodes can be used as high-capacity anodes for large-scale energy storage system.

Embedding cobalt sulfide in reduced graphene oxide for superior lithium-ion storage

Cobalt sulfide is regarded as a candidate for high-capacity lithium-ion batteries. However, it suffers from large volumetric variation during the charge/discharge cycling. Herein, cobalt sulfide/reduced graphene oxide nanocomposite has been fabricated via an unique synthetic methodology with solid cobalt/reduced graphene oxide as the precursor, which can inhibit the agglomeration of cobalt sulfide effectively. In the composite, cobalt sulfide nanoparticles are uniformly embedded in reduced graphene oxide. When utilized in lithium–ion batteries, the nanocomposite demonstrates a high discharge capacity of 796 mAh g−1 after 50 cycles. The superior lithium-ion storage performance can be ascribed to the hybrid nanostructure and the synergistic effect originated from the unique synthetic methodology.

Highly Reversible Conversion Anodes Composed of Ultralarge Monolithic Grains with Seamless Intragranular Binder and Wiring Network

Conversion anodes enable a high capacity for lithium-ion batteries due to more than one electron transfer. However, the collapse of the host structure during cycling would cause huge volume expansion and phase separation, leading to the degradation and disconnection of the mixed conductive network of the electrode. The initial nanostructuring and loose spatial distribution of active species are often resorted to in order to alleviate the evolution of the electrode morphology, but at the cost of the decrease of grain packing density. The utilization of ultralarge microsized grains of high density as the conversion anode is still highly challenging. Here, a proof-of-concept grain architecture characterized byendogenetic binder matrix and wiring network is proposed to guarantee the structural integrity of monolithic grains as large as 50-100 μm during deep conversion reaction. Such big grains were fabricated by self-assembly and pyrolysis of a Keggin-type polyoxometalate-based complex with protonated tris[2-(2-methoxyethoxy)-ethyl]amine (TDA-1-H+). The metal-organic precursor can guarantee the firm adherence of numerous Mo-O clusters and nuclei into a highly elastic monolithic structure without evident grain boundaries and intergranular voids. The pyrolyzed TDA-1-H+ not only serves as in situ binder and conductive wire to glue adjacent Mo-O moieties but also acts as a Li-ion pathway to promote sufficient lithiation on surrounding Mo-O. Such a monolithic electrode design leads to an unusual high-conversion-capacity performance (1000 mAh/g) with satisfactory reversibility (reaching at least 750 cycles at 1 A/g). These cycled grains are not disassembled even after undergoing long-term cycling. The conception of the intragranular binder is further confirmed by consolidating the MoO2 porous network after in situ stuffing of MoS2 nanobinders.

Confronting the Challenges of Next-Generation Silicon Anode-Based Lithium-Ion Batteries: Role of Designer Electrolyte Additives and Polymeric Binders.

Silicon has emerged as the next-generation anode material for high-capacity lithium-ion batteries (LIBs). It is currently of scientific and practical interest to encounter increasingly growing demands for high energy/power density electrochemical energy-storage devices for use in electric vehicles (xEVs), renewable energy sources, and smart grid/utility applications. Improvements to existing conventional LIBs are required to provide higher energy, longer cycle lives. This is attributed to its unparalleled theoretical capacity (4200 mAh g-1 for Li4.4 Si), which is approximately 10 times higher than that of a state-of-the-art graphitic anode (372 mAh g-1 for LiC6 ), with a suitable operating voltage, natural abundance, environmental benignity, nontoxicity, high safety, and so forth. However, despite the overwhelming beneficial features, the practical integration of LIBs containing a silicon anode beyond the commercial niche is hampered by unavoidable challenges, such as excessive volume changes during the (de-)alloying process, inherently low electrical and ionic conductivities, an unstable solid-electrolyte interphase, and electrolyte drying out. Among various extenuating strategies, non-electrode factors encompassing electrolyte additives and polymeric binders are regarded as the most economical, and effective approaches towards circumventing these disadvantages are in short supply. With the aim of providing an in-depth insight into rapidly growing accounts of electrolyte additives and binders for use with silicon anode-based LIBs, this Review assesses the current state of the art of research and thereby examines opportunities to open up new avenues for the practical realization of these silicon anode-based LIBs.

Yolk-shell structured V2O3 microspheres wrapped in N, S co-doped carbon as pea-pod nanofibers for high-capacity lithium ion batteries

High-capacity anode materials are widely studied for rechargeable batteries, which have the capability of storing more Li+ ions per formula. However, they normally experience large volume expansion and suffer inferior cycling stability. Herein, we propose pea-pod structured V2O3 yolk-shell microspheres@N, S co-doped carbon fiber network as an excellent anode material for lithium ion batteries. The prepared vanadium dioxide precursor is uniformly embedded into the carbon fibers by electrospinning treatment and further converted into V2O3 yolk-shell microspheres during the calcination process. The conductive carbon fiber framework which links V2O3 microspheres enhanced the electrical conductivity and structural stability significantly. Moreover, the co-doped N and S atoms derived from polymer could produce extrinsic defects, thereby improving Li+ diffusion and electrochemical active sites. When used as anodes for lithium ion batteries, the composite exhibits a high reversible capacity (793.7 mA h g−1 after 100 cycles at 100 mA g−1), excellent rate performance and cycle stability.

Characterization of dynamic morphological changes of tin anode electrode during (de)lithiation processes using in operando synchrotron transmission X-ray microscopy

The morphological evolution of tin particles with different sizes during the first lithiation and delithiation processes has been visualized by an in operando synchrotron transmission X-ray microscope (TXM). The in operando lithium ion battery cell was operated at constant current condition during TXM imaging. Two-dimensional projection images with 40 nm resolution showing morphological evolution were obtained and analyzed. The analysis of relative area change shows that the morphology of tin particles with different sizes changed simultaneously. This phenomenon is mainly due to a negative feedback mechanism among tin particles in the battery electrode at a constant current operating condition. For irregular-shaped tin particles, the contour analysis shows that the regions with higher curvature started volume expansion first, and then the entire particle expanded almost homogeneously. This study provides insights for understanding the dynamic morphological change and the particle-particle interactions in high capacity lithium ion battery electrodes.

Current Collector Interface for Phase Changing Tin Anode in Sodium Ion Batteries: Insight from First Principles Calculations

Performance of an efficient and high capacity Lithium-ion battery (LIB) and Sodium-ion battery (NIB) greatly depends upon electrode-current collector interface. While copper (Cu) is most extensively used current collector at the anode end, it has been associated with numerous functional issues such as debonding, corrosion, strain accommodation, low flexibility, and high cost and weight. In this work, we investigate the comparative performance of Graphene with Cu as the current collector for NIB anode. Graphene not only provides the battery system much-needed flexibility, cost, and weight efficiency but also imparts mechanical stability to the system during the sodiation and de-sodiation cycles. Tin (Sn) has been taken up as model anode material owing to its potential and promising high theoretical specific capacity of 994 mAh/g. However, the anodic performance of Sn is limited by its high-volume expansion and multiple phase changes which leads to subsequent mechanical failure. Therefore, the effect of mechanical strains and phase transitions during battery performance on the interface has been investigated in detail. We have employed vdW inclusive GGA based Density Functional Theory (DFT) implemented in VASP to study the effect of sodiation and de-sodiation on the mechanical integrity of anode and current collector interface. We report that Graphene is more efficient in combatting mechanical stresses generated in the anode during the performance and also allows easy expansion to Sn. We hope that this work will throw more light on the mechanics and chemistry that are prominent at the interface of an anode and current collector.

Effect of Different Carbon Precursors on SiO2/C Anodes for Li-Ion Batteries

Lithium ion batteries (LIBs) are widely used as a power source for different portable electronic devices and are considered as potential power sources for future electric vehicles and large-scale grid energy storage. However, in order to meet the demands of large-scale applications, higher energies and power densities need to be reached. In the case of commercial negative electrodes, a benchmark of a stable capacity of 1000 mAhg-1 has been established for next-generation high capacity LIBs [1]. Current LIBs use graphite as anode material, which reacts with lithium ions via intercalation inside its host structure. This kind of interaction causes minor structural changes in the host material and provides high stability and long durability to the anode. However, as the number of lithium ions that can be retained by the host structure is limited, its reversible capacity of 372 mAhg-1 cannot be enhanced. Therefore, in order to use LIBs for large-scale applications, different materials are being currently explored to replace low-capacity graphite anodes. Among different materials, Silicon has been pinpointed as a very promising anode for next-generation high capacity LIBs, since it presents a maximum theoretical capacity of 4200 mAhg-1. However, as its interaction with lithium is via alloying/dealloying reactions, the material suffers from large volume changes during lithiation and delithiation, which causes strain and stress on the silicon lattice, leading to mechanical instabilities and fast degradation in the electrochemical performance of the anode. Another possible candidate is silica, which presents a compromise solution between the two former materials. It has a maximum theoretical capacity of 1695mAhg-1 and exhibits much less volume variation during lithiation/delithiation compared with silicon. Besides, silica is one of the most abundant materials on earth [2-4], which is of key importance from the point of view of large-scale applications. Given that silica is an insulator, carbon-coating treatments are essential in order to decrease the electronic resistance of the electrode. In this work, we perform a systematic study to evaluate the effect of three different carbon precursors on the carbon coating of amorphous SiO2 nanoparticles to be used as anode material in LIBs. SiO2 particles were carbon coated with different amounts (20%, 40%, 60% and 80%) of glucose, sucrose and cornstarch and heat treated at high temperature under inert atmosphere. Structural, microstructural and textural properties of SiO2/C samples were analyzed in order to select the most suitable carbon precursor and to determine which amount leads to better properties. Results of thermogravimetric analysis showed a non-linear dependence between the effective carbon content on carbon coated samples and the amount of carbon precursor used. Raman spectroscopy results revealed the presence of D and G bands, which are characteristic of carbonaceous materials. Results of EDX mapping showed that carbon was homogeneously distributed on SiO2 particles and TEM bright field micrographs revealed the porous nature of the carbon layer that surrounded SiO2 particles. Gas absorption measurements indicated, in most of the cases, an increase in the total area with increasing carbon precursor content. X-ray diffraction measurements showed that SiO2 was still amorphous after the high temperature heat treatment. Finally, the electrochemical performance of the anode was evaluated and related to microstructural and textural properties. [1] Erk, C., Brezesinski, T., Sommer, H., Schneider, R., Janek, J. ACS Appl. Materi. Interfaces 2013, 5. 7299. [2] Chang, W-S., Park, C-M., Kim, J-H., Jeong G., Sohn H-J. Energy Environ. Sci., 2012, 5,6895. [3] Lv, P., Zhao, H., wang, J., Liu, X., Zhang, T., Xia, Q. Journal of Power Sources, 2013, 237,291. [4] Nita, C., Fullenwarth J., Monconduit L., Le Meins, J-M., Fioux, P., Parmentier, J., Ghimbeu, C.M. Carbon 2019, 143, 598.

Facile-synthesized amorphous CoCO3 for high-capacity lithium-ion battery anode

Transition metal carbonates are high specific capacity and high initial coulombic efficiency anode materials of the lithium-ion batteries (LiBs). Herein, molecular dynamics simulation found the amorphous instead of the crystallized CoCO3 is more favorable for Li-ion storage. Guided by the dynamics simulations results, the amorphous CoCO3 was synthesized by a facile one-step precipitation method and then compounded with reduced graphene oxide (RGO) sheets. The as-synthesized CoCO3/RGO shows one of the best electrochemical performances compared with the recently reported CoCO3-based anodes. CoCO3/RGO delivered a reversible capacity of 881.4 mAh g−1 at 50th cycle under the current density of 100 mA g−1 and 1250.5, 898.7, 718.3 mAh g−1 at 1st, 2nd, and 50th cycles under the current density of 200 mA g−1. This work could provide a rational design and manufacture method of high-performance carbonate-based LiB anodes.

Separated and intermixed phases of borophene as anode material for lithium-Ion batteries

In this work, density functional theory calculations along with ab initio molecular dynamics simulations are employed to evaluate the potential of intermixed and separated phases of borophene as anode materials for lithium-ion batteries. The most stable binding positions are identified, followed by a gradual increase of lithium-ion concentration until a maximum value of theoretical specific capacity is achieved. The results indicate that separate phases of striped, and show adsorption energies of −1.16, −1.42 and −1.25 to lithium adatom, respectively. Moreover, the maximum lithium concentration for the mentioned phases are , and with their corresponding specific capacities being 1864, 1983 and 1487 mAh g−1, accordingly. Moreover, the energy barrier for lithium diffusion is calculated along different pathways to determine the performance of each of the discussed phases. As intermixing of the phases is an inevitable phenomenon in the synthesis process of borophene, three possible types of intermixing are analyzed. The predicted capacity for both separated and intermixed phases are well above the highest reported values for common materials, which renders this material a promising candidate for future high capacity lithium-ion batteries.

High specific capacity lithium ion battery cathode material prepared by synthesizing vanadate–phosphate glass in reducing atmosphere

Although vanadium-based materials are potential electrode materials for Li-ion batteries, the development of commonly known vanadium-based crystalline phases is hindered by their inferior cyclic performance. Unlike crystalline phases, the amorphous vanadium-based materials do not exhibit undesirable phase transformations during the charge/discharge process leading to poor cyclic performance. Herein, we demonstrate the influence of a reducing atmosphere on the structure of vanadate–phosphate (V2O5-P2O5) glass and its electrochemical properties as a lithium-ion battery cathode. By employing various characterization techniques, we unveil the influence of reducing atmosphere on valence state of vanadium ions and structure of V2O5-P2O5 glass. The V2O5-P2O5 glass, synthesized in a reducing atmosphere, exhibits an ultra-high specific capacity of 270 mAh g−1 with excellent capacity retention of ∼90% after 100 cycles. Moreover, a stable specific capacity of 220 mAh g−1 is delivered at a high current density of 85 mA g−1 after 300 cycles, corresponding to 80% capacity retention. Overall, the V2O5-P2O5 glass, synthesized in a reducing atmosphere, renders higher capacity, excellent rate performance and stable cyclic performance than the V2O5-P2O5 glass, synthesized in the air atmosphere. The current work provides a novel route to develop multi-valence transition metal oxide electrodes for Li-ion batteries.