Oxide Cathode Materials Research Articles

A water-stable high-voltage P3-type cathode for sodium-ion batteries

The Na-deficient P3-type layered oxide cathode material usually experience complex in-plane Na+/vacancy ordering rearrangement and undesirable P3-O3 phase transitions in the high-voltage region, leading to inferior cycling performance. Additionally, they exhibit unsatisfactory stability when exposed to water for extended periods. To address these challenges, we propose a Cu/Ti co-doped P3-type cathode material (Na0.67Ni0.3Cu0.03Mn0.6Ti0.07O2), which effectively mitigates Na+/vacancy ordering and suppresses P3-O3 phase transitions at high voltages. As a result, the as-prepared sample exhibited outstanding cyclic performance, with 81.9% retention after 500 cycles within 2.5–4.15 V, and 75.7% retention after 300 cycles within 2.5–4.25 V. Meanwhile, it demonstrates enhanced Na+ transport kinetics during desodiation/sodiation and reduced growth of charge transfer impedance (Rct) after various cycles. Furthermore, the sample showed superb stability against water, exhibiting no discernible degradation in structure, morphology, or electrochemical performance. This co-doping strategy provides new insights for innovative and prospective cathode materials.

Origins and Importance of Intragranular Cracking in Layered Lithium Transition Metal Oxide Cathodes.

Li-ion batteries have a pivotal role in the transition toward electric transportation. Ni-rich layered transition metal oxide (LTMO) cathode materials promise high specific capacity and lower cost but exhibit faster degradation compared with lower Ni alternatives. Here, we employ high-resolution electron microscopy and spectroscopy techniques to investigate the nanoscale origins and impact on performance of intragranular cracking (within primary crystals) in Ni-rich LTMOs. We find that intragranular cracking is widespread in charged specimens early in cycle life but uncommon in discharged samples even after cycling. The distribution of intragranular cracking is highly inhomogeneous. We conclude that intragranular cracking is caused by local stresses that can have several independent sources: neighboring particle anisotropic expansion/contraction, Li- and TM-inhomogeneities at the primary and secondary particle levels, and interfacing of electrochemically active and inactive phases. Our results suggest that intragranular cracks can manifest at different points of life of the cathode and can potentially lead to capacity fade and impedance rise of LTMO cathodes through plane gliding and particle detachment that lead to exposure of additional surfaces to the electrolyte and loss of electrical contact.

Unleashing the impact of Nb-doped, single crystal, cobalt-free P2-type Na0.67Ni0.33Mn0.67O2 on elevating the cycle life of sodium-ion batteries

A synergistic stabilization effect in a Nb-doped P2-type single crystal cobalt-free layered oxide cathode material, offering remarkable cycling stability and high-power performance for Na-ion batteries have unveiled in this study. The introduction of Nb in the transition metal layer not only reduces the electronic band gap but also enhances electronic conductivity and mitigates ionic diffusion energy barriers. The induction of a robust Nb-O bond expedites electron and Na+ transfer, contributing to the stabilization of the host structure is further confirmed through the density functional theory calculations, including electron localization function (ELF) and crystal orbital Hamiltonian population (COHP). To the best of our knowledge, this study is the first to demonstrate a homogeneous distribution of niobium throughout the single crystal, specifically doped at the nickel site within the bulk, without inducing atomic-scale surface reorganization. The presence of single crystals improves various kinetic factors, demonstrating the profound correlation between structural defects and chemical proliferation, thereby reducing the evolution of oxygen gas. The P2-type Nb-doped single crystal cathode (Na0.67Ni0.31Mn0.67Nb0.02O2) exhibits remarkable capacity retention, >95 % after 100 cycles at 0.1 C and >90 % after an extended cycling of 2000 cycles at 1 C. Practical assessments in complete cell setups with a pre-sodiated hard carbon anode further validate the material's viability, showcasing capacity retention of over 93 % after 100 cycles in a coin cell and approximately 89 % in a pouch cell format. This comprehensive study establishes the transformative potential of Nb-doped single crystal cobalt-free P2-type layered oxide cathode materials, marking a significant advancement in sodium-ion battery technology.

Improving the Crystal Stability of O3-type Metal Oxide Cathode Materials by Cu Substitution for Na-Ion Batteries

Improving the Crystal Stability of O3-type Metal Oxide Cathode Materials by Cu Substitution for Na-Ion Batteries

Prediction of Ground State Configurations and Electrochemical Properties of Li3InCl6 Doped with F, Br, and Ga

Compared with conventional solid-state electrolytes, halide solid-state electrolytes have several advantages such as a wider electrochemical window, better compatibility with oxide cathode materials, improved air stability, and easier preparation conditions making them conductive to industrial production. We concentrate on a typical halide solid-state electrolyte, Li3InCl6, predict the most stable structure after doping with Br, F, and Ga by using the Alloy Theoretic Automated Toolkit based on first-principles calculations, and verify the accuracy of the prediction model. To investigate the potential of three equivalently doped ground state configurations of Li3InCl6 as solid-state electrolytes for all-solid-state lithium-ion batteries, their specific properties such as crystal structure, band gap, convex packing energy, electrochemical stability window, and lithium-ion conductivity are computationally analyzed using first-principles calculations. After a comprehensive evaluation, it is determined that the F-doped ground state configuration Li3InCl2.5F3.5 exhibits better thermal stability, wider electrochemical stability window, and better lithium ion conductivity (1.80 mS⋅cm−1 at room temperature). Therefore, Li3InCl2.5F3.5 has the potential to be used in the field of all-solid-state lithium-ion batteries as a new type of halide electrolyte.

Homogenous coating of Li+ conductive Li5AlO4 on single-crystalline nonstoichiometric Li1.04Ni0.92Al0.04O2 for rechargeable lithium-ion batteries

Cobalt-free, nickel-rich LiNi1-xAlxO2 (x ≤ 0.1) is an attractive cathode material because of high energy density and low cost but suffers from severe structural degradation and poor rate performance. In this study, we propose a molten salt-assisted synthesis in combination with a Li-refeeding induced aluminum segregation strategy to prepare Li5AlO4-coated single-crystalline slightly Li-rich Li1.04Ni0.92Al0.04O2. The symbiotic formation of Li5AlO4 from reaction between molten lithium hydroxide and doped aluminum in the bulk ensures a high lattice matching between the Ni-rich oxide and the homogenous conductive Li5AlO4 that permits high Li+ conductivity. Benefiting from mitigated undesirable side reactions and phase evolution, the Li5AlO4-coated single-crystalline Li1.04Ni0.92Al0.04O2 delivers a high specific capacity of 220.2 mA h g−1 at 0.1 C and considerable rate capability (182.5 mA h g−1 at 10 C). Besides, superior capacity retention of 90.8% is obtained at 1/3 C after 100 cycles in a 498.1 mA h pouch full cell. Furthermore, the particulate morphology of Li1.04Ni0.92Al0.04O2 remains intact after cycling at a cutoff voltage of 4.3 V, whereas slightly Li-deficient Li0.98Ni0.97Al0.05O2 features intragranular cracks and irreversible lattice distortion. The results highlight the value of molten salt-assisted synthesis and Li-refeeding induced elemental segregation strategy to upgrade Ni-based layered oxide cathode materials for advanced Li-ion batteries.

Precise modulation of surface lattice to reinforce structural stability of high-nickel layered oxide cathode by hafnium gradient doping

The quest for high-energy lithium-ion batteries has intensified interest in high-nickel layered oxide cathode materials, while the rise in nickel content adversely impacts structural stability and cycling performance. Herein, Hafnium (Hf) anchored at nickel (Ni) site precisely modulates the surface crystal lattice of high-nickel cathode (LiNi0.9Co0.05Mn0.05O2, NCM90) that is confirmed by Rietveld refinement of neutron powder diffraction. Notably, the strengthened structural stability thanks to Hf gradient doping is firmly substantiated by in-situ X-ray diffraction and in-situ X-ray adsorption spectroscopy. This enhancement can be ascribed to the substantial atomic mass of Hf and large radius of Hf4+, facilitating the minimization of potential alterations of interlayer or intralayer. The intensified Hf-O bond significantly increases the formation energy of oxygen vacancies and efficiently restrains the detrimental Li+/Ni2+ disorder, thereby mitigating lattice oxygen loss and enhancing both cycling and thermal stability of high-nickel cathode. Consequently, the 0.3 % Hf-doping cathode exhibits considerable improvement in electrochemical performance, delivering superior capacity retention of 95.0% after 100 cycles at 1C (1 C = 200 mA g−1) and 83.9 % after 500 cycles at 1C/5C in the voltage range of 3.0∼4.3 V. This work highlights the benefits of precise modulation strategy for high-nickel cathodes, offering a viable approach to enhance structural stability and electrochemical performance of high-nickel cathodes.

Fast Na+ Kinetics and Suppressed Voltage Hysteresis Enabled by a High-Entropy Strategy for Sodium Oxide Cathodes.

O3-type layered transition metal cathodes are promising energy storage materials due to their sufficient sodium reservoir. However, sluggish sodium ions kinetics and large voltage hysteresis, which are generally associated with Na+ diffusion properties and electrochemical phase transition reversibility, drastically minimize energy density, reduce energy efficiency, and hinder further commercialization of sodium-ion batteries (SIBs). Here, this work proposes a high-entropy tailoring strategy through manipulating the electronic local environment within transition metal slabs to circumvent these issues. Experimental analysis combined with theoretical calculations verify that high-entropy metal ion mixing contributes to the improved reversibility of redox reaction and O3-P3-O3 phase transition behaviors as well as the enhanced Na+ diffusivity. Consequently, the designed O3-Na0.9Ni0.2Fe0.2Co0.2Mn0.2Ti0.15Cu0.05O2 material with high-entropy characteristic could display a negligible voltage hysteresis (<0.09 V), impressive rate capability (98.6 mAh g-1 at 10 C) and long-term cycling stability (79.4% capacity retention over 2000 cycles at 5 C). This work provides insightful guidance in mitigating the voltage hysteresis and facilitating Na+ diffusion of layered oxide cathode materials to realize high-rate and high-energy SIBs.

Application metal oxide cathode materials for lithium ion batteries

The popularity of portable electronic devices has boosted the speedy advancement of devices for storing electrical energy. At the same time, the development of electric vehicles urgently requires lithium batteries to have higher power density and performance. The strong points of lithium ion battery are environmental friendliness, also specific capacity of high level. Lithium cathode material is one of the key factors affecting battery performance. The requirements for positive electrode materials are good safety, good service life, and less self-discharge. Among all cathode materials, metal oxide cathode material is the most potential types, which comes from a wide range of sources and has rich production experience. In this paper, four kinds of lithium metal oxide cathode materials including lithium cobaltate, lithium nickelate, lithium manganate and ternary composite oxide cathode material were analyzed, and discussed the performance of lithium metal oxide cathode materials in practical applications, where further pointed out the existing problems of metal oxide cathode materials and put forward several directions for future improvement to improve the performance of lithium ion battery cathode materials in the future development and production process.

Recent progress of interface modification of layered oxide cathode material for sodium‐ion batteries

AbstractWith the advantages of similar theoretical basis to lithium batteries, relatively low budget and the abundance of sodium resources, sodium ion batteries (SIBs) are recognized as the most competitive alternative to lithium‐ion batteries. Among various types of cathodes for SIBs, advantages of high theoretical capacity, nontoxic and facile synthesis are introduced for layered transition metal oxide cathodes and therefore they have attracted huge attention. Nevertheless, layered oxide cathodes suffer from various degradation issues. Among these issues, interface instability including surface residues, phase transitions, loss of active transition metal and oxygen loss takes up the major part of the degradation of layered oxides. These degradation mechanisms usually lead to irreversible structure collapse and cracking generation, which significantly influence the interface stability and electrochemical performance of layered cathodes. This review briefly introduces the background of researches on layered cathodes for SIBs and their basic structure types. Then the origins and effects on layered cathodes of degradation mechanisms are systematically concluded. Finally, we will summarize various interface modification methods including surface engineering, doping modification and electrolyte composition which are aimed to improve interface stability of layered cathodes, perspectives of future research on layered cathodes are mentioned to provide some theoretical proposals.

Mo-based compounds coating to stabilize Mn-based layered oxide cathode material towards high-performance Na-ion batteries with ultrahigh cycling stability

Layered oxide cathode materials have good structural stability and high capacity, making them ideal cathode materials of Na-ion batteries (SIBs). Nonetheless, the irreversible phase transitions and metal dissolution often result in poor cycling stability. Here, a simple strategy was developed to Na2MoO4 and MoO3 coated Na0.67Fe0.15Cu0.1Mn0.65Ni0.1O2 (NFCMN-M) as cathode material of SIBs with ultrahigh cycling stability caused by the enhanced kinetic. The formed Na2MoO4 layer on the surface of Na0.67Fe0.15Cu0.1Mn0.65Ni0.1O2 (NFCMN) particles supplies a good conductive connection, and inhibits side effects between cathode material and electrolyte. Thanks to the unique component, the as-prepared NFCMN-M shows a good rate performance with a reversible discharge capacity of 132.4, 112.6, 102.3, 87.1 and 79.3 mAh g−1 at 0.1, 0.5, 1, 3 and 5C, respectively. The NFCMN-M also delivers an initial capacity of 73.7 mAh g−1 at 10C and an ultrahigh cycling stability with a capacity retention rate of about 80 % after 1000 cycles. The result confirms that the Na2MoO4 modification is a direct and effective strategy to improve the capacity and enhance cycling stability of NFCMN at high charge-discharge rates.

Design of high-entropy P2/O3 hybrid layered oxide cathode material for high-capacity and high-rate sodium-ion batteries

High-entropy layered cathode materials have garnered significant attention due to their exceptional structural stability and capacity retention. However, the complex composition of these materials has posed challenges for performance optimization. Herein, an innovative high-entropy P2/O3 hybrid layered oxide cathode material with impressive reversible capacity and high-rate capabilities is designed according to the configurational entropy adjustment strategy. Specifically, the unique structure of Na0.85Li0.05Ni0.3Fe0.1Mn0.5Ti0.05O2 (LNFMT) exhibits not only enhanced anionic activity but also mitigated migration of transition metals at high voltage. The high-entropy effect facilitates the migration of Li+ to Na layer, forming a pseudo-tetrahedral structure that hinders the movement of Fe3+. Additionally, the robust Ti-O bond ensures the internal cohesion of transition metal layers, enhancing the structural stability during de-/intercalation processes. As a result, the undesirable P2-O2 phase transformation is effectively suppressed in 1.5–4.5 V, leading to a remarkable capacity retention of over 70% after 100 cycles at 0.2 C. Moreover, LNFMT shows a high discharge capacity of 116 mAh/g at 10 C with excellent capacity retention of 94.23% after 150 cycles in 2.0–4.2 V, demonstrating its superior rate capability. This research showcases the significant impact of the high-entropy effect and provides a novel perspective for the design of sodium-ion cathode materials.

Enhancing performance and stability of LiNi0.8Co0.1Mn0.1O2 cathode via Na/Y dual doping for Lithium-Ion batteries

Nickel-rich layered oxide cathode materials face limitations in practical applications due to trade-offs between capacity and structural stability. As more Li+ is extracted during charging, the layered structure of nickel-rich materials becomes increasingly fragile. To address this, a double doping strategy with Na and Y is proposed in this study to enhance the strength of the layered structure. The research findings demonstrate that Na doping enlarges the spacing between Li layers in the crystal structure, while Y doping improves the reversibility of the H2-H3 phase transition but narrows the Li layer spacing in nickel-rich materials. Na and Y double doping, the advantages of Na in enlarging the Li layer, and Y in improving the H2-H3 phase transition can be harnessed simultaneously. This double doping strategy ensures that the laminar structure of the cathode material remains stable even when it is highly detached, effectively solving the trade-off between the capacity and structural stability of nickel-rich laminar cathode materials. The application in LiNi0.8Co0.1Mn0.1O2 shows that the capacity and cycle life of cathode materials can be significantly improved after Na/Y double doping. These findings open up opportunities for practical applications of nickel-rich cathode materials in lithium-ion batteries.

Cold-plasma activation converting conductive agent in spent Li-ion batteries to bifunctional oxygen reduction/evolution electrocatalyst for zinc-air batteries

Considerable amount of high-value transition metals components can be recycled in spent ternary lithium-ion batteries. In this study, we utilized the conductive agent carbon black, obtained from the leaching waste resulting from the chemical recovery of spent lithium-nickel-manganese-cobalt (NCM) oxide cathode materials. This process allows us to create valuable bifunctional catalysts for the oxygen reduction reaction and oxygen evolution reaction (ORR/OER), facilitated by a facile cold plasma activation method, as a part of lithium batteries circular economy. The activated conductive agent (RCA-30) exhibited an ORR half-wave potential of 0.74 V (vs. RHE) in 0.1 mol/L KOH solution, and an OER overpotential of 360 mV at 10 mA cm-2 in 1 mol/L KOH electrolyte, owing to nitrogen doping of carbon black and activation of surface metal oxides. The complete zinc-air batteries incorporating the activated catalysts at the cathode exhibited an open circuit potential of up to 1.48 V and sustained cycling for 100 h at a current density of 5 mA cm-2. Additionally, the activated catalysts contributed to a power density of 92 mW cm-2 and a full discharge capacity of 640 mAh/g.

Effective incorporation of cobalt near surface region for cobalt-free cathodes in lithium-ion batteries

Cobalt-free cathode materials, particularly Ni-rich layered oxide cathode materials, are ideal for electric vehicle Li-ion batteries, offering high energy density and cost-effectiveness. However, high Ni content in high-temperature synthesis leads to issues like increased Li/Ni cation mixing and reduced rate capability, mainly due to the absence of Co. Therefore, this study investigated the utilization of a small amount of Co instead of completely removing it to enhance electrochemical performance. A simple pre-calcination process was used to induce Co substitution beneath the Ni-rich layered oxide cathode materials surface. A coating process was also performed for comparison. The Li/Ni cation mixing in the Co-substituted sample during high-temperature calcination was 2.43%, demonstrating a superior value compared to the Co-coating process. Rate capability tests showed superior performance for Co-substituted sample (164.2 mAh g−1) at 2 C compared to coated sample (151.0 mAh g−1). Moreover, Co substitution improved not only the cycle stability but also the high-temperature stability at an elevated state of charge.This study focuses on the surface modification of cobalt-free cathode, providing direct insight into the effects of Co substitution and typical Co coating and suggests an optimal process that uses small amounts of Co.

Enhancing rate and stability performance of O3-type NiFeMnTi-based layered oxides via Sb/Co dual-doping

O3-type layered metal oxides have been consider as a highly suitable cathode materials for Na-ion batteries (SIBs) due to their distinct advantages of high capacity, simple synthesis and affordable price. Nonetheless, the rapid capacity attenuation and the sluggish Na+ diffusion kinetic seriously impede their practical application. Herein, a dual-doping strategy of incorporating Stibium (Sb) and cobalt (Co) elements to a quaternary oxide cathode material (Na(Ni0.3Fe0.2Mn0.5)0.9Ti0.1O2) was proposed to further ameliorate the rate capability and the cycle stability. Because of the enlarged Na and TM interlayer spacing, Sb/Co dual-doping is verified to provide a higher Na+ diffusion rate and a more stable structure. Furthermore, Co doping is found to inhibit the formation of Ni2O3 and Na0.7MnO2 impurities triggered by Sb doping. The modified Na(Ni0.3Fe0.2Mn0.5)0.8Ti0.1Sb0.05Co0.05O2 electrode represents a high discharge specific capacity of 171.6 mAh g-1 at 0.1C within the voltage range from 2.0 V to 4.3 V, and an excellent rate capability of 82.0 mAh g-1 at 5C. More significantly, it shows a splendid capacity retention of 74.69 % over 300 cycles at 1C.

Interfacial Engineering of P2-Type Ni/Mn-Based Layered Oxides by a Facile Water-Washing Method for Superior Sodium-Ion Batteries.

Owing to the strong basicity and reactivity, residual sodium compounds (RSCs) on the surface of Na-based layered oxides for sodium-ion batteries (SIBs) cause the deterioration of the electrochemical performance and processability of the oxide cathode materials. Herein, considering P2-type Na0.66Ni0.26Zn0.07Mn0.67O2 as the model material, the water-washing treatment is proven to be a facile, economic, and highly efficient method to improve the electrochemical performance of P2-type Ni/Mn-based layered oxides. Experimental results show that RSCs on material surfaces can be effectively removed by water washing without causing severe damage to the bulk structure. Notably, water washing triggers the formation of an ultrathin (2-3 nm thick) Na-poor disordered interfacial layer on the surface of Na0.66Ni0.26Zn0.07Mn0.67O2. This layer plays a passivating role in further enhancing the material's resistance to water and reduces the reactivity of the material surface with the electrolyte. These compositional and structural optimizations for P2-type Na0.66Ni0.26Zn0.07Mn0.67O2 effectively suppress the release of gaseous CO2, formation of thick cathode-electrolyte interphase films, and consumption of active Na+, enabling good Na+ transport kinetics during cycling. The water-washed Na0.66Ni0.26Zn0.07Mn0.67O2 exhibits significantly improved cycling stability with a capacity retention of 89.1% at 100 mA g-1 after 100 cycles and rate capability with a discharge capacity of 76.3 mA g-1 at 2000 mA g-1; these values are higher than those of the unwashed Na0.66Ni0.26Zn0.07Mn0.67O2 (83.3%, 71.4 mA h g-1). This work provides fundamental insights into the detrimental effect of RSCs on the electrochemical performance of layered oxides and highlights the importance of regulating interfacial compositions for developing high-performance layered-oxide cathode materials for SIBs.

O3‐Type Cathodes for Sodium‐Ion Batteries: Recent Advancements and Future Perspectives

AbstractOver recent decades, rapid advancements in energy technology have transformed human life. Lithium‐ion batteries (LIBs) have played a pivotal role nevertheless concerns about limited lithium resources and price fluctuations underscore the need for sustainability. Sodium‐ion batteries (SIBs), operating on principles akin to LIBs, have emerged as promising candidates for rechargeable batteries in the next generation of energy storage systems, primarily due to their cost‐effectiveness and sustainable attributes. Analogous to LIBs, the cathode in SIBs assumes a critical role in dictating the electrochemical performance of the battery. Therefore, the research and development of cathode materials for SIBs take on paramount significance. O3‐type SIB cathodes, inspired by the successful O3‐type LIB cathodes (e. g., LiCoO2 and NMC variants), hold promise for commercial applications. This comprehensive overview offers an in‐depth exploration of various unary‐metal oxide cathode materials characterized by an O3‐layered structure. Subsequently, nickel (Ni), manganese (Mn), and Ni/Mn‐based O3 cathode materials are conducted a comprehensive study, assessing the effects of element substitution and doping on capacity, phase transitions, and cycle life. In light of the current challenges, advancing SIB cathode materials of future directions will propose, addressing key considerations in the pursuit of enhanced performance and sustainable energy storage solutions.

Sb-Doped Biphasic P2/O3-Type Mn-Rich Layered Oxide Cathode Material for High-Performance Sodium-Ion Batteries.

Mn-rich P2-type layered oxide cathode materials suffer from severe capacity loss caused by detrimental phase transition and transition metal dissolution, making their implementation difficult in large-scale sodium-ion battery applications. Herein, we introduced a high-valent Sb5+ substitution, leading to a biphasic P2/O3 cathode that suppresses the P2-O2 phase transformation in the high-voltage condition attributed to the stronger Sb-O covalency that introduces extra electrons to the O atom, reducing oxygen loss from the lattices and improving structural stability, as confirmed by first-principle calculations. Besides, the enhanced Na+ diffusion kinetics and thermodynamics in the modified sample are associated with the enlarged lattice parameters. As a result, the proposed cathode delivers a discharge capacity of 142.6 mAh g-1 at 0.1C between 1.5 and 4.3 V and excellent performance at a high mass loading of 8 mg cm3 with a specific capacity of 131 mAh g-1 at 0.2C. Furthermore, it also possesses remarkable rate capability (90.3 mAh g-1 at 5C), specifying its practicality in high-energy-density sodium-ion batteries. Hence, this work provides insights into incorporating high-valent dopants for high-performance Mn-rich cathodes.

Synchronous organic-inorganic co-intercalated ammonium vanadate cathode for advanced aqueous zinc-ion batteries

Vanadium-based cathode materials are attractive for aqueous zinc-ion batteries (AZIBs) owing to the high capacity from their open frameworks and multiple valences. However, the cycle stability and rate capability are still restricted by the low electrical conductivity and trapped diffusion kinetics. Here, we propose an organic–inorganic co-intercalation strategy to regulate the structure of ammonium vanadate (NH4V4O10, NVO). The introduction of Al3+ and polyaniline (PANI) induces the optimized layered structure and generation of urchin-like hierarchical construction (AP-NVO), based on heterogeneous nucleation and dissolution–recrystallization growth mechanism. Owing to these favorable features, the AP-NVO electrode delivers a desirable discharge capacity of 386 mA h g−1 at 1.0 A g−1, high-rate capability of 263 mA h g−1 at 5.0 A g−1 and excellent cycling stability with 80.4% capacity retention over 2000 cycles at 5.0 A g−1. Such satisfactory electrochemical performance is believed to result from the enhanced reaction kinetics provided by the stable layered structure and a high intercalation pseudo-capacitance reaction. These results could provide enlightening insights into the design of layered vanadium oxide cathode materials.