Tin antimony oxide @graphene as a novel anode material for lithium ion batteries

Bimetal oxides have attracted much attention due to their unique characteristics caused by the synergistic effect of bimetallic elements, such as adjustable operating voltage and improved electronic conductivity. Here, a novel bimetal oxide Sn_0.918Sb_0.109O₂@graphene (TAO@G) was synthesized via hydrothermal method, and applied as anode material for lithium ion batteries. Compared with SnO₂, the addition of Sb to form a bimetallic oxide Sn_0.918Sb_0.109O₂ can shorten the band gap width, which is proved by DFT calculation. The narrower band gap width can speed up the lithium ions transport and improve the electrochemical performances of TAO@G. TAO@G is a structure in which graphene supports nano-sized TAO particles, and it is conducive to the electrons transport and can improve its electrochemical performances. TAO@G achieved a high initial reversible discharge specific capacity of 1176.3 mA h g^?1 at 0.1 A g^?1 and a good capacity of 648.1 mA h g^?1 at 0.5 A g^?1 after 365 cycles. Results confirm that TAO@G is a novel prospective anode material for LIBs.     

Electrospinning-derived ZnCo2O4@carbon nanofiber composite for high-performance lithium ion storage

The degradation of the cobalt-zinc oxide structure and its poor conductivity during the charge and discharge limit their further applications for lithium ion storage. Herein, ZnCo₂O₄@carbon nanofiber composite with nano-fibrous structure is obtained by electrospinning, annealing in argon and low-temperature oxidation to effectively overcome the above issue. The active sites of ZnCo₂O₄ are evenly dispersed inside the carbon nanofibers, which can effectively avoid its aggregation and improve electrical conductivity. Additionally, the stable nanofibrous structure can maintain structural stability. The composite exhibits superior lithium ion storage capacity when being served as anode electrode. The ZnCo₂O₄@carbon nanofiber electrode possesses a high capacity of 1071 mA h g⁻¹ at 0.1 A g⁻¹. Besides, the electrode shows an outstanding rate capability of 505 mA h g⁻¹ at 3 A g⁻¹ and maintain 714 mA h g⁻¹ after 250 cycles when current density is adjusted to 0.2 A g⁻¹ again. Additionally, the electrode has an outstanding long-cycle performance, which remains a capacity of 447.165 mA h g⁻¹ at 0.5 A g⁻¹ after 500 cycles and 421.477 mA h g⁻¹ at 1 A g⁻¹ after 518 cycles. This result demonstrates that ZnCo₂O₄@carbon nanofiber composite has potential application prospects in the fields of advanced energy storage.     

Biotemplate synthesis of mesoporous α-Fe2O3 hierarchical structure with assisted pseudocapacitive as an anode for long-life lithium ion batteries

The oriented biotemplate synthesis of nanostructured metal oxides as anode materials for lithium-ion batteries (LIBs) has recently attracted widespread attentions. Herein, mesoporous α-Fe₂O₃ hierarchical tubes (named as Fe-400) were successfully prepared by facile iron salt impregnation and air calcination at 400 °C using waste poplar branch as biotemplate. The hierarchical structure of Fe-400 is constructed from cross-linked small nanoparticles (~29 nm), which then results in large specific surface area (37.7 m² g^?1) and uniform mesoporous size distribution (12.2 nm). As anode material for LIBs, Fe-400 displays reversible capacity of 880.7 mA h g^?1 after long-cycle of 800^th at 1 A g^?1, indicating that this material has high capacity retention and good long-cycle stability. The prominent electrochemical properties are mainly ascribed to the large specific surface area, unique homogeneous mesopores, and the assisted pseudocapacitive behaviors of Fe-400. In view of the low-cost, environment-friendly and easily large-scale synthesis of Fe-400 electrode material, the present biotemplate strategy can present useful reference for the synthesis of other transition metal oxide-based anode materials for LIBs.     

Ti2Nb10O29@C hollow submicron ribbons for superior lithium storage

Titanium niobate prepared by traditional techniques has the shortcomings of low ion diffusion coefficient as well as poor electrical conductivity, which drastically reduce its applicability. In this work, we prepare carbon coated Ti₂Nb₁₀O₂₉ hollow submicron ribbons (Ti₂Nb₁₀O₂₉@C HSR) using a simple electrospinning procedure. As anode material for lithium-ion batteries (LIBs), it delivers a high charge capacity of 259.7 mAh g^?1 at 1 C with low capacity loss of 0.013% in long-term cycles. Increased the current density to 5 C, Ti₂Nb₁₀O₂₉@C HSR can maintain a reversible capacity of 189.9 mAh g^?1, indicating its good rate performance. Additionally, this work uses in-situ X-ray diffraction (XRD) to provide an explanation for the lithium storage process in Ti₂Nb₁₀O₂₉@C HSR, demonstrating the high reversibility during charge/discharge cycles. Therefore, Ti₂Nb₁₀O₂₉@C HSR has outstanding cycle adaptability and structural reversibility to be a promising anode for LIBs.     

Carbon-coated Bi5Nb3O15 as anode material in rechargeable batteries for enhanced lithium storage

Bismuth can alloy with lithium to generate Li₃Bi with the volumetric capacity of about 3765 mAh cm^?3 (386 mAh g^?1), rendering bismuth-based materials as attractive alloying-type electrode materials for rechargeable batteries. In this work, bismuth-based material Bi₅Nb₃O₁₅ @C is fabricated as anode material through a traditional solid-state reaction with glucose as carbon source. Bi₅Nb₃O₁₅ @C composite is well dispersed, with small particle size of 0.5–2.0?µm. The electrochemical performance of Bi₅Nb₃O₁₅ @C is reinforced by carbon-coated layer as desired. The Bi₅Nb₃O₁₅ @C exhibits a high specific capacity of 338.56 mAh g^?1 at a current density of 100?mA?g^?1. And it also presents an excellent cycling stability with a capacity of 212.06 mAh g^?1 over 100 cycles at 100?mA?g^?1. As a comparison, bulk Bi₅Nb₃O₁₅ without carbon-coating only remains 319.62 mAh g^?1 at 100?mA?g^?1, revealing poor cycle and rate performances. Furthermore, in-situ X-ray diffraction experiments investigate the alloying/dealloying behavior of Bi₅Nb₃O₁₅ @C. These insights will benefit the discovery of novel anode materials for lithium-ion batteries.     

Micro/nanostructured Bi2Mn4O10 with hierarchical spindle morphology as a highly efficient anode material for lithium-ion batteries

Mullite-type compound Bi₂Mn₄O₁₀ has shown the feasibility as anodes of next lithium-ion batteries (LIBs). Herein micro/nano-Bi₂Mn₄O₁₀ with hierarchical spindle-like architectures has been successfully synthesized using a one-step hydrothermal method without any no surfactant or template. A time-dependent experiment is carried out to observe the morphology evolution, suggesting a nucleation–aggregation/growth–dissolution–recrystallization process. As anode of LIBs, the as-prepared spindle-shaped micro/nano Bi₂Mn₄O₁₀ harvests a significantly high initial discharge capacity of 1022 mA h g⁻¹ at 1 C, an excellent cyclability performance (563.8 mA h g⁻¹ after 400 cycles), a better high-rate capability (100 mA h g⁻¹ at 10 C), quick diffusion kinetics (1.8 × 10⁻¹² cm² s⁻¹), and low active energy (19.5 kJ mol⁻¹), which are significantly superior to that of its bulk counterparts and the previous reports. The encouraging lithium storage performance largely stems from the synergistic effect of the unique spindle-shaped micro/nanostructure.     

Nanoparticles constructed mesoporous coral-like Mn2O3 as high performance anode for lithium-ion batteries

As well established, the morphology and architecture of electrode materials greatly contribute to the electrochemical properties. Herein, a novel structure of mesoporous coral-like manganese (III) oxide (Mn₂O₃) is synthesized via a facile solvothermal method coupled with the carbonization under air. When fabricated as anode electrode for lithium-ion batteries (LIBs), the as-prepared Mn₂O₃ exhibits good electrochemical properties, showing a high discharge capacity of 1090.4 mAh g^?1 at 0.1 A g^?1, and excellent rate performance of 410.4 mAh g^?1 at 2 A g^?1. Furthermore, it maintains the reversible discharge capacity of 1045 mAh g^?1 at 0.1 A g^?1 after 380 cycles, and 755 mAh g^?1 at 1 A g^?1 after 450 cycles. The durable cycling stability and outstanding rate performance can be attributed to its unique 3D mesoporous structure, which is favorable for increasing active area and shortening Li⁺ diffusion distance.     

Piezoelectric-driven self-accelerated anion migration for SiOX-C/PbZr0.52Ti0.48O3 with durable lithium storage performance

Silicon oxides (SiO_X) based materials with great specific capacity and suitable working potential have caused widespread concern. During alloying process, the volume expansion of SiO_X is approximately 200%, which limits its practical application for lithium-ion batteries (LIBs). For the purpose of surmounting the shortcomings of large volume change, a lot of efforts have been made, such as regulating the structure and morphology of active materials, incorporating with other conductive materials, and matching the suitable battery systems. However, to date, the volume expansion of SiO_X anode in the cycle process cannot be absolutely avoided due to its intrinsic characteristics. In this work, these seeming drawback is creatively exploited to increase the electrochemical performance of SiO_X materials. PbZr_0.52Ti_0.48O₃ (PZT) is taken advantage as functional addition agent, which is based on piezoelectric effect elicited by volume expansion of SiO_X. Specifically, the large volume change of SiO_X-C could be transmitted to PZT particles, thus resulting in a polarization process. Then the piezoelectric potential is generated, so as to promote Li ⁺ mobility. SiO_X-C/PZT was synthesized via a sol-gel method and high energy ball-milling procedure. Accordingly, SiO_X-C/PZT anode exhibits excellent the superior cycling capability, it retains 570 mA h g^-1 after 200 cycles at 400 mA g^-1. Besides, it also has stable long-cycling life (430 mA h g^-1 after 500 cycles at 500 mA g^-1 with a retention of 75%). The relevant results demonstrate that PZT piezoelectric material can favorably increase the electrochemical property of SiO_X anode materials.     

Tunable oxygen vacancies in MoO3 lattice with improved electrochemical performance for Li-ion battery thin film cathode

MoO₃ is a kind of promising cathode material for lithium-ion batteries (LIBs), owing to its high specific capacity (279 mA h g⁻¹) and layered structure. However, low electrical conductivity and sluggish reaction kinetics results in poor rate and Li-ions storage capability. The introduction of oxygen vacancies (OVs) can promote Li⁺ diffusion, and produce great electrical conductivity. Here, we report a strategy to synergize the merits of OVs by pulsed laser deposition (PLD) by adjusting oxygen partial pressures (2～20 Pa). The appropriate OVs concentration not only significantly approves electrochemical performance but also increases pseudocapacitance contribution. The Li-ion diffusion coefficient of MoO_3−x is remarkably improved by one or two orders of magnitude compared with that of MoO₃. Therefore, this facile and efficient strategy on OVs could afford a reference for other metal oxides for high-performance electrode materials.     

Hierarchical nanoarchitecture of vanadium disulfide decorated 3D porous carbon skeleton with improved electrochemical performance toward Li ion battery and supercapacitor

Vanadium disulfide (VS₂) is deemed to be a competitive active material in electrochemical energy storage field in both lithium-ion battery and supercapacitor owing to its unique chemical and physical property. Nevertheless, serious aggregation and structure damage in continuous charge-discharges would result in a decreased capacity, an inferior cycling stability and a poor rate capability, which severly limits the practical application of VS₂. In this current work, a hierarchical porous nanostructured composite composed of VS₂ nanoparticles confined in gelatin-derived nitrogen-doped carbon network (VS₂-NC) was successfully designed and synthesized via a simple freeze drying plus an annealing method. In this VS₂-NC composite, porous architecture is conductive to providing high active surface areas, facilitating the access of electrolyte into active materials and ion diffusion. The confinement of carbon matrix on VS₂ nanoparticles is beneficial to inhibition of the volume change, reinforcement of the structural stability and improvement of the overall electrical conductivity of composite. Benefitting from the advantages mentioned above, the as-prepared VS₂-NC electrode demonstrates outstanding electrochemical performances. Employed as an anode for lithium ion battery, VS₂-NC delivers a relatively high reversible capacity about ～1061 mA h g^?1 in 200-cycle test at 100 mA g^?1. When applied in supercapacitor, VS₂-NC electrode manifests a large pseudocapacitance of 407.3 F g^?1 at a current density of 10 A g^?1 and superior cycling stability.     

N-doped carbon coated NaV3O8 cathodes towards high-capacity and ultrafast Na-ion storage

In this work, nitrogen-doped carbon-coated NaV₃O₈ (NVO@NC) were successfully synthesized by a simple rheological phase method using melamine as a nitrogen source. X-ray powder diffraction (XRD) and Scanning electron microscopy (SEM) analyses revealed that nitrogen-doped carbon-coated didn't change the crystal structure of NVO but altered the thickness and properties of the surface coating. Among obtained composites, NVO@NC containing a molar ratio of melamine to citric acid of 2.75:1.25 displayed the best electrochemical properties. The electrochemical tests suggested discharge capacity reaching 231.3 mAh g^?1 at 150 mA g^?1, with discharge capacity remaining at 169.4 mAh g^?1 after 100 cycles. Electrochemical impedance spectroscopy (EIS) proved that the coated materials delivered a much lower resistance than that of bulk NVO. Galvanostatic intermittent titration technique (GITT) tests demonstrated sodium ion diffusion coefficient was greatly enhanced after nitrogen-doped carbon coating. In conclusion, nitrogen-doped carbon might increase material conductivity, aid in the formation of SEI films on electrode surfaces, and improve electrode material stability, resulting in NVO materials with high-capacity and ultrafast Na-ion storage.     

Zn–Mn-ptcda derived two-dimensional leaf-like Zn0·697Mn0·303Se/C composites as anode materials for high-capacity Li-ion batteries

As the most widely used energy storage device today, lithium-ion batteries (LIBs) will determine the convenience and durability of people's future energy life to a certain extent. At present, there are many and mature researches on cathode materials for LIBs, so it is crucial to seek a high-performance anode material. In recent years, due to considerable theoretical capacity, abundant raw material reserves and unique physicochemical properties, Zn and Mn selenium compounds have become research hotspots for LIBs anode materials. In this work, a new MOF material Zn–Mn-ptcda was synthesized by a simple hydrothermal reaction. Using Zn–Mn-ptcda as the precursor, two-dimensional (2D) elliptical leaf-shaped Zn_0·697Mn_0·303Se/C composites were synthesized by direct selenization. Zn_0.697Mn_0.303Se/C has a large specific surface area of 213.9 m² g^?1, belongs to the mesoporous structure, and possesses excellent lithium storage performance, especially the rate performance. It has a reversible capacity of 1005.14 mAh g^?1 after 110 cycles at a current density of 100 mA g^?1. After 1000 cycles at a high current density of 1 A g^?1, it still maintains a good capacity of 653.79 mAh g^?1.     

Facile fabrication of flower-like binary metal oxide as a potential electrode material for high-performance hybrid supercapacitors

Developing efficient electrode material with rational design and structure remains a crucial and great challenge for the significant improvement of high-performance hybrid supercapacitors (HSCs). Particularly, the performance of the HSCs can be largely enhanced by designing the battery-type Faradaic material with well-defined morphology and defective engineering. Here, a facile and effective strategy is utilized to develop oxygen-deficient flower-like three-dimensional NiMoO_4?δ (O_d-NMO) nanomaterial via hydrothermal process and following thermal-treatment under an inert-gas atmosphere. The presence of oxygen deficiency in the O_d-NMO is evaluated utilizing various spectroscopy techniques by comparing the pristine NiMoO₄ (P-NMO) heat treated under an ambient atmosphere. The electrochemical studies indicate that the oxygen defect sites in the O_d-NMO electrode have a considerable role in the betterment of supercapacitive performances. Hence, the O_d-NMO electrode provides a large specific capacity of 789 mA h g^?1 at 1 A g^?1 with an excellent rate capability than the P-NMO (579 mA h g^?1). Besides, the fabricated HSC based on O_d-NMO flower and activated carbon as the positive and negative electrodes, delivers a specific capacitance as high as 153 F g^?1 and accomplishes a large energy density (47.76 W h kg^?1) and power density (51.69 kW kg^?1) with improved long-term stability.     

Carbon-coated cation-disordered rocksalt-type transition metal oxide composites for high energy Li-ion batteries

Li-excess cation-disordered rocksalt oxides have attracted extensive attention for their high capacity (>210 mA h g^?1) and energy density. In these oxides, both cationic and anionic redox take responsibility for bringing capacity. However, anionic evolution as well as their intrinsic poor electronic conductivity raises the problem in large polarization and inferior rate performance of these oxides, especially for Ni-based ones. Herein, we report a facile strategy to synthesize a series of Li_1·2Ni_0·3Ti_0·3Nb_0·2O₂ (LNTNO20) @ C using different mass ratios of carbon precursor and calcination temperatures. It is found that carbon-coated materials possess impressive electrochemical properties with both high specific capacity and rate performance. Specifically, Li_1·2Ni_0·3Ti_0·3Nb_0·2O₂@C synthesized with ratio of 6:1 (LNTNO20: sucrose) and calcination temperature of 450 ^○C exhibits an initial specific capacity of 268.2 mA h g^?1 and a high capacity retention of 90.1% after 50 cycles. Based on multi-scale test results, we propose that carbon coating process using moderate mass ratio of carbon precursor and calcination temperature will increase tetrahedron height making Li diffuse easily. Besides, carbon coating layer reduces polarization upon cycling, protects cathode from reacting with electrolyte retarding SEI layer thickening and enhances electronic conductivity. Therefore, carbon coating is a facile and effective strategy to improve properties of Ni-based cation-disordered oxides.     

Unique CNTs-chained Li4Ti5O12 nanoparticles as excellent high rate anode materials for Li-ion capacitors

Composite anode materials with a unique architecture of carbon nanotubes (CNTs)-chained spinel lithium titanate (Li₄Ti₅O₁₂, LTO) nanoparticles are prepared for lithium ion capacitors (LICs). The CNTs networks derived from commercial conductive slurry not only bring out a steric hindrance effect to restrict the growth of Li₄Ti₅O₁₂ particles but greatly enhance the electronic conductivity of the CNTs/LTO composites, both have contributed to the excellent rate capability and cycle stability. The capacity retention at 30 C (1 C = 175 mA g^?1) is as high as 89.7% of that at 0.2 C with a CNTs content of 11 wt%. Meanwhile, there is not any capacity degradation after 500 cycles at 5 C. The LIC assembled with activated carbon (AC) cathode and such a CNTs/LTO composite anode displays excellent energy storage properties, including a high energy density of 35 Wh kg^?1 at 7434 W kg^?1, and a high capacity retention of 87.8% after 2200 cycles at 1 A g^?1. These electrochemical performances outperform the reported data achieved on other LTO anode-based LICs. Considering the facile and scalable preparation process proposed herein, the CNTs/LTO composites can be very potential anode materials for hybrid capacitors towards high power-energy outputs.     

Nitrogen-doped carbon-coated hierarchical Li4Ti5O12-TiO2 hybrid microspheres as excellent high rate anode of Li-ion battery

Nitrogen-doped carbon-coated Li₄Ti₅O₁₂-TiO₂ (LTO-TO) hybrid microspheres were prepared by heat treating the dry mixture of urea and chemically lithiated dandelion-like TiO₂ microspheres in a stainless steel autoclave at 550 °C for 5 h. The hybrid materials were tested as anode of Li-ion batteries. As compared to the pristine sample, the N-doped carbon-coated LTO-TO microspheres exhibited higher specific capacity at both low and high current rates. Discharge capacities of 184 and 123 mAh g⁻¹ were obtained at 0.2 C and 20 C, respectively. Moreover, the LTO-TO/C electrode showed excellent cycle performance, with a discharge capacity of 121.3 mAh g⁻¹ remained after 300 cycles at 5 C, corresponding to an average capacity degradation rate of 0.073% per cycle. These high specific capacity, excellent rate capability and cycle performance demonstrated the high potentiality of the N-doped carbon-coated LTO-TO microspheres as anode material of both energy storage-type and power-type Li-ion batteries.     

Binder-free carbon-coated TiO2@graphene electrode by using copper foam as current collector as a high-performance anode for lithium ion batteries

Anatase TiO₂ is widely used in lithium ion batteries (LIBs) due to its excellent safety and excellent structural stability. However, due to the poor ion and electron transport and low specific capacity (335 mAh g⁻¹) of TiO₂, its application in LIBs is severely limited. For the first time, we report a binder-free, carbon-coated TiO₂@graphene hybrid by using copper foam as current collector (TG-CM) to enhance the ionic and electronic conductivity and increase the discharge specific capacity of the electrode material without adding conductive carbon (such as super P, etc.) and a binder (such as polyvinylidene fluoride (PVDF), etc.). When serving as an anode material for LIBs, TG-CM displays excellent electrochemical performance in the voltage range of 0.01–3.0 V. Moreover, the TG-CM hybrid delivers a high reversible discharge capacity of 687.8 mAh g⁻¹ at 0.15 A g⁻¹. The excellent electrochemical performance of the TG-CM hybrid is attributed to the increased lithium ion diffusion rate due to the introduction of graphene and amorphous carbon layer, and the increased contact area between the active material and electrolyte, and small resistance with copper foam as the current collector without an additional binder (PVDF) and conductivity carbon (super P).     

Ultrathin carbon layer enhanced Cu2Nb34O87 nanowires as high-performance lithium host

Cu₂Nb₃₇O₈₇ exhibits excellent electrochemical properties, high theoretical capacity (401 mAh g^?1), safe working voltage (~1.7 V) and outstanding rate performance for lithium-ion batteries. However, poor electrical conductivity inhibits its further development. In this study, Cu₂Nb₃₇O₈₇@C nano-wires are prepared by combining electrospinning and carbon-coating techniques to mitigate this issue, which breaks through the barrier of low conductivity, improves the ion diffusion rate and relieves the change of crystal volume. Besides, the sample is tested by scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy and most importantly, the mechanism of lithium-ion storage is explored by an in-situ X-ray diffraction analysis. Moreover, according to a sequence of electrochemical tests, it is clarified that the electronic conductivity and electrochemical activity of Cu₂Nb₃₇O₈₇ are enhanced significantly. All these are inseparable from the synergistic effect of the nano-crystallisation and carbon coating. Therefore, nano-structures and surface cladding provide effective tactics to construct effective ion-migration interfaces and enhance conductivity for the further study of Cu₂Nb₃₇O₈₇ and other electrode materials.     

Stable composite electrolytes of PVDF modified by inorganic particles for solid-state lithium batteries

Polymer electrolytes have been attracting much attention because of their flexibility and easy follow-up processing, but their Li⁺ conductivity in lithium-metal batteries (LIBs) is unsatisfactory. Stable composite electrolytes of poly (vinylidene fluoride) (PVDF) polymer with high lithium-ion conductivity have been prepared by a trigger structural modification of Li_6.5La₃Zr_1.5Nb_0.25Ta_0.25O₁₂ (LLZNTO) garnet ceramic and TiO₂ oxide. The influences of various amounts of TiO₂ and LLZNTO on electrochemical performance were systematically examined. These composite electrolytes exhibited maximal Li⁺ conductivity of 2.89 × 10⁻⁴ S cm⁻¹, which is consistent with the value of pure ceramic electrolytes. Furthermore, it possessed the stable long-term Li cycling and the wide electrochemical window, involving repeated Li plating/stripping at 0.2 mA cm⁻² over 280 h without failure. The discharge specific capacity and Coulomb efficiency for all-solid-state LIBs assembled with these membranes delivered outstanding cycling stability with high discharge capacities (117.9 mA h g⁻¹) at 0.1 C rate and Coulomb efficiency reached 99.9% after 25 cycles. The high Li⁺ conduction capability can be ascribed function of introducing TiO₂ and LLZNTO to restrain tremendously the crystalline behavior of the polymer. Furthermore, the LLZNTO can be complex with PVDF for dehydrofluorination, and it can also offer a burst transportation route for lithium ions. This system might serve as an attractive use for polymer solid electrolytes and open up new possibilities for safe all-solid-state LIBs.     

NiFe-NiFe2O4/rGO composites: Controlled preparation and superior lithium storage properties

Binary transition-metal oxides with spinel structure have great potential as advanced anode materials for lithium-ion batteries (LIBs). Herein, NiFe-NiFe₂O₄/ reduced graphene oxide (rGO) composites are obtained via a facile cyanometallic framework precursor strategy to improve the lithium storage performance of NiFe₂O₄. In the composites, NiFe-NiFe₂O₄ nanoparticles with adjustable mass ratios of NiFe₂O₄ to NiFe alloy are homogeneously deposited on rGO sheets. As anode material for LIBs, the optimized NiFe-NiFe₂O₄/rGO composite displays remarkably enhanced lithium storage performance with an initial specific capacity as high as 1362 mAh g⁻¹ at 0.1 A g⁻¹ and a decent capacity retention of ca. 80% after 130 cycles. Besides, the composite delivers a reversible capacity of 550 mAh g⁻¹ at 1 A g⁻¹ after 300 cycles. During the charge–discharge cycles, the aggregation of the NiFe-NiFe₂O₄ nanoparticles and the structural collapse of the electrode can be well alleviated by rGO sheets. Moreover, the conductivity of the electrode can be significantly improved by the well-conductive NiFe alloy and rGO sheets. All these contribute to the improved lithium storage performance of NiFe-NiFe₂O₄/rGO composites.