Cathode For Sodium-ion Batteries Research Articles

Zr4+-doped sodium manganese oxide: enhanced electrochemical performance as a cathode in sodium ion batteries.

Sodium manganese oxides are regarded as a valuable class of cathode materials for sodium-ion batteries. By varying the stoichiometry of Na, Mn and O, it is possible to obtain layered, tunnel and spinel type structures, which can withstand the electrochemically-triggered sodiation-desodiation process. In this work, we report the electrochemical performance of Na4Mn2O5, a sodium-rich manganese oxide, which has been previously reported to suffer from structural instability due to the Jahn-Teller distortion of the Mn3+ ion. It was observed that the Na4Mn2-xZrxO5 (x = 0.1) cathode delivered a discharge capacity of ∼203 mA h g-1 post 250 cycles with a capacity retention rate of ∼82.8% on doping with Zr4+ ions. The improvement in cycling ability and rate capability is attributed to the enhanced structural stability and improved electronic conduction brought about by the substitution of Mn3+ by Zr4+ in Na4Mn2O5. Density functional theory-based studies were conducted, which adequately support the obtained results.

Nitrogen-doped carbon coated Na3V2O2(PO4)2F as a cathode for high-performance sodium-ion batteries

Na3V2O2(PO4)2F (NVOPF), a cathode known for the advantages of high voltage, exceptional energy density, and thermal stability, is seen as a promising candidate for sodium-ion battery cathodes. However, the NVOPF exhibits poor performance in sodium storage. Here, we report a NVOPF composite cathode with a nitrogen-doped carbon produced from dopamine hydrochloride at an elevated temperature. Firstly, neutron power diffraction (NPD) is employed to determine the structure of pure NVOPF at different temperatures, including oxygen coordination and the mobility of Na+. The nitrogen-doped carbon layer facilitates electron conduction, prevents NVOPF nanoparticle agglomeration, and thus promotes efficient electron and ion transfer during sodium ion insertion/extraction processes, thereby improving the stability of the material structure. These results indicate that the N doped carbon@NVOPF cathode material exhibits outstanding electrochemical performance (111mAh/g at 0.1C and 85mAh/g at 1C), while maintaining 91.06 % capacity retention after 500 cycles. The enhanced electrochemical performance attributes to efficient charge transfer kinetics offer novel perspectives, and the methodology can be effectively adapted to other cathode materials.

A multichambered carbon based electrode materials to realize efficient sodium-ion batteries

Sodium-ion batteries (SIBs) have emerged as a compelling alternative to lithium-ion counterparts, owing to the widespread availability and low cost of sodium. However, to achieve successful commercialization, the development of a high-performance electrode material is crucial. This study presents a facile synthesis strategy for the production of multichambered carbon cubes (MCCs) derived from ZIF-8 precursors. The optimized process mesoporous MCCs which were then embedded with zinc selenide (ZnSe@MCCs) for the anode and infused with sulfur (S@ZnSe@MCCs) to create the cathode of SIBs. The uniform, hierarchically porous MCC morphologies enable deep electrolyte penetration, unlocking the full potential of these electrode materials. SIBs utilizing ZnSe@MCCs anodes exhibited impressive sodium storage capacities (exceeding 300 mAh g−1 after 1000 cycles) and rate capabilities. Moreover, when employed as the cathode, the S@ZnSe@MCCs effectively suppressed the polysulfide shuttle phenomenon. The performance of these sodium-ion cells underscores the potential of MCCs to enable high capacity, long cycle life, and fast kinetics, paving the way for practical and efficient sodium-ion battery technologies.

Excellent Performance of Sodium Ion Battery Cathode Materials Benefiting from the Inorganic Acid Regulating Strategy

Excellent Performance of Sodium Ion Battery Cathode Materials Benefiting from the Inorganic Acid Regulating Strategy

Lattice strengthening enables reversible anionic redox chemistry in sodium-ion batteries

Triggering anionic redox reaction (ARR) in layered oxide cathodes has emerged as an effective approach to overcoming the energy density limitations of conventional sodium-ion batteries (SIBs) solely based on cationic redox. However, the local structural deterioration and lattice oxygen loss associated with ARR remain challenging and unsolved, resulting in severe capacity and voltage decay. To address these issues, we herein present a lattice-strengthened P2-Na0.66Ca0.03[Li0.24Mn0.76]O2 (NCLMO) cathode. The introduction of Ca into the Na layers enables the compressed TMO2 slabs and reinforced TM–O bonds (TM = Li/Mn). Moreover, the incorporation of Ca into the Na layers effectively mitigates the out-of-plane migration of Li and impedes the in-plane migration of Mn during the anionic redox. The reduction of ion migration reduces the variation of the local environment surrounding O and hinders the formation of TM vacancy clusters, significantly mitigating the loss of lattice oxygen. Consequently, NCLMO delivers an impressive capacity retention of 76.04% at 1 C after 200 cycles. Our findings highlight the significance of maintaining local structural stability and offer novel insights towards achieving highly reversible ARR in layered oxide cathodes for high-energy SIBs.

Close‐Packed One‐Dimensional Coordination Polymer Cathode with Fast Kinetics for Sodium‐Ion Batteries

AbstractSustainable sodium‐ion batteries (SIBs) have gained tremendous attention; however, the large‐sized Na+ poses serious challenges on the development of inorganic‐based cathodes. To overcome the issues, metal–organic electrode materials are appealing because they combine attractive characteristics of organic redox centers (e. g., flexibility, highly reversible redox properties, fast kinetics (regardless of size and charge of guest ions), structural/redox tunability, and resource abundance) with structural stability arising from metal‐ligand coordination. Herein, a one‐dimensional copper−benzoquinoid coordination polymer (CP), [CuL(Py)2]n, (LH4=1,4‐dicyano‐2,3,5,6‐tetrahydroxybenzene, Py=pyridine) is investigated as cathode for SIBs. As opposed to most CPs reported for SIBs which possess high porosity and surface area, this close‐packed CP can deliver discharge capacity as high as 277 mAh g−1 at 2C (~523 mA g−1), and at extremely high rates of 50C and 300C (~13 and 78 A g−1), reversible capacities of 131 and 74 mAh g−1 still can be delivered, respectively. The transport kinetics of Na+ in [CuL(Py)2]n is found to be even faster than that of Li+ despite the close‐packed structure. The mechanistic and kinetic studies have been performed. The findings gained in this work undoubtedly unravel a potential design strategy for high‐performance metal–organic electrode materials for emerging post‐Li‐ion batteries.

Improving Oxygen-Redox-Active Layered Oxide Cathodes for Sodium-Ion Batteries Through Crystal Facet Modulation and Fluorinated Interfacial Engineering.

Layered oxides with active oxygen redox are attractive cathode materials for sodium-ion batteries (SIBs) due to high capacity but suffer from rapid capacity/voltage deterioration and sluggish reaction kinetics stemming from lattice oxygen release, interfacial side reactions, and structural reconstruction. Herein, a synergistic strategy of crystal-facet modulation and fluorinated interfacial engineering is proposed to achieve high capacity, superior rate capability, and long cycle stability in Na0.67Li0.24Mn0.76O2. The synthesized single-crystal Na0.67Li0.24Mn0.76O2 (NLMO{010}) featuring increased {010} active facet exposure exhibits faster anionic redox kinetics and delivers a high capacity (272.4 mAh g-1 at 10mA g-1) with superior energy density (713.9Wh kg-1) and rate performance (116.4 mAh g-1 at 1 A g-1). Moreover, by incorporating N-Fluorobenzenesulfonimide (NFBS) as electrolyte additive, the NLMO{010} cathode retains 84.6% capacity after 400 cycles at 500mA g-1 with alleviated voltage fade (0.27mV per cycle). Combined in situ analysis and theoretical calculations unveil dual functionality of NFBS, which results in thin yet durable fluorinated interfaces on the NLMO{010} cathode and hard carbon anode and scavenges highly reactive oxygen species. The results indicate the importance of fast-ion-transfer facet engineering and fluorinated electrolyte formulation to enhance oxygen redox-active cathode materials for high-energy-density SIBs.

Nitrogen-doped carbon-coating enables high-rate capability and long-cycle stability of NaCrO2 cathode for sodium-ion battery

We report nitrogen-doped carbon-coating to increase rate capability and cycle stability of NaCrO2 cathode for sodium ion battery application. The nitrogen-doped carbon coating layer can effectively reduce electrode surface impedance and accelerate Na+ ion diffusion to allow high-rate performance. The coating layer can suppress the electrode/electrolyte side reactions and inhibit the degradation of NaCrO2, thereby markedly enhancing cathode cycling stability. Consequently, the NaCrO2 cathode exhibits a specific capacity of 95.6mAh/g at 50 C and a capacity retention of 91.4 % after 1000 cycles at 10 C.

High-Na-Content Birnessite via P'3-Stacking with Tunable Active Facets for Advanced Aqueous Sodium-Ion Batteries.

Layered Na-birnessites are promising cathode materials for aqueous sodium-ion batteries due to their high theoretical capacity, low cost, and environmental benignity. However, the general O'3 Na-birnessites possess low Na content and dominant inactive {001} exposed facets, which compromise their Na storage capability and cycling stability. Herein, we develop a high-Na-content P'3-Na0.71MnO2·0.15H2O with highly enriched {010} active facets by a hydrothermal conversion method. In comparison with the O'3 Na-birnessite, the P'3 Na-birnessite with a high ratio of {010}/{001} exposed facets provides greatly increased open channels for Na+ diffusion, while the P'3 stacking affords a lower Na+ diffusion barrier, resulting in improved electrode kinetics with a large specific capacity of 176 mAh g-1 at 0.2 A g-1. More importantly, the P'3 Na-birnessite manifests solo Na+ intercalation/deintercalation with extraordinary cycling stability in an aqueous electrolyte, achieving 90.5% capacity retention after 60,000 cycles. When coupled with the NaTi2(PO4)3 anode, the P'3 Na-birnessite-based full cell delivers both high energy density and long cycle life, demonstrating the potential application in aqueous sodium-ion batteries. This study demonstrates an efficient method to prepare high-Na-content P'3 birnessite with tunable exposed facets and provides important insights into developing highly stable layered cathodes for sustainable aqueous sodium-ion batteries.

Lattice sulfuration enhanced sodium storage performance of Na0.9Li0.1Zn0.05Ni0.25Mn0.6O2 cathode

Introducing lattice oxygen redox for charge compensation in layered metal oxides is an effective way to develop advanced cathodes for high energy density sodium-ion batteries (SIBs). However, the asymmetry of lattice oxygen oxidation and reduction incurs oxygen release and crystal structure rearrangement, leading to poor reversibility of the charge and discharge process. Herein, a Na2S-assisted sulfuration strategy is firstly proposed to incorporate active sulfur into the crystal lattice of Na0.9Li0.1Zn0.05Ni0.25Mn0.6O2 cathode. The sulfur anions within the interior lattice participate in the redox process and enhance the integral coordination stability by mitigating undesired excessive oxygen redox, while the exterior sulfur forms a polyanionic layer to protect the particle surface against electrolyte corrosion. The incorporation of an extra redox center efficiently facilitates the increase of the discharge capacity from 159.9 to 179.2 mAh g−1 within the voltage range of 1.5–4.5 V. Moreover, the larger ionic radius of sulfur enlarges the interplanar spacing, thus facilitating Na+ ions transfer, especially at high current density. As a result, the modified cathode exhibits significantly enhanced electrochemical performance, with a capacity retention of 87 % after 100 cycles at 0.2 C and an excellent rate capability of 98.0 mAh g−1 at 10 C. Moreover, the assembled Na ion full cell based on a commercial hard carbon anode achieves an impressive capacity of 160.4 mAh g−1 at 0.1 C and could cycled steadily for over 100 cycles. The modification of layer oxides via sulfuration strategy provides a promising pathway for the structural design of novel cathodes with superior cycle performance for high-energy-density SIBs applications.

Inhomogeneous Coordination in High-Entropy O3-Type Cathodes Enables Suppressed Slab Gliding and Durable Sodium Storage.

O3-type layered oxides are highly promising cathodes for sodium-ion batteries (SIBs), however they undergo complex phase transitions and exhibit high sensibility to air, leading to subpar cycling performance and commercial viability. In this work, we report a layered cathode material (NaNi0.29Cu0.1Mg0.05Li0.05Mn0.2Ti0.2Sn0.11O2) with a sate-of-the-art high-entropy compositional design. We unveil that such a configuration featuring inhomogeneous coordination environment of transition metal (TM) elements, can enable enhanced gliding energy (-0.38 vs -0.58 eV) of TMO2 slabs upon desodiation both theoretically and experimentally, which underlies the fundamental origin of the outstanding structural stability of HEO materials. As a consequence, the complex phase transitions (O3-O'3-P3-P'3-P3'-O3') of conventional O3-type cathode have been eliminated, and the as-obtained material demonstrates exceptional structural robustness and integrity with an ultra-long cycle life in a quasi-solid-state cell (maintaining 73.2 % capacity after 1000 cycles at 2 C). Moreover, the material presents satisfactory air stability, with minimal structural and electrochemical degradation when directly exposed to the air. An Ah-scale pouch cell based on the cathode material is constructed, demonstrating a capacity retention of 83.6 % after 500 cycles, signaling substantial promise for commercial applications.

Boosting sodium-ion battery performance with vanadium substituted Fe, Ni dual doped fluorophosphate cathode over a wide temperature range

Recently, polyanionic material has been identified as the most attractive choice for the cathode in sodium-ion batteries. However, the poor electronic conductivity of Na3V2(PO4)2F3 (NVPF) limits its electrochemical performance, while the presence of vanadium increases material costs. To address these challenges, we have synthesized carbon-coated Fe, Ni dual-doped NVPF (Na3V1.9Fe0.01Ni0.09(PO4)2F3) via a rota tumbler assisted sol-gel process and reported for the first time. Comprehensive studies reveal that dual doping significantly affects the structural, morphological, and electrochemical properties of the material. Rietveld refinement shows that doping adjusts the crystal structure, enlarging Na⁺ diffusion pathways and enhancing diffusion kinetics. Na3V1.9Fe0.01Ni0.09(PO4)2F3 exhibits a superior capacity of 115.58 mAhg−1 at 0.1C, 92.86 mAhg−1 at 2C, 87.79 % cyclic retention at 2C after 500 cycles. The optimized material demonstrates robust performance across a wide temperature range (55 °C to −21.1 °C). Furthermore, full-cell constructed using Na3V1.9Fe0.01Ni0.09(PO4)2F3 as cathode and hard carbon as anode delivers an impressive capacity of 87.01 mAhg−1 at 1C and a retention of 94.50 % for 100 cycles at 0.5C. Moreover, reducing the vanadium content in the cathode helps lower the overall manufacturing costs. Our research demonstrates that Na3V1.9Fe0.01Ni0.09(PO4)2F3 is a promising option for a high-performance cathode in sodium-ion batteries.

Understanding of a Ni-Rich O3-Layered Cathode for Sodium-Ion Batteries: Synthesis Mechanism and Al-Gradient Doping.

O3-type NaNi0.8Mn0.1Co0.1O2 (NaNMC811) cathode active materials for sodium-ion batteries (SIBs), with a theoretical high specific capacity (∼187mAhg-1), are in the preliminary exploration stage. This study comprehensively investigates NaNMC811 from multiple perspectives. For the first time, the phase evolution ( - - ) during the solid-state synthesis is systemically investigated, which elucidates in-depth the mechanisms of the thermal sodiation process. Furthermore, an Al-gradient doping of NaNMC811 wassuccessfully implemented through Al2O3 coating on the cathode active material (CAM) precursor. The modified Al-NaNi0.8Mn0.1Co0.1O2 (Al-NaNMC811) exhibits excellent electrochemical dynamics and performance, maintaining a specific capacity above 100mAhg-1 after 100 cycles at 0.1 C (1.5-4.1 V) while providing a promising capacity retention of 63%. Additionally, the material demonstrates excellent rate capabilities, retaining a specific capacity of 107 mAh g-1 at 5 C. Compared to pristine NaNMC811, the modified Al-NaNMC811 is proven to have improved electrochemical kinetics with a higher Na+ diffusion coefficient due to dilated (003) interplanar spacing, and a more stable structure during the electrochemical charge-discharge processes, which is attributed to stronger Al-O bond energy. Understanding phase formations during the synthesis and comprehensive insight in the gradient doping for O3-type NaNMC811 CAMs guides further development of next-generation SIBsmaterials.

Research of Cathode Materials for Sodium-Ion Batteries

Sodium-ion batteries are being extensively studied as a replacement for lithium-ion batteries in some areas. However, there are also some problems with cathode materials at present. Sodium-ion batteries perform worse performance than lithium-ion batteries, which is due to the properties of sodium. For instance, sodium ions possess a greater ionic radius and increased atomic weight compared to lithium ions. This piece presents an overview of the operational principles behind sodium-ion batteries, examining the preparation techniques, structure, and effectiveness of three main cathode materials. Moreover, the current challenges of cathodes and the corresponding solutions for sodium-ion batteries are systematically recognized. This article provides a new perspective or idea for solving the problem of sodium-ion battery cathode.

Sodium-Rich, Co-Ni-Free P2-Layered Manganese Oxide Cathodes for Sodium-Ion Batteries.

The rapid capacity loss attributed to irreversible phase reactions and structural instability has consistently affected the development of P2-layered cathode materials. Moreover, the introduction of costly elements such as single or multiple dopants has failed to resolve the sustainability challenges in designing an optimal Mn-based layered oxide cathode. This study proposes a Co-Ni-free, poly-elemental doping strategy (Li, Mg, and Cu) combined with high sodium content for an Mn-based P2-layered cathode designed for Na+ ion storage. In situ X-ray diffraction analysis confirms the absence of P2 - O2 phase transitions during cycling for both NLMMC87 (Na0.87Li0.1Mg0.1Mn0.7Cu0.1O2) and NLMMC77 (Na0.77Li0.1Mg0.1Mn0.7Cu0.1O2). This can be attributed to the co-substitution of the electronegative Cu element and the stabilizing dopants Li and Mg, which suppress oxygen evolution. Simultaneously, the high sodium content within the host structure promotes high reversible capacity, enhances structural stability, and minimizes internal stress due to volume changes. Moreover, NLMMC87 demonstrates a reversible capacity of 167.9mA h g-1 at 0.1 C (97% Coulombic efficiency) and maintains excellent stability across various current rates. Further investigations into the practical application of NLMMC87 in a sodium full cell will be a critical step toward realizing an ideal cathode for sodium-ion batteries.

Challenges and Modification Strategies on High-Voltage Layered Oxide Cathode for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) have attracted great attention due to their advantages on resource abundance, cost and safety. Layered oxide cathodes (LOCs) of SIBs possess high theoretical capacity, facile synthesis and low cost, and are promising candidates for large scale energy storage application. Increasing operating voltage is an effective strategy to achieve higher specific capacity and also high energy density of SIBs. However, at high operating voltages, LOCs will undergo a series of phase transitions in bulk phase, leading to huge change of volume and layer spacings accompanied by severe lattice stress and cracking formation. Degeneration of surface also occurs between LOCs and electrolytes, resulting in sustained growth of cathode electrolyte interphase (CEI) and release of O2 and CO2. These induce structural destruction and electrochemical performance degradation in high voltage regions. Recently, many strategies have been proposed to improve electrochemical performance of LOCs under high voltages, including bulk element doping, structural design, surface coating and gradient doping. This review describes pivotal challenges and occurrence mechanisms at high voltages, and summarizes strategies to improve stability of bulk and surface. Viewpoints will be provided to promote development of high energy density SIBs.

In-Situ Constructing N,S-Codoped Carbon Heterointerface for High-Rate Cathode of Sodium-Ion Batteries.

Na3V2(PO4)3 (NVP) is considered one of the promising choices for cathodes of sodium-ion batteries, but the poor conductivity resulted inferior rate performance limited the practical development of NVP cathodes. In this study, we successfully synthesized N/S dual-atom doped carbon coatings in situ through a simple one-step solid-state sintering method. The uniformly coated carbon layer can inhibit the agglomeration and growth of active materials during the sintering process, shorten the Na+ migration path, and increase the contact area with the electrolyte, thus facilitating rapid Na+ migration. Notably, the doping of N elements can alter the electron distribution of carbon coating, enhancing electron conductivity. Furthermore, the introduction of S elements in the carbon layer can induce the formation of stable C-S-C bonds in the molecular layer, expanding the interlayer spacing, which is beneficial for Na+ transport and storage. Therefore, the modified NVP@NSC composite provides a high specific capacity of 90.3 mAh g-1 at a rate of 20 C, with a capacity retention rate of 94.4% after 8000 cycles, demonstrating excellent stability at high current densities. Moreover, the full cell exhibits remarkable electrochemical performance at 5 C. This research contributes to the practical development of NVP cathodes.

Ca/Li Synergetic-Doped Na0.67Ni0.33Mn0.67O2 to Realize P2-O2 Phase Transition Suppression for High-Performance Sodium-Ion Batteries.

P2-type layered transition metal oxide Na0.67Ni0.33Mn0.67O2 is considered as a promising cathode for advanced sodium-ion batteries due to its high theoretical specific capacity. However, the P2-type cathode suffers severe P2-O2 phase transition during cycling process, resulting unsatisfactory cyclic stability and rate capability. Herein, a Ca/Li co-doped P2-type Na0.62Ca0.05Ni0.33Mn0.57Li0.10O2 (NCNMLO) cathode material was synthesized through a simple sol-gel method. With the synergistic effect of Ca-doping at Na sites and Li substitution at transition metal (TM) sites, the cathode achieves an excellent electrochemical performance due to the inhibited P2-O2 phase transition and improved ion diffusion with Na+/vacancy disordering arrangement. The NCNMLO cathode exhibits a good cyclic stability with 70.8 % of capacity retention at 1 C after 200 cycles and excellent rate capability with 40.1 mAh g-1 at 20 C. The dual sites doping strategy provides an effective and simple approach for designing high-performance layered oxide cathode materials for sodium-ion batteries.

Enhancing Cyclability of Fe2O3-V2O5-P2O5 Ceramic Cathode for High-Performance Sodium-ion Batteries through Heat Treatment

Due to the ability to form more open structures, glass and glass-ceramic materials can accommodate larger Na+ ions and enable rapid solid-state diffusion of Na+ at room temperature (RT). Regardless of the larger ionic radius of Na, iron-based mixed-vanadium-phosphate ceramics show promising potential as cathode materials in sodium-ion batteries (SIBs). However, their practical applicability is significantly hindered by slow Na+ diffusion and low intrinsic electrical conductivity. In the present study, a ceramic sample with the composition of 5Na2O−45Fe2O3−10V2O5−40P2O5, denoted as (5NFVP), was synthesized before (BHT) and after heat treatment (HT) at 500, 600, and 700 °C for 2h to be used as a cathode material in SIBs. The outstanding electrochemical performance of the 5NFVP ceramic is attributed to improved electronic and ionic conductivity and enhanced structural stability during Na+ insertion/de-insertion. This is supported by various analyses, including X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), 57Fe Mössbauer spectroscopy, and electrochemical impedance spectroscopy (EIS). All prepared samples show two doublets, with the first doublet associated with Fe3+(Td), confirming the XRD results that indicate the main crystalline phase of FePO4. The second doublet observed in the 5NFVP-HT500 and 600°C is related to Fe3+(Oh), while 5NFVP-BHT exhibits a large δ value of 1.19 mm s−1, indicating the presence of Fe2+(Oh) due to NaFePO4 crystalline phase. The Fe-K absorption edge analysis reveals that 5NFVP-HT600°C ceramics predominantly consist of Fe3+, whereas 5NFVP-BHT has the most abundant Fe2+ compared with HT samples. The largest DC conductivity is achieved by the 5NFVP-HT600°C ceramic, reaching 5.08×10−9S cm−1 at RT. The initial capacity of 5NFVP-HT ceramics is approximately doubled compared to 5NFVP-BHT. The 5NFVP-HT600°C ceramic as a cathode demonstrates excellent long-cycling stability, retaining 60 % of its capacity over 100 cycles under a current rate of 50 mA g−1. These findings underscore the significant potential of 5NFVP-HT600°C for advanced energy storage systems, given its affordability and robust cyclability.

Earth-abundant FeSO4-based conversion-type cathode for rechargeable sodium-ion batteries

Sodium-ion batteries (SIBs) have gained prominence as the ideal choice for next-generation large-scale energy storage systems owing to advantages such as sodium abundance and cost-effectiveness. However, their synthesis requires harsh conditions such as high pressure and temperature, and the cathode materials exhibit poor electrical conductivity and sluggish kinetics, hindering SIBs from meeting the requirements for practical applications. In this study, a conversion-type Gr/FeSO4 nanocomposite based on earth-abundant and environmentally friendly elements was developed using a high-energy mechanical ball-milling method. The conversion reaction in FeSO4 was triggered via a simple direct-contact pre-sodiation method, wherein the FeSO4 particles were reversibly converted to Fe0 and Na2SO4 and recovered in the next charging process. Meanwhile, graphene in Gr/FeSO4 acted as a conductive matrix that provided additional electron transfer paths, resulting in increased ionic and electronic conductivities and enhanced diffusion kinetics. Owing to these matrices, the as-prepared Gr/FeSO4 nanocomposite exhibited remarkable long-term cyclability. This study highlights the advantages of combining pre-sodiation and conversion reactions for cathodes and demonstrates the feasibility of employing naturally abundant FeSO4 for high-performance SIBs.