Cathode For Sodium-ion Batteries Research Articles

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.

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.

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.

Robust interface for O3-type layered cathode towards stable ether-based sodium-ion full batteries

Developing a robust cathode-electrolyte interface (CEI) is crucial for stable layered cathode in sodium-ion batteries (SIBs). A CEI based on ester electrolytes often exhibit poor stability and robustness, which cannot address the issues of structural collapse and material dissolution in layered cathodes. However, there are few reports on constructing a stable CEI for layered cathode based on ether electrolytes. Here we develop a robust CEI for O3-type cathode via DME solvent, which enables a long-term stability of full SIBs. The results indicate that unique decomposition process of DME yields favorable organic component (e.g. RCH2ONa) and high content of inorganic components (e.g. NaF and Na2CO3) in the CEI, which is quite different from ester electrolyte, improving Na+ diffusion kinetic and interfacial stability. Notably, the O3-NaNi0.5Mn0.5O2||Na cell with the designed electrolyte demonstrates outstanding stability up to 500 cycles. Furthermore, the full cell exhibits remarkable cycling performance with a capacity retention of 85% over 200 cycles. This work provides an opportunity for stable operation of layered cathode materials via inexpensive ether electrolytes.

Dual-site defects engineering to eliminate impurities and optimize reversible reaction kinetics of Na4Fe3(PO4)2P2O7 cathode for superior performance sodium ion batteries

Na4Fe3(PO4)2P2O7 is a prominent polyanionic material widely studied as a cathode for sodium-ion batteries, valued for its stable cycling performance and cost-effectiveness. However, the sluggish diffusion kinetics of Na+ associated with electrochemically inert NaFePO4 impurities during synthesis strictly limit the rate performance and energy density of Na4Fe3(PO4)2P2O7. In this study, dual-site defects engineered Na4-2xFe3-1.5yLay(PO4-xBrx)2P2O7 cathode materials were synthesized using a facile mechanical activation method, by introducing trace amounts of LaBr3 as additive. Fe defects originating from La doping eliminate the maricite-NaFePO4 inert impurities and Na defects stemming from Br doping optimize the microchemical valence states and ion transport kinetics. The density functional theory demonstrates that Fe/Na dual-site defects in the lattice of Na4Fe3(PO4)2P2O7 reduce band gap and facilitate Na+ migration passageway, thereby leading to a superior rate capability and stable sodium storage performance. Moreover, the sodium storage mechanism of the dual-site defects engineered Na4Fe3(PO4)2P2O7 cathode material is revealed. The optimal dual-site defects engineered cathode sample delivers excellent rate performance (55.2 mAh g-1 at 50 C) and long cycling stability (capacity retention of 93% after 2000 cycles at 10 C). This study provides a promising strategy for engineering dual-site defects to synthesize impurities-free Na4Fe3(PO4)2P2O7 cathode material with superior electrochemical performance.

Vanadium-site multivalent cation doping strategy of fluorophosphate cathode for low self-discharge sodium-ion batteries

Vanadium-site multivalent cation doping strategy of fluorophosphate cathode for low self-discharge sodium-ion batteries

Crystal Modulation of Mn-Based Layered Oxide toward Long-Enduring Anionic Redox with Fast Kinetics for Sodium-Ion Batteries.

Mn-based layered oxide cathodes for sodium-ion batteries with anionic redox reactions hold great potential for energy storage applications due to their ultra-high capacity and cost effectiveness. However, achieving high capacity requires overcoming challenges such as oxygen-redox failure, sluggish kinetics, and structural degradation. Herein, we employ an innovative crystal modulation strategy, using Mn-based Na0.72Li0.24Mn0.76O2 as a representative cathode material, which shows that the highly exposed {010} active facets enable an enhanced rate capability (119.6 mAh g-1 at 10C) with fast kinetics. Meanwhile, the reinforced Mn-O bond inhibits excessive oxidation of lattice oxygen and O-O cohesion loss, stabilizing and maintaining a long-enduring reversible oxygen-redox activity (100% high capacity retention after 100 cycles at 0.5C and 84.28% retention after 300 cycles at 5C). Time-resolved operando two-dimensional X-ray diffraction reveals the robust structural stability, zero-strain behavior, and suppressed phase transition with ultra-low volume variation during cycling at different rates (0.1C: 1.75%, 1C: 0.31%, 5C: 0.04%). Additionally, the full cell coupled with hard carbon achieves a high energy density of approximately 211 Wh kg-1 with superior performance. This work highlights the significance of crystal modulation and presents a universal approach in developing Mn-based oxide cathodes with stable anionic redox for high-performance sodium-ion batteries.

Insights into the ternary substitution Na2.96+xK0.04 V2-xNix(PO4)2.98F0.06 with superior rate capability and near-zero strain property

Na3V2(PO4)3 (NVP) is considered the most favorable cathode for sodium-ion batteries due to its solid NASICON skeleton. Nevertheless, poor intrinsic conductivity is insufficient for its further commercialization. In this paper, we present a promising K/Ni/F co-doped and carbon nanotubes (CNTs) encapsulated Na2.96+xK0.04 V2-xNix(PO4)2.98F0.06 (KNF@CNTsx) cathode materials. The synthesis of KNF@CNTsx is achieved using a facile sol-gel method. The replacement of Na+ with K+ broadens the migratory pathway and supports the crystal skeleton, while F− substitution reduces the average grain dimension, thereby increasing the diffusion rate of Na+. Furthermore, the reduction of resistance by Ni2+ doping enables optimization of the transport of electrical charge, while also facilitating the optimization of chemically-defined properties. Concurrently, the optimal quantity of carbon capping and wrapping of CNTs facilitate the formation of efficacious conductive network, which diminishes the size of grains and shortens the pathway for the diffusion of Na+. This network could also serve as a buffer against crystal deformation. In conclusion, the modified KNF@CNTsx samples exhibit notable enhancements in their conductivity, ion diffusion capacity, and structural stability. Among them, the KNF@CNTs0.04 sample exhibits a capacity for reversibility of 93.3 mAh g−1 at 50C, with a remaining capacity of 68.5 mAh g−1 after 4000 successive long charge-discharge cycles. Ex-situ electrochemical XRD demonstrates the V3+/V4+ redox reaction occurs accompanied by the phase transfer reaction, during which Na+ prefers to diffuse along c-axial in the crustal structure. Moreover, volume alteration of this KNF@CNTs0.04 cellular entity is miniscule and reversible during the charge-discharge process, further confirming the stabilized construction and near-zero strain property. The after-cycled XRD/SEM/XPS certify the improved chemical and structural stability of KNF@CNTs0.04, indicating the constructive effects of K/Ni/F ternary substitution.

Enhanced cyclability of O3-NaNi0.33Fe0.31Mn0.36O2 by Mg and Cu synergistic doping with strengthened Mn[sbnd]O bonds

Among some practical O3-type layered oxide cathodes, NaNi1/3Fe1/3Mn1/3O2 (NFM) features a high specific capacity and moderate cyclability. However, sluggish Na+ transfer kinetics, low structural stability, and rapid capacity loss during long-term cycling, are still posing a challenge to commercial applications of this material. In this work, we propose a Mg and Cu co-doped O3-type NaMg0.02Cu0.02Ni0.33Fe0.27Mn0.36O2 (MC-NFM) with a stable structure and good cycling stability. It was found that the MnO bonds in MC-NFM are obviously reinforced by synergistic doping with small amounts of Mg and Cu, leading to enhanced structural robustness, decreased Na+ migration barrier, and delayed O3-P3 phase transition. As a result, longer cycle life and enhanced rate performance are achieved. MC-NFM can yield a specific capacity of 142.1 mAh g−1 at 0.1C and 116.0 mAh g−1 at 5C, and maintain 83.6 % of its initial capacity after 400 cycles at 1C. This work provides a promising design of O3-type cathode for sodium-ion batteries.

STUDYING THE ELECTROCHEMICAL PROPERTIES OF POTASSIUM-DOPED SODIUM-MANGANESE OXIDE CATHODE MATERIALS FOR SODIUM-ION BATTERIES

The development of layered sodium manganese oxide cathode materials with high capacity and long life is one of the keys to boosting the performance of sodium-ion batteries (SIBs), but it remains a great challenge. In this work, a potassium doped P2-type sodium manganese oxide, Na0.8K0.1Mn0.9O2 (NKMO), is developed as a high-capacity and long-lasting cathode for high-performance SIBs. Sodium-potassium-manganese oxide Na0.8K0.1Mn0.9O2 was synthesized by a conventional solid-state reaction method. Crystal structure and morphology of the NKMO material were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The NKMO material was utilized to fabricate CR2032-type coin cells, and later evaluated for its electrochemical characteristics. The electrochemical characteristics of NKMO were evaluated through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charging-discharging (GCD) at different current densities on a NEWARE battery testing system. The NKMO material had a superior initial charge and discharge capacity, approximately 130 mAh.g-1 and 125 mAh.g-1, respectively, within the voltage range of 1.5-4 V at a current density of 0.1 C. Remarkably, the capacity remained stable at 100 mAh.g-1 even after 100 cycles. These findings indicate that NKMO is a highly promising cathode material for sodium-ion batteries.

A two-pronged approach:Bulk-phase substitution and second-phase synergism to enhance the anion redox stability of layered oxide cathode for sodium-ion batteries

As a supplement to lithium-ion batteries, sodium-ion batteries have great application potential in large-scale energy storage equipment, vehicle start-stop power supplies, and low-speed electric vehicle power. P3-NaxLiyMn1-yO2 (NLMO), has received widespread attention due to its higher charge voltage and discharge capacity. However, poor cycle stability and rapid voltage platform decay caused by the release of oxygen during charging hinder its practical application. This paper reports a new NLMO modification strategy, which effectively improves the cycling stability of NLMO by substituting Zr4+ for Mn4+ in the bulk phase to suppress the O2−/On− redox couple activity and stabilize the ZrO2 second phase lattice. Under the combined action of substitution and second phase, the capacity retention rate of NLMO@Zr0.15 was 85.4 % after 100 cycles at a rate of 5 C. The results show that Zr4+ changes the coordination environment and electronic structure of O in the crystal lattice, prompting further splitting of Mn t2 g, thereby increasing the proportion of Mn 3d orbitals near the Fermi level. During the first discharge process, due to the charge balancing effect, Mn3+/Mn4+ replaced the electrochemical activity of O2−/On−, obtaining a specific capacity of up to 161 mAh g−1. This internal and external improvement idea provides a new direction for solving the poor cycle stability of NLMO high specific energy sodium-ion battery cathode materials and improving the specific capacity.

Dynamic Lock-And-Release Mechanism Enables Reduced ΔG at Low Temperatures for High-Performance Polyanionic Cathode in Sodium-Ion Batteries.

Low-temperature synthesis of polyanionic cathodes for sodium-ion batteries is highly desirable but often plagued by prolonged reaction times and suboptimal crystallinity. To address these challenges, a novel self-adaptive coordination field regulation (SACFR) strategy based on a dynamic lock-and-release (DLR) mechanism is introduced. Specifically, urea is used as a DLR carrier during synthesis, which dynamically "locks" and "releases" vanadium ions for controlled release, simultaneously "locking" H+ ions to enhance phosphate group release, thereby creating a self-adaptive coordination field that can intelligently respond to real-time demands of the reaction system. This dynamic coordination behavior contributes to both an improvement in reaction kinetics and a significant reduction in Gibbs free energy change (ΔG). As a result, the kinetic efficiency and thermodynamic spontaneity of the reaction are greatly enhanced, enabling the efficient synthesis of high-crystalline Na3V2O2(PO4)2F (NVOPF) at 90 °C within just 3 hours. The as-prepared NVOPF cathode exhibits exceptional rate performance and ultra-stable cycling stability across a broad temperature range. Furthermore, the successful kilogram-scale synthesis underscores the practical potential of the innovative strategy. This work pioneers the regulation of coordination field chemistry for polyanionic cathode synthesis, providing transformative insights into material design.

Enhanced Performance of Sodium-Ion Battery Cathodes with Ti and V Co-Doped P2-Type Na0.67Fe0.5Mn0.5O2 Materials

Enhanced Performance of Sodium-Ion Battery Cathodes with Ti and V Co-Doped P2-Type Na0.67Fe0.5Mn0.5O2 Materials

Maximizing the Structural Stability of the Na-Rich Prussian Blue Analogue Electrode through Charge Cutoff Voltage Regulation.

Prussian blue and its analogues (PB/PBAs) are promising sodium-ion battery cathode materials due to their easy synthesis and excellent discharge capacity. However, their low structural stability poses a challenge. One critical factor affecting stability is the charge cutoff voltage. Increasing this voltage can enhance lithium-ion battery capacity but may reduce cycle retention due to intensified electrode-electrolyte interface reactions. This study investigates whether this phenomenon also applies to sodium-ion batteries and proposes an optimal voltage to improve both the capacity and stability. By cycling between 3.8 and 4.2 V, the charge/discharge profiles and redox reaction intensity were analyzed. The correlation between structural stability and charge cutoff voltage was re-evaluated based on these findings. An optimal charge cutoff voltage of 4.1 V was identified, creating an additional plateau during initial charging and altering Na+ ion positioning to enhance capacity. Enhanced mobility of ions and electrons was observed through a stable solid-electrolyte interphase (SEI) formation. Ex situ X-ray diffraction (XRD) confirmed reversible phase transitions and excellent structural stability. This study underscores the strategic use of charge cutoff voltage to enhance both discharge capacity and structural stability, offering insights for advancing PB/PBA cathode materials with improved stability and capacity.