Cathode Material For Batteries Research Articles

Cobalt-free spinel–layered structurally integrated Li0.8Mn0.64Ni0.183Fe0.091O2 cathodes for lithium-ion batteries

Cobalt-free, Li-rich layered-spinel structurally integrated positive electrode (cathode) materials for lithium-ion batteries (LIBs), with nominal composition 0.6(Li1.2Mn0.56Fe0.08Ni0.16O2) 0.4(LiFe0.2Mn1.4Ni0.4O4) which can otherwise be written as Li0.8Mn0.64Ni0.183Fe0.091O2 (FeSL) are synthesized via simple citric acid-assisted sol-gel route. Four different final annealing temperatures (550 °C, 650 °C, 750 °C, and 850 °C) were chosen to investigate their influence on electrochemical performance. The obtained composite materials contain spinel (space group Fd3¯m) as well as Li-rich layered phases (space group C2/m) as revealed by X-ray diffraction (XRD), HRTEM and cyclic voltammetry investigations. The excellent electrochemical performance of the composite material could be attributed to the structural stability achieved by the integration of spinel and layered components. Selected synthesized composite materials exhibit high discharge capacities close to 200 mAh g−1. The FeSL750 shows better capacity retention (92(3)% at the 50th cycle and 82(5)% at the 70th cycle) and rate capability than the FeSL550 and FeSL650 samples. However, the FeSL850 sample shows different charge-discharge behaviour. The charge capacity corresponding to FeSL850 is found to increase up to the 20th cycle, then stabilizes and displays a capacity retention of almost 100 % at the 50th cycle and 91(1)% at the 70th cycle. The electrochemical mechanism of FeSL750 was elucidated via in operando XAS investigations, which reveal electrochemical activity from all transition metals.

Conducting LixPOy Interface Generated From Insulating Residual Lithium Compounds on LiNi0.8Mn0.1Co0.1O2 Surface Improves Cycle Life and Assists in Fast Cycling.

LiNi0.8Mn0.1Co0.1O2 (NMC811) is the most promising cathode material for future Li-ion batteries (LIBs). However, the bulk and surface structural instabilities retard its commercial success. Surface chemical instability toward exposure to moisture (H2O and CO2) leads to the formation of residual lithium compounds (RLCs: Li2CO3, LiOH) on the surface. The alkaline RLCs form a resistive layer on the surface of NMC811 by undergoing parasitic side reactions with electrolytes. Herein, an "Adverse-to-Beneficial" approach is proposed to eliminate RLCs by chemically transforming them into a LixPOy (Li3PO4 and LiPO3) interface. The interface protects the NMC811 surface from moisture attack and unwanted side reactions with electrolytes. It enhances the cycle life by retaining 70% of the initial capacity after 300 cycles at a 0.5C rate and 60% after 500 cycles, even at a 5C rate in a voltage window of 3.0-4.3V versus Li+/Li. The coexistence of two Li-conducting phases lowers the voltage polarization of the kinetically sluggish H1 → M phase transition to unlock fast cycling, reduces cationic disorder, improves coulombic efficiency, enhances ion diffusion kinetics, and minimizes particle crack formation after long-term cycling. Hence, the LixPOy interface yields multifaceted benefits in the storage, processing, and electrochemistry of NMC811.

Cluster intercalation of aluminum tetrachloride in AlN cathode: Exploration and analysis of aluminum ion batteries.

When chloroaluminate (AlCl4-) serves as the electrolyte, aluminum nitride (AlN) has shown promise as a cathode material in aluminum ion batteries. However, there is currently a lack of research on the mechanisms of charge transfer and cluster intercalation between AlCl4 and AlN cathode materials. Herein, first-principles calculations are employed to investigate the intercalation mechanism of AlCl4 within the AlN cathode. By calculating the formation energies of stage-1-5 AlN-AlCl4 intercalation compounds with the insertion of individual AlCl4 cluster, we found that the structure of the stage-4 intercalation compounds exhibits the highest stability, suggesting that when the clusters begin to intercalate, it is important to start with the formation of the stage-4 intercalation compounds. In the subsequent phases of the charging process (stages 1 and 2), the stabilized structure with four inserted clusters demonstrates two characteristics: the coexistence of standing and lying clusters and the insertion of two standing clusters in an upside-down doubly stacked configuration, which further improve the spatial utilization while maintaining the structural stability. In addition, we infer that a phenomenon of coexisting intercalation compounds with mixed stages will occur in the course of the charging and discharging processes. More importantly, the diffusion barrier of AlCl4 in AlN-AlCl4 intercalation compounds decreases with the reduction of stage number, ensuring the rate performance of batteries. Therefore, we expect that our work will contribute to comprehend the intercalation mechanism of AlCl4 into the AlN cathode materials of aluminum ion batteries, providing guidance for related experimental work.

Surface Reconstruction Enhanced Li-Rich Cathode Materials for Durable Lithium-Ion Batteries.

Regulating the distribution of surface elements in lithium-rich cathode materials can effectively change the electrochemical performance of cathode materials. Considering that the enrichment of Mn element on the surface is the main reason for the irreversible phase transition and dissolution of its surface structure, which in turn is the main reason for performance degradation. Based on the molten salt-assisted sintering method, a lithium rich cathode material with surface rich Ni and Co is designed and prepared. The surface enrichment of Ni and Co effectively reduces the dissolution of Mn, promotes the occurrence of irreversible collapse of surface structure from layered phase to rock salt phase on the material surface, improves the stability of surface crystal phase structure, and improves the cycling stability of positive electrode materials. Notably, after 500 cycles at 1 C current density, the discharge-specific capacity attained 189.8 mAh g -1, with a capacity retention rate of 88.9%, indicating a 42.1% improvement in capacity retention. Molten salt treatment is widely used in the modification of positive electrode materials. The research work will provide new ideas for improving the stability of lithium rich materials and promoting their commercial applications.

Heterostructure VO2@VS2 tailored by one-step hydrothermal synthesis for stable and highly efficient Zn-ion storage

Abstract The increasing demand for advanced energy storage solutions has driven extensive research into Zn-ion batteries due to their safety, cost-effectiveness, and environmental compatibility. This study presents a synthesis and evaluation of VO2@VS2 hollow nanospheres as a novel cathode material for Zn-ion batteries. The VO2@VS2 composite, synthesized via a one-step hydrothermal method, demonstrates a significant improvement in electrochemical performance. The material exhibits a reversible capacity of 468 mAh g−1 at 0.1 A g−1 and maintains a high capacity of 237 mAh g−1 at 1.0 A g−1 over 1000 cycles with a retention rate of 85%. Electrochemical analyses reveal enhanced charge transfer and Zn-ion storage, attributed to the synergistic effect and built-in electric field of the VO2 and VS2 heterostructure. Additionally, the composite shows superior electrochemical kinetics, facilitating rapid ion transport and charge transfer. In-situ Raman analysis confirms the reversible Zn-ion storage mechanism, further validating the composite’s structural stability during cycling. Density functional theory calculations further support these findings, indicating the composite’s potential for high-rate capability and long-term cycling stability. This research highlights the promise of VO2@VS2 hollow nanospheres in advancing the performance of aqueous Zn-ion batteries.

Charge Carrier Dynamics in Bandgap Modulated Covellite-CuS Nanostructures.

Copper Sulfide (CuS) semiconductors have garnered interest, but the effect of transition metal doping on charge carrier kinetics and bandgap remains unclear. In this study, the interactions between dopant atoms (Nickel, Cobalt, and Manganese) and the CuS lattice using spectroscopy and electrochemical analysis are explored. The findings show that sp-d exchange interactions between band electrons and the dopant ions, which replace Cu2+, are key to altering the material's properties. Specifically, these interactions result in a reduced bandgap by shifting the conduction and valence band edges and increasing carrier concentration. It is observed that undoped CuS nanoflowers exhibit a carrier lifetime of 2.16 ns, whereas Mn-doped CuS shows an extended lifetime of 2.62 ns. This increase is attributed to longer carrier scattering times (84 ± 5 fs for Mn-CuS compared to 53 ± 14 fs for CuS) and slower trapping (∼1.5 ps) with prolonged de-trapping (∼100 ps) rates. These dopant-induced energy levels enhance mobility and carrier lifetime by reducing recombination rates. This study highlights the potential of doped CuS as cathode materials for sodium-ion batteries and emphasizes the applicability of metal sulfides in energy solutions.

Free-Standing Poly(vinyl benzoquinone)/Reduced Graphene Oxide Composite Films as a Cathode for Lithium-Ion Batteries.

Quinones with a rapid reduction-oxidation rate are promising high-capacity cathodes for lithium-ion batteries. However, the high solubility of quinone molecules in polar organic electrolytes results in low cycle stability, while their low electric conductivity causes low utilization of electrode materials. In this article, a new p-benzoquinone derivative, poly(vinyl benzoquinone) (PVBQ), is designed and synthesized, and a solution-based method of preparing free-standing PVBQ/reduced graphene oxide (RGO) composite films is developed. PVBQ has a high theoretical specific capacity (400 mA h g-1) because of its low dead moiety mass. In the produced composite films, PVBQ nanoparticles are uniformly dispersed on RGO sheets, which endows the composite films with high electric conductivity and inhibits the dissolution of PVBQ through strong adsorption. As a result, the composite films show a high active material utilization, high practical specific capacity, and excellent cycling stability. PVBQ in the composite membrane containing 60.2 wt % RGO deliver 244 mA h g-1 capacity after 200 charge-discharge cycles at a current density of 300 mA g-1. At a current density of 1500 mA g-1, the reversible specific capacity is still 170 mA h g-1. This work provides a high-performance cathode material for lithium-ion batteries, and the molecular structure and electrode structure design ideas are also instructive for developing other organic electrode materials.

Simultaneous Tailoring of Chemical Composition and Morphology Configuration in Metal Hexacyanoferrate for Ultrafast and Durable Sodium-ion Storage.

Metal hexacyanoferrates (MHCFs) with adjustable composition and open framework structures have been considered as intriguing cathode materials for sodium-ion batteries (SIBs). Exploiting MHCFs with ultrafast and durable sodium storage capability as well as comparable capacity is always a goal that many investigators pursue, but remains challenging. Herein, simultaneous tailoring of chemical composition and morphology configuration is carried out to design a hollow monoclinic high-entropy MHCF (HMHE-HCF) assembled by nanocubes for the first time to realize the objective. The "cocktail effect" of high-entropy construction, rich sodium content of monoclinic phase, and unique hollow structure endow HMHE-HCF cathode with fast reaction kinetics and energetically stable performance during continuous charging/discharging processes. As a result, the HMHE-HCF cathode demonstrates superior rate performance up to an ultra-high rate of 100 C (71.1% retention to 0.1 C), and remarkable cycling stability with a capacity retention of 77.8% over 25,000 cycles at 100 C, outperforming most reported sodium-ion cathodes. Further, the HMHE-HCF//hard carbon full-cell delivers capacities of 99.0 and 82.3 mAh g-1 at 0.1 C and 10 C, respectively, and retains 98.1% of the initial capacity after 1,600 cycles at 5C, demonstrating its potential application for sodium-ion storage.

An ultrafast, stable and highly reversible nickel magnesium vanadate cathode for magnesium ion batteries

Rechargeable magnesium batteries are one among the strongest candidates over lithium ion batteries with abundance, cost effective and less environmental hazard. However, limitations including slow Mg2+ ion kinetics in the electrode-electrolyte interface and formation of passivating layers on the surface of magnesium metal anode affecting the rechargeable behavior of a cathode. Herein, hydrothermally synthesized NiMg2(VO4)2 nanomaterial used as cathode. The oxidation and reduction properties of Mg and V facilitates the diffusion pathway for Mg2+ and Li+ ions. Additionally, the employment of activated carbon cloth as anode diminishes the strong ionic interactions between Mg2+ ions and crystal lattice, enabling the faster diffusion of Mg2+ ions. All the electrochemical investigations are carried out at room temperature in the potential window of 1.23 V to 3.83 V against Mg/Mg2+. At a lower current density of 100 mA g−1, the specific discharge capacity have been 220 mAh g−1 for the 2nd cycle and retention of 97.1 % over 25 cycles. The specific capacity increases with more Mg2+ involvement in the reaction. At the highest current rate of 5000 mA g−1 the capacity retention is 96.8 % after 1000 cycles. Calculated energy density for a low current density is 556 Wh kg−1. The presence of multivalent V ions in the cathode reduces volume expansion, assisting charge redistribution to maintain electroneutrality. The dynamic valence property of. Vanadium ions (V2+/V5+) assist the intercalation of Mg2+ ions into the crystal lattice of cathode and possibly contribute to the highly stable and reversible discharge capacity over cycles. These findings provide a new perspective on NiMg2(VO4)2 as cathode material for magnesium ion batteries.

Copper and nickel hexacyanoferrates/carbon nanotube nanocomposites thin films as high-performance light cathode materials for aqueous sodium-ion batteries

Aqueous rechargeable Na-ion batteries are gaining popularity as an attractive alternative for energy storage systems due to their low cost, wide range of raw material sources, non-flammability, and ultrahigh ionic conductivity. Currently, Because of their three-dimensional open structure, high specific capacity, and inexpensive cost, Prussian blue analogues are being investigated as electrode materials for electrochemistry. In this work, we present an innovative strategy to create novel two-component nanoarchitected thin films that exhibit exceptional performance as cathodes in aqueous sodium-ion batteries (SIBs). By leveraging the versatility of the liquid-liquid interfacial method, we have prepared two distinct transparent nanocomposite films composed of carbon nanotubes and either copper or nickel hexacyanoferrate nanoparticles. The results show that the NiHCF/CNT and CuHCF/CNT deliver a high specific capacity of 152 mA h g−1 and 135 mA h g−1, respectively, at a high current density of 1 A g−1. Moreover, the cells (rGO//NiHCF and rGO//CuHCF) show that the energy density of the battery can reach up to 7.75 Wh kg−1 at a power density of 27.92 W kg−1 for rGO//NiHCF/CNT, while rGO//CuHCF/CNT showed an energy density of 3.67 Wh kg−1 at a power density of 13.21 W kg−1. The results demonstrate that NiHCF/CNT and CuHCF/CNT nanocomposite films provide new insight into the design of high-performance PBA cathodes.

In situ-grown nitrogen-sulfur co-doped carbon nanotubes encapsulated with FeS particles as cathode materials for zinc-air batteries

Transition metal sulfides as ideal oxygen reduction reaction (ORR) catalysts have great potential to regulate multiple reaction pathways and understand their corresponding internal reaction mechanisms at cathode in zinc-air batteries (ZABS), effectively. This work adopted a facile one-pot synthesis method based on chemical vapor deposition (CVD), which utilizes the synergistic effect of zeolite imidazolium ester skeleton (ZIF-8) and polypyrrole (PPY) to grow nitrogen-sulfur co-doped carbon nanotubes (NS-CNT) in the shape of colonic with a relatively uniform size and encapsulated with FeS nanoparticles as the main active sites. The synthesized purpose catalyst noted as FeS-NS-CNT-900, in which that the FeS nanoparticles were tightly encapsulated in carbon nanotubes, and this special structure ensures that the FeS particles do not detach during the reaction, thus greatly enhancing their electrochemical activity and stability. As expected, the FeS-NS-CNT-900 catalyst exhibited a half-wave potential of 0.877 V which is higher than that of commercial platinum charcoal (0.847 V), at 0.1 mol KOH. More importantly, the formation of abundant FeS catalytic active sites, the optimal conditions for NS-CNT growth, and the covered mechanisms of the enhanced ORR reaction activity of FeS-NS-CNT-900 were thoroughly investigated. Additionally, whileFeS-NS-CNT-900 was used as an air cathode material for the assembly of a zinc-air battery, it exhibited a peak power density and specific capacity of 123 mW cm−2 and 785.81 mA h g−1, respectively, which were significantly better than that of platinum-carbon cathode (92.8 mW cm−2 and 740.4 mA h g−1). And surprisingly, the battery with FeS-NS-CNT-900 cathode exhibited (delivered/showed) a high cycle stability of 260 h at 5 mA cm−2. Conclusively, present work provides a feasible method for in situ growth of sulfur and nitrogen co-doped carbon nanotube encapsulated transition metal sulfide nanoparticle catalysts, which may pave a new avenue for the preparation of high ORR performance air cathode material for ZABS.

One-step oil bath preparation of cobalt-doped MnO2/coconut activated carbon composite with superior zinc ion storage performance

MnO2 is a prospective cathode material for aqueous zinc ion batteries due to its high theoretical capacity and low cost. However, bare MnO2 usually suffers from large volume change and dissolution problems. In this work, Co-doped MnO2/coconut activated carbon composite (Co-β-MO/CAC) has been successfully synthesized by a one-step oil bath method. The electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) tests demonstrate that both the Co doping and the incorporation of coconut activated carbon can effectively reduce the electrochemical reaction resistance of MnO2 and improve the intercalation and deintercalation abilities of H+ and Zn2+. The combined effect of the Co doping and CAC compositing has resulted in excellent electrochemical property of Co-β-MO/CAC. After 120 cycles at 0.2 A g−1, the capacity of Co-β-MO/CAC increases from 224.7 mAh g−1 to 436.7 mAh g−1. Moreover, the composite can also deliver a high reversible capacity of 233.2 mAh g−1 after 900 cycles at 0.5 A g−1.

First-principles study of strain behavior in iron-based fluorides of tungsten bronze type as cathode materials for alkali-ion batteries

<b>First-principles study of strain behavior in iron-based fluorides of tungsten bronze type as cathode materials for alkali-ion batteries</b>

P/n-Type Polyimide Covalent Organic Frameworks for High-Performance Cathodes in Sodium-Ion Batteries.

Covalent organic frameworks (COFs) are viewed as promising organic electrode materials for metal-ion batteries due to their structural diversity and tailoring capabilities. In this work, firstly using the monomers N,N,N',N'-tetrakis(4-aminophenyl)-1,4-phenylenediamine (TPDA) and terephthaldehyde (TA), p-type phenylenediamine-based imine-linked TPDA-TA-COF is synthesized. To construct a bipolar redox-active, porous and highly crystalline polyimide-linked COF, i.e., TPDA-NDI-COF, n-type 1,4,5,8-naphthalene tetracarboxylic dianhydride (NDA) molecules are incorporated into p-type TPDA-TA-COF structure via postsynthetic linker exchange method. This tailored COF demonstrated a wide potential window (1.03.6 V vs Na+/Na) with dual redox-active centers, positioning it as a favorable cathode material for sodium-ion batteries (SIBs). Owing to the inheritance of multiple redox functionalities, TPDA-NDI-COF can deliver a specific capacity of 67 mAh g-1 at 0.05 A g-1, which is double the capacity of TPDA-TA-COF (28 mAh g-1). The incorporation of carbon nanotube (CNT) into the TPDA-NDI-COF matrix resulted in an enhancement of specific capacity to 120 mAh g-1 at 0.02 A g-1. TPDA-NDI-50%CNT demonstrated robust cyclic stability and retained a capacity of 92 mAh g-1 even after 10 000 cycles at 1.0 A g-1. Furthermore, the COF cathode exhibited an average discharge voltage of 2.1 V, surpassing the performance of most reported COF as a host material.

Revealing the regulation mechanism of Na3V2(PO4)2O2F crystal growth in sodium alginate solution for high-performance sodium ion batteries

Na3V2(PO4)2O2F (NVPFO) attracts tremendous attention as a cathode material for sodium-ion batteries (SIBs) because of its higher capacity and structural stability. However, its inherent poor conductivity affects rate performance and long cycle performance. Herein, a special lamellar NVPFO are successfully synthesized by sodium alginate (SA) assisted hydrothermal method. SA dissolves in water to form hydrogel, due to the specific cross-linking of SA and V4+, which restricts the crystal growth of nanoparticles. Meanwhile, a conductive carbon layer for sodium ion transport channels is constructed after carbonization. Based on multidimensional experiments and density functional theory (DFT) calculations, a mechanism for formation of special lamellar NVPFO in SA solution is proposed for the first time. The results show that special lamellar morphology shortens Na+ migration path and conductive coating facilitates electronic transmission. The optimized NVPFO@C-2 has better electrochemical performance with outstanding high rate capacity (106.8 mAh g–1 at 15 C) and long-term cyclability (99.8 mAh g−1 capacity retention of 87.1 % even after 1000 cycles at 5 C).

Oxygen-deficient NH4V4O10 cathode with Ag quantum dots and interlayer Ag+ towards high-performance aqueous zinc ion batteries

Herein, oxygen-deficient NH4V4O10 micro-flowers with loaded Ag quantum dots and pre-intercalated Ag+ (NVO-Ag) for aqueous zinc ion battery (AZIB) cathode materials were successfully synthesized by a one-step hydrothermal method. The reversible redox reaction between Ag+ and Ag quantum dots, and the abundant Zn2+ storage sites from oxygen vacancies provided capacity contributions for NVO-Ag. Meanwhile, the loaded Ag quantum dots, pre-intercalated Ag+ and introduced oxygen vacancies synergistically optimized the electronic structure and distribution of NVO-Ag, promoting the transport of electrons in NVO-Ag. The pre-intercalated Ag+ could also replace the NH4+ in the interlayer of NH4V4O10, weakening the repulsion between the interlayer NH4+ and Zn2+, which achieved rapid Zn2+ diffusion kinetics. Moreover, the abundant oxygen vacancies in NVO-Ag could alleviate the strong electrostatic interaction between Zn2+ and V-O framework, boosting the transmission of Zn2+ in NVO-Ag. Finally, the structural stability of NH4V4O10 micro-flowers was improved due to the high bonding strength between Ag+ and V-O layers. Benefiting from the above effects, NVO-Ag-100 achieved excellent capacity performance (387.2 mAh g−1 at 0.5 A g−1), rate performance (178.9 mAh g−1 at 12 A g−1) and cycle stability (91.7 % capacity retention after 1700 cycles at 8 A g−1). This work provided effective ideas to achieve high-performance AZIB cathode materials.

Fluorinated ionic liquid mediated nanostructure with enhanced conductivity and fluorine retention in Na3V2(PO4)2F3 cathode toward high-performance sodium-ion batteries

Na3V2(PO4)2F3 (NVPF) is considering as a promising cathode material for sodium-ion batteries (SIBs), due to its framework robustness and high working voltage. For NVPF cathodes, the main obstacle of poor conductivity could be well-addressed by carbon hybridization or nano-crystallization strategies. However, carbon compositing process would bring up fluorine-loss issue and the designation of tailor-made nanocomposite remains challenging. Here, we realize the optimal regulation on crystal growth by virtue of a fluorinated ionic liquid usage, which could compensate the fluorine-loss during high-temperature annealing process. As a structural-directing agent, ionic liquid with low surface tension also helps to reduce surficial Gibbs free energy of NVPF crystal, facilitating to reduce the particle size. Meanwhile, the π-cation interaction between reduced graphene oxide (rGO) and cations of ionic liquid is beneficial to fabricate ultrathin rGO-wrapped NVPF nanoplates (I-NVPF@rGO). The tailored I-NVPF@rGO exhibits enhanced conductivity and optimized crystal planes, resulting in excellent rate capability and improved energy density. When coupling with MoS2/SnS/rGO anode, the MoS2/SnS/rGO||I-NVPF@rGO full battery delivers a capacity of 116 mA h g−1 at 0.2 C. This strategy offers valuable insights into the development of sodium-ion batteries.

Diammonium Hydrogen Citrate-Assisted Spray Pyrolysis Synthesis of Nanostructured LiCoPO4 Microspheres as High-Voltage Cathode Material for Lithium-Ion Batteries

Diammonium Hydrogen Citrate-Assisted Spray Pyrolysis Synthesis of Nanostructured LiCoPO₄ Microspheres as High-Voltage Cathode Material for Lithium-Ion Batteries

Enhancing the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 by surface modification with homemade high-purity hexagonal phase tungsten oxide nanoparticles

Nickel-rich layered oxides with high energy density and acceptable cost are considered as one of the most ideal cathode materials for power batteries. However, its large-scale production and application still face the challenge in terms of rapid capacity fading and poor structural stability, which has prompted research into surface coating materials/technologies within both academic and industrial fields. In this work, A feasible and environmental friendly fabrication method of high-purity hexagonal phase tungsten oxide (h-WO3) nanoparticles as surface modification of LiNi0.8Co0.1Mn0.1O2(NCM) is proposed.The results indicate that NCM modified with h-WO3 has lower Li+/Ni2+ mixing rate, superior rate performance, and better cycling stability than the pristine NCM. Although tungsten oxide is widely used as surface modification due to its excellent physical and chemical properties, but its crystal type has not been considered, and there is little research on the theoretical explanation of h-WO3 modification.This work reveals the working mechanism of h-WO3 from the perspective of interface and crystal type, which can provide meaningful reference for obtaining nickel-rich layered oxides with excellent electrochemical properties.

Topography control and component design strategies to enhance electrochemical performance of O3-Type cathode materials for Sodium-ion batteries

Layered transition metal oxides (NaxTMO2, 0 < x ≤ 1) are considered one of the most promising cathodes for Sodium-ion batteries (SIBs) due to their high theoretical capacity and operability. However, NaxTMO2 still faces significant challenges, including poor kinetic performance and low energy efficiency. Herein, in order to enhance the kinetics of NaNi1/3Fe1/3Mn1/3O2 (NaNFMO), topography control and component design were proposed: First, Cu doping (Cu-NaNFMO) was used to expand lattice channels and improve “flat sheet” of layered oxide, which synergistically enhanced transport kinetics of Na+. Second, Co coating (NaNFMO@Co) reacted with surface residue to form a fast-ionic conductor NaxCoO2 (0 < x ≤ 1), which inhibited interfacial side reactions and enhanced transport kinetics of Na+. Furthermore, the presence of strong Cu-O bonds in Cu-NaNFMO and fast-ionic conductor NaxCoO2 in NaNFMO@Co led to better electrochemical redox performance, the initial charge specific capacity of NaNFMO was increased from 141.5 mAh g⁻1 to 145.8 mAh g⁻1 and 144 mAh g⁻1, with capacity retention improving by nearly 10 % after 100 cycles. Furthermore, NaNFMO@Co improves ICE from 90.56 % to 93.57 %. With the improved kinetics, the DCR of pouch cells decreased, and the energy efficiency increased from 93.3 % to 94 % and 95.7 %.