Lattice-coherent interface-reinforced sodium-layered oxide cathodes

Abstract

Sodium-layered transition metal oxide (Na _x TMO₂) is recognized as a promising cathode material for high energy density sodium ion batteries (SIBs). Nevertheless, its practical implementation is hindered by persistent issues such as structural degradation, sluggish Na⁺ diffusion kinetics, and air sensitivity. To counteract these drawbacks, a lattice-coherent interface is employed to reform Na _x TMO₂. Herein, recent progress related to the construction of lattice-coherent interfaces in Na _x TMO₂ cathodes is summarized in this review, including bi-phase and tri-phase heterostructures. The constraining of interlayer sliding and phase structure degradation as a result of the high thermodynamic energy barrier originating from the lattice-coherent interface is comprehensively analyzed. The ion transport kinetics and moisture stability of Na _x TMO₂ with regard to the lattice-coherent interface are also disscussed in depth. The relationships between the interface interlocking heterostructure in the lattice and electrochemical performance are elucidated. To explore the lattice-coherent configuration, we emphasized AI and state-of-the-art in situ characterization techniques during the design and construction of Na _x TMO₂ cathodes. These insights are expected to establish a new design paradigm for high-performance layered cathode materials for SIBs.

Fig. 1. (a) A comparison of the abundances of Li and Na in the Earth's crust. Copyright 2022, Royal Society of Chemistry. (b) A comparison of the costs of LIBs and SIBs (the data originated from the HiNa Battery Technology Co., Ltd). (c) Research hotspots and (d) the number of publications with regard to Na_xTMO₂ cathodes (the data were collected using the Web of Science during November 2025).

Fig. 2. The key challenges faced by Na_xTMO₂ during application.

Fig. 3. A schematic representation of the performance enhancement mechanisms for the lattice-coherent interfaces in Na_xMnO₂.

Fig. 4. (a) The phase changes in Na_0.85Ni_0.34Mn_0.66−xTi_xO₂ as a function of Ti content. (b) Operando XRD patterns of P2/O3-NMT₃ during the first charge/discharge cycle at 0.1 C within 2.2–4.4 V. (c) The volume changes of NM, NMT₃, and NMT₄ when charged to 4.4 V. (d) Rate performances of NM, NMT₁, NMT₂, NMT₃, and NMT₄ at various current densities. Copyright 2022, Elsevier. (e) Crystal structure diagrams and E_f values of P2, O3, and P2/O3 bi-phase Na_0.736Ni_0.264Mg_0.1Mn_0.636O₂. (f) TEM images of P2/O3-Com₉₅₀ 0.8. (g) Rate capabilities of Na_0.67Ni_0.23Mg_0.1Mn_0.67O₂, NaNi_0.4Mg_0.1Mn_0.5O₂, P₂/O₃-Com₉₅₀ 0.8, P2/O3-Com₉₅₀ 0.67, P2/O3-Com₉₅₀ 0.5, and P2/O3-Com₉₅₀ 0.33. (h) In situ XRD patterns and corresponding charge and discharge curves (i) as well as the phase configurations of P2/O3-Com₉₅₀ 0.8. Copyright 2023, Elsevier.

Fig. 5. Schematic diagrams of phase evolutions induced by the probable interphase gliding behaviours according to pattern (a) 1 and (b) 2. (c) Contour maps of in situ synchrotron XRD patterns for P2/P3-NaMNO during the first cycle. (d) Cycling performance over 500 cycles at 2 C. Copyright 2025, Springer Nature. (e) A schematic diagram of the dynamic structural evolution of NMO, NaMC-0.3, and Na_0.44Mn_0.5Co_0.5O₂ with different phase structures. (f) The powder XRD pattern, (g) SEM image, and (h) in situ XRD patterns of NaMC-0.3. Copyright 2024, Royal Society of Chemistry.

Fig. 6. (a) An ABF-STEM image of Na_0.44Mn_0.8Mg_0.2O₂. The von Mises stress of (b) P2 and (c) P2/spinel structures in the pristine state. (d) A schematic representation of the layered/spinel structure. (e) In situ XRD patterns of the Na_0.44Mn_0.8Mg_0.2O₂ cathode in the first cycle. (f) Cycling performance of the Na_0.44Mn_0.8Mg_0.2O₂. Copyright 2025, Wiley-VCH GmbH. (g) A schematic illustration of the P2/tunnel biphasic structure. (h) Ex situ XRD patterns of Na_0.6Mn_0.93Fe_0.04Mg_0.03O₂ in the first cycle. (i) Cycle performance of Na_0.6Mn_0.93Fe_0.04Mg_0.03O₂ at 5 C over 400 cycles. Copyright 2024, Elsevier.

Fig. 7. (a) A HR-TEM image of P2, P3, and spinel structures. (b) In situ XRD patterns and (c) corresponding intensity contour maps of LLS-NaNCMM15 during the first and second charge/discharge processes at 0.1 C in the voltage range of 1.5–4.3 V. (d) A schematic illustration of the crystal structure evolution during cycling. Copyright 2022, Wiley-VCH GmbH. (e) HRTEM images and (f) in operando powder diffraction patterns of Na/LS-NMNF. Copyright 2022, American Chemical Society.

Fig. 8. (a) A schematic diagram, (b) TEM image, (c) GITT plots, and (d) log(i) vs. log(v) plots for Na_0.6MnO₂. Copyright 2023, American Chemical Society. (e) A schematic diagram of the phase transition process for Na_0.44Mn_1−xMo_xO₂ with increasing Mo content. (f) GITT curves and corresponding Na ion diffusion coefficients for NMO-3M. Copyright 2024, Elsevier.

Fig. 9. (a) A schematic diagram of the structures of Ni_0.3Mn_0.55Cu_0.1Ti_0.05 before and after quenching. (b) Schematic illustrations of the structural enhancement mechanisms in P2/P3/O3-NMCT and P2/P3/O3-NMCTF. (c) The Na⁺ diffusion barrier energies in O3-NMCT and O3-NMCTF collected using NEB calculation. (d) A schematic diagram of the built-in electric field formed between a semiconductor and a metal upon contact between different structures. Copyright 2025, Wiley-VCH GmbH. (e) XRD pattern and Rietveld refinement plot and (f) the Na⁺ migration roadmap in NNMO-S as well as the Na⁺ migration barrier energies in NNMO-S and NNMO. (g) The GITT plots of NNMO and NNMO-S in the first cycle within 1.5–4.25 V. Copyright 2025, Elsevier.

Fig. 10. (a) A schematic diagram of O3/P2-type NFCM-MX. (b) A HRTEM image of NFCM-M2. (c) XRD patterns of NFCM and NFCM-M2 after exposure to air for 3 days. (d) Cycling stability at 55 °C of NFCM and NFCM-MX. (e) A schematic diagram of the structural enhancement mechanisms for Mn-doped NCFM. Copyright 2024, Elsevier. (f) A HRTEM image of O3@5% P2 heterostructure. (g) A schematic diagram of the synthesis, morphology, and crystal architecture of O3/P2-type O3@2% P2, O3@5% P2, O3@15% P2, and O3@40% P2. XRD patterns of (h) O3-NNMO and (i) O3@5% P2 after exposure to air (with a relative humidity of 55%) for 3 days. (j) The rate capability of O3-NNMO and O3@5% P2 after exposure to air. Copyright 2022, Elsevier.

Fig. 11. (a) A schematic representation of the crystal configurations of Na_2/3Mn_1−xTi_xO₂ with different Ti contents. (b) A TEM image of L/T-NaMT-1. (c) A schematic diagram of the crystal configuration of Na_2/3Mn_1−xTi_xO₂ with a P2/tunnel structure. Contact angles of (d) L-NaMT-0 and (e) L/T-NaMT-1. Copyright 2024, Elsevier. (f) A comparison of the crystal structures and physical/electrochemical properties for P2- and P2/tunnel-type cathodes. Average contact angles of (g) NaNMT-L and (h) NaNMT@5% Tunnel-L. Copyright 2025, American Chemical Society.

Fig. 12. The applications of characterization techniques and machine learning during the development of layered oxide cathodes with a lattice-coherent interface.