A Water Stable,Near‐Zero‐Strain O3‐Layered Titanium‐Based Anode for Long Cycle Sodium‐Ion Battery

Layered transition metal (TM) oxides of the stoichiometry Na_xMO₂ (M = TM) have shown great promise in sodium‐ion batteries (SIBs); however, they are extremely sensitive to moisture. To date, most reported titanium‐based layered anodes exhibit a P2‐type structure. In contrast, O3‐type compounds are rarely investigated and their synthesis is challenging due to their higher percentage of unstable Ti³⁺ than the P2 type. Here, a pure phase and highly crystalline O3‐type Na_0.73Li_0.36Ti_0.73O₂ with high performance is successfully proposed in SIBs. This material delivers a reversible capacity of 108 mAh g^?1 with a stable and safe potential of 0.75 V versus Na/Na⁺. In situ X‐ray diffraction reveals that this material does not undergo any phase transitions and exhibits a near‐zero volume change upon Na⁺ insertion/de‐insertion, which ensures exceptional long cycle life over 6000 cycles. Importantly, it is found that this O3‐Na_0.73Li_0.36Ti_0.73O₂ shows superior moisture stability, even when immersed into water, which are both elusive for conventional layered TM oxides in SIBs. It is believed that the small interlayer distance and high occupation of interlayer vacancy promise such unprecedented water stability.     

From Rotten to Magical: Transition Metal Migration in Layered Sodium-Ion Battery Cathodes

Layered oxides, the most commercially promising cathode materials for sodium-ion batteries (SIBs), are extensively investigated due to their low cost, abundant raw materials, flexible structure, and high capacity. However, although the “rotten” transition metal (TM) migration phenomenon in layered oxide cathode materials leads to unfavorable structure reconstruction, sluggish Na⁺ diffusion and subsequent performance degradation, TM migration has not been systematically summarized and intensively discussed. Herein, a comprehensive insight into the recent advances of TM migration in layered SIB cathodes is provided, aiming to realize the “magical” utilization of TM migration. First, the negative effects of TM migration on crystal structure and electrochemical properties are discussed. Then, the origin of TM migration is intensively analyzed, and three main mechanisms of the migration are presented, including Cr⁴⁺–Cr⁴⁺–Cr⁴⁺ triplets, Jahn–Teller Fe⁴⁺ and Na-free layers. Additionally, the latest research findings on exploring the origin are fully discussed. Finally, the suppression and utilization of TM migration are discussed, and the further exploration of TM migration and the future directions of suppressing/utilizing TM migration are outlooked. It is believed that this perspective will provide guidelines for the design of high-performance layered oxide cathodes involving TM migration by turning the “rotten” into the “magical.”     

Origin of Fast Capacity Decay in Fe-Mn Based Sodium Layered Oxides

Fe-Mn based layered oxides are recognized as promising cathode materials for sodium-ion batteries (SIBs) with high capacities and earth-abundant ingredients. However, their real-world applications are still constrained by fast capacity decay accompanied with the requirements of deeper insights into the principles behind. Herein, taking O3-Na_xFe_1/2Mn_1/2O₂ as a classic sample, the capacity fading mechanism of Fe-Mn based layered oxides is comprehensively investigated through combined techniques. For the first time, it is revealed that Fe migration is merely triggered after the oxidation of ≈0.3 mol Fe³⁺ based on solid proofs from ex situ X-ray absorption spectroscopy and Mössbauer spectroscopy, which implies the crucial role of the accumulated structural distortion induced by Jahn–Teller active Fe⁴⁺. O3-P3 phase transition during cycling is obviously constrained along with Fe migration as evidenced by in situ/ex situ X-ray diffraction, well interpreting the intensified polarization and the resulting large capacity loss. More importantly, within the desodiation depth (≈80% of sodium extraction) where Fe migration is almost absent, the capacity fading is dominantly rooted in the Fe⁴⁺ activated and Mn-dissolution aggravated surface passivation as confirmed by mass/X-ray spectroscopies and electrochemical analysis. These renewed understandings of the fast capacity decay in Fe-Mn based layered oxides offer clearer clues for designing desirable cathodes for SIBs.     

Unveiling the Anionic Redox Chemistry in Phosphate Cathodes for Sodium-Ion Batteries

Anionic redox chemistry has aroused increasing attention in sodium-ion batteries (SIBs) by virtue of the appealing additional capacity. However, up to now, anionic redox reaction has not been reported in the mainstream phosphate cathodes for SIBs. Herein, the ultrathin VOPO₄ nanosheets are fabricated as promising cathodes for SIBs, where the oxygen redox reaction is first activated accompanied by reversible ClO₄⁻ (from the electrolyte) insertion/extraction. As a result, the VOPO₄ cathode harvests a record-high capacity (168 mAh g⁻¹ at 0.1 C) among its counterparts ever reported. Moreover, the ClO₄⁻ insertion efficiently expands the interlayer spacing of VOPO₄ and accelerates the ion diffusion, enabling an unprecedentedly high rate performance (69 mAh g⁻¹ at 30 C). Via systematic ex situ characterizations and theoretical computations, the anionic redox chemistry and charge storage mechanism upon cycling are thoroughly elucidated. This study opens up a new avenue toward high-energy phosphate cathodes for SIBs by triggering anionic redox reactions.     

Surface Lattice-Matched Engineering Based on In Situ Spinel Interfacial Reconstruction for Stable Heterostructured Sodium Layered Oxide Cathodes

Layered transition metal oxide (Na_xTMO₂), being one of the most promising cathode candidates for sodium-ion batteries (SIBs), have attracted intensive interest because of their nontoxicity, high theoretical capacities, and easy manufacturability. However, their physical and electrochemical properties of water sensitivity, sluggish Na⁺ transport kinetics, and irreversible multiple-phase translations hinder the practical application. Here, a concept of surface lattice-matched engineering is proposed based on in situ spinel interfacial reconstruction to design a spinel coating P2/P3 heterostructure cathode material with enhanced air stability, rate, and cycle performance. The novel structure and its formation process are verified by transmission electron microscopy and in situ high-temperature X-ray diffraction. The electrode exhibits an excellent rate performance with the highly reversible phase transformation demonstrated by in situ charging/discharging X-ray diffraction. Additionally, even after a rigorous water sensitivity test, the electrode materials still retain almost the same superior electrochemical performance as the fresh sample. The results show that the surface spinel phase can play a vital role in preventing the ingress of water molecules, improving transport kinetics, and enhancing structural integrity for Na_xTMO₂ cathodes. The concept of surface lattice-matched engineering based on in situ spinel interfacial reconstruction will be helpful for designing new ultra-stable cathode materials for high-performance SIBs.     

Enhanced Reversible Sodium‐Ion Intercalation by Synergistic Coupling of Few‐Layered MoS2 and S‐Doped Graphene

Sodium‐ion batteries (SIBs) are regarded as the best alternative to lithium‐ion batteries due to their low cost and similar Na⁺ insertion chemistry. It is still challenging but greatly desired to design and develop novel electrode materials with high reversible capacity, long cycling life, and good rate capability toward high‐performance SIBs. This work demonstrates an innovative design strategy and a development of few‐layered molybdenum disulfide/sulfur‐doped graphene nanosheets (MoS₂/SG) composites as the SIB anode material providing a high specific capacity of 587 mA h g^?1 calculated based on the total composite mass and an extremely long cycling stability over 1000 cycles at a current density of 1.0 A g^?1 with a high capacity retention of ≈85%. Systematic characterizations reveal that the outstanding performance is mainly attributed to the unique and robust composite architecture where few‐layered MoS₂ and S‐doped graphene are intimately bridged at the hetero‐interface through a synergistic coupling effect via the covalently doped S atoms. The design strategy and mechanism understanding at the molecular level outlined here can be readily applied to other layered transition metal oxides for SIBs anode and play a key role in contributing to the development of high‐performance SIBs.     

Creating an Air‐Stable Sulfur‐Doped Black Phosphorus‐TiO2 Composite as High‐Performance Anode Material for Sodium‐Ion Storage

With the increasing demand for low cost, long lifetime, high energy density storage systems, an extensive amount of effort has recently been focused on the development of sodium‐ion batteries (SIBs), and a variety of cathode materials have been discovered. However, looking for the most suitable anode material for practical application is a major challenge for SIBs. Herein, a high capacity sulfur‐doped black phosphorus‐TiO₂ (TiO₂‐BP‐S) anode material for SIBs is first synthesized by a feasible and large‐scale high‐energy ball‐milling approach, and its stability in air exposure is investigated through X‐ray photoelectron spectroscopy. The morphology of TiO₂‐BP‐S is characterized using transmission electron microscopy, indicating that the TiO₂ nanoparticles produce P? Ti bonds with BP. The TiO₂‐BP‐S composite with P? S and P? Ti bonds exhibits excellent stability in air and the superior electrochemical performance. For example, the discharge specific capacity is up to 490 mA h g^?1 after 100 cycles at 50 mA g^?1, and it remains at 290 mA h g^?1 after 600 cycles at 500 mA g^?1. Meanwhile, the scientific insight that the formation of stable P? S and P? Ti bonds can provide a guide for the practical large‐scale application of SIBs in other titanium base and black phosphorus materials is looked forward.     

Layered Oxide Cathodes Promoted by Structure Modulation Technology for Sodium‐Ion Batteries

Considering the ever‐growing climatic degeneration, sustainable and renewable energy sources are needed to be effectively integrated into the grid through large‐scale electrochemical energy storage and conversion (EESC) technologies. With regard to their competent benefit in cost and sustainable supply of resource, room‐temperature sodium‐ion batteries (SIBs) have shown great promise in EESC, triumphing over other battery systems on the market. As one of the most fascinating cathode materials due to the simple synthesis process, large specific capacity, and high ionic conductivity, Na‐based layered transition metal oxide cathodes commonly suffer from the sluggish kinetics, multiphase evolution, poor air stability, and insufficient comprehensive performance, restricting their commercialization application. Here, this review summarizes the recent advances in layered oxide cathode materials for SIBs through different optimal structure modulation technologies, with an emphasis placed on strategies to boost Na⁺ kinetics and reduce the irreversible phase transition as well as enhance the store stability. Meanwhile, a thorough and in‐depth systematical investigation of the structure–function–property relationship is also discussed, and the challenges as well as opportunities for practical application electrode materials are sketched. The insights brought forward in this review can be considered as a guide for SIBs in next‐generation EESC.     

Hierarchical Engineering of Porous P2‐Na2/3Ni1/3Mn2/3O2 Nanofibers Assembled by Nanoparticles Enables Superior Sodium‐Ion Storage Cathodes

Layered transition metal oxides (TMOs) are appealing cathode candidates for sodium‐ion batteries (SIBs) by virtue of their facile 2D Na⁺ diffusion paths and high theoretical capacities but suffer from poor cycling stability. Herein, taking P2‐type Na_2/3Ni_1/3Mn_2/3O₂ as an example, it is demonstrated that the hierarchical engineering of porous nanofibers assembled by nanoparticles can effectively boost the reaction kinetics and stabilize the structure. The P2‐Na_2/3Ni_1/3Mn_2/3O₂ nanofibers exhibit exceptional rate capability (166.7 mA h g^?1 at 0.1 C with 73.4 mA h g^?1 at 20 C) and significantly improved cycle life (≈81% capacity retention after 500 cycles) as cathode materials for SIBs. The highly reversible structure evolution and Ni/Mn valence change during sodium insertion/extraction are verified by in operando X‐ray diffraction and ex situ X‐ray photoelectron spectroscopy, respectively. The facilitated electrode process kinetics are demonstrated by an additional study using the electrochemical measurements and density functional theory computations. More impressively, the prototype Na‐ion full battery built with a Na_2/3Ni_1/3Mn_2/3O₂ nanofibers cathode and hard carbon anode delivers a promising energy density of 212.5 Wh kg^?1. The concept of designing a fibrous framework composed of small nanograins offers a new and generally applicable strategy for enhancing the Na‐storage performance of layered TMO cathode materials.     

Prussian Blue@C Composite as an Ultrahigh‐Rate and Long‐Life Sodium‐Ion Battery Cathode

Rechargeable sodium ion batteries (SIBs) are surfacing as promising candidates for applications in large‐scale energy‐storage systems. Prussian blue (PB) and its analogues (PBAs) have been considered as potential cathodes because of their rigid open framework and low‐cost synthesis. Nevertheless, PBAs suffer from inferior rate capability and poor cycling stability resulting from the low electronic conductivity and deficiencies in the PBAs framework. Herein, to understand the vacancy‐impacted sodium storage and Na‐insertion reaction kinetics, we report on an in‐situ synthesized PB@C composite as a high‐performance SIB cathode. Perfectly shaped, nanosized PB cubes were grown directly on carbon chains, assuring fast charge transfer and Na‐ion diffusion. The existence of [Fe(CN)₆] vacancies in the PB crystal is found to greatly degrade the electrochemical activity of the Fe^LS(C) redox couple via first‐principles computation. Superior reaction kinetics are demonstrated for the redox reactions of the Fe^HS(N) couple, which rely on the partial insertion of Na ions to enhance the electron conduction. The synergistic effects of the structure and morphology results in the PB@C composite achieving an unprecedented rate capability and outstanding cycling stability (77.5 mAh g^?1 at 90 C, 90 mAh g?¹ after 2000 cycles at 20 C with 90% capacity retention).     

Quasi-Zero Volume Strain Cathode Materials for Sodium Ion Battery through Synergetic Substitution Effect of Li and Mg

P2-type layered oxide material Na_2/3Ni_1/3Mn_2/3O₂ is a competitive candidate for sodium-ion batteries (SIBs). Nevertheless, it suffers from the strong P2–O2 phase transition during charging to the high voltage regime, rendering drastic volume variations and poor cycling performance. Here, a Quasi-zero strain P2-Na_0.75Li_0.15Mg_0.05Ni_0.1Mn_0.7O₂ cathode is synthesized, which reflects the vanishing P2–O2 transition with a volume change as low as 0.49%, thus resulting in the material an excellent cycling performance (83.9% capacity retention after 500 cycles at 5 C). The low-volume strain can be attributed to two aspects: (1) the Mg²⁺ riveted in the Na layer can act as a “pillar” to stabilize the crystal structure under the condition of sodium removal, thus restricting the structural changes under high voltage. (2) The entry of Li⁺ into the transition metal (TM) layer can mitigate the electron localization in the highly desodiation state and can effectively immobilize the coordination oxygen atoms, thus suppressing the slip of P2–O2 transition. This study not only provides a new insight of Li and Mg synergetic substitution effect on the structural stability of P2-type cathode, but also an efficient avenue for developing cathode materials of SIBs with ultralow bulk strain.     

Lithium Phosphonate Functionalized Polymer Coating for High-Energy Li[Ni0.8Co0.1Mn0.1]O2 with Superior Performance at Ambient and Elevated Temperatures

High-energy Ni-rich lithium transition metal oxides such as Li[Ni_0.8Co_0.1Mn_0.1]O₂ (NCM₈₁₁) are appealing positive electrode materials for next-generation lithium batteries. However, the high sensitivity toward moist air during storage and the high reactivity with common organic electrolytes, especially at elevated temperatures, are hindering their commercial use. Herein, an effective strategy is reported to overcome these issues by coating the NCM₈₁₁ particles with a lithium phosphonate functionalized poly(aryl ether sulfone). The application of this coating allows for a substantial reduction of lithium-based surface impurities (e.g., LiOH, Li₂CO₃) and, generally, the suppression of detrimental side reactions upon both storage and cycling. As a result, the coated NCM₈₁₁-based cathodes reveal superior Coulombic efficiency and cycling stability at ambient and, particularly, at elevated temperatures up to 60 ° C (a temperature at which the non-coated NCM₈₁₁ electrodes rapidly fail) owing to the formation of a stable cathode electrolyte interphase with enhanced Li⁺ transport kinetics and the well-retained layered crystal structure. These results render the herein presented coating strategy generally applicable for high-performance lithium battery cathodes.     

The Role of Electron Localization in Covalency and Electrochemical Properties of Lithium-Ion Battery Cathode Materials

Following the fundamental research conducted by J. B. Goodenough, the important role of electron localization induced by elemental substitution is studied. The size and electron negativity of host and substituting ions are two important factors in tuning material properties such as local structure and transition metal (TM) oxygen covalency. However, another factor, electron localization, which is widely studied in catalyst research but largely overlooked for battery materials, deserves systematic studies. A combined investigation using synchrotronbased X-ray spectroscopy and theoretical calculations is carried out on the Li-Co-Mn-O model system in which the substituting cation Mn⁴⁺, with its 3d³ electronic structure, is used as a promoter for electron localization. Results indicate that electron localization greatly influences the Co O bond by making it less covalent, which increases the delithiation voltage. It is also found that during charge/discharge, electron localization tends to make TM K-edge X-ray absorption near edge spectroscopy (XANES) spectra show a more “rigid shift” behavior while electron delocalization makes the XANES exhibit a “shape change.” It clearly explains why the K-edge XANES data of some TM oxides show no “rigid shift” while the nominal valence states changed. This work highlights the importance of electron localization with guidance for XANES interpretation.     

Accessible Li Percolation and Extended Oxygen Oxidation Boundary in Rocksalt-like Cathode Enabled by Initial Li-deficient Nanostructure

Disordered rocksalt cathodes have shown attractive electrochemical performance via oxygen redox, but are limited by a necessary Li-excess level above the percolation threshold (x > 1.09 in Li_xTM_2-xO₂, TM = transition metals) to obtain electrochemical activity. However, a relatively low-Li content is essential to alleviate excessive oxygen charge compensation in rocksalt oxides. Herein, taking the homogeneous Li₂MnO₃ and LiMn₂O₄ as the starting point, disordered rocksalt-like cathodes are prepared with initial Li-deficient nanostructures, cation vacancies, and partial spinel-type structures that provide a solution for the acquisition of fast Li⁺ percolation channels under Li-deficient condition. As a result, the prepared sample exhibits high initial discharge capacity (363 mAh g⁻¹) and energy density (1081 Wh kg⁻¹). Advanced spectroscopy and in situ measurements observe highly reversible charge compensation during electrochemical process and assign coupled Mn- and O-related redox contribution. Theoretical calculations also suggest the novel and chemical reversible trapped molecular O₂ model in the rocksalt structure with vacancies, demonstrating a dual role of Li-deficient structure in promoting cationic oxidation and extending reversible oxygen redox boundary. This work is expected to breakthrough the existing ideas of oxygen oxidation and opens up a higher degree of freedom in the design of disordered rocksalt structures.     

Conduction band states of transition metal (TM) high-k gate dielectrics as determined from X-ray absorption spectra

This paper uses X-ray absorption spectroscopy to study the electronic structure of the high-k gate dielectrics including TM and RE oxides. The results are applicable to TM and rare earth (RE) silicate and aluminate alloys, as well as complex oxides comprised of mixed TM/TM and TM/RE oxides. These studies identify the nature of the lowest conduction band d^* states, which define the optical band gap, E_g, and the conduction band offset energy with respect to crystalline Si, E_B. E_g and E_B scale with the atomic properties of the TM and RE atoms providing important insights for identification high-k dielectrics that meet performance targets for advanced CMOS devices.     

Transition-Metal Vacancy Manufacturing and Sodium-Site Doping Enable a High-Performance Layered Oxide Cathode through Cationic and Anionic Redox Chemistry

Triggering the anionic redox chemistry in layered oxide cathodes has emerged as a paradigmatic approach to efficaciously boost the energy density of sodium-ion batteries. However, their practical applications are still plagued by irreversible lattice oxygen release and deleterious structure distortion. Herein, a novel P2-Na_0.76Ca_0.05[Ni_0.23□_0.08Mn_0.69]O₂ cathode material featuring joint cationic and anionic redox activities, where native vacancies are produced in the transition-metal (TM) layers and Ca ions are riveted in the Na layers, is developed. Random vacancies in the TM sites induce the emergence of nonbonding O 2p orbitals to activate anionic redox, which is confirmed by systematic electrochemical measurements, ex situ X-ray photoelectron spectroscopy, in situ X-ray diffraction, and density functional theory computations. Benefiting from the pinned Ca ions in the Na sites, a robust layered structure with the suppressed P2-O2 phase transition and enhanced anionic redox reversibility upon charge/discharge is achieved. Therefore, the electrode displays exceptional rate capability (153.9 mA h g⁻¹ at 0.1 C with 74.6 mA h g⁻¹ at 20 C) and improved cycling life (87.1% capacity retention at 0.1 C after 50 cycles). This study provides new opportunities for designing high-energy-density and high-stability layered sodium oxide cathodes by tuning local chemical environments.     

Comprehensively Strengthened Metal-Oxygen Bonds for Reversible Anionic Redox Reaction

Introducing anionic redox in layered oxides is an effective approach to breaking the capacity limit of conventional cationic redox. However, the anionic redox reaction generally suffers from excessive oxidation of lattice oxygen to O₂ and O₂ release, resulting in local structural deterioration and rapid capacity/voltage decay. Here, a Na_0.71Li_0.22Al_0.05Mn_0.73O₂ (NLAM) cathode material is developed by introducing Al³⁺ into the transition metal (TM) sites. Thanks to the strong Al–O bonding strength and small Al³⁺ radius, the TMO₂ skeleton and the holistic TM–O bonds in NLAM are comprehensively strengthened, which inhibits the excessive lattice oxygen oxidation. The obtained NLAM exhibits a high reversible capacity of 194.4 mAh g^-1 at 20 mA g^-1 and decent cyclability with 98.6% capacity retention over 200 cycles at 200 mA g⁻¹. In situ characterizations reveal that the NLAM experiences phase transitions with an intermediate OP4 phase during the charge–discharge. Theoretical calculations further confirm that the Al substitution strategy is beneficial for improving the overlap between Mn 3d and O 2p orbitals. This finding sheds light on the design of layered oxide cathodes with highly reversible anionic redox for sodium storage.     

Anti‐Oxygen Leaking LiCoO2

LiCoO₂ is a prime example of widely used cathodes that suffer from the structural/thermal instability issues that lead to the release of their lattice oxygen under nonequilibrium conditions and safety concerns in Li‐ion batteries. Here, it is shown that an atomically thin layer of reduced graphene oxide can suppress oxygen release from Li_xCoO₂ particles and improve their structural stability. Electrochemical cycling, differential electrochemical mass spectroscopy, differential scanning calorimetry, and in situ heating transmission electron microscopy are performed to characterize the effectiveness of the graphene‐coating on the abusive tolerance of Li_xCoO₂. Electrochemical cycling mass spectroscopy results suggest that oxygen release is hindered at high cutoff voltage cycling when the cathode is coated with reduced graphene oxide. Thermal analysis, in situ heating transmission electron microscopy, and electron energy loss spectroscopy results show that the reduction of Co species from the graphene‐coated samples is delayed when compared with bare cathodes. Finally, density functional theory and ab initio molecular dynamics calculations show that the rGO layers could suppress O₂ formation more effectively due to the strong C? O_cathode bond formation at the interface of rGO/LCO where low coordination oxygens exist. This investigation uncovers a reliable approach for hindering the oxygen release reaction and improving the thermal stability of battery cathodes.     

A Critical Review on Functionalization of Air‐Cathodes for Nonaqueous Li–O2 Batteries

This review reports on the most updated technological aspects of Li–air battery cathode materials. It provides the reader with recent developments, alongside critical views. The requirements for air‐cathodes, as well as the classification and characterization of carbon‐based and carbon‐free air cathodes, are listed. The effects of two major substituent groups of materials, namely carbon and advanced materials (metals, metal‐oxides, metal‐carbides, and metal‐nitrides) aimed at replacing carbon, are discussed in terms of their chemical and electrochemical stability. The report covers aspects of surface chemistry and structure influence on the electrolyte and discharge products stability. The review also reports on the efforts to suppress side reactions and deterioration of the polymeric binders (if a composite electrode is being considered). This is recognized as a means to enhance Li–air battery performance. The report concludes with an outlook and perspective, providing the readers with some insight on other factors and their impact on the long road toward a viable air‐cathode suitable for Li–air battery operations.     

Advances in Manganese‐Based Oxides Cathodic Electrocatalysts for Li–Air Batteries

Li–air batteries, characteristic of superhigh theoretical specific energy density, cost‐efficiency, and environment‐friendly merits, have aroused ever‐increasing attention. Nevertheless, relatively low Coulomb efficiency, severe potential hysteresis, and poor rate capability, which mainly result from sluggish oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) kinetics, as well as pitiful cycle stability caused by parasitic reactions, extremely limit their practical applications. Manganese (Mn)‐based oxides and their composites can exhibit high ORR and OER activities, reduce charge/discharge overpotential, and improve the cycling stability when used as cathodic catalyst materials. Herein, energy storage mechanisms for Li–air batteries are summarized, followed by a systematic overview of the progress of manganese‐based oxides (MnO₂ with different crystal structures, MnO, MnOOH, Mn₂O₃, Mn₃O₄, MnOx, perovskite‐type and spinel‐type manganese oxides, etc.) cathodic materials for Li–air batteries in the recent years. The focus lies on the effects of crystal structure, design strategy, chemical composition, and microscopic physical parameters on ORR and OER activities of various Mn‐based oxides, and even the overall performance of Li–air batteries. Finally, a prospect of the research for Mn‐based oxides cathodic catalysts in the future is made, and some new insights for more reasonable design of Mn‐based oxides electrocatalysts with higher catalytic efficiency are provided.