Metal–Organic Frameworks‐Derived Tunnel Structured Co3(PO4)2@C as Cathode for New Generation High‐Performance Al‐Ion Batteries

Despite great progress in aluminum ion batteries (AIBs), the commercialization and performance improvement of AIBs‐based carbon cathodes is greatly impeded by sluggish intercalation/extraction and redox kinetics due to large‐sized AlCl₄^? anions. Phosphates with tunnel channels and much larger d‐spacing than the radius of Al³⁺ could be an alternative candidate as a cathode for potential high‐performance AIBs. Herein, elaborately designed porous tunnel structured Co₃(PO₄)₂@C composites derived from ZIF‐67 as AIBs cathodes are demonstrated, showing increased active sites, high ionic mobility, and high Al³⁺ ion diffusion coefficient, leading to remarkably enhanced discharge–charge redox reaction kinetics. Furthermore, the carbon shell and porous structure performs as armor to alleviate volume change and maintain the structure integrity of the cathodes. As expected, the rationally constructed Co₃(PO₄)₂@C composite exhibits a superior capacity of 111 mA h g^?1 at a high current density of 6 A g^?1 and 151 mA h g^?1 at 2 A g^?1 after 500 cycles with capacity decay of 0.02% per cycle. This innovative strategy could be a big step forward for long‐term cycle stable AIBs and reveals significant insights into the redox reaction mechanism for high‐performance AIBs based on Al³⁺ rather than large‐sized AlCl₄^?.     

Ti‐Gradient Doping to Stabilize Layered Surface Structure for High Performance High‐Ni Oxide Cathode of Li‐Ion Battery

High‐Ni layered oxide cathodes are considered to be one of the most promising cathodes for high‐energy‐density lithium‐ion batteries due to their high capacity and low cost. However, surfice residues, such as NiO‐type rock‐salt phase and Li₂CO₃, are often formed at the particle surface due to the high reactivity of Ni³⁺, and inevitably result in an inferior electrochemical performance, hindering the practical application. Herein, unprecedentedly clean surfaces without any surfice residues are obtained in a representative LiNi_0.8Co_0.2O₂ cathode by Ti‐gradient doping. High‐resolution transmission electron microscopy (TEM) reveals that the particle surface is composed of a disordered layered phase (≈6 nm in thickness) with the same rhombohedra structure as its interior. The formation of this disordered layered phase at the particle surface is electrochemically favored. It leads to the highest rate capacity ever reported and a superior cycling stability. First‐principles calculations further confirm that the excellent electrochemical performance has roots in the excellent chemical/structural stability of such a disordered layered structure, mainly arising from the improved robustness of the oxygen framework by Ti doping. This strategy of constructing the disordered layered phase at the particle surface could be extended to other high‐Ni layered transition metal oxides, which will contribute to the enhancement of their electrochemical performance.     

High Voltage Operation of Ni‐Rich NMC Cathodes Enabled by Stable Electrode/Electrolyte Interphases

The lithium (Li) metal battery (LMB) is one of the most promising candidates for next‐generation energy storage systems. However, it is still a significant challenge to operate LMBs with high voltage cathodes under high rate conditions. In this work, an LMB using a nickel‐rich layered cathode of LiNi_0.76Mn_0.14Co_0.10O₂ (NMC76) and an optimized electrolyte [0.6 m lithium bis(trifluoromethanesulfonyl)imide + 0.4 m lithium bis(oxalato)borate + 0.05 m LiPF₆ dissolved in ethylene carbonate and ethyl methyl carbonate (4:6 by weight)] demonstrates excellent stability at a high charge cutoff voltage of 4.5 V. Remarkably, these Li||NMC76 cells can deliver a high discharge capacity of >220 mA h g^?1 (846 W h kg^?1) and retain more than 80% capacity after 1000 cycles at high charge/discharge current rates of 2C/2C (1C = 200 mA g^?1). This excellent electrochemical performance can be attributed to the greatly enhanced structural/interfacial stability of both the Ni‐rich NMC76 cathode material and the Li metal anode using the optimized electrolyte.     

Countering Voltage Decay and Capacity Fading of Lithium‐Rich Cathode Material at 60 °C by Hybrid Surface Protection Layers

Li‐rich layered metal oxides have attracted much attention for their high energy density but still endure severe capacity fading and voltage decay during cycling, especially at elevated temperature. Here, facile surface treatment of Li_1.17Ni_0.17Co_0.17Mn_0.5O₂ (0.4Li₂MnO₃·0.6LiNi_1/3Co_1/3Mn_1/3O₂) spherical cathode material is designed to address these drawbacks by hybrid surface protection layers composed of Mg²⁺ pillar and Li‐Mg‐PO₄ layer. As a result, the surface coated Li‐rich cathode material exhibits much enhanced cycling stability at 60 °C, maintaining 72.6% capacity retention (180 mAh g^?1) between 3.0 and 4.7 V after 250 cycles. More importantly, 88.7% average discharge voltage retention can be obtained after the rigorous cycle test. The strategy developed here with novel hydrid surface protection effect can provide a vital approach to inhibit the undesired side reactions and structural deterioration of Li‐rich cathode materials and may also be useful for other layered oxides to increase their cycling stability at elevated temperature.     

Unlocking Few‐Layered Ternary Chalcogenides for High‐Performance Potassium‐Ion Storage

Potassium‐ion batteries (KIBs) have attracted increasing attention for grid‐scale energy storage due to the abundance of potassium resources, low cost, and competitive energy density. The key challenge for KIBs is to develop high‐performance electrode materials. However, the exploration of high‐capacity and ultrastable electrodes for KIBs remains challenging because of the sluggish diffusion kinetics of K⁺ ions during the charging/discharging processes. This study reports for the first time a facile ion‐intercalation‐mediated exfoliation method with Mg²⁺ cations and NO₃^– anions as ion assistants for the fabrication of expanded few‐layered ternary Ta₂NiSe₅ (EF‐TNS) flakes with interlayer spacing up to 1.1 nm and abundant Se sites (NiSe₄ tetrahedra/TaSe₆ octahedra clusters) for superior potassium‐ion storage. The EF‐TNS deliver a high capacity of 315 mAh g^–1, excellent rate capability (121 mAh g^–1 at a current density of 1000 mA g^–1), and ultrastable cycling performance (81.4% capacity retention after 1100 cycles). Detailed theoretical analysis via first‐principles calculations and experimental results elucidate that K⁺ ions intercalate through the expanded interlayers effectively and prefer to transport along zigzag pathways in layered Ta₂NiSe₅. This work provides a new avenue for designing novel ternary intercalation/pseudocapacitance‐type KIBs with high capacity, excellent rate capability, and superior long‐term cycling performance.     

Interlayer-Engineering and Surface-Substituting Manganese-Based Self-Evolution for High-Performance Potassium Cathode

Manganese-based layered oxides cathodes have attracted enormous interest due to their advantages in cost and energy density. The significant challenges of Mn-based layered oxides for potassium-ion batteries (PIBs) are complex phase transition and Mn dissolution upon K⁺ intercalation/deintercalation. Here, a P3-type K_0.45Rb_0.05Mn_0.85Mg_0.15O₂ (KRMMO) cathode material is proposed to address the above challenges. The results show that rubidium acts as a pillar to expand interlayer spacing and stabilize the structure, while magnesium partially replaces Mn to suppress the Jahn–Teller distortion of the Mn³⁺. The KRMMO cathode exhibits high capacity of 108.0 and 77.3 mAh g⁻¹ at 20 and 500 mA g⁻¹, respectively, and retains 98.2% of its initial capacity after 200 cycles. Compared with P3-K_0.5MnO₂, the capacity fading of P3-KRMMO is effectively suppressed, which is mainly due to the synergistic contribution of Rb and Mg ions in the alleviation of volume change and suppression of phase transition. This work may open a new avenue for the design and optimization of layered cathode materials for PIBs and beyond.     

Insight of a Phase Compatible Surface Coating for Long‐Durable Li‐Rich Layered Oxide Cathode

Li‐rich layered oxides (LLOs) can deliver almost double the capacity of conventional electrode materials such as LiCoO₂ and LiMn₂O₄; however, voltage fade and capacity degradation are major obstacles to the practical implementation of LLOs in high‐energy lithium‐ion batteries. Herein, hexagonal La_0.8Sr_0.2MnO_3?y (LSM) is used as a protective and phase‐compatible surface layer to stabilize the Li‐rich layered Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ (LM) cathode material. The LSM is Mn? O? M bonded at the LSM/LM interface and functions by preventing the migration of metal ions in the LM associated with capacity degradation as well as enhancing the electrical transfer and ionic conductivity at the interface. The LSM‐coated LM delivers an enhanced reversible capacity of 202 mAh g^?1 at 1 C (260 mA g^?1) with excellent cycling stability and rate capability (94% capacity retention after 200 cycles and 144 mAh g^?1 at 5 C). This work demonstrates that interfacial bonding between coating and bulk material is a successful strategy for the modification of LLO electrodes for the next‐generation of high‐energy Li‐ion batteries.     

A Dual‐Insertion Type Sodium‐Ion Full Cell Based on High‐Quality Ternary‐Metal Prussian Blue Analogs

Prussian blue analogs (PBAs) are especially investigated as superior cathodes for sodium‐ion batteries (SIBs) due to high theoretical capacity (≈170 mA h g^?1) with 2‐Na storage and low cost. However, PBAs suffer poor cyclability due to irreversible phase transition in deep charge/discharge states. PBAs also suffer low crystallinity, with considerable [Fe(CN)₆] vacancies, and coordinated water in crystal frameworks. Presently, a new chelating agent/surfactant coassisted crystallization method is developed to prepare high‐quality (HQ) ternary‐metal Ni_xCo_1?x[Fe(CN)₆] PBAs. By introducing inactive metal Ni to suppress capacity fading caused by excessive lattice distortion, these PBAs have tunable limits on depth of charge/discharge. HQ‐Ni_xCo_1?x[Fe(CN)₆] (x = 0.3) demonstrates the best reversible Na‐storage behavior with a specific capacity of ≈145 mA h g^?1 and a remarkably improved cycle performance, with ≈90% capacity retention over 600 cycles at 5 C. Furthermore, a dual‐insertion full cell on the cathode and NaTi₂(PO₄)₃ anode delivers reversible capacity of ≈110 mA h g^?1 at a current rate of 1.0 C without capacity fading over 300 cycles, showing promise as a high‐performance SIB for large‐scale energy‐storage systems. The ultrastable cyclability achieved in the lab and explained herein is far beyond that of any previously reported PBA‐based full cells.     

Layered Na‐Ion Cathodes with Outstanding Performance Resulting from the Synergetic Effect of Mixed P‐ and O‐Type Phases

Herein, the synthesis of new quaternary layered Na‐based oxides of the type Na_xMn_yNi_zFe_0.1Mg_0.1O₂ (0.67≤ x ≤ 1.0; 0.5≤ y ≤ 0.7; 0.1≤ z ≤ 0.3) is described. The synthesis can be tuned to obtain P2‐ and O3‐type as well as mixed P‐/O‐type phases as demonstrated by structural, morphological, and electrochemical properties characterization. Although all materials show good electrochemical performance, the simultaneous presence of the P‐ and O‐type phases is found to have a synergetic effect resulting in outstanding performance of the mixed phase material as a sodium‐ion cathode. The mixed P3/P2/O3‐type material, having an average elemental composition of Na_0.76Mn_0.5Ni_0.3Fe_0.1Mg_0.1O₂, overcomes the specific drawbacks associated with the P2‐ and O3‐type materials, allowing the outstanding electrochemical performance. In detail, the mixed phase material is able to deliver specific discharge capacities of up to 155 mAh g^?1 (18 mA g^?1) in the potential range of 2.0–4.3 V. In the narrower potential range of 2.5–4.3 V the material exhibits high average discharge potential (3.4 V versus Na/Na⁺), exceptional average coulombic efficiencies (>99.9%), and extraordinary capacity retention (90.2% after 601 cycles). The unexplored class of P‐/O‐type mixed phases introduces new perspectives for the development of layered positive electrode materials and powerful Na‐ion batteries.     

In Situ Probing and Synthetic Control of Cationic Ordering in Ni‐Rich Layered Oxide Cathodes

Ni‐rich layered oxides (LiNi_1–x M_x O₂; M = Co, Mn, …) are appealing alternatives to conventional LiCoO₂ as cathodes in Li‐ion batteries for automobile and other large‐scale applications due to their high theoretical capacity and low cost. However, preparing stoichiometric LiNi_1–x M_x O₂ with ordered layer structure and high reversible capacity, has proven difficult due to cation mixing in octahedral sites. Herein, in situ studies of synthesis reactions and the associated structural ordering in preparing LiNiO₂ and the Co‐substituted variant, LiNi_0.8Co_0.2O₂, are made, to gain insights into synthetic control of the structure and electrochemical properties of Ni‐rich layered oxides. Results from this study indicate a direct transformation of the intermediate from the rock salt structure into hexagonal phase, and during the process, Co substitution facilities the nucleation of a Co‐rich layered phase at low temperatures and subsequent growth and stabilization of solid solution Li(Ni, Co)O₂ upon further heat treatment. Optimal conditions are identified from the in situ studies and utilized to obtain stoichiometric LiNi_0.8Co_0.2O₂ that exhibits high capacity (up to 200 mA h g^?1 ) with excellent retention. The findings shed light on designing high performance Ni‐rich layered oxide cathodes through synthetic control of the structural ordering in the materials.     

High‐Performance Reversible Aqueous Zn‐Ion Battery Based on Porous MnOx Nanorods Coated by MOF‐Derived N‐Doped Carbon

Rechargeable aqueous zinc‐ion batteries (ZIBs) have been emerging as potential large‐scale energy storage devices due to their high energy density, low cost, high safety, and environmental friendliness. However, the commonly used cathode materials in ZIBs exhibit poor electrochemical performance, such as significant capacity fading during long‐term cycling and poor performance at high current rates, which significantly hinder the further development of ZIBs. Herein, a new and highly reversible Mn‐based cathode material with porous framework and N‐doping (MnO_x@N‐C) is prepared through a metal–organic framework template strategy. Benefiting from the unique porous structure, conductive carbon network, and the synergetic effect of Zn²⁺ and Mn²⁺ in electrolyte, the MnO_x@N‐C shows excellent cycling stability, good rate performance, and high reversibility for aqueous ZIBs. Specifically, it exhibits high capacity of 305 mAh g^?1 after 600 cycles at 500 mA g^?1 and maintains achievable capacity of 100 mAh g^?1 at a quite high rate of 2000 mA g^?1 with long‐term cycling of up to 1600 cycles, which are superior to most reported ZIB cathode materials. Furthermore, insight into the Zn‐storage mechanism in MnO_x@N‐C is systematically studied and discussed via multiple analytical methods. This study opens new opportunities for designing low‐cost and high‐performance rechargeable aqueous ZIBs.     

Review on Challenges and Recent Advances in the Electrochemical Performance of High Capacity Li‐ and Mn‐Rich Cathode Materials for Li‐Ion Batteries

Li and Mn‐rich layered oxides, xLi₂MnO₃·(1–x)LiMO₂ (M=Ni, Mn, Co), are promising cathode materials for Li‐ion batteries because of their high specific capacity that can exceed 250 mA h g^?1. However, these materials suffer from high 1^st cycle irreversible capacity, gradual capacity fading, low rate capability, a substantial charge‐discharge voltage hysteresis, and a large average discharge voltage decay during cycling. The latter detrimental phenomenon is ascribed to irreversible structural transformations upon cycling of these cathodes related to potentials ≥4.5 V required for their charging. Transition metal inactivation along with impedance increase and partial layered‐to‐spinel transformation during cycling are possible reasons for the detrimental voltage fade. Doping of Li, Mn‐rich materials by Na, Mg, Al, Fe, Co, Ru, etc. is useful for stabilizing capacity and mitigating the discharge‐voltage decay of xLi₂MnO₃·(1–x)LiMO₂ electrodes. Surface modifications by thin coatings of Al₂O₃, V₂O₅, AlF₃, AlPO₄, etc. or by gas treatment (for instance, by NH₃) can also enhance voltage and capacity stability during cycling. This paper describes the recent literature results and ongoing efforts from our groups to improve the performance of Li, Mn‐rich materials. Focus is also on preparation of cobalt‐free cathodes, which are integrated layered‐spinel materials with high reversible capacity and stable performance.     

Controlled Oxygen Redox for Excellent Power Capability in Layered Sodium‐Based Compounds

A high‐rate of oxygen redox assisted by cobalt in layered sodium‐based compounds is achieved. The rationally designed Na_0.6[Mg_0.2Mn_0.6Co_0.2]O₂ exhibits outstanding electrode performance, delivering a discharge capacity of 214 mAh g^?1 (26 mA g^?1) with capacity retention of 87% after 100 cycles. High rate performance is also achieved at 7C (1.82 A g^?1) with a capacity of 107 mAh g^?1. Surprisingly, the Na_0.6[Mg_0.2Mn_0.6Co_0.2]O₂ compound is able to deliver capacity for 1000 cycles at 5C (at 1.3 A g^?1), retaining 72% of its initial capacity of 108 mAh g^?1. X‐ray absorption spectroscopy analysis of the O K‐edge indicates the oxygen‐redox species (O^2?/1?) is active during cycling. First‐principles calculations show that the addition of Co reduces the bandgap energy from ≈2.65 to ≈0.61 eV and that overlapping of the Co 3d and O 2p orbitals facilitates facile electron transfer, enabling the long‐term reversibility of the oxygen redox, even at high rates. To the best of the authors' knowledge, this is the first report on high‐rate oxygen redox in sodium‐based cathode materials, and it is believed that the findings will open a new pathway for the use of oxygen‐redox‐based materials for sodium‐ion batteries.     

An Open‐Structured Matrix as Oxygen Cathode with High Catalytic Activity and Large Li2O2 Accommodations for Lithium–Oxygen Batteries

The nonaqueous lithium–oxygen (Li–O₂) battery is considered as one of the most promising candidates for next‐generation energy storage systems because of its very high theoretical energy density. However, its development is severely hindered by large overpotential and limited capacity, far less than theory, caused by sluggish oxygen redox kinetics, pore clogging by solid Li₂O₂ deposition, inferior Li₂O₂/cathode contact interface, and difficult oxygen transport. Herein, an open‐structured Co₉S₈ matrix with sisal morphology is reported for the first time as an oxygen cathode for Li–O₂ batteries, in which the catalyzing for oxygen redox, good Li₂O₂/cathode contact interface, favorable oxygen evolution, and a promising Li₂O₂ storage matrix are successfully achieved simultaneously, leading to a significant improvement in the electrochemical performance of Li–O₂ batteries. The intrinsic oxygen‐affinity revealed by density functional theory calculations and superior bifunctional catalytic properties of Co₉S₈ electrode are found to play an important role in the remarkable enhancement in specific capacity and round‐trip efficiency for Li–O₂ batteries. As expected, the Co₉S₈ electrode can deliver a high discharge capacity of ≈6875 mA h g^?1 at 50 mA g^?1 and exhibit a low overpotential of 0.57 V under a cutoff capacity of 1000 mA h g^?1, outperforming most of the current metal‐oxide‐based cathodes.     

Open‐Structured V2O5·nH2O Nanoflakes as Highly Reversible Cathode Material for Monovalent and Multivalent Intercalation Batteries

The high‐capacity cathode material V₂O₅·n H₂O has attracted considerable attention for metal ion batteries due to the multielectron redox reaction during electrochemical processes. It has an expanded layer structure, which can host large ions or multivalent ions. However, structural instability and poor electronic and ionic conductivities greatly handicap its application. Here, in cell tests, self‐assembly V₂O₅·n H₂O nanoflakes shows excellent electrochemical performance with either monovalent or multivalent cation intercalation. They are directly grown on a 3D conductive stainless steel mesh substrate via a simple and green hydrothermal method. Well‐layered nanoflakes are obtained after heat treatment at 300 °C (V₂O₅·0.3H₂O). Nanoflakes with ultrathin flower petals deliver a stable capacity of 250 mA h g^?1 in a Li‐ion cell, 110 mA h g^?1 in a Na‐ion cell, and 80 mA h g^?1 in an Al‐ion cell in their respective potential ranges (2.0–4.0 V for Li and Na‐ion batteries and 0.1–2.5 V for Al‐ion battery) after 100 cycles.     

Dial the Mechanism Switch of VN from Conversion to Intercalation toward Long Cycling Sodium‐Ion Battery

Transition metal nitrides are promising energy storage materials in regard to good metallic conductivity and high theoretical specific capacity, but their cycling stability is impeded by the huge volume change caused by the conversion reaction mechanism. Here, a simple strategy to produce an intercalation pseudocapacitive‐type vanadium nitride (VN) by one‐step ammonification of V₂C MXene for sodium‐ion batteries is reported. Profiting from a distinctive layered structure pillared by Al atoms in the layer spacing, it delivers a high capacity of 372 mA h g^?1 at 50 mA g^?1 and a desirable rate performance. More importantly, it shows remarkably long cycling stability over 7500 cycles without capacity attenuation at 500 mA g^?1. As expected, it is found that the intercalation pseudocapacitance plays an important role in the excellent performance, by using in situ X‐ray diffraction and ex situ X‐ray absorption structure characterization. Even more remarkable, are the high energy and power density of the sodium‐ion capacitor after coupling with a carbon‐based cathode. The hybrid device possesses an energy density of 78.43 Wh kg^?1 at power density of 260 W kg^?1. The results clearly show that such a unique‐layered VN with outstanding Na storage capability is an excellent new material for energy storage systems.     

Nickel‐Rich and Lithium‐Rich Layered Oxide Cathodes: Progress and Perspectives

Ni‐rich layered oxides and Li‐rich layered oxides are topics of much research interest as cathodes for Li‐ion batteries due to their low cost and higher discharge capacities compared to those of LiCoO₂ and LiMn₂O₄. However, Ni‐rich layered oxides have several pitfalls, including difficulty in synthesizing a well‐ordered material with all Ni³⁺ ions, poor cyclability, moisture sensitivity, a thermal runaway reaction, and formation of a harmful surface layer caused by side reactions with the electrolyte. Recent efforts towards Ni‐rich layered oxides have centered on optimizing the composition and processing conditions to obtain controlled bulk and surface compositions to overcome the capacity fade. Li‐rich layered oxides also have negative aspects, including oxygen loss from the lattice during first charge, a large first cycle irreversible capacity loss, poor rate capability, side reactions with the electrolyte, low tap density, and voltage decay during extended cycling. Recent work on Li‐rich layered oxides has focused on understanding the surface and bulk structures and eliminating the undesirable properties. Followed by a brief introduction, an account of recent developments on the understanding and performance gains of Ni‐rich and Li‐rich layered oxide cathodes is provided, along with future research directions.     

Charge and Discharge Processes and Sodium Storage in Disodium Pyridine‐2,5‐Dicarboxylate Anode—Insights from Experiments and Theory

A combined experimental and computational study of disodium pyridine‐2,5‐dicarboxylate (Na₂PDC) is presented exploring the possibility of using it as a potential anode for organic sodium‐ion batteries. This electrode material can reversibly insert/release two Na cations per formula unit, resulting in high reversible capacity of 270 mA h g^?1 (236 mA h g^?1 after accounting for the contribution from Super P carbon) with excellent cyclability 225 mA h g^?1, with retention of 83% capacity after 100 cycles, and good rate performance with reversible capacity of 138 mA h g^?1 at a 5 C rate. The performance of disodium pyridine dicarboxylate is therefore found to be superior to that of the related and well investigated disodium terephthalate. The material shows two voltage plateaus at about 0.6 V up to Na₂₊₁PDC and then 0.4 V up to full sodiation, Na₂₊₂PDC. The first plateau is attributed to the coordination of inserted Na to nitrogen atoms with bond formation, i.e., a different mechanism from the terephthalate analog. The subsequent plateau is due to coordination to the carboxylic groups.     

An Ion‐Exchange Promoted Phase Transition in a Li‐Excess Layered Cathode Material for High‐Performance Lithium Ion Batteries

A new approach to intentionally induce phase transition of Li‐excess layered cathode materials for high‐performance lithium ion batteries is reported. In high contrast to the limited layered‐to‐spinel phase transformation that occurred during in situ electrochemical cycles, a Li‐excess layered Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ is completely converted to a Li₄Mn₅O₁₂‐type spinel product via ex situ ion‐exchanges and a post‐annealing process. Such a layered‐to‐spinel phase conversion is examined using in situ X‐ray diffraction and in situ high‐resolution transmission electron microscopy. It is found that generation of sufficient lithium ion vacancies within the Li‐excess layered oxide plays a critical role for realizing a complete phase transition. The newly formed spinel material exhibits initial discharge capacities of 313.6, 267.2, 204.0, and 126.3 mAh g^?1 when cycled at 0.1, 0.5, 1, and 5 C (1 C = 250 mA g^?1), respectively, and can retain a specific capacity of 197.5 mAh g^?1 at 1 C after 100 electrochemical cycles, demonstrating remarkably improved rate capability and cycling stability in comparison with the original Li‐excess layered cathode materials. This work sheds light on fundamental understanding of phase transitions within Li‐excess layered oxides. It also provides a novel route for tailoring electrochemical performance of Li‐excess layered cathode materials for high‐capacity lithium ion batteries.