The rapid capacity loss suffered by P2‐type Mn‐based layered oxide cathode materials, caused by deleterious high‐voltage phase transformations and the dissolution of active materials, greatly limits ...their application in large‐scale sodium‐ion battery installations. In this study, a novel P2/O3 biphasic cathode is developed using a multi‐element (Fe, Mg, and Li) co‐substitution strategy. The results of ex situ X‐ray diffraction analyses and the absence of significant voltage plateaus in the charge–discharge profiles of cells featuring the proposed cathode indicate that deleterious phase transformations and concomitant lattice mismatch in the high‐voltage region are effectively suppressed because of the topotactic intergrown structure of the resulting cathode. The optimized cathode also demonstrates improved structural stability and enhanced Na+ diffusion kinetics, owing to the incorporation of stabilizing dopant pillars and suppressed metal‐ion dissolution. Hence, the resulting Na half cell demonstrates a high initial capacity of 170.5 mA h g−1 at 0.1 C and excellent rate capability (106.6 mA h g−1 at 10 C). Furthermore, the resulting Na full cell, featuring a hard carbon anode, displays excellent cycling stability (72.1% capacity retention after 400 cycles), demonstrating its practical viability. This study presents the design and optimization of high‐performance Mn‐based cathodes.
A novel multi‐element co‐substituted P2/O3 heterostructured cathode material is developed and comprehensively evaluated. Benefiting from its topotactic intergrown structure, the optimized cathode material exhibits smooth phase evolution and less mechanical damage. In addition, the incorporation of low‐valence dopants increases the Na content and alleviates the dissolution of active materials, which improves the Na storage performance.
The high demand for clean and renewable energy has fueled the exploration of advanced energy storage systems. As a potential alternative device for lithium ion batteries, sodium ion batteries (NIBs) ...have attracted extraordinary attention and are becoming a promising candidate for energy storage due to their low cost and high efficiency. Recent progress has demonstrated that metal sulfides (MSs) are very promising electrode candidates for efficient Na‐storage devices, because of their excellent redox reversibility and relatively high capacity. In this review, recent developments of MSs as anode materials for NIBs are presented. The corresponding electrochemical mechanisms are briefly discussed. We also present critical issues, challenges, and perspectives with the hope of providing a fuller understanding of the associated electrochemical processes. Such an understanding is critical for tailoring and designing metal sulfides with the desired activity and stability.
Metal sulfides (MSs) hold great promise and attract wide‐ranging interest as anode materials for sodium ion batteries (NIBs) by virtue of their excellent redox reversibility and relatively high capacity. This review presents recent developments of MSs as anode materials for NIBs, providing a comprehensive understanding of the associated research progress.
The topic of sustainable and eco‐friendly energy storage technologies is an issue of global significance. To date, this heavy burden is solely addressed by lithium‐ion battery technology. However, ...the ongoing depletion of limited global lithium resources has restricted their future availability for Li‐ion battery technology, and hence, a significant price increase is expected. This grim situation is the driving force for the development of the “beyond Li‐ion battery” strategy involving alternatives that have several advantages over conventional Li‐ion batteries in terms of cost, durability, safety, and sustainability. Potassium, the closest neighboring alkali element after sodium, offers some unique advantages over lithium and sodium as a charge carrier in rechargeable batteries. Potassium intercalation chemistry in potassium‐ion batteries (KIBs) is successfully demonstrated to be compatible with Li‐ion batteries and sodium‐ion batteries. In addition to KIBs, potassium–sulfur and potassium–oxygen batteries have emerged as new energy‐storage systems due to their low costs and high specific energy densities. This review covers the key technological developments and scientific challenges for a broad range of rechargeable potassium batteries, while also providing valuable insight into the scientific and practical issues concerning the development of potassium‐based rechargeable batteries.
Batteries that use potassium ions, such as potassium‐ion, potassium–sulfur, and potassium–oxygen batteries, are emerging technologies that can compete with lithium‐ion batteries in large‐scale energy‐storage applications. This review covers the key technological developments and scientific challenges for a broad range of potassium‐based batteries, while also providing valuable insight into the scientific and practical issues concerning the development of rechargeable potassium batteries.
The exploitation of effective strategies to accelerate the Na+ diffusion kinetics and improve the structural stability in the electrode is extremely important for the development of high efficientcy ...sodium‐ion batteries. Herein, Se vacancies and heterostructure engineering are utilized to improve the Na+‐storage performance of transition metal selenides anode prepared through a facile two‐in‐one route. The experimental results coupled with theoretical calculations reveal that the successful construction of the Se vacancies and heterostructure interfaces can effectively lower the Na+ diffusion barrier, accelerate the charge transfer efficiency, improve Na+ adsorption ability, and provide an abundance of active sites. Consequently, the batteries based on the constructed ZnSe/CoSe2‐CN anode manifest a high initial Coulombic efficiency (97.7%), remarkable specific capacities (547.1 mAh g–1 at 0.5 A g–1), superb rate capability (362.1 mAh g–1 at 20 A g–1), as well as ultrastable long‐term stability (1000 cycles) with a satisfied specific capacity (535.6 mAh g–1) at 1 A g–1. This work facilitates an in‐depth understanding of the synergistic effect of vacancies and heterojunctions in improving the Na+ reaction kinetics, providing an effective strategy to the rational design of key materials for high efficiency rechargeable batteries.
Vacancy and interface synergistic engineering is utilized to boost the electrochemical performance of bimetallic selenide (ZnSe/CoSe2‐CN)‐based sodium‐ion batteries. The as‐prepared composite manifests appealing Na+‐storage performance, including high initial Coulombic efficiency, good rate capability, and excellent stability. The proposed strategy is considerably facile and may shed light on designing advanced electrodes with intriguing electrochemical performance.
With the ever‐increasing requirement for high‐energy density lithium‐ion batteries (LIBs) to drive pure/hybrid electric vehicles (EVs), considerable attention has been paid to the development of ...cathode materials with high energy densities because they ultimately determine the energy density of LIBs. Notably, the cost of cathode materials is still the main obstacle hindering the extensive application of EVs, with the cost accounting for 40% of the total cost of fabricating LIBs. Therefore, enhancing the energy density and simultaneously decreasing the cost of LIBs are essential for the success of EV/hybrid EV industries. Among the existing commercial cathodes, Ni‐rich layered cathodes are widely employed because of their high energy density, relatively good rate capability, and reasonable cycling performance. Ni‐rich layered cathodes containing Co are now being reconsidered due to the increasing price of Co, which is much higher than that of Ni and Mn. In this report, the recent developments and strategies in the improvement of the stabilities of the bulk and surface for Co‐less Ni‐rich layered cathode materials are reviewed.
A perspective on Co‐less Ni‐rich cathodes for lithium‐ion batteries (LIBs) is provided. LiNiO2, binary‐, ternary‐, and quaternary cathodes are classified as the past, present, and future of LIBs. Surface modification is a strategy for present ternary cathodes. Gradient strategies categorized into five types, from core–shell to hybrid structures, are the foundation for future cathodes to develop.
Herein, a new P2‐type layered oxide is proposed as an outstanding intercalation cathode material for high energy density sodium‐ion batteries (SIBs). On the basis of the stoichiometry of sodium and ...transition metals, the P2‐type Na0.55Ni0.1Fe0.1Mn0.8O2 cathode is synthesized without impurities phase by partially substituting Ni and Fe into the Mn sites. The partial substitution results in a smoothing of the electrochemical charge/discharge profiles and thus greatly improves the battery performance. The P2‐type Na0.55Ni0.1Fe0.1Mn0.8O2 cathode delivers an extremely high discharge capacity of 221.5 mAh g−1 with a high average potential of ≈2.9 V (vs Na/Na+) for SIBs. In addition, the fast Na‐ion transport in the P2‐type Na0.55Ni0.1Fe0.1Mn0.8O2 cathode structure enables good power capability with an extremely high current density of 2400 mA g−1 (full charge/discharge in 12 min) and long‐term cycling stability with ≈80% capacity retention after 500 cycles at 600 mA g−1. A combination of electrochemical profiles, in operando synchrotron X‐ray diffraction analysis, and first‐principles calculations are used to understand the overall Na storage mechanism of P2‐type Na0.55Ni0.1Fe0.1Mn0.8O2.
On the basis of the stoichiometry of sodium and transition metals, pure P2‐type Na0.55Ni0.1Fe0.1Mn0.8O2 is designed and synthesized as a high‐performance cathode material for sodium‐ion batteries. With smooth electrochemistry, the P2‐Na0.55Ni0.1Fe0.1Mn0.8O2 cathode delivers an extremely high discharge capacity of 221.5 mAh g−1 with a high average potential of ≈2.9 V (vs Na/Na+), outstanding cycling stability, and excellent power capability.
High‐voltage lithium‐ion batteries (LIBs) enabled by high‐voltage electrolytes can effectively boost energy density and power density, which are critical requirements to achieve long travel ...distances, fast‐charging, and reliable safety performance for electric vehicles. However, operating these batteries beyond the typical conditions of LIBs (4.3 V vs Li/Li+) leads to severe electrolyte decomposition, while interfacial side reactions remain elusive. These critical issues have become a bottleneck for developing electrolytes for applications in extreme conditions. Herein, an additive‐free electrolyte is presented that affords high stability at high voltage (4.5 V vs Li/Li+), lithium‐dendrite‐free features upon fast‐charging operations (e.g., 162 mAh g−1 at 3 C), and superior long‐term battery performance at low temperature. More importantly, a new solvation structure‐related interfacial model is presented, incorporating molecular‐scale interactions between the lithium‐ion, anion, and solvents at the electrolyte–electrode interfaces to help interpret battery performance. This report is a pioneering study that explores the dynamic mutual‐interaction interfacial behaviors on the lithium layered oxide cathode and graphite anode simultaneously in the battery. This interfacial model enables new insights into electrode performances that differ from the known solid electrolyte interphase approach to be revealed, and sets new guidelines for the design of versatile electrolytes for metal‐ion batteries.
A new solvation structure‐related interfacial model is presented, which involves the molecular‐scale interactions between the lithium‐ion, anion, and solvents on the electrolyte–electrode surface, to interpret the high performance enabled by a newly designed high voltage electrolyte. This report is a pioneering study that explores the dynamic mutual‐interaction interfacial behaviors on the Ni‐rich cathode and graphite anode simultaneously in the battery.
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.
Ni‐rich layered oxides and Li‐rich layered oxides are part of a new generation of high‐capacity Li‐ion battery cathodes currently under development. The current state of research on these two families of materials, some of the obstacles to further implementation, and some future areas of exploration are outlined.
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