An Ultrastable Anode for Long‐Life Room‐Temperature Sodium‐Ion Batteries

Sodium‐ion batteries are important alternative energy storage devices that have recently come again into focus for the development of large‐scale energy storage devices because sodium is an abundant and low‐cost material. However, the development of electrode materials with long‐term stability has remained a great challenge. A novel negative‐electrode material, a P2‐type layered oxide with the chemical composition Na_2/3Co_1/3Ti_2/3O₂, exhibits outstanding cycle stability (ca. 84.84 % capacity retention for 3000 cycles, very small decrease in the volume (0.046 %) after 500 cycles), good rate capability (ca. 41 % capacity retention at a discharge/charge rate of 10 C), and a usable reversible capacity of about 90 mAh g^?1 with a safe average storage voltage of approximately 0.7 V in the sodium half‐cell. This P2‐type layered oxide is a promising anode material for sodium‐ion batteries with a long cycle life and should greatly promote the development of room‐temperature sodium‐ion batteries.     

Germanium‐Based Nanomaterials for Rechargeable Batteries

Germanium‐based nanomaterials have emerged as important candidates for next‐generation energy‐storage devices owing to their unique chemical and physical properties. In this Review, we provide a review of the current state‐of‐the‐art in germanium‐based materials design, synthesis, processing, and application in battery technology. The most recent advances in the area of Ge‐based nanocomposite electrode materials and electrolytes for solid‐state batteries are summarized. The limitations of Ge‐based materials for energy‐storage applications are discussed, and potential research directions are also presented with an emphasis on commercial products and theoretical investigations.     

Bio‐Inspired Isoalloxazine Redox Moieties for Rechargeable Aqueous Zinc‐Ion Batteries

Organic electrode materials hold great potential for fabricating sustainable energy storage systems, however, the development of organic redox‐active moieties for rechargeable aqueous zinc‐ion batteries is still at an early stage. Here, we report a bio‐inspired riboflavin‐based aqueous zinc‐ion battery utilizing an isoalloxazine ring as the redox center for the first time. This battery exhibits a high capacity of 145.5 mAh g^?1 at 0.01 A g^?1 and a long‐life stability of 3000 cycles at 5 A g^?1. We demonstrate that isoalloxazine moieties are active centers for reversible zinc‐ion storage by using optical and photoelectron spectroscopies as well as theoretical calculations. Through molecule‐structure tailoring of riboflavin, the obtained alloxazine and lumazine molecules exhibit much higher theoretical capacities of 250.3 and 326.6 mAh g^?1, respectively. Our work offers an effective redox‐active moiety for aqueous zinc batteries and will enrich the valuable material pool for electrode design.     

High‐Capacity Anode Materials for Sodium‐Ion Batteries

Na‐ion batteries are an attractive alternative to Li‐ion batteries for large‐scale energy storage systems because of their low cost and the abundant Na resources. This Review provides a comprehensive overview of selected anode materials with high reversible capacities that can increase the energy density of Na‐ion batteries. Moreover, we discuss the reaction and failure mechanisms of those anode materials with a view to suggesting promising strategies for improving their electrochemical performance.     

Rechargeable Room‐Temperature Na–CO2 Batteries

Developing rechargeable Na–CO₂ batteries is significant for energy conversion and utilization of CO₂. However, the reported batteries in pure CO₂ atmosphere are non‐rechargeable with limited discharge capacity of 200 mAh g^?1. Herein, we realized the rechargeability of a Na–CO₂ battery, with the proposed and demonstrated reversible reaction of 3 CO₂+4 Na?2 Na₂CO₃+C. The battery consists of a Na anode, an ether‐based electrolyte, and a designed cathode with electrolyte‐treated multi‐wall carbon nanotubes, and shows reversible capacity of 60000 mAh g^?1 at 1 A g^?1 (≈1000 Wh kg^?1) and runs for 200 cycles with controlled capacity of 2000 mAh g^?1 at charge voltage <3.7 V. The porous structure, high electro‐conductivity, and good wettability of electrolyte to cathode lead to reduced electrochemical polarization of the battery and further result in high performance. Our work provides an alternative approach towards clean recycling and utilization of CO₂.     

An Efficient Halogen‐Free Electrolyte for Use in Rechargeable Magnesium Batteries

Unlocking the full potential of rechargeable magnesium batteries has been partially hindered by the reliance on chloride‐based complex systems. Despite the high anodic stability of these electrolytes, they are corrosive toward metallic battery components, which reduce their practical electrochemical window. Following on our new design concept involving boron cluster anions, monocarborane CB₁₁H₁₂^? produced the first halogen‐free, simple‐type Mg salt that is compatible with Mg metal and displays an oxidative stability surpassing that of ether solvents. Owing to its inertness and non‐corrosive nature, the Mg(CB₁₁H₁₂)₂/tetraglyme (MMC/G4) electrolyte system permits standardized methods of high‐voltage cathode testing that uses a typical coin cell. This achievement is a turning point in the research and development of Mg electrolytes that has deep implications on realizing practical rechargeable Mg batteries.     

High‐Performance Sodium‐Ion Batteries and Sodium‐Ion Pseudocapacitors Based on MoS2/Graphene Composites

Sodium‐ion energy storage, including sodium‐ion batteries (NIBs) and electrochemical capacitive storage (NICs), is considered as a promising alternative to lithium‐ion energy storage. It is an intriguing prospect, especially for large‐scale applications, owing to its low cost and abundance. MoS₂ sodiation/desodiation with Na ions is based on the conversion reaction, which is not only able to deliver higher capacity than the intercalation reaction, but can also be applied in capacitive storage owing to its typically sloping charge/discharge curves. Here, NIBs and NICs based on a graphene composite (MoS₂/G) were constructed. The enlarged d‐spacing, a contribution of the graphene matrix, and the unique properties of the MoS₂/G substantially optimize Na storage behavior, by accommodating large volume changes and facilitating fast ion diffusion. MoS₂/G exhibits a stable capacity of approximately 350 mAh g^?1 over 200 cycles at 0.25 C in half cells, and delivers a capacitance of 50 F g^?1 over 2000 cycles at 1.5 C in pseudocapacitors with a wide voltage window of 0.1–2.5 V.     

Halide‐Based Materials and Chemistry for Rechargeable Batteries

Rechargeable batteries are considered one of the most effective energy storage technologies to bridge the production and consumption of renewable energy. The further development of rechargeable batteries with characteristics such as high energy density, low cost, safety, and a long cycle life is required to meet the ever‐increasing energy‐storage demands. This Review highlights the progress achieved with halide‐based materials in rechargeable batteries, including the use of halide electrodes, bulk and/or surface halogen‐doping of electrodes, electrolyte design, and additives that enable fast ion shuttling and stable electrode/electrolyte interfaces, as well as realization of new battery chemistry. Battery chemistry based on monovalent cation, multivalent cation, anion, and dual‐ion transfer is covered. This Review aims to promote the understanding of halide‐based materials to stimulate further research and development in the area of high‐performance rechargeable batteries. It also offers a perspective on the exploration of new materials and systems for electrochemical energy storage.     

Regulation of Cathode‐Electrolyte Interphase via Electrolyte Additives in Lithium Ion Batteries

As the power supply of the prosperous new energy products, advanced lithium ion batteries (LIBs) are widely applied to portable energy equipment and large‐scale energy storage systems. To broaden the applicable range, considerable endeavours have been devoted towards improving the energy and power density of LIBs. However, the side reaction caused by the close contact between the electrode (particularly the cathode) and the electrolyte leads to capacity decay and structural degradation, which is a tricky problem to be solved. In order to overcome this obstacle, the researchers focused their attention on electrolyte additives. By adding additives to the electrolyte, the construction of a stable cathode‐electrolyte interphase (CEI) between the cathode and the electrolyte has been proven to competently elevate the overall electrochemical performance of LIBs. However, how to choose electrolyte additives that match different cathode systems ideally to achieve stable CEI layer construction and high‐performance LIBs is still in the stage of repeated experiments and exploration. This article specifically introduces the working mechanism of diverse electrolyte additives for forming a stable CEI layer and summarizes the latest research progress in the application of electrolyte additives for LIBs with diverse cathode materials. Finally, we tentatively set forth recommendations on the screening and customization of ideal additives required for the construction of robust CEI layer in LIBs. We believe this minireview will have a certain reference value for the design and construction of stable CEI layer to realize desirable performance of LIBs.     

Na2S–Carbon Nanotube Fabric Electrodes for Room‐Temperature Sodium–Sulfur Batteries

A unique sodium sulfide (Na₂S) cathode is developed, which will allow the use of sodium‐free anodes for room‐temperature sodium–sulfur (Na–S) batteries. To overcome the “inert” nature of the Na₂S, a special cathode structure is developed by spreading the multi‐walled carbon nanotube (MWCNT)‐wrapped Na₂S particles onto MWCNT fabrics. Spectroscopic and electrochemical analyses reveal a series of polysulfide intermediates involved in the charge/discharge of the cell. The Na–S battery prepared in full discharge state with the Na₂S/MWCNT cathode provides a remarkable capacity of 500 A h kg^?1 (based on sulfur mass) after 50 cycles.     

Antimony‐ and Bismuth‐Based Chalcogenides for Sodium‐Ion Batteries

Sodium‐ion batteries (SIBs) have received much attention, owing to their great potential for large‐scale application. A lack of efficient anode materials with high reversible capacity is one main challenge facing the development of SIBs. Antimony‐ and bismuth‐based chalcogenides materials can store large amounts of Na⁺ ions, owing to the alloying/dealloying reaction mechanism within a low potential range, and thus, are regarded as promising anodes for SIBs. However, these materials face great challenges of poor ion diffusion rate, multiple phase transformations, and severe morphology pulverization. Herein, recent developments in antimony‐ and bismuth‐based chalcogenides materials, mainly rational structural design strategies used and the electrochemical reaction mechanisms involved, are summarized. Perspectives for further improving antimony‐ and bismuth‐based chalcogenides anodes are also provided.     

From Lithium‐Ion to Sodium‐Ion Batteries: Advantages,Challenges, and Surprises

Mobile and stationary energy storage by rechargeable batteries is a topic of broad societal and economical relevance. Lithium‐ion battery (LIB) technology is at the forefront of the development, but a massively growing market will likely put severe pressure on resources and supply chains. Recently, sodium‐ion batteries (SIBs) have been reconsidered with the aim of providing a lower‐cost alternative that is less susceptible to resource and supply risks. On paper, the replacement of lithium by sodium in a battery seems straightforward at first, but unpredictable surprises are often found in practice. What happens when replacing lithium by sodium in electrode reactions? This review provides a state‐of‐the art overview on the redox behavior of materials when used as electrodes in lithium‐ion and sodium‐ion batteries, respectively. Advantages and challenges related to the use of sodium instead of lithium are discussed.     

A Stable,Non‐Corrosive Perfluorinated Pinacolatoborate Mg Electrolyte for Rechargeable Mg Batteries

Mg batteries are a promising energy storage system because of the physicochemical merits of Mg as an anode material. However, the lack of electrochemically and chemically stable Mg electrolytes impedes the development of Mg batteries. In this study, a newly designed chloride‐free Mg perfluorinated pinacolatoborate, Mg[B(O₂C₂(CF₃)₄)₂]₂ (abbreviated as Mg‐FPB ), was synthesized by a convenient method from commercially available reagents and fully characterized. The Mg‐FPB electrolyte delivered outstanding electrochemical performance, specifically, 95 % Coulombic efficiency and 197 mV overpotential, enabling reversible Mg deposition, and an anodic stability of up to 4.0 V vs. Mg. The Mg‐FPB electrolyte was applied to assemble a high voltage, rechargeable Mg/MnO₂ battery with a discharge capacity of 150 mAh g^?1.     

Porphyrin‐Based Symmetric Redox‐Flow Batteries towards Cold‐Climate Energy Storage

Electrochemical energy storage with redox‐flow batteries (RFBs) under subzero temperature is of great significance for the use of renewable energy in cold regions. However, RFBs are generally used above 10 °C. Herein we present non‐aqueous organic RFBs based on 5,10,15,20‐tetraphenylporphyrin (H₂TPP) as a bipolar redox‐active material (anode: [H₂TPP]^2?/H₂TPP, cathode: H₂TPP/[H₂TPP]²⁺) and a Y‐zeolite–poly(vinylidene fluoride) (Y‐PVDF) ion‐selective membrane with high ionic conductivity as a separator. The constructed RFBs exhibit a high volumetric capacity of 8.72 Ah L^?1 with a high voltage of 2.83 V and excellent cycling stability (capacity retention exceeding 99.98 % per cycle) in the temperature range between 20 and ?40 °C. Our study highlights principles for the design of RFBs that operate at low temperatures, thus offering a promising approach to electrochemical energy storage under cold‐climate conditions.     

Enhanced Performance of a Lithium–Sulfur Battery Using a Carbonate‐Based Electrolyte

The lithium–sulfur battery is regarded as one of the most promising candidates for lithium–metal batteries with high energy density. However, dendrite Li formation and low cycle efficiency of the Li anode as well as unstable sulfur based cathode still hinder its practical application. Herein a novel electrolyte (1 m LiODFB/EC‐DMC‐FEC) is designed not only to address the above problems of Li anode but also to match sulfur cathode perfectly, leading to extraordinary electrochemical performances. Using this electrolyte, lithium|lithium cells can cycle stably for above 2000 hours and the average Coulumbic efficiency reaches 98.8 %. Moreover, the Li–S battery delivers a reversible capacity of about 1400 mAh g^?1_sulfur with retention of 89 % for 1100 cycles at 1 C, and a capacity above 1100 mAh g^?1_sulfur at 10 C. The more advantages of this cell system are its outstanding cycle stability at 60 °C and no self‐discharge phenomena.     

Molybdenum Disulfide Based Nanomaterials for Rechargeable Batteries

The rapid development of electrochemical energy storage systems requires new electrode materials with high performance. As a two-dimensional material, molybdenum disulfide (MoS₂) has attracted increasing interest in energy storage applications due to its layered structure, tunable physical and chemical properties, and high capacity. In this review, the atomic structures and properties of different phases of MoS₂ are first introduced. Then, typical synthetic methods for MoS₂ and MoS₂-based composites are presented. Furthermore, the recent progress in the design of diverse MoS₂-based micro/nanostructures for rechargeable batteries, including lithium-ion, lithium-sulfur, sodium-ion, potassium-ion, and multivalent-ion batteries, is overviewed. Additionally, the roles of advanced in situ/operando techniques and theoretical calculations in elucidating fundamental insights into the structural and electrochemical processes taking place in these materials during battery operation are illustrated. Finally, a perspective is given on how the properties of MoS₂-based electrode materials are further improved and how they can find widespread application in the next-generation electrochemical energy-storage systems.     

Sulfur‐Based Electrodes that Function via Multielectron Reactions for Room‐Temperature Sodium‐Ion Storage

Emerging rechargeable sodium‐ion storage systems—sodium‐ion and room‐temperature sodium–sulfur (RT‐NaS) batteries—are gaining extensive research interest as low‐cost options for large‐scale energy‐storage applications. Owing to their abundance, easy accessibility, and unique physical and chemical properties, sulfur‐based materials, in particular metal sulfides (MS_x) and elemental sulfur (S), are currently regarded as promising electrode candidates for Na‐storage technologies with high capacity and excellent redox reversibility based on multielectron conversion reactions. Here, we present current understanding of Na‐storage mechanisms of the S‐based electrode materials. Recent progress and strategies for improving electronic conductivity and tolerating volume variations of the MS_x anodes in Na‐ion batteries are reviewed. In addition, current advances on S cathodes in RT‐NaS batteries are presented. We outline a novel emerging concept of integrating MS_x electrocatalysts into conventional carbonaceous matrices as effective polarized S hosts in RT‐NaS batteries as well. This comprehensive progress report could provide guidance for research toward the development of S‐based materials for the future Na‐storage techniques.     

Realizing Complete Solid‐Solution Reaction in High Sodium Content P2‐Type Cathode for High‐Performance Sodium‐Ion Batteries

P2‐type layered oxides suffer from an ordered Na⁺/vacancy arrangement and P2→O2/OP4 phase transitions, leading them to exhibit multiple voltage plateaus upon Na⁺ extraction/insertion. The deficient sodium in the P2‐type cathode easily induces the bad structural stability at deep desodiation states and limited reversible capacity during Na⁺ de/insertion. These drawbacks cause poor rate capability and fast capacity decay in most P2‐type layered oxides. To address these challenges, a novel high sodium content (0.85) and plateau‐free P2‐type cathode‐Na_0.85Li_0.12Ni_0.22Mn_0.66O₂ (P2‐NLNMO) was developed. The complete solid‐solution reaction over a wide voltage range ensures both fast Na⁺ mobility (10^?11 to 10^?10 cm² s^?1) and small volume variation (1.7 %). The high sodium content P2‐NLNMO exhibits a higher reversible capacity of 123.4 mA h g^?1, superior rate capability of 79.3 mA h g^?1 at 20 C, and 85.4 % capacity retention after 500 cycles at 5 C. The sufficient Na and complete solid‐solution reaction are critical to realizing high‐performance P2‐type cathodes for sodium‐ion batteries.     

Wet‐Chemical Synthesis of Phase‐Pure FeOF Nanorods as High‐Capacity Cathodes for Sodium‐Ion Batteries

It is challenging to prepare phase‐pure FeOF by wet‐chemical methods. Furthermore, nanostructured FeOF has never been reported. In this study, hierarchical FeOF nanorods were synthesized through a facile, one‐step, wet‐chemical method by the use of just FeF₃?3H₂O and an alcohol. It was possible to significantly control the FeOF nanostructure by the selection of alcohols with an appropriate molecular structure. A mechanism for the formation of the nanorods is proposed. An impressive high specific capacity of approximately 250 mAh g^?1 and excellent cycling and rate performances were demonstrated for sodium storage. The hierarchical FeOF nanorods are promising high‐capacity cathodes for SIBs.     

Graphite‐Nanoplate‐Coated Bi2S3 Composite with High‐Volume Energy Density and Excellent Cycle Life for Room‐Temperature Sodium–Sulfide Batteries

Graphite‐nanoplate‐coated Bi₂S₃ composite (Bi₂S₃@C) has been prepared by a simple, scalable, and energy‐efficient precipitation method combined with ball milling. The Bi₂S₃@C composite was used as the cathode material for sodium–sulfide batteries. It delivered an initial capacity of 550 mAh g^?1 and high stable specific energy in the range of 275–300 Wh kg^?1 at 0.1 C, with an enhanced capacity retention of 69 % over 100 cycles. The unique structure demonstrates superior cycling stability, with a capacity drop of 0.3 % per cycle over 100 cycles, compared with that of bare Bi₂S₃. The sodium storage mechanism of Bi₂S₃ was investigated based on ex situ X‐ray diffraction and scanning transmission electron microscopy.