Hierarchical Porous Nanosheets Constructed by Graphene‐Coated,Interconnected TiO2 Nanoparticles for Ultrafast Sodium Storage

Sodium‐ion batteries (SIBs) are considered promising next‐generation energy storage devices. However, a lack of appropriate high‐performance anode materials has prevented further improvements. Here, a hierarchical porous hybrid nanosheet composed of interconnected uniform TiO₂ nanoparticles and nitrogen‐doped graphene layer networks (TiO₂@NFG HPHNSs) that are synthesized using dual‐functional C₃N₄ nanosheets as both the self‐sacrificing template and hybrid carbon source is reported. These HPHNSs deliver high reversible capacities of 146 mA h g^?1 at 5 C for 8000 cycles, 129 mA h g^?1 at 10 C for 20 000 cycles, and 116 mA h g^?1 at 20 C for 10 000 cycles, as well as an ultrahigh rate capability up to 60 C with a capacity of 101 mA h g^?1. These results demonstrate the longest cyclabilities and best rate capability ever reported for TiO₂‐based anode materials for SIBs. The unprecedented sodium storage performance of the TiO₂@NFG HPHNSs is due to their unique composition and hierarchical porous 2D structure.     

Hierarchically Porous Fe2CoSe4 Binary‐Metal Selenide for Extraordinary Rate Performance and Durable Anode of Sodium‐Ion Batteries

Owing to high energy capacities, transition metal chalcogenides have drawn significant research attention as the promising electrode materials for sodium‐ion batteries (SIBs). However, limited cycle life and inferior rate capabilities still hinder their practical application. Improvement of the intrinsic conductivity by smart choice of elemental combination along with carbon coupling of the nanostructures may result in excellence of rate capability and prolonged cycling stability. Herein, a hierarchically porous binary transition metal selenide (Fe₂CoSe₄, termed as FCSe) nanomaterial with improved intrinsic conductivity was prepared through an exclusive methodology. The hierarchically porous structure, intimate nanoparticle–carbon matrix contact, and better intrinsic conductivity result in extraordinary electrochemical performance through their synergistic effect. The synthesized FCSe exhibits excellent rate capability (816.3 mA h g^?1 at 0.5 A g^?1 and 400.2 mA h g^?1 at 32 A g^?1), extended cycle life (350 mA h g^?1 even after 5000 cycles at 4 A g^?1), and adequately high energy capacity (614.5 mA h g^?1 at 1 A g^?1 after 100 cycles) as anode material for SIBs. When further combined with lab‐made Na₃V₂(PO₄)₃/C cathode in Na‐ion full cells, FCSe presents reasonably high and stable specific capacity.     

Porous Carbon Nanofibers Encapsulated with Peapod‐Like Hematite Nanoparticles for High‐Rate and Long‐Life Battery Anodes

Fe₂O₃ is regarded as a promising anode material for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) due to its high specific capacity. The large volume change during discharge and charge processes, however, induces significant cracking of the Fe₂O₃ anodes, leading to rapid fading of the capacity. Herein, a novel peapod‐like nanostructured material, consisting of Fe₂O₃ nanoparticles homogeneously encapsulated in the hollow interior of N‐doped porous carbon nanofibers, as a high‐performance anode material is reported. The distinctive structure not only provides enough voids to accommodate the volume expansion of the pea‐like Fe₂O₃ nanoparticles but also offers a continuous conducting framework for electron transport and accessible nanoporous channels for fast diffusion and transport of Li/Na‐ions. As a consequence, this peapod‐like structure exhibits a stable discharge capacity of 1434 mAh g^?1 (at 100 mA g^?1) and 806 mAh g^?1 (at 200 mA g^?1) over 100 cycles as anode materials for LIBs and SIBs, respectively. More importantly, a stable capacity of 958 mAh g^?1 after 1000 cycles and 396 mAh g^?1 after 1500 cycles can be achieved for LIBs and SIBs, respectively, at a large current density of 2000 mA g^?1. This study provides a promising strategy for developing long‐cycle‐life LIBs and SIBs.     

S‐Doped Carbon Fibers Uniformly Embedded with Ultrasmall TiO2 for Na+/Li+ Storage with High Capacity and Long‐Time Stability

Building a rechargeable battery with high capacity, high energy density, and long lifetime contributes to the development of novel energy storage devices in the future. Although carbon materials are very attractive anode materials for lithium‐ion batteries (LIBs), they present several deficiencies when used in sodium‐ion batteries (SIBs). The choice of an appropriate structural design and heteroatom doping are critical steps to improve the capacity and stability. Here, carbon‐based nanofibers are produced by sulfur doping and via the introduction of ultrasmall TiO₂ nanoparticles into the carbon fibers (CNF‐S@TiO₂). It is discovered that the introduction of TiO₂ into carbon nanofibers can significantly improve the specific surface area and microporous volume for carbon materials. The TiO₂ content is controlled to obtain CNF‐S@TiO₂‐5 to use as the anode material for SIBs/LIBs with enhanced electrochemical performance in Na⁺/Li⁺ storage. During the charge/discharge process, the S‐doping and the incorporation of TiO₂ nanoparticles into carbon fibers promote the insertion/extraction of the ions and enhance the capacity and cycle life. The capacity of CNF‐S@TiO₂‐5 can be maintained at ≈300 mAh g^?1 over 600 cycles at 2 A g^?1 in SIBs. Moreover, the capacity retention of such devices is 94%, showing high capacity and good stability.     

Unique Cobalt Sulfide/Reduced Graphene Oxide Composite as an Anode for Sodium‐Ion Batteries with Superior Rate Capability and Long Cycling Stability

Exploitation of high‐performance anode materials is essential but challenging to the development of sodium‐ion batteries (SIBs). Among all proposed anode materials for SIBs, sulfides have been proved promising candidates due to their unique chemical and physical properties. In this work, a facile solvothermal method to in situ decorate cobalt sulfide (CoS) nanoplates on reduced graphene oxide (rGO) to build CoS@rGO composite is described. When evaluated as anode for SIBs, an impressive high specific capacity (540 mAh g^?1 at 1 A g^?1), excellent rate capability (636 mAh g^?1 at 0.1 A g^?1 and 306 mAh g^?1 at 10 A g^?1), and extraordinarily cycle stability (420 mAh g^?1 at 1 A g^?1 after 1000 cycles) have been demonstrated by CoS@rGO composite for sodium storage. The synergetic effect between the CoS nanoplates and rGO matrix contributes to the enhanced electrochemical performance of the hybrid composite. The results provide a facile approach to fabricate promising anode materials for high‐performance SIBs.     

N‐Doped Carbon Nanofibers with Interweaved Nanochannels for High‐Performance Sodium‐Ion Storage

Although graphite materials have been applied as commercial anodes in lithium‐ion batteries (LIBs), there still remain abundant spaces in the development of carbon‐based anode materials for sodium‐ion batteries (SIBs). Herein, an electrospinning route is reported to fabricate nitrogen‐doped carbon nanofibers with interweaved nanochannels (NCNFs‐IWNC) that contain robust interconnected 1D porous channels, produced by removal of a Te nanowire template that is coelectrospun within carbon nanofibers during the electrospinning process. The NCNFs‐IWNC features favorable properties, including a conductive 1D interconnected porous structure, a large specific surface area, expanded interlayer graphite‐like spacing, enriched N‐doped defects and active sites, toward rapid access and transport of electrolyte and electron/sodium ions. Systematic electrochemical studies indicate that the NCNFs‐IWNC exhibits an impressively high rate capability, delivering a capacity of 148 mA h g^?1 at current density of as high as 10 A g^?1, and has an attractively stable performance over 5000 cycles. The practical application of the as‐designed NCNFs‐IWNC for a full SIBs cell is further verified by coupling the NCNFs‐IWNC anode with a FeFe(CN)₆ cathode, which displays a desirable cycle performance, maintaining acapacity of 97 mA h g^?1 over 100 cycles.     

Controllable N‐Doped CuCo2O4@C Film as a Self‐Supported Anode for Ultrastable Sodium‐Ion Batteries

Rational synthesis of flexible electrodes is crucial to rapid growth of functional materials for energy‐storage systems. Herein, a controllable fabrication is reported for the self‐supported structure of CuCo₂O₄ nanodots (≈3 nm) delicately inserted into N‐doped carbon nanofibers (named as 3‐CCO@C); this composite is first used as binder‐free anode for sodium‐ion batteries (SIBs). Benefiting from the synergetic effect of ultrasmall CuCo₂O₄ nanoparticles and a tailored N‐doped carbon matrix, the 3‐CCO@C composite exhibits high cycling stability (capacity of 314 mA h g^?1 at 1000 mA g^?1 after 1000 cycles) and high rate capability (296 mA h g^?1, even at 5000 mA g^?1). Significantly, the Na storage mechanism is systematically explored, demonstrating that the irreversible reaction of CuCo₂O₄, which decomposes to Cu and Co, happens in the first discharge process, and then a reversible reaction between metallic Cu/Co and CuO/Co₃O₄ occurrs during the following cycles. This result is conducive to a mechanistic study of highly promising bimetallic‐oxide anodes for rechargeable SIBs.     

Ultrahigh Rate Performance of Hollow Antimony Nanoparticles Impregnated in Open Carbon Boxes for Sodium‐Ion Battery under Elevated Temperature

Antimony is a competitive and promising anode material for sodium‐ion batteries (SIBs) due to its high theoretical capacity. However, the poor rate capability and fast capacity fading greatly restrict its practical application. To address the above issues, a facile and eco‐friendly sacrificial template method is developed to synthesize hollow Sb nanoparticles impregnated in open carbon boxes (Sb HPs@OCB). The as‐obtained Sb HPs@OCB composite exhibits excellent sodium storage properties even when operated at an elevated temperature of 50 °C, delivering a robust rate capability of 345 mAh g^?1 at 16 A g^?1 and rendering an outstanding reversible capacity of 187 mAh g^?1 at a high rate of 10 A g^?1 after 300 cycles. Such superior electrochemical performance of the Sb HPs@OCB can be attributed to the comprehensive characteristics of improved kinetics derived from hollow Sb nanoparticles impregnated into 2D carbon nanowalls, the existence of robust Sb? O? C bond, and enhanced pseudocapacitive behavior. All those factors enable Sb HPs@OCB great potential and distinct merit for large‐scale energy storage of SIBs.     

A Universal Strategy for Intimately Coupled Carbon Nanosheets/MoM Nanocrystals (M = P,S, C,and O) Hierarchical Hollow Nanospheres for Hydrogen Evolution Catalysis and Sodium‐Ion Storage

Intimately coupled carbon/transition‐metal‐based hierarchical nanostructures are one of most interesting electrode materials for boosting energy conversion and storage applications owing to the strong synergistic effect between the two components and appealing structural stability. Herein, a universal method is reported for making hierarchical hollow carbon nanospheres (HCSs) with intimately coupled ultrathin carbon nanosheets and Mo‐based nanocrystals. The in situ and confined reaction of the synthetic strategy can not only allow the aggregation of the nanocrystals to be impeded, but also endows extremely intimate coupled interaction between the conductive carbon nanosheets and the nanocrystals MoM (M = P, S, C and O). As a proof of concept, the as‐prepared MoP/C HCSs exhibit extraordinary hydrogen evolution reaction electrocatalytic activity with small overpotential and robust durability in both acidic and alkaline solutions. In addition, the unique sheet‐on‐sheet MoS₂/C HCSs as an anode demonstrate high capacity, great rate capabilities, and long‐term cycles for sodium‐ion batteries (SIBs). The capacity can be maintained at 410 mA h g^?1 even after 1000 cycles even at a high current density of 4 A g^?1, one of the best reported values for MoS₂‐based electrode materials for SIBs. The present work highlights the importance of designing and fabricating functional strongly coupled hybrid materials for enhancing energy conversion and storage applications.     

High‐Performance Flexible Freestanding Anode with Hierarchical 3D Carbon‐Networks/Fe7S8/Graphene for Applicable Sodium‐Ion Batteries

Sodium‐ion batteries (SIBs) have gained tremendous interest for grid scale energy storage system and power energy batteries. However, the current researches of anode for SIBs still face the critical issues of low areal capacity, limited cycle life, and low initial coulombic efficiency for practical application perspective. To solve this issue, a kind of hierarchical 3D carbon‐networks/Fe₇S₈/graphene (CFG) is designed and synthesized as freestanding anode, which is constructed with Fe₇S₈ microparticles well‐welded on 3D‐crosslinked carbon‐networks and embedded in highly conductive graphene film, via a facile and scalable synthetic method. The as‐prepared freestanding electrode CFG represents high areal capacity (2.12 mAh cm^?2 at 0.25 mA cm^?2) and excellent cycle stability of 5000 cycles (0.0095% capacity decay per cycle). The assembled all‐flexible sodium‐ion battery delivers remarkable performance (high areal capacity of 1.42 mAh cm^?2 at 0.3 mA cm^?2 and superior energy density of 144 Wh kg^?1), which are very close to the requirement of practical application. This work not only enlightens the material design and electrode engineering, but also provides a new kind of freestanding high energy density anode with great potential application prospective for SIBs.     

Graphitic Carbon Nitride (g‐C3N4)‐Derived N‐Rich Graphene with Tuneable Interlayer Distance as a High‐Rate Anode for Sodium‐Ion Batteries

Heteroatom‐doped carbon materials with expanded interlayer distance have been widely studied as anodes for sodium‐ion batteries (SIBs). However, it remains unexplored to further enlarge the interlayer spacing and reveal the influence of heteroatom doping on carbon nanostructures for developing more efficient SIB anode materials. Here, a series of N‐rich few‐layer graphene (N‐FLG) with tuneable interlayer distance ranging from 0.45 to 0.51 nm is successfully synthesized by annealing graphitic carbon nitride (g‐C₃N₄) under zinc catalysis and selected temperature (T = 700, 800, and 900 °C). More significantly, the correlation between N dopants and interlayer distance of resultant N‐FLG‐T highlights the effect of pyrrolic N on the enlargement of graphene interlayer spacing, due to its stronger electrostatic repulsion. As a consequence, N‐FLG‐800 achieves the optimal properties in terms of interlayer spacing, nitrogen configuration and electronic conductivity. When used as an anode for SIBs, N‐FLG‐800 shows remarkable Na⁺ storage performance with ultrahigh rate capability (56.6 mAh g^?1 at 40 A g^?1) and excellent long‐term stability (211.3 mAh g^?1 at 0.5 A g^?1 after 2000 cycles), demonstrating the effectiveness of material design.     

Confinement Growth of Layered WS2 in Hollow Beaded Carbon Nanofibers with Synergistic Anchoring Effect to Reinforce Li+/Na+ Storage Performance

Novel nitrogen doped (N‐doped) hollow beaded structural composite carbon nanofibers are successfully applied for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). Tungsten disulfide (WS₂) nanosheets are confined, through synergistic anchoring, on the surface and inside of hollow beaded carbon nanofibers (HB CNFs) via a hydrothermal reaction method to construct the hierarchical structure HB WS₂@CNFs. Benefiting from this unique advantage, HB WS₂@CNFs exhibits remarkable lithium‐storage performance in terms of high rate capability (≈351 mAh g^?1 at 2 A g^?1) and stable long‐term cycle (≈446 mAh g^?1 at 1 A g^?1 after 100 cycles). Moreover, as an anode material for SIBs, HB WS₂@CNFs obtains excellent long cycle life and rate performance. During the charging/discharging process, the evolution of morphology and composition of the composite are analyzed by a set of ex situ methods. This synergistic anchoring effect between WS₂ nanosheets and HB CNFs is capable of effectively restraining volume expansion from the metal ions intercalation/deintercalation process and improving the cycling stability and rate performance in LIBs and SIBs.     

Mesoporous NiS2 Nanospheres Anode with Pseudocapacitance for High‐Rate and Long‐Life Sodium‐Ion Battery

It is of great importance to exploit electrode materials for sodium‐ion batteries (SIBs) with low cost, long life, and high‐rate capability. However, achieving quick charge and high power density is still a major challenge for most SIBs electrodes because of the sluggish sodiation kinetics. Herein, uniform and mesoporous NiS₂ nanospheres are synthesized via a facile one‐step polyvinylpyrrolidone assisted method. By controlling the voltage window, the mesoporous NiS₂ nanospheres present excellent electrochemical performance in SIBs. It delivers a high reversible specific capacity of 692 mA h g^?1. The NiS₂ anode also exhibits excellent high‐rate capability (253 mA h g^?1 at 5 A g^?1) and long‐term cycling performance (319 mA h g^?1 capacity remained even after 1000 cycles at 0.5 A g^?1). A dominant pseudocapacitance contribution is identified and verified by kinetics analysis. In addition, the amorphization and conversion reactions during the electrochemical process of the mesoporous NiS₂ nanospheres is also investigated by in situ X‐ray diffraction. The impressive electrochemical performance reveals that the NiS₂ offers great potential toward the development of next generation large scale energy storage.     

Construction of Bimetallic Selenides Encapsulated in Nitrogen/Sulfur Co‐Doped Hollow Carbon Nanospheres for High‐Performance Sodium/Potassium‐Ion Half/Full Batteries

Metallic selenides have been widely investigated as promising electrode materials for metal‐ion batteries based on their relatively high theoretical capacity. However, rapid capacity decay and structural collapse resulting from the larger‐sized Na⁺/K⁺ greatly hamper their application. Herein, a bimetallic selenide (MoSe₂/CoSe₂) encapsulated in nitrogen, sulfur‐codoped hollow carbon nanospheres interconnected reduced graphene oxide nanosheets (rGO@MCSe) are successfully designed as advanced anode materials for Na/K‐ion batteries. As expected, the significant pseudocapacitive charge storage behavior substantially contributes to superior rate capability. Specifically, it achieves a high reversible specific capacity of 311 mAh g^?1 at 10 A g^?1 in NIBs and 310 mAh g^?1 at 5 A g^?1 in KIBs. A combination of ex situ X‐ray diffraction, Raman spectroscopy, and transmission electron microscopy tests reveals the phase transition of rGO@MCSe in NIBs/KIBs. Unexpectedly, they show quite different Na⁺/K⁺ insertion/extraction reaction mechanisms for both cells, maybe due to more sluggish K⁺ diffusion kinetics than that of Na⁺. More significantly, it shows excellent energy storage properties in Na/K‐ion full cells when coupled with Na₃V₂(PO₄)₂O₂F and PTCDA@450 °C cathodes. This work offers an advanced electrode construction guidance for the development of high‐performance energy storage devices.     

Golden Bristlegrass‐Like Hierarchical Graphene Nanofibers Entangled with N‐Doped CNTs Containing CoSe2 Nanocrystals at Each Node as Anodes for High‐Rate Sodium‐Ion Batteries

Golden bristlegrass‐like unique nanostructures comprising reduced graphene oxide (rGO) matrixed nanofibers entangled with bamboo‐like N‐doped carbon nanotubes (CNTs) containing CoSe₂ nanocrystals at each node (denoted as N‐CNT/rGO/CoSe₂ NF) are designed as anodes for high‐rate sodium‐ion batteries (SIBs). Bamboo‐like N‐doped CNTs (N‐CNTs) are successfully generated on the rGO matrixed nanofiber surface, between rGO sheets and mesopores, and interconnected chemically with homogeneously distributed rGO sheets. The defects in the N‐CNTs formed by a simple etching process allow the complete phase conversion of Co into CoSe₂ through the efficient penetration of H₂Se gas inside the CNT walls. The N‐CNTs bridge the vertical defects for electron transfer in the rGO sheet layers and increase the distance between the rGO sheets during cycles. The discharge capacity of N‐CNT/rGO/CoSe₂ NF after the 10 000th cycle at an extremely high current density of 10 A g^?1 is 264 mA h g^?1, and the capacity retention measured at the 100th cycle is 89%. N‐CNT/rGO/CoSe₂ NF has final discharge capacities of 395, 363, 328, 304, 283, 263, 246, 223, 197, 171, and 151 mA h g^?1 at current densities of 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 A g^?1, respectively.     

Bismuth Nanoparticle@Carbon Composite Anodes for Ultralong Cycle Life and High‐Rate Sodium‐Ion Batteries

Bismuth has emerged as a promising anode material for sodium‐ion batteries (SIBs), owing to its high capacity and suitable operating potential. However, large volume changes during alloying/dealloying processes lead to poor cycling performance. Herein, bismuth nanoparticle@carbon (Bi@C) composite is prepared via a facile annealing method using a commercial coordination compound precursor of bismuth citrate. The composite has a uniform structure with Bi nanoparticles embedded within a carbon framework. The nanosized structure ensures a fast kinetics and efficient alleviation of stress/strain caused by the volume change, and the resilient and conductive carbon matrix provides an interconnected electron transportation pathway. The Bi@C composite delivers outstanding sodium‐storage performance with an ultralong cycle life of 30 000 cycles at a high current density of 8 A g^?1 and an excellent rate capability of 71% capacity retention at an ultrahigh current rate of 60 A g^?1. Even at a high mass loading of 11.5 mg cm^?2, a stable reversible capacity of 280 mA h g^?1 can be obtained after 200 cycles. More importantly, full SIBs by pairing with a Na₃V₂(PO₄)₃ cathode demonstrates superior performance. Combining the facile synthesis and the commercial precursor, the exceptional performance makes the Bi@C composite very promising for practical large‐scale applications.     

In Situ Carbon‐Doped Mo(Se0.85S0.15)2 Hierarchical Nanotubes as Stable Anodes for High‐Performance Sodium‐Ion Batteries

Sodium‐ion batteries (SIBs) are promising energy storage devices, but suffer from poor cycling stability and low rate capability. In this work, carbon doped Mo(Se_0.85S_0.15)₂ (i.e., Mo(Se_0.85S_0.15)₂:C) hierarchical nanotubes have been synthesized for the first time and serve as a robust and high‐performance anode material. The hierarchical nanotubes with diameters of 300 nm and wall thicknesses of 50 nm consist of numerous 2D layered nanosheets, and can act as a robust host for sodiation/desodiation cycling. The Mo(Se_0.85S_0.15)₂:C hierarchical nanotubes deliver a discharge capacity of 360 mAh g⁻¹ at a high current density of 2000 mA g⁻¹ and keep a 81.8% capacity retention compared to that at a current density of 50 mA g⁻¹, showing superior rate capability. Comparing with the second cycle discharge capacities, the nanotube anode can maintain capacities of 102.2%, 101.9%, and 97.8% after 100 cycles at current densities of 200, 500, and 1000 mA g⁻¹, respectively. This work demonstrates the best cycling performance and high‐rate sodium storage capabilities of MoSe₂ for SIBs to date. The hollow interior, hierarchical organization, layered structure, and carbon doping are beneficial for fast Na⁺‐ion and electron kinetics and are responsible for the stable cycling performance and high rate capabilities.     

Rational Construction of Hollow Core‐Branch CoSe2 Nanoarrays for High‐Performance Asymmetric Supercapacitor and Efficient Oxygen Evolution

Metal selenides have great potential for electrochemical energy storage, but are relatively scarce investigated. Herein, a novel hollow core‐branch CoSe₂ nanoarray on carbon cloth is designed by a facile selenization reaction of predesigned CoO nanocones. And the electrochemical reaction mechanism of CoSe₂ in supercapacitor is studied in detail for the first time. Compared with CoO, the hollow core‐branch CoSe₂ has both larger specific surface area and higher electrical conductivity. When tested as a supercapacitor positive electrode, the CoSe₂ delivers a high specific capacitance of 759.5 F g^?1 at 1 mA cm^?2, which is much larger than that of CoO nanocones (319.5 F g^?1). In addition, the CoSe₂ electrode exhibits excellent cycling stability in that a capacitance retention of 94.5% can be maintained after 5000 charge–discharge cycles at 5 mA cm^?2. An asymmetric supercapacitor using the CoSe₂ as cathode and an N‐doped carbon nanowall as anode is further assembled, which show a high energy density of 32.2 Wh kg^?1 at a power density of 1914.7 W kg^?1, and maintains 24.9 Wh kg^?1 when power density increased to 7354.8 W kg^?1. Moreover, the CoSe₂ electrode also exhibits better oxygen evolution reaction activity than that of CoO.     

Focus on Spinel Li4Ti5O12 as Insertion Type Anode for High‐Performance Na‐Ion Batteries

Sodium‐ion batteries (SIBs) toward large‐scale energy storage applications has fascinated researchers in recent years owing to the low cost, environmental friendliness, and inestimable abundance. The similar chemical and electrochemical properties of sodium and lithium make sodium an easy substitute for lithium in lithium‐ion batteries. However, the main issues of limited cycle life, low energy density, and poor power density hamper the commercialization process. In the last few years, the development of electrode materials for SIBs has been dedicated to improving sodium storage capacities, high energy density, and long cycle life. The insertion type spinel Li₄Ti₅O₁₂ (LTO) possesses “zero‐strain” behavior that offers the best cycle life performance among all reported oxide‐based anodes, displaying a capacity of 155 mAh g^?1 via a three‐phase separation mechanism, and competing for future topmost high energy anode for SIBs. Recent reports offer improvement of overall electrode performance through carbon coating, doping, composites with metal oxides, and surface modification techniques, etc. Further, LTO anode with its structure and properties for SIBs is described and effective methods to improve the LTO performance are discussed in both half‐cell and practical configuration, i.e., full‐cell, along with future perspectives and solutions to promote its use.     

In Situ Encapsulating α‐MnS into N,S‐Codoped Nanotube‐Like Carbon as Advanced Anode Material: α → β Phase Transition Promoted Cycling Stability and Superior Li/Na‐Storage Performance in Half/Full Cells

Incorporation of N,S‐codoped nanotube‐like carbon (N,S‐NTC) can endow electrode materials with superior electrochemical properties owing to the unique nanoarchitecture and improved kinetics. Herein, α‐MnS nanoparticles (NPs) are in situ encapsulated into N,S‐NTC, preparing an advanced anode material (α‐MnS@N,S‐NTC) for lithium‐ion/sodium‐ion batteries (LIBs/SIBs). It is for the first time revealed that electrochemical α → β phase transition of MnS NPs during the 1st cycle effectively promotes Li‐storage properties, which is deduced by the studies of ex situ X‐ray diffraction/high‐resolution transmission electron microscopy and electrode kinetics. As a result, the optimized α‐MnS@N,S‐NTC electrode delivers a high Li‐storage capacity (1415 mA h g^?1 at 50 mA g^?1), excellent rate capability (430 mA h g^?1 at 10 A g^?1), and long‐term cycling stability (no obvious capacity decay over 5000 cycles at 1 A g^?1) with retained morphology. In addition, the N,S‐NTC‐based encapsulation plays the key roles on enhancing the electrochemical properties due to its high conductivity and unique 1D nanoarchitecture with excellent protective effects to active MnS NPs. Furthermore, α‐MnS@N,S‐NTC also delivers high Na‐storage capacity (536 mA h g^?1 at 50 mA g^?1) without the occurrence of such α → β phase transition and excellent full‐cell performances as coupling with commercial LiFePO₄ and LiNi_0.6Co_0.2Mn_0.2O₂ cathodes in LIBs as well as Na₃V₂(PO₄)₂O₂F cathode in SIBs.