Compactly Coupled Nitrogen‐Doped Carbon Nanosheets/Molybdenum Phosphide Nanocrystal Hollow Nanospheres as Polysulfide Reservoirs for High‐Performance Lithium–Sulfur Chemistry

Lithium–sulfur (Li–S) batteries have been disclosed as one of the most promising energy storage systems. However, the low utilization of sulfur, the detrimental shuttling behavior of polysulfides, and the sluggish kinetics in electrochemical processes, severely impede their application. Herein, 3D hierarchical nitrogen‐doped carbon nanosheets/molybdenum phosphide nanocrystal hollow nanospheres (MoP@C/N HCSs) are introduced to Li–S batteries via decorating commercial separators to inhibit polysulfides diffusion. It acts not only as a polysulfides immobilizer to provide strong physical trapping and chemical anchoring toward polysulfides, but also as an electrocatalyst to accelerate the kinetics of the polysulfides redox reaction, and to lower the Li₂S nucleation/dissolution interfacial energy barrier and self‐discharge capacity loss in working Li–S batteries, simultaneously. As a result, the Li–S batteries with MoP@C/N HCS‐modified separators show superior rate capability (920 mAh g^?1 at 2 C) and stable cycling life with only 0.04% capacity decay per cycle over 500 cycles at 1 C with nearly 100% Coulombic efficiency. Furthermore, the Li–S battery can achieve a high area capacity of 5.1 mAh cm^?2 with satisfied capacity retention when the cathode loading reaches 5.5 mg cm^?2. This work offers a brand new guidance for rational separator design into the energy chemistry of high‐stable Li–S batteries.     

An Advanced MoS2/Carbon Anode for High‐Performance Sodium‐Ion Batteries

Molybdenum disulfide (MoS₂) is a promising anode for high performance sodium‐ion batteries due to high specific capacity, abundance, and low cost. However, poor cycling stability, low rate capability and unclear electrochemical reaction mechanism are the main challenges for MoS₂ anode in Na‐ion batteries. In this study, molybdenum disulfide/carbon (MoS₂/C) nanospheres are fabricated and used for Na‐ion battery anodes. MoS₂/C nanospheres deliver a reversible capacity of 520 mAh g^?1 at 0.1 C and maintain at 400 mAh g^?1 for 300 cycles at a high current density of 1 C, demonstrating the best cycling performance of MoS₂ for Na‐ion batteries to date. The high capacity is attributed to the short ion and electron diffusion pathway, which enables fast charge transfer and low concentration polarization. The stable cycling performance and high coulombic efficiency (～100%) of MoS₂/C nanospheres are ascribed to (1) highly reversible conversion reaction of MoS₂ during sodiation/desodiation as evidenced by ex‐situ X‐ray diffraction (XRD) and (2) the formation of a stable solid electrolyte interface (SEI) layer in fluoroethylene carbonate (FEC) based electrolyte as demonstrated by fourier transform infrared spectroscopy (FTIR) measurements.     

MoS2/Celgard Separator as Efficient Polysulfide Barrier for Long‐Life Lithium–Sulfur Batteries

A high lithium conductive MoS₂/Celgard composite separator is reported as efficient polysulfides barrier in Li–S batteries. Significantly, thanks to the high density of lithium ions on MoS₂ surface, this composite separator shows high lithium conductivity, fast lithium diffusion, and facile lithium transference. When used in Li–S batteries, the separator is proven to be highly efficient for depressing polysulfides shuttle, leading to high and long cycle stability. With 65% of sulfur loading, the device with MoS₂/Celgard separator delivers an initial capacity of 808 mAh g^?1 and a substantial capacity of 401 mAh g^?1 after 600 cycles, corresponding to only 0.083% of capacity decay per cycle that is comparable to the best reported result so far. In addition, the Coulombic efficiency remains more than 99.5% during all 600 cycles, disclosing an efficient ionic sieve preventing polysulfides migration to the anode while having negligible influence on Li⁺ ions transfer across the separator. The strategy demonstrated in this work will open the door toward developing efficient separators with flexible 2D materials beyond graphene for energy‐storage devices.     

3D Graphene Networks Encapsulated with Ultrathin SnS Nanosheets@Hollow Mesoporous Carbon Spheres Nanocomposite with Pseudocapacitance‐Enhanced Lithium and Sodium Storage Kinetics

The lithium and sodium storage performances of SnS anode often undergo rapid capacity decay and poor rate capability owing to its huge volume fluctuation and structural instability upon the repeated charge/discharge processes. Herein, a novel and versatile method is described for in situ synthesis of ultrathin SnS nanosheets inside and outside hollow mesoporous carbon spheres crosslinked reduced graphene oxide networks. Thus, 3D honeycomb‐like network architecture is formed. Systematic electrochemical studies manifest that this nanocomposite as anode material for lithium‐ion batteries delivers a high charge capacity of 1027 mAh g^?1 at 0.2 A g^?1 after 100 cycles. Meanwhile, the as‐developed nanocomposite still retains a charge capacity of 524 mAh g^?1 at 0.1 A g^?1 after 100 cycles for sodium‐ion batteries. In addition, the electrochemical kinetics analysis verifies the basic principles of enhanced rate capacity. The appealing electrochemical performance for both lithium‐ion batteries and sodium‐ion batteries can be mainly related to the porous 3D interconnected architecture, in which the nanoscale SnS nanosheets not only offer decreased ion diffusion pathways and fast Li⁺/Na⁺ transport kinetics, but also the 3D interconnected conductive networks constructed from the hollow mesoporous carbon spheres and reduced graphene oxide enhance the conductivity and ensure the structural integrity.     

Promoting Reversible Redox Kinetics by Separator Architectures Based on CoS2/HPGC Interlayer as Efficient Polysulfide‐Trapping Shield for Li–S Batteries

Main obstacles from the shuttle effect and slow conversion rate of soluble polysulfide compromise the sulfur utilization and cycling life for lithium sulfur (Li–S) batteries. In pursuit of a practically viable high performance Li–S battery, a separator configuration (CoS₂/HPGC/interlayer) as efficient polysulfide trapping barrier is reported. This configuration endows great advantages, particularly enhanced conductivity, promoted polysulfide trapping capability, accelerated sulfur electrochemistry, when using the functional interlayer for Li–S cells. Attributed to the above merits, such cell shows excellent cyclability, with a capacity of 846 mAh g^?1 after 250 cycles corresponding to a high capacity retention of 80.2% at 0.2 C, and 519 mAh g^?1 after 500 cycles at 1C (1C = 1675 mA g^?1). In addition, the optimized separator exhibits a high initial areal capacity of 4.293 mAh cm^?2 at 0.1C. Moreover, with CoS₂/HPGC/interlayer, the sulfur cell enables a low self‐discharge rate with a very high capacity retention of 97.1%. This work presents a structural engineering of the separator toward suppressing the dissolution of soluble Li₂Sn moieties and simultaneously promoting the sulfur conversion kinetics, thus achieving durable and high capacity Li–S batteries.     

Highly Safe Electrolyte Enabled via Controllable Polysulfide Release and Efficient Conversion for Advanced Lithium–Sulfur Batteries

Conventional lithium–sulfur batteries often suffer from fatal problems such as high flammability, polysulfide shuttling, and lithium dendrites growth. Here, highly‐safe lithium–sulfur batteries based on flame‐retardant electrolyte (dimethoxyether/1,1,2,2‐tetrafluoroethyl 2,2,3,3‐tetrafluoropropyl ether) coupled with functional separator (nanoconductive carbon‐coated cellulose nonwoven) to resolve aforementioned bottle‐neck issues are demonstrated. It is found that this flame‐retardant electrolyte exhibits excellent flame retardancy and low solubility of polysulfide. In addition, Li/Li symmetrical cells using such flame‐retardant electrolyte deliver extraordinary long‐term cycling stability (less than 10 mV overpotential) for over 2500 h at 1.0 mA cm^?2 and 1.0 mAh cm^?2. Moreover, bare sulfur cathode–based lithium–sulfur batteries using this flame retardant electrolyte coupled with nanoconductive carbon‐coated cellulose separator can retain 83.6% discharge capacity after 200 cycles at 0.5 C. Under high charge/discharge rate (4 C), lithium–sulfur cells still show high charge/discharge capacity of ≈350 mAh g^?1. Even at an elevated temperature of 60 °C, discharge capacity of 870 mAh g^?1 can be retained. More importantly, high‐loading bare sulfur cathode (4 mg cm^?2)–based lithium–sulfur batteries can also deliver high charge/discharge capacity over 806 mAh g^?1 after 56 cycles. Undoubtedly, the strategy of flame retardant electrolyte coupled with carbon‐coated separator enlightens highly safe lithium–sulfur batteries at a wide range of temperature.     

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.     

Tin Nanodots Derived From Sn2+/Graphene Quantum Dot Complex as Pillars into Graphene Blocks for Ultrafast and Ultrastable Sodium‐Ion Storage

Tin (Sn) is considered to be an ideal candidate for the anode of sodium ion batteries. However, the design of Sn‐based electrodes with maintained long‐term stability still remains challenging due to their huge volume expansion (≈420%) and easy pulverization during cycling. Herein, a facile and versatile strategy for the synthesis of nitrogen‐doped graphene quantum dot (GQD) edge‐anchored Sn nanodots as the pillars into reduced graphene oxide blocks (NGQD/Sn‐NG) for ultrafast and ultrastable sodium‐ion storage is reported. Sn nanodots (2–5 nm) anchored at the edges of “octopus‐like” GQDs via covalent Sn? O? C/Sn? N? C bonds function as the pillars that ensure fast Na‐ion/electron transport across the graphene blocks. Moreover, the chemical and spatial (layered structure) confinements not only suppress Sn aggregation, but also function as physical barriers for buffering volume change upon sodiation/desodiation. Consequently, the NGQD/Sn‐NG with high structural stability exhibits excellent rate performance (555 mAh g^?1 at 0.1 A g^?1 and 198 mAh g^?1 at 10 A g^?1) and ultra‐long cycling stability (184 mAh g^?1 remaining even after 2000 cycles at 5 A g^?1). The confinement‐induced synthesis together with remarkable electrochemical performances should shed light on the practical application of highly attractive tin‐based anodes for next generation rechargeable sodium batteries.     

Rational Integration of Polypropylene/Graphene Oxide/Nafion as Ternary‐Layered Separator to Retard the Shuttle of Polysulfides for Lithium–Sulfur Batteries

The reversible electrochemical transformation from lithium (Li) and sulfur (S) into Li₂S through multielectron reactions can be utilized in secondary Li–S batteries with very high energy density. However, both the low Coulombic efficiency and severe capacity degradation limits the full utilization of active sulfur, which hinders the practical applications of Li–S battery system. The present study reports a ternary‐layered separator with a macroporous polypropylene (PP) matrix layer, graphene oxide (GO) barrier layer, and Nafion retarding layer as the separator for Li–S batteries with high Coulombic efficiency and superior cyclic stability. In the ternary‐layered separator, ultrathin layer of GO (0.0032 mg cm^?2, estimated to be around 40 layers) blocks the macropores of PP matrix, and a dense ion selective Nafion layer with a very low loading amount of 0.05 mg cm^?2 is attached as a retarding layer to suppress the crossover of sulfur‐containing species. The ternary‐layered separators are effective in improving the initial capacity and the Coulombic efficiency of Li–S cells from 969 to 1057 mAh g^?1, and from 80% to over 95% with an LiNO₃‐free electrolyte, respectively. The capacity degradation is reduced from 0.34% to 0.18% per cycle within 200 cycles when the PP separator is replaced by the ternary‐layered separators. This work provides the rational design strategy for multifunctional separators at cell scale to effective utilizing of active sulfur and retarding of polysulfides, which offers the possibility of high energy density Li–S cells with long cycling life.     

Enhancing the Sequential Conversion‐Alloying Reaction of Mixed Sn–S Hybrid Anode for Efficient Sodium Storage by a Carbon Healed Graphene Oxide

To date, the possible depletion of lithium resources has become relevant, giving rise to the interest in Na‐ion batteries (NIBs) as promising alternatives to Li‐ion batteries. While extensive investigations have examined various transition metal oxides and chalcogenides as anode materials for NIBs, few of these have been able to utilize their high specific capacity in sodium‐based systems because of their irreversibility in a charge/discharge process. Here, the mixed Sn–S nanocomposites uniformly distributed on reduced graphene oxide are prepared via a facile hydrothermal synthesis and a unique carbothermal reduction process, producing ultrafine nanoparticle with the size of 2 nm. These nanocomposites are experimentally confirmed to overcome the intrinsic drawbacks of tin sulfides such as large volume change and sluggish diffusion kinetics, demonstrating an outstanding electrochemical performance: an excellent specific capacity of 1230 mAh g^?1, and an impressive rate capability (445 mAh g^?1 at 5000 mA g^?1). The electrochemical behavior of a sequential conversion‐alloying reaction for the anode materials is investigated, revealing both the structural transition and the chemical state in the discharge/charge process. Comprehension of the reaction mechanism for the mixed Sn–S/rGO hybrid nanocomposites makes it a promising electrode material and provides a new approach for the Na‐ion battery anodes.     

Ultrafast Sodium/Potassium‐Ion Intercalation into Hierarchically Porous Thin Carbon Shells

The large‐scale application of sodium/potassium‐ion batteries is severely limited by the low and slow charge storage dynamics of electrode materials. The crystalline carbons exhibit poor insertion capability of large Na⁺/K⁺ ions, which limits the storage capability of Na/K batteries. Herein, porous S and N co‐doped thin carbon (S/N@C) with shell‐like (shell size ≈20–30 nm, shell wall ≈8–10 nm) morphology for enhanced Na⁺/K⁺ storage is presented. Thanks to the hollow structure and thin shell‐wall, S/N@C exhibits an excellent Na⁺/K⁺ storage capability with fast mass transport at higher current densities, leading to limited compromise over charge storage at high charge/discharge rates. The S/N@C delivers a high reversible capacity of 448 mAh g^‐1 for Na battery, at the current density of 100 mA g^‐1 and maintains a discharge capacity up to 337 mAh g^‐1 at 1000 mA g^‐1. Owing to shortened diffusion pathways, S/N@C delivers an unprecedented discharge capacity of 204 and 169 mAh g^‐1 at extremely high current densities of 16 000 and 32 000 mA g^‐1, respectively, with excellent reversible capacity for 4500 cycles. Moreover, S/N@C exhibits high K⁺ storage capability (320 mAh g^‐1 at current density of 50 mA g^‐1) and excellent cyclic life.     

Hierarchically Well‐Developed Porous Graphene Nanofibers Comprising N‐Doped Graphitic C‐Coated Cobalt Oxide Hollow Nanospheres As Anodes for High‐Rate Li‐Ion Batteries

Hierarchically well‐developed porous graphene nanofibers comprising N‐doped graphitic C (NGC)‐coated cobalt oxide hollow nanospheres are introduced as anodes for high‐rate Li‐ion batteries. For this, three strategies, comprising the Kirkendall effect, metal–organic frameworks, and compositing with highly conductive C, are applied to the 1D architecture. In particular, NGC layers are coated on cobalt oxide hollow nanospheres as a primary transport path of electrons followed by graphene‐nanonetwork‐constituting nanofibers as a continuous and secondary electron transport path. Superior cycling performance is achieved, as the unique nanostructure delivers a discharge capacity of 823 mAh g^?1 after 500 cycles at 3.0 A g^?1 with a low decay rate of 0.092% per cycle. The rate capability is also noteworthy as the structure exhibits high discharge capacities of 1035, 929, 847, 787, 747, 703, 672, 650, 625, 610, 570, 537, 475, 422, 294, and 222 mAh g^?1 at current densities of 0.5, 1.5, 3, 5, 7, 10, 12, 15, 18, 20, 25, 30, 40, 50, 80, and 100 A g^?1, respectively. In view of the highly efficient Li⁺ ion/electron diffusion and high structural stability, the present nanostructuring strategy has a huge potential in opening new frontiers for high‐rate and long‐lived stable energy storage systems.     

Plasma Treatment for Nitrogen‐Doped 3D Graphene Framework by a Conductive Matrix with Sulfur for High‐Performance Li–S Batteries

Carbon materials have received considerable attention as host cathode materials for sulfur in lithium–sulfur batteries; N‐doped carbon materials show particularly high electrocatalytic activity. Efforts are made to synthesize N‐doped carbon materials by introducing nitrogen‐rich sources followed by sintering or hydrothermal processes. In the present work, an in situ hollow cathode discharge plasma treatment method is used to prepare 3D porous frameworks based on N‐doped graphene as a potential conductive matrix material. The resulting N‐doped graphene is used to prepare a 3D porous framework with a S content of 90 wt% as a cathode in lithium–sulfur cells, which delivers a specific discharge capacity of 1186 mAh g^?1 at 0.1 C, a coulombic efficiency of 96% after 200 cycles, and a capacity retention of 578 mAh g^?1 at 1.0 C after 1000 cycles. The performance is attributed to the flexible 3D structure and clustering of pyridinic N‐dopants in graphene. The N‐doped graphene shows high electrochemical performance and the flexible 3D porous stable structure accommodates the considerable volume change of the active material during lithium insertion and extraction processes, improving the long‐term electrochemical performance.     

Graphene‐Protected 3D Sb‐based Anodes Fabricated via Electrostatic Assembly and Confinement Replacement for Enhanced Lithium and Sodium Storage

Alloy anodes have shown great potential for next‐generation lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). However, these applications are still limited by inherent huge volume changes and sluggish kinetics. To overcome such limitations, graphene‐protected 3D Sb‐based anodes grown on conductive substrate are designed and fabricated by a facile electrostatic‐assembling and subsequent confinement replacement strategy. As binder‐free anodes for LIBs, the obtained electrode exhibits reversible capacities of 442 mAh g⁻¹ at 100 mA g⁻¹ and 295 mAh g⁻¹ at 1000 mA g⁻¹, and a capacity retention of above 90% (based on the 10th cycle) after 200 cycles at 500 mA g⁻¹. As for sodium storage properties, the reversible capacities of 517 mAh g⁻¹ at 50 mA g⁻¹ and 315 mAh g⁻¹ at 1000 mA g⁻¹, the capacity retention of 305 mAh g⁻¹ after 100 cycles at 300 mA g⁻¹ are obtained, respectively. Furthermore, the 3D architecture retains good structural integrity after cycling, confirming that the introduction of high‐stretchy and robust graphene layers can effectively buffer alloying anodes, and simultaneously provide sustainable contact and protection of the active materials. Such findings show its great potential as superior binder‐free anodes for LIBs and SIBs.     

Highly Electrochemically‐Reversible Mesoporous Na2FePO4F/C as Cathode Material for High‐Performance Sodium‐Ion Batteries

As promising cathode materials, iron‐based phosphate compounds have attracted wide attention for sodium‐ion batteries due to their low cost and safety. Among them, sodium iron fluorophosphate (Na₂FePO₄F) is widely noted due to its layered structure and high operating voltage compared with NaFePO₄. Here, a mesoporous Na₂FePO₄F@C (M‐NFPF@C) composite derived from mesoporous FePO₄ is synthesized through a facile ball‐milling combined calcination method. Benefiting from the mesoporous structure and highly conductive carbon, the M‐NFPF@C material exhibits a high reversible capacity of 114 mAh g^?1 at 0.1 C, excellent rate capability (42 mAh g^?1 at 10 C), and good cycling performance (55% retention after 600 cycles at 5 C). The high plateau capacity obtained (>90% of total capacity) not only shows high electrochemical reversibility of the as‐prepared M‐NFPF@C but also provides high energy density, which mainly originates from its mesoporous structure derived from the mesoporous FePO₄ precursor. The M‐NFPF@C serves as a promising cathode material with high performance and low cost for sodium‐ion batteries.     

Nitrogen Doped γ‐Graphyne: A Novel Anode for High‐Capacity Rechargeable Alkali‐Ion Batteries

High energy density is the major demand for next‐generation rechargeable batteries, while the intrinsic low alkali metal adsorption of traditional carbon–based electrode remains the main challenge. Here, the mechanochemical route is proposed to prepare nitrogen doped γ‐graphyne (NGY) and its high capacity is demonstrated in lithium (LIBs)/sodium (SIBs) ion batteries. The sample delivers large reversible Li (1037 mAh g^?1) and Na (570.4 mAh g^?1) storage capacities at 100 mA g^?1 and presents excellent rate capabilities (526 mAh g^?1 for LIBs and 180.2 mAh g^?1 for SIBs) at 5 A g^?1. The superior Li/Na storage mechanisms of NGY are revealed by its 2D morphology evolution, quantitative kinetics, and theoretical calculations. The effects on the diffusion barriers (E_b) and adsorption energies (E_ad) of Li/Na atoms in NGY are also studied and imine‐N is demonstrated to be the ideal doping format to enhance the Li/Na storage performance. Besides, the Li/Na adsorption routes in NGY are optimized according to the experimental and the first‐principles calculation results. This work provides a facile way to fabricate high capacity electrodes in LIBs/SIBs, which is also instructive for the design of other heteroatomic doped electrodes.     

A Highly Conductive MOF of Graphene Analogue Ni3(HITP)2 as a Sulfur Host for High‐Performance Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries have been considered as one of the most promising energy storage systems owing to their high theoretical capacity and energy density. However, their commercial applications are obstructed by sluggish reaction kinetics and rapid capacity degradation mainly caused by polysulfide shuttling. Herein, the first attempt to utilize a highly conductive metal–organic framework (MOF) of Ni₃(HITP)₂ graphene analogue as the sulfur host material to trap and transform polysulfides for high‐performance Li–S batteries is made. Besides, the traditional conductive additive acetylene black is replaced by carbon nanotubes to construct matrix conduction networks for triggering the rate and cycling performance of the active cathode. As a result, the S@Ni₃(HITP)₂ with sulfur content of 65.5 wt% shows excellent sulfur utilization, rate performance, and cyclic durability. It delivers a high initial capacity of 1302.9 mAh g^?1 and good capacity retention of 848.9 mAh g^?1 after 100 cycles at 0.2 C. Highly reversible discharge capacities of 807.4 and 629.6 mAh g^?1 are obtained at 0.5 and 1 C for 150 and 300 cycles, respectively. Such kinds of pristine MOFs with high conductivity and abundant polar sites reveal broad promising prospect for application in the field of high‐performance Li–S batteries.     

Implanting Atomic Cobalt within Mesoporous Carbon toward Highly Stable Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries hold great promise to serve as next‐generation energy storage devices. However, the practical performances of Li–S batteries are severely limited by the sulfur cathode regarding its low conductivity, huge volume change, and the polysulfide shuttle effect. The first two issues have been well addressed by introducing mesoporous carbon hosts to the sulfur cathode. Unfortunately, the nonpolar nature of carbon materials renders poor affinity to polar polysulfides, leaving the shuttling issue unaddressed. In this contribution, atomic cobalt is implanted within the skeleton of mesoporous carbon via a supramolecular self‐templating strategy, which simultaneously improves the interaction with polysulfides and maintains the mesoporous structure. Moreover, the atomic cobalt dopants serve as active sites to improve the kinetics of the sulfur redox reactions. With the atomic‐cobalt‐decorated mesoporous carbon host, a high capacity of 1130 mAh g_S^?1 at 0.5 C and a high stability with a retention of 74.1% after 300 cycles are realized. Implanting atomic metal in mesoporous carbon demonstrates a feasible strategy to endow nanomaterials with targeted functions for Li–S batteries and broad applications.     

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.     

Dual‐Function,Tunable, Nitrogen‐Doped Carbon for High‐Performance Li Metal–Sulfur Full Cell

Lithium metal–sulfur (Li–S) batteries are attracting broad interest because of their high capacity. However, the batteries experience the polysulfide shuttle effect in cathode and dendrite growth in the Li metal anode. Herein, a bifunctional and tunable mesoporous carbon sphere (MCS) that simultaneously boosts the performance of the sulfur cathode and the Li anode is designed. The MCS homogenizes the flux of Li ions and inhibits the growth of Li dendrites due to its honeycomb structure with high surface area and abundance of nitrogen sites. The Li@MCS cell exhibits a small overpotential of 29 mV and long cycling performance of 350 h under the current density of 1 mA cm^‐2. Upon covering one layer of amorphous carbon on the MCS (CMCS), an individual carbon cage is able to encapsulate sulfur inside and reduce the polysulfide shuttle, which improves the cycling stability of the Li–S battery. As a result, the S@CMCS has a maximum capacity of 411 mAh g^‐1 for 200 cycles at a current density of 3350 mA g^‐1. Based on the excellent performance, the full Li–S cell assembled with Li@MCS anode and S@CMCS cathode shows much higher capacity than a cell assembled with Li@Cu anode and S@CMCS cathode.