Bifunctional Conducting Polymer Coated CoP Core–Shell Nanowires on Carbon Paper as a Free‐Standing Anode for Sodium Ion Batteries

This study proposes a conformal surface coating of conducting polymer for protecting 1D nanostructured electrode material, thereby enabling a free‐standing electrode without binder for sodium ion batteries. Here, polypyrrole (PPy), which is one of the representative conducting polymers, encapsulated cobalt phosphide (CoP) nanowires (NWs) grown on carbon paper (CP), finally realizes 1D core–shell CoP@PPy NWs/CP. The CoP core is connected to the PPy shell via strong chemical bonding, which can maintain a Co–PPy framework during charge/discharge. It also possesses bifunctional features that enhances the charge transfer and buffers the volume expansion. Consequently, 1D core–shell CoP@PPy NWs/CP demonstrates superb electrochemical performance, delivering a high areal capacity of 0.521 mA h cm^?2 at 0.15 mA cm^?2 after 100 cycles, and 0.443 mA h cm^?2 at 1.5 mA cm^?2 even after 1000 cycles. Even at a high current density of 3 mA cm^?2, a significant areal discharge capacity reaching 0.285 mA h cm^?2 is still maintained. The outstanding performance of the CoP@PPy NWs/CP free‐standing anode provides not only a novel insight into the modulated volume expansion of anode materials but also one of the most effective strategies for binder‐free and free‐standing electrodes with decent mechanical endurance for future secondary batteries.     

Interpenetrating Triphase Cobalt‐Based Nanocomposites as Efficient Bifunctional Oxygen Electrocatalysts for Long‐Lasting Rechargeable Zn–Air Batteries

Rational construction of atomic‐scale interfaces in multiphase nanocomposites is an intriguing and challenging approach to developing advanced catalysts for both oxygen reduction (ORR) and evolution reactions (OER). Herein, a hybrid of interpenetrating metallic Co and spinel Co₃O₄ “Janus” nanoparticles stitched in porous graphitized shells (Co/Co₃O₄@PGS) is synthesized via ionic exchange and redox between Co²⁺ and 2D metal–organic‐framework nanosheets. This strategy is proven to effectively establish highways for the transfer of electrons and reactants within the hybrid through interfacial engineering. Specifically, the phase interpenetration of mixed Co species and encapsulating porous graphitized shells provides an optimal charge/mass transport environment. Furthermore, the defect‐rich interfaces act as atomic‐traps to achieve exceptional adsorption capability for oxygen reactants. Finally, robust coupling between Co and N through intimate covalent bonds prohibits the detachment of nanoparticles. As a result, Co/Co₃O₄@PGS outperforms state‐of‐the‐art noble‐metal catalysts with a positive half‐wave potential of 0.89 V for ORR and a low potential of 1.58 V at 10 mA cm^?2 for OER. In a practical demonstration, ultrastable cyclability with a record lifetime of over 800 h at 10 mA cm^?2 is achieved by Zn–air batteries with Co/Co₃O₄@PGS within the rechargeable air electrode.     

Metal Sulfide‐Decorated Carbon Sponge as a Highly Efficient Electrocatalyst and Absorbant for Polysulfide in High‐Loading Li2S Batteries

Owing to its high theoretical specific capacity (1166 mA h g^?1) and particularly its advantage to be paired with a lithium‐metal‐free anode, lithium sulfide (Li₂S) is regarded as a much safer cathode for next‐generation advanced lithium–sulfur (Li–S) batteries. However, the low conductivity of Li₂S and particularly the severe “polysulfide shuttle” of lithium polysulfide (LiPS) dramatically hinder their practical application in Li–S batteries. To address such issues, herein a bifuctional 3D metal sulfide‐decorated carbon sponge (3DTSC), which is constructed by 1D carbon nanowires cross‐linked with 2D graphene nanosheets with high conductivity and polar 0D metal sulfide nanodots with efficient electrocatalytic activity and strong chemical adsorption capability for LiPSs, is presented. Benefiting from the well‐designed multiscale, multidimensional 3D porous nanoarchitecture with high conductivity, and efficient electrocatalytic and absorption ability, the 3DTSC significantly mitigates LiPS shuttle, improves the utilization of Li₂S, and facilitates the transport of electrons and ions. As a result, even with a high Li₂S loading of 8 mg cm^?2, the freestanding 3DTSC‐Li₂S cathode without a polymer binder and metallic current collector delivers outstanding electrochemical performance with a high areal capacity of 8.44 mA h cm^?2.     

Long‐Life,High‐Rate Lithium–Sulfur Cells with a Carbon‐Free VN Host as an Efficient Polysulfide Adsorbent and Lithium Dendrite Inhibitor

Lithium–sulfur (Li‐S) batteries are a promising next‐generation energy‐storage system, but the polysulfide shuttle and dendritic Li growth seriously hinder their commercial viability. Most of the previous studies have focused on only one of these two issues at a time. To address both the issues simultaneously, presented here is a highly conductive, noncarbon, 3D vanadium nitride (VN) nanowire array as an efficient host for both sulfur cathodes and lithium‐metal anodes. With fast electron and ion transport and high porosity and surface area, VN traps the soluble polysulfides, promotes the redox kinetics of sulfur cathodes, facilitates uniform nucleation/growth of lithium metal, and inhibits lithium dendrite growth at an unprecedented high current density of 10 mA cm^?2 over 200 h of repeated plating/stripping. As a result, VN‐Li||VN‐S full cells constructed with VN as both an anode and cathode host with a negative to positive electrode capacity ratio of only ≈2 deliver remarkable electrochemical performance with a high Coulombic efficiency of ≈99.6% over 850 cycles at a high 4 C rate and a high areal capacity of 4.6 mA h cm^?2. The strategy presented here offers a viable approach to realize high‐energy‐density, safe Li‐metal‐based batteries.     

Amorphous MoS3 Infiltrated with Carbon Nanotubes as an Advanced Anode Material of Sodium‐Ion Batteries with Large Gravimetric,Areal, and Volumetric Capacities

The search for earth‐abundant and high‐performance electrode materials for sodium‐ion batteries represents an important challenge to current battery research. 2D transition metal dichalcogenides, particularly MoS₂, have attracted increasing attention recently, but few of them so far have been able to meet expectations. In this study, it is demonstrated that another phase of molybdenum sulfide—amorphous chain‐like MoS₃—can be a better choice as the anode material of sodium‐ion batteries. Highly compact MoS₃ particles infiltrated with carbon nanotubes are prepared via the facile acid precipitation method in ethylene glycol. Compared to crystalline MoS₂, the resultant amorphous MoS₃ not only exhibits impressive gravimetric performance—featuring excellent specific capacity (≈615 mA h g^?1), rate capability (235 mA h g^?1 at 20 A g^?1), and cycling stability but also shows exceptional volumetric capacity of ≈1000 mA h cm^?3 and an areal capacity of >6.0 mA h cm^?2 at very high areal loadings of active materials (up to 12 mg cm^?2). The experimental results are supported by density functional theory simulations showing that the 1D chains of MoS₃ can facilitate the adsorption and diffusion of Na⁺ ions. At last, it is demonstrated that the MoS₃ anode can be paired with an Na₃V₂(PO₄)₃ cathode to afford full cells with great capacity and cycling performance.     

High‐Performance Lithium‐Iodine Flow Battery

A cathode‐flow lithium‐iodine (Li–I) battery is proposed operating by the triiodide/iodide (I₃^?/I^?) redox couple in aqueous solution. The aqueous Li–I battery has noticeably high energy density (≈0.28 kWh kg^?1_cell) because of the considerable solubility of LiI in aqueous solution (≈8.2 m ) and reasonably high power density (≈130 mW cm^?2 at a current rate of 60 mA cm^?2, 328 K). In the operation of cathode‐flow mode, the Li–I battery attains high storage capacity (≈90% of the theoretical capacity), Coulombic efficiency (100% ± 1% in 2–20 cycles) and cyclic performance (>99% capacity retention for 20 cycles) up to total capacity of 100 mAh.     

Scaling Printable Zn–Ag2O Batteries for Integrated Electronics

Printed batteries are an emerging solution for integrated energy storage using low‐cost, high accuracy fabrication techniques. While several printed batteries have been previously shown, few have designed a battery that can be incorporated into an integrated device. Specifically, a fully printed battery with a small active electrode area (<1 cm²) achieving high areal capacities (>10 mAh cm^?2) at high current densities (1–10 mA cm^?2) has not been demonstrated, which represents the minimum form‐factor and performance requirements for many low‐power device applications. This work addresses these challenges by investigating the scaling limits of a fully printed Zn–Ag₂O battery and determining the electrochemical limitations for a mm²‐scale battery. Processed entirely in air, Zn–Ag₂O batteries are well suited for integration in typical semiconductor packaging flows compared to lithium‐based chemistries. Printed cells with electrodes as small as 1 mm² maintain steady operating voltages above (>1.4 V) at high current densities (1–12 mA cm^?2) and achieve the highest reported areal capacity for a fully printed battery at 11 mAh cm^?2. The findings represent the first demonstration of a small, packaged, fully printed Zn–Ag₂O battery with high areal capacities at high current densities, a crucial step toward realizing chip‐scale energy storage for integrated electronic systems.     

In Situ Formation of Co9S8 Quantum Dots in MOF‐Derived Ternary Metal Layered Double Hydroxide Nanoarrays for High‐Performance Hybrid Supercapacitors

Layered double hydroxides (LDHs) are promising cathode materials for supercapacitors because of the enhanced flow efficiency of ions in the interlayers. However, the limited active sites and monotonous metal species further hinder the improvement of the capacity performance. Herein, cobalt sulfide quantum dots (Co₉S₈‐QDs) are effectively created and embedded within the interlayer of metal‐organic‐frameworks‐derived ternary metal LDH nanosheets based on in situ selective vulcanization of Co on carbon fibers. The hybrid CF@NiCoZn‐LDH/Co₉S₈‐QD retains the lamellar structure of the ternary metal LDH very well, inheriting low transfer impedance of interlayer ions. Significantly, the selectively generated Co₉S₈‐QDs expose more abundant active sites, effectively improving the electrochemical properties, such as capacitive performance, electronic conductivity, and cycling stability. Due to the synergistic relationship, the hybrid material delivers an ultrahigh electrochemical capacity of 350.6 mAh g^?1 (2504 F g^?1) at 1 A g^?1. Furthermore, hybrid supercapacitors fabricated with CF@NiCoZn‐LDH/Co₉S₈‐QD and carbon nanosheets modified by single‐walled carbon nanotubes display an outstanding energy density of 56.4 Wh kg^?1 at a power density of 875 W kg^?1, with an excellent capacity retention of 95.3% after 8000 charge–discharge cycles. Therefore, constructing hybrid electrode materials by in situ‐created QDs in multimetallic LDHs is promising.     

An Iodine Quantum Dots Based Rechargeable Sodium–Iodine Battery

Rechargeable sodium–iodine batteries represent a promising scalable electrochemical energy storage alternative as sodium and iodine are both low cost and widely abundant elements. Here, the authors demonstrate a rechargeable sodium–iodine battery that employs free‐standing iodine quantum dots (IQDs) decorated reduced graphene oxide (IQDs@RGO) as the cathode. Consistent with the density functional theory the authors find the Na⁺ ions to intercalate into the I unit cell forming stable NaI, and the battery exhibits high capacity, outstanding cycle stability (with a reversible specific capacity of 141 mA h g^?1 after 500 cycles at current density of 100 mA g^?1), and high rate performance (170, 146, 127, 112, and 95 mA h g^?1 at current densities of 100, 200, 400, 600, and 1000 mA g^?1, respectively). The reversible reactions, I₂/I₃ ^? and I₃ ^?/I^? redox couples on insertion of Na⁺ ions, are confirmed via in situ Raman spectroscopy. Notably, even after 500 cycles the morphology and structure of the IQDs exhibit no noticeable change implying their use as a stable cathode material for sodium–iodine batteries. Moreover, the IQDs based flexible full‐cells also exhibit high capacity and long cycle life (the capacity with 123 mA h g^?1 at current density of 100 mA g^?1 after 100 cycles).     

In Situ Generation of Artificial Solid‐Electrolyte Interphases on 3D Conducting Scaffolds for High‐Performance Lithium‐Metal Anodes

Rational structure design of the current collector along with further engineering of the solid‐electrolyte interphases (SEI) layer is one of the most promising strategies to achieve uniform Li deposition and inhibit uncontrolled growth of Li dendrites. Here, a Li₂S layer as an artificial SEI with high compositional uniformity and high lithium ion conductivity is in situ generated on the surface of the 3D porous Cu current collector to regulate homogeneous Li plating/stripping. Both simulations and experiments demonstrate that the Li₂S protective layer can passivate the porous Cu skeleton and balance the transport rate of lithium ions and electrons, thereby alleviating the agglomerated Li deposition at the top of the electrode or at the defect area of the SEI layer. As a result, the modified current collector exhibits long‐term cycling of 500 cycles at 1 mA cm^?2 and stable electrodeposition capabilities of 4 mAh cm^?2 at an ultrahigh current density of 4 mA cm^?2. Furthermore, full batteries (LiFePO₄ as cathode) paired with this designed 3D anode with only ≈200% extra lithium show superior stability and rate performance than the batteries paired with lithium foil (≈3000% extra lithium). These explorations provide new strategies for developing high‐performance Li metal anodes.     

An Improved Li–SeS2 Battery with High Energy Density and Long Cycle Life

Selenium–sulfur solid solutions are a class of potential cathode materials for high energy batteries, since they have higher theoretical capacities than selenium and improved conductivity over sulfur. Here, a high‐performance cathode material by confining 70 wt% of SeS₂ in a highly ordered mesoporous carbon (CMK‐3) framework with a polydopamine (PDA) protection sheath for novel Li–Se/S batteries is reported. With a relatively high SeS₂ mass loading of 2.6–3 mg cm^?2, the CMK‐3/SeS₂@PDA cathode exhibits a high capacity of >1200 mA h g^?1 at 0.2 A g^?1, excellent C‐rate capability of 535 mA h g^?1 at 5 A g^?1, and prolonged life over 500 cycles. Benefitting from the unique advantages of SeS₂ and the rationally designed host framework, this new cathode material demonstrates a feasible strategy to overcome the bottlenecks of current Li–S systems for high energy density rechargeable 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.     

Pseudo‐Zn–Air and Zn‐Ion Intercalation Dual Mechanisms to Realize High‐Areal Capacitance and Long‐Life Energy Storage in Aqueous Zn Battery

Aqueous zinc batteries are considered as promising alternatives to lithium ion batteries owing to their low cost and high safety. However, the developments of state‐of‐the‐art zinc‐ion batteries (ZIB) and zinc–air batteries (ZAB) are limited by the unsatisfied capacities and poor cycling stabilities, respectively. It is of significance in utilizing the long‐cycle life of ZIB and high capacity of ZAB to exploit advanced energy storage systems. Herein, a bulk composite of graphene oxide and vanadium oxide (V₅O₁₂·6H₂O) as cathode material for aqueous Zn batteries in a mild electrolyte is employed. The battery performance is demonstrated to arise from a combination of the reversible cations insertion/extraction in vanadium oxide and especially the electrochemical redox reactions on the surface functional groups of graphene oxide (named as pseudo‐Zn–air mechanism). Along with adjusting the hydroxyl content on the surface of graphene oxide, the specific capacity is significantly increased from 342 mAh g^?1 to a maximum of 496 mAh g^?1 at 100 mA g^?1. The surface‐controlled kinetics occurring in the bulk composite ensure a high areal capacity of 10.6 mAh cm^?2 at a mass loading of 26.5 mg cm^?2, and a capacity retention of 84.7% over 10 000 cycles at a high current density of 10 A g^?1.     

Active‐Site Imprinting: Preparation of Fe–N–C Catalysts from Zinc Ion–Templated Ionothermal Nitrogen‐Doped Carbons

Atomically dispersed Fe–N–C catalysts are considered the most promising precious‐metal‐free alternative to state‐of‐the‐art Pt‐based oxygen reduction electrocatalysts for proton‐exchange membrane fuel cells. The exceptional progress in the field of research in the last ≈30 years is currently limited by the moderate active site density that can be obtained. Behind this stands the dilemma of metastability of the desired FeN₄ sites at the high temperatures that are believed to be a requirement for their formation. It is herein shown that Zn²⁺ ions can be utilized in the novel concept of active‐site imprinting based on a pyrolytic template ion reaction throughout the formation of nitrogen‐doped carbons. As obtained atomically dispersed Zn–N–Cs comprising ZnN₄ sites as well as metal‐free N₄ sites can be utilized for the coordination of Fe²⁺ and Fe³⁺ ions to form atomically dispersed Fe–N–C with Fe loadings as high as 3.12 wt%. The Fe–N–Cs are active electocatalysts for the oxygen reduction reaction in acidic media with an onset potential of E₀ = 0.85 V versus RHE in 0.1 m HClO₄. Identical location atomic resolution transmission electron microscopy imaging, as well as in situ electrochemical flow cell coupled to inductively coupled plasma mass spectrometry measurements, is employed to directly prove the concept of the active‐site imprinting approach.     

Highly Efficient Oxygen Evolution by a Thermocatalytic Process Cascaded Electrocatalysis Over Sulfur‐Treated Fe‐Based Metal–Organic‐Frameworks

The oxygen evolution reaction (OER) is a bottleneck process for water splitting and finding highly efficient, durable, low‐cost, and earth‐abundant electrocatalysts is still a major challenge. Here a sulfur‐treated Fe‐based metal–organic‐framework is reported as a promising electrocatalyst for the OER, which shows a low overpotential of 218 mV at the current density of 10 mA cm^?2 and exhibits a very low Tafel slope of 36.2 mV dec^?1 at room temperature. It can work on high current densities of 500 and 1000 mA cm^?2 at low overpotentials of 298 and 330 mV, respectively, by keeping 97% of its initial activity after 100 h. Notably, it can achieve 1000 mA cm^?2 at 296 mV with a good stability at 50 °C, fully fitting the requirements for large‐scale industrial water electrolysis. The high catalytic performance can be attributed to the thermocatalytic processes of H⁺ capture by –SO₃ groups from *OH or *OOH species, which cascades to the electrocatalytic pathway and then significantly reduces the OER overpotentials.     

Hierarchical Fabric Decorated with Carbon Nanowire/Metal Oxide Nanocomposites for 1.6 V Wearable Aqueous Supercapacitors

Aqueous asymmetric supercapacitors (ASCs) may offer comparable or higher energy density than electric double‐layer capacitors (EDLCs) based on organic electrolytes. As such, ASCs may be more suitable for integration into smart textiles, where the use of flammable organic solvents is not acceptable. However, reported ASC devices typically suffer from poor rate capability and low areal loadings. This study demonstrates the development of nitrogen‐doped carbon (N‐C) nanowire/metal oxide (Fe₂O₃ and MnO₂) nanocomposite electrodes directly produced on the internal surface of a conductive fabric for use as high‐rate electrodes for solid‐state ASCs. The N‐C nanowires provide fast and efficient pathways for electrons, while short diffusion paths within nanosized metal oxides enable fast ion transport, leading to greatly enhanced performance at high rates. The porous structure of the fabric enables high areal capacitance loading in each electrode (≈150 mF cm^?2). Both electrodes show high specific capacitance of ≈180 F g^?1 (Fe₂O₃) and ≈250 F g^?1 (MnO₂) and excellent rate capability. Solid‐state ASCs assembled by using an aqueous gel electrolyte operate at 1.6 V and deliver over 60 mF cm^?2 during ≈50 s charging/discharging time and over 30 mF cm^?2 for ≈5 s discharge.     

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.     

High‐Performance Trifunctional Electrocatalysts Based on FeCo/Co2P Hybrid Nanoparticles for Zinc–Air Battery and Self‐Powered Overall Water Splitting

Currently, it is still a significant challenge to simultaneously boost various reactions by one electrocatalyst with high activity, excellent durability, as well as low cost. Herein, hybrid trifunctional electrocatalysts are explored via a facile one‐pot strategy toward an efficient oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The catalysts are rationally designed to be composed by FeCo nanoparticles encapsuled in graphitic carbon films, Co₂P nanoparticles, and N,P‐codoped carbon nanofiber networks. The FeCo nanoparticles and the synergistic effect from Co₂P and FeCo nanoparticles make the dominant contributions to the ORR, OER, and HER activities, respectively. Their bifunctional activity parameter (?E) for ORR and OER is low to 0.77 V, which is much smaller than those of most nonprecious metal catalysts ever reported, and comparable with state‐of‐the‐art Pt/C and RuO₂ (0.78 V). Accordingly, the as‐assembled Zn–air battery exhibits a high power density of 154 mW cm^?2 with a low charge–discharge voltage gap of 0.83 V (at 10 mA cm^?2) and excellent stability. The as‐constructed overall water‐splitting cell achieves a current density of 10 mA cm^?2 (at 1.68 V), which is comparable to the best reported trifunctional catalysts.     

Wearable High‐Performance Supercapacitors Based on Silver‐Sputtered Textiles with FeCo2S4–NiCo2S4 Composite Nanotube‐Built Multitripod Architectures as Advanced Flexible Electrodes

To achieve high‐performance wearable supercapacitors (SCs), a new class of flexible electrodes with favorable architectures allowing large porosity, high conductivity, and good mechanical stability is strongly needed. Here, this study reports the rational design and fabrication of a novel flexible electrode with nanotube‐built multitripod architectures of ternary metal sulfides' composites (FeCo₂S₄–NiCo₂S₄) on a silver‐sputtered textile cloth. Silver sputtering is applicable to almost all kinds of textiles, and S^2? concentration is optimized during sulfidation process to achieve such architectures and also a complete sulfidation assuring high conductivity. New insights into concentration‐dependent sulfidation mechanism are proposed. The additive‐free FeCo₂S₄–NiCo₂S₄ electrode shows a high specific capacitance of 1519 F g^?1 at 5 mA cm^?2 and superior rate capability (85.1% capacitance retention at 40 mA cm^?2). All‐solid‐state SCs employing these advanced electrodes deliver high energy density of 46 W h kg^?1 at 1070 W kg^?1 as well as achieve remarkable cycling stability retaining 92% of initial capacitance after 3000 cycles at 10 mA cm^?2, and outstanding reliability with no capacitance degradation under large twisting. These are attributed to the components' synergy assuring rich redox reactions, high conductivity as well as highly porous but robust architectures. An almost linear increase in capacitance with devices' area indicates possibility to meet various energy output requirements. This work provides a general, low‐cost route to wearable power sources.     

Sulfur‐Embedded Activated Multichannel Carbon Nanofiber Composites for Long‐Life,High‐Rate Lithium–Sulfur Batteries

Despite the 3–5 fold higher energy density than the conventional Li‐ion cells at a lower cost, commercialization of Li–S batteries is hindered by the insulating nature of sulfur and the dissolution of intermediate polysulfides (Li₂S _X , 4 < X ≤ 8) into the electrolyte. The authors demonstrate here multichannel carbon nanofibers that are composed of parallel mesoporous channels connected with micropores as sulfur containment. In addition, hydroxyl functional groups are formed on the carbon surface through a chemical activation to enhance the interaction between sulfur and carbon. In the sulfur embedded composite, the mesoporous multichannel enhances the active material utilization and sulfur loading, while the micropores act as a reaction chamber for sulfur component and trap site for polysulfide with the assistance of the functional groups. This sulfur–carbon composite electrode with 2.2 mg cm^?2 sulfur displays excellent performance with high rate capability (initial capacity of 1351 mA h g^?1 at C/5 rate and 847 mA h g^?1 at 5C rate), maintaining 920 mA h g^?1 even after 300 cycles (a decay of 0.07% per cycle). Furthermore, a stable reversible capacity of as high as ≈1100 mA h g^?1 is realized with a higher sulfur loading of 4.6 mg cm^?2.