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Recently, silicon has been considered one of the preferred materials for the anodes of next-generation high-energy-density Li-ion batteries due to its advantages of high specific capacity, low working voltage, and abundant reserves. However, the huge volume change and poor electrical conductivity of silicon anodes during the lithiation and de-lithiation process seriously affect their practical application. Herein, honeycomb porous silicon is synthesized by a modified Stöber method and magnesium thermal reduction, which avoids using toxic gases (such as silane) in the traditional preparation of commercial nano-silicon. Moreover, the honeycomb porous structure can effectively alleviate the volume expansion during the charge/discharge process and agglomeration behavior of nano-silicon. Therefore, thanks to its unique structural merits, the honeycomb porous silicon anode is endowed with a reversible specific capacity of 824.1 mA h g−1 after 100 cycles at 0.5 A g−1 and 679.2 mA h g−1 even at an ultrahigh current density of 1.0 A g−1 after an extended cycling period of 200 cycles, which is almost twice that of commercial nano-silicon. More importantly, this finding offers promising advancements in designing silicon anodes in energy storage. [ABSTRACT FROM AUTHOR]

The orthorhombic CuNb2O6 (O–CNO) is established as a competitive anode for lithium‐ion capacitors (LICs) owing to its attractive compositional/structural merits. However, the high‐temperature synthesis (>900 °C) and controversial charge‐storage mechanism always limit its applications. Herein, we develop a low‐temperature strategy to fabricate a nano‐blocks‐constructed hierarchical accordional O–CNO framework by employing multilayered Nb2CTx as the niobium source. The intrinsic stress‐induced formation/transformation mechanism of the monoclinic CuNb2O6 to O–CNO is tentatively put forward. Furthermore, the integrated phase conversion and solid solution lithium‐storage mechanism is reasonably unveiled with comprehensive in(ex) situ characterizations. Thanks to its unique structural merits and lithium‐storage process, the resulted O–CNO anode is endowed with a large capacity of 150.3 mAh g−1 at 2.0 A g−1, along with long‐duration cycling behaviors. Furthermore, the constructed O–CNO‐based LICs exhibit a high energy (138.9 Wh kg−1) and power (4.0 kW kg−1) densities with a modest cycling stability (15.8% capacity degradation after 3000 consecutive cycles). More meaningfully, the in‐depth insights into the formation and charge‐storage process here can promote the extensive development of binary metal Nb‐based oxides for advanced LICs. [ABSTRACT FROM AUTHOR]

Modest rate behaviors and structural collapse of battery‐type anodes limit the commercial application of lithium‐ion capacitors (LICs). For this, rational design of advanced anodes with both structural stability and high ionic/electronic conductivities becomes essential to advanced LICs. Herein, a general avenue is developed to construct a series of single‐crystal nano‐blocks assembled as "zero‐strain" columbite‐structured MNb2O6 (M = Cd, Co, Zn, Mn, Mg, Ca) accordion frameworks toward LICs. The intrinsic Li+ (de)insertion involves a solid‐solution charge storage mechanism with a volumetric change of <0.59% over (de)lithiation as established with systematical in(ex) situ analysis. The MNb2O6 exhibits M‐dependent electron/ion transport capabilities, along with the highest electronic and Li+ diffusion rates and the smallest volume change (0.32%) for CdNb2O6. Thanks to its robust structure and superb electron/ion conductivities originating from the "internal (i.e., ionic/electronic transport optimization) and external (i.e., structural design) cultivation" design, the CdNb2O6 shows the optimum electrochemical behaviors with a capacity of 102.8 mAh g−1 at 10 A g−1 and capacity retention of 80.3% after 20 000 cycles at 5 A g−1. The assembled CdNb2O6‐based LICs display high‐rate energy density and long‐duration stability. More importantly, the devised strategy provides meaningful guidance for optimum design of next‐generation LICs. [ABSTRACT FROM AUTHOR]

Spinel ZnMn2O4 is considered a promising anode material for high-capacity Li-ion batteries due to their higher theoretical capacity than commercial graphite anode. However, the insufficient cycling and rate properties seriously limit its practical application. In this work, porous ZnMn2O4 hollow micro-rods (ZMO HMRs) are synthesized by a facile co-precipitation method coupled with annealing treatment. On the basis of electrochemical analyses, the as-obtained samples are first characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy techniques. The influences of different polyethylene glycol 400 (PEG 400) additions on the formation of the hollow rod structure are also discussed. The abundant multi-level pore structure and hollow feature of ZMO HMRs effectively alleviate the volume expansion issue, rendering abundant electroactive sites and thereby guaranteeing convenient Li+ diffusion. Thanks to these striking merits, the ZMO HMRs anode exhibits excellent electrochemical lithium storage performance with a reversible specific capacity of 761 mAh g−1 at a current density of 0.1 A g−1, and a long-cycle specific capacity of 529 mAh g−1 after 1000 cycles at 2.0 A g−1 and keep a remarkable rate capability. In addition, the assembled ZMO HMRs-based full cells deliver an excellent rate capacity, and when the current density returns to 0.05 A g−1, the specific capacity can still reach 105 mAh g−1 and remains at 101 mAh g−1 after 70 cycles, maintaining a material-level energy density of approximately 273 Wh kg−1. More significantly, such striking electrochemical performance highlights that porous ZMO HMRs could be a promising anode candidate material for LIBs. [ABSTRACT FROM AUTHOR]

With the increasing demand for clean energy, rechargeable batteries with K+ as carriers have attracted wide attention due to their advantages of expandability and low cost. High‐performance anode materials are the key to the development of potassium ion batteries (PIBs), improving their competitiveness and feasibility. Carbon materials have become promising anodes for PIBs due to their abundant resources, low cost, non‐toxicity and electrochemical diversity. This article reviews the research progress of carbon based anode materials in recent years. Firstly, the unique characteristics of carbon as a competitive anode for advanced PIBs are discussed, which provides guidance for optimal design and exploration. Then, various carbon materials as the anodes towards PIBs are summarized in detail, and the involved problems and corresponding solutions are analyzed. Finally, the future development and perspective of advanced carbons for next‐generation PIBs are proposed. [ABSTRACT FROM AUTHOR]

Spinel ZnMn2O4 with high theoretical lithium storage capacity and appropriate oxidation potential has been regarded as a promising anode material for lithium-ion batteries (LIBs). However, its practical application is always hindered by serious volume expansion, stability and modest rate performance. Herein, we firstly devised a template-free strategy to prepare mesoporous ZnMn2O4 tube-in-tube nanofibers (ZMO TiT NFs) by utilizing the electrospinning strategy and subsequent heat-treatment process. Furthermore, detailed experimental analyses clearly shed light upon the formation mechanism of ZMO TiT NFs. When utilized as anode materials for LIBs, they exhibit even better electrochemical Li-storage behavior in terms of reversible capacity (∼495.7 mA h g−1 at 2.0 A g−1) and cycling stability (564.6 mA h g−1 at 2.0 A g−1 after 1000 cycles), when compared to ZMO nanotubes, benefiting from their unique structural merits. The contribution here promises our designed ZMO TiT NFs as competitive anode materials for advanced LIBs and beyond. [ABSTRACT FROM AUTHOR]

Metallic bismuth has drawn attention as a promising alloying anode for advanced potassium ion batteries (PIBs). However, serious volume expansion/electrode pulverization and sluggish kinetics always lead to its inferior cycling and rate properties for practical applications. Therefore, advanced Bi‐based anodes via structural/compositional optimization and sur‐/interface design are needed. Herein, we develop a bottom‐up avenue to fabricate nanoscale Bi encapsulated in a 3D N‐doped carbon nanocages (Bi@N‐CNCs) framework with a void space by using a novel Bi‐based metal‐organic framework as the precursor. With elaborate regulation in annealing temperatures, the optimized Bi@N‐CNCs electrode exhibits large reversible capacities and long‐duration cyclic stability at high rates when evaluated as competitive anodes for PIBs. Insights into the intrinsic K+‐storage processes of the Bi@N‐CNCs anode are put forward from comprehensive in situ characterizations. [ABSTRACT FROM AUTHOR]

Hierarchical hybrid heteroarchitectures possess attractive structural/compositional merits for lithium‐ion batteries (LIBs). Herein, a facile yet in situ growth strategy is proposed to scalably synthesize hierarchical porous ZnO/ZnFe2O4 hybrid nanofibers (NFs) with robust core/shell heterostructure toward LIBs. In such hybrids, 2D ZnFe2O4 nanosheets (NSs) are uniformly decorated on single‐crystalline ZnO core NFs, thereby affording more exposed active sites, a fast ion diffusion kinetic, and structural stability of electrodes during repeated cycling. As a result, benefiting from the unique hierarchical porous core/shell architecture and synergistic effects between the stable substrate of ZnO NFs and high‐capacity promoter of ZnFe2O4 NSs, the optimized ZnO/ZnFe2O4 hybrid as an anode for LIBs delivers a large reversible capacity of ≈688 mAh g−1 at 0.1 A g−1, high rate capability (≈288 mAh g−1 at 2.0 A g−1), and remarkable cyclability (≈491 mAh g−1 even over 250 cycles at 0.5 A g−1) for efficient lithium storage. This work highlights the rational design of a hierarchical architecture with a stable substrate and high‐capacity phases for next‐generation energy storage applications. [ABSTRACT FROM AUTHOR]

Red P has drawn extensive attention as a promising low‐cost anode for potassium‐ion batteries (PIBs) thanks to its large theoretical capacity and natural abundance. However, serious pulverization/aggregation issues during consecutive cycles and sluggish kinetics limit its practical commercial applications. Herein, hollow red P nanospheres confined in hierarchical N‐doped carbon nanosheets/nanotubes framework are designed and controllably fabricated via a simple yet efficient magnetic field assisted methodology. The involved magnetic field induced formation mechanism of the 3D hybrid architecture is tentatively put forward here. Comprehensive physicochemical/structural characteristics and theoretical simulation authenticate that the resultant hybrid anode is endowed with exceptional structural/compositional merits, which ameliorate volumetric expansion/compression over potassiation/depotassiation processes, and guarantee abundant active sites, rigid structure stability, and convenient electronic/ionic transport network for efficient potassium storage. As a result, the unique hollow red P based hybrid electrode delivers superb electrochemical performance in both half and full cells in terms of reversible capacities, rate properties, and long‐duration cycling behaviors as a competitive anode toward advanced PIBs. More significantly, this work proposes an innovative strategy for efficient fabrication of hollow red P architectures for next‐generation PIBs and beyond. [ABSTRACT FROM AUTHOR]

Herein, a bottom‐up electrospinning protocol is first developed to finely synthesize MoO2 nanocrystals@N‐doped carbon nanofibers (MoO2 NCs@N‐CNFs) film. The monodispersed MoO2 NCs of ≈2.1 nm in size are well confined in the 1D N‐CNFs. When evaluated as a self‐supporting anode for quasi‐solid‐state (QS) sodium‐ion batteries (SIBs) using the polyvinylidene fluoride hexafluoropropylene‐based Na+‐conducting gel electrolyte, the resultant MoO2 NCs@N‐CNFs exhibit remarkable Na+ storage behaviors in terms of reversible capacities and high‐rate cycling capabilities, benefiting from its synergistically structural and componential merits. More significantly, the contribution herein offers a simple yet efficient method to synthesize advanced hybrid anodes for QS SIBs. [ABSTRACT FROM AUTHOR]

Conductive metal–organic frameworks (MOFs), as a newly emerging multifunctional material, hold enormous promise in electrochemical energy‐storage systems owing to their merits including good electronic conductivity, large surface area, appropriate pore structure, and environmental friendliness. In this contribution, a scalable solvothermal strategy was devised for the bottom‐up fabrication of 1D Cu‐based conductive MOF, that is, Cu3(2,3,6,7,10,11‐hexahydroxytriphenylene)2 (Cu‐CAT) nanowires (NWs), which were further utilized as a competitive anode for lithium‐ion batteries (LIBs). The intrinsic Li storage mechanism of the Cu‐CAT electrode was also explored. Benefiting from its structural virtues, the resultant 1D Cu‐CAT NWs were endowed with superb Li+ diffusion coefficients and electrochemical conductivities and exhibited remarkably high‐rate reversible capacities of approximately 631 mAh g−1 at 0.2 A g−1 and even approximately 381 mAh g−1 at 2 A g−1, along with striking capacity retention of 81 % after 500 cycles at 0.5 A g−1. In addition, a Cu‐CAT NWs‐based full cell assembled with LiNi0.8Co0.1Mn0.1O2 as the cathode displayed a large energy density of approximately 275 Wh kg−1 as well as excellent cycling behavior. These results manifest the promising application of 1D conductive Cu‐CAT NWs in advanced LIBs and even other potential versatile energy‐related fields. [ABSTRACT FROM AUTHOR]

The exploration of anode materials with a high degree of electrochemical utilization for Li‐ion batteries (LIBs) still remains a huge challenge despite pioneering breakthroughs. Rational engineering of electrode structures/components by facile strategies would offer infinite possibilities for the development of LIBs. In this study, one‐dimensional ultralong nanohybrids of ultrafine NiCoO2 nanoparticles dispersed in situ in and/or on the surface of amorphous N‐doped carbon nanofibers (NCO@ANCNFs) were fabricated by a bottom‐up electrospinning protocol. By virtue of synergistic structural/component features, the obtained ultralong NCO@ANCNFs with low NCO loading (≈33.6 wt %) show highly efficient Li+ storage performance with high reversible capacity, high rate capability, and long cycle life. The unusual reversible crystalline transformation during cycling was analyzed. Quantitative analysis revealed that the pseudocapacitive contribution mainly accounts for the superior lithium storage of the NCO@ANCNFs. Besides, the ability of the hybrid anode to deliver competitive Li‐storage properties even without conductive carbon greatly enhances its commercial applicability. An NCO@ANCNFs//LiNi0.8Co0.15Al0.05O2 full battery was assembled and exhibited striking electrochemical properties. This contribution offers a scalable methodology to fabricate highly efficient hybrid anodes for advanced next‐generation LIBs. Nanohybrid anodes: Ultralong 1D nanohybrids in which ultrafine NiCoO2 nanoparticles are dispersed in and/or on the surface of amorphous N‐doped carbon nanofibers were fabricated, and they exhibited a high electrochemical degree of utilization for lithium storage as anodes for advanced lithium‐ion batteries (see figure). [ABSTRACT FROM AUTHOR]

In the work, a facile and green two-step synthetic strategy was purposefully developed to efficiently fabricate hierarchical shuttle-shaped mesoporous ZnFe2O4 microrods (MRs) with a high tap density of ∼0.85 g cm3, which were assembled by 1D nanofiber (NF) subunits, and further utilized as a long-life anode for advanced Li-ion batteries. The significant role of the mixed solvent of glycerin and water in the formation of such hierarchical mesoporous MRs was systematically investigated. After 488 cycles at a large current rate of 1000 mA g−1, the resulting ZnFe2O4 MRs with high loading of ∼1.4 mg per electrode still preserved a reversible capacity as large as ∼542 mAh g−1. Furthermore, an initial charge capacity of ∼1150 mAh g−1 is delivered by the ZnFe2O4 anode at 100 mA g−1, resulting in a high Coulombic efficiency of ∼76 % for the first cycle. The superior Li-storage properties of the as-obtained ZnFe2O4 were rationally associated with its mesoprous micro-/nanostructures and 1D nanoscaled building blocks, which accelerated the electron transportation, facilitated Li+ transfer rate, buffered the large volume variations during repeated discharge/charge processes, and provided rich electrode-electrolyte sur-/interfaces for efficient lithium storage, particularly at high rates. [ABSTRACT FROM AUTHOR]

To achieve high‐quality hard carbon nanofibers (HCNFs), and particularly flexible HCNFs films is the eternal pursuit from low‐cost coal pitch (CP). However, it is still trapped seriously by the inborn bottleneck of low‐softening‐point (LSP) characteristics of CP itself. Herein, an efficient Bi(NO3)3·5H2O‐assisted electrospinning‐carbonization methodology is creatively devised to obtain flexible HCNFs films directly from LSP CP. The essential roles of Bi(NO3)3·5H2O and pre‐oxidation in constructing flexible films are rationally proposed. With further regulation in Bi(NO3)3·5H2O dosage and calcination temperatures, specific micro‐structures/morphologies of flexible HCNFs films are finely optimized. The optimum HCNFs‐1.2 film is endowed with robust structural flexibility/stability, high‐content active oxygen/nitrogen groups, abundant graphic microcrystalline zones of large interlayer spacing, and convenient ion‐diffusion channels. Thanks to such remarkable merits, HCNFs‐1.2 retains a large reversible capacity of 125.3 mAh g‒1 over 1000 cycles at 1.0 A g‒1, when evaluated as a self‐supporting film anode for sodium dual‐ion batteries (SDIBs). Furthermore, the HCNFs‐1.2‐based SDIBs deliver a specific capacity of 90.9 mAh g‒1 at 0.1 A g‒1, along with a capacity retention of 78.4% after 1500 cycles at 1.0 A g‒1. The insightful understanding here will provide meaningful guidance for rational design of advanced flexible film electrodes toward next‐generation SDIBs and beyond. [ABSTRACT FROM AUTHOR]

In this work, from a practical point of view, a scalable spray-drying strategy is developed to prepare nickel/cobalt/molybdenum-based nano carbides embedded in porous microspherical carbon architectures for LIBs as competitive anodes. The resulted porous Ni 1.5 Co 1.5 Mo 3 C/Mo 2 C@C (NCMC/MC@C) microspheres exhibit even better lithium storage performance in terms of first Coulombic efficiency, reversible capacities, rate behaviors, and cycling stability than their counterparts including Co 3 Mo 3 C/Mo 2 C@C and Ni 3 Mo 3 C/Mo 2 C@C MSs, thanks to the involved synergistic contributions from the nanoscale effect, solid-solution feature, porous structure, and abundant hetero-interfaces, which cooperatively guarantee the rapid Li+/electron transport and buffered volume changes over (de)lithiation process. Besides, the NCMC/MC@C-based full LIBs demonstrate remarkable electrochemical characteristics with high energy density and cycling stability. More significantly, the methodology here holds great promise for achieving other versatile nano carbides towards advanced LIBs and beyond. [Display omitted]. [ABSTRACT FROM AUTHOR]

• Solid-solution Ni 0.5 Co 0.5 MoO 4 is endowed with superb electronic conductivity. • Conductive Ni 0.5 Co 0.5 MoO 4 solid-solution nanoparticles are electrospun in flexible CNFs framework. • Elastic CNFs buffer mechanical stress/volume change and ensure structural integrity of electrodes. • The hybrid anode brings about abundant active phases/boundaries for Li+-storage properties. • Synergistic component/composition and structure merits make the hybrid efficient lithium storage in half/full cells. Transition metal oxides as promising electrode materials have been widely explored for lithium-ion batteries (LIBs). Nonetheless, their practical applications are still hindered by their modest electronic conductivities, poor rate properties, and huge volume changes/rapid capacity degradation over the ceaseless delithiation/lithiation processes. To address the issues, we firstly encapsulate nano-dimensional Ni 0.5 Co 0.5 MoO 4 with a solid solution structure in the carbon nanofibers (denoted as NCMO-SS@CNFs) via a simple electrospinning technique. The uniform distribution of self-confined conductive NCMO-SS nanoparticles (NPs) with a high loading of ∼54.5 wt.% in the elastic CNFs framework effectively buffers the mechanical stress/volume change, reinforces the structural integrity, and brings abundant active phase boundaries, favoring their enhanced lithium-storage properties. It is the synergistic component/composition and structure merits that make the as-obtained mesoporous NCMO-SS@CNFs exhibit larger reversible capacities and better electrochemical stability for efficient lithium storage particularly at high rates, compared to the simple Ni/Co-molybdates and even their physical mixture. Moreover, the NCMO-SS@CNFs-based full LIBs provide an energy density of ∼225.4 Wh kg‒1 and good cyclic stability. The contribution here promises a huge potential of our constructed carbon-matrix-confined NCMO-SS NPs for advanced LIBs and beyond. [ABSTRACT FROM AUTHOR]

Abstract Recently, CoCO 3 is attracting extensive interests as a promising anode for Li-ion batteries (LIBs) thanks to its large capacities and simple synthesis. However, its modest electrochemical behaviors and ambiguous lithium storage mechanisms still need to be well addressed. Herein, we devise a scalable bottom-up solvothermal methodology to fabricate monodispersed pinecone-like CoCO 3 sub-microspheroids constructed with nanosheet subunits. When evaluated as appealing anode for LIBs, the resultant CoCO 3 anode exhibits high initial Coulombic efficiency of ∼75.2%, and large reversible capacity of ∼1008 mAh g−1 at a rate of 200 mA g−1, and even ∼663 mAh g−1 at 2 A g−1, benefiting its hierarchical micro-/nanostructures. Besides, the enhanced interfacial charge-storage capability of the CoCO 3 sub-microspheroids with cycling accounts for the long-duration capacity retention of ∼138% over 500 consecutive cycles. More significantly, comprehensive lithium storage mechanism of the CoCO 3 , involving conventional conversion reactions, reversible redox reaction of low-valence C/C(IV), and debut observation of reversible Co(II)/Co(III) transition, is proposed with in-situ and ex-situ physicochemical and electrochemical investigations. Furthermore, a CoCO 3 //LiNi 0.8 Co 0.15 Al 0.05 O 2 full battery is assembled and delivers prominent electrochemical properties, hugely highlighting the enormous potential of our CoCO 3 sub-microspheroids in next-generation LIBs as competitive anodes. Graphical abstract Monodispersed hierarchical CoCO 3 sub-microspheroids were scale-up fabricated and displayed superior electrochemical behaviors. More significantly, intrinsic lithium storage mechanisms were proposed as a competitive anode towards Li-ion batteries. Image 1 Highlights • A solvothermal method was devised to fabricate CoCO 3 sub-microspheroids. • The monodispersed sub-microspheroids were constructed with nanosheets. • The resultant CoCO 3 anode exhibited superior Li-storage behaviors. • The comprehensive lithium-storage mechanism of CoCO 3 was proposed. • A CoCO 3 -based full device with prominent Li-storage properties was assembled. [ABSTRACT FROM AUTHOR]

• Porous single-crystal NTP micro-sized framework coated with conductive carbon nano-layer (NTP@C) is designed. • The carbon coating enhances conductivity of NTP@C, and protects it from O2 erosion serves as a protective phase. • Regulations in both the dissolved O2 content and pH values of aqueous Na2SO4 electrolyte are conducted. • The NTP@C displays superb electrochemical properties in the optimized Na2SO4 electrolyte (N2 purged and pH = 8.0). • The NTP@C based full devices exhibit high energy density and cycling stability with the optimum electrolyte. NASICON-type NaTi 2 (PO 4) 3 (NTP) is one of the most competitive anode materials for aqueous sodium-ion batteries (ASIBs), thanks to its unique three-dimensional open framework structure, high ionic conductivity and good chemical stability. However, the low electrical conductivity of NTP and the oxygen reduction induced side reactions seriously affect its practical applications. To well address the above issues, the synergistic regulation strategy in electrode materials and electrolytes is motivatively put forward. The porous single-crystal NTP micro-sized framework coated with conductive carbon nano-layer (denoted as NTP@C) is designed with significantly improved electronic conductivity and structural stability. With further regulations in both the dissolved oxygen content and pH values of aqueous Na 2 SO 4 electrolyte, the enhanced reversible capacities and cyclic stability especially at high rates are achieved by effectively alleviating side reactions. As a result, the fabricated NTP@C anode is optimized with a high-rate capability and remarkable long-duration electrochemical stability in the N 2 -purged aqueous Na 2 SO 4 electrolyte with pH = 8.0. Furthermore, the assembled NTP@C//Na 0.44 MnO 2 ASIBs exhibit high energy density of ∼40.0 Wh kg‒1 along with excellent cycling stability. More significantly, our work provides an insightful guideline for rational construction of other advanced aqueous rechargeable batteries. Hierarchical porous single-crystal NaTi 2 (PO 4) 3 @C framework is first designed, and exhibits enhanced electrochemical Na+-storage properties in half/full cells with detailed regulation in both the dissolved oxygen content and pH values of electrolytes, when evaluated a competitive anode platform for aqueous sodium-ion batteries. [Display omitted] [ABSTRACT FROM AUTHOR]